A Closer Look at Yoga Nidra: Sleep Lab Analyses
Phase: NA
Conditions: Electroencephalography, Electrocardiography, Respiratory Rate, Surveys and Questionnaires
Sponsor: National University of Natural Medicine

 
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Protocol  
Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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PROTOCOL 
 
Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
 
Principal Investigator: 
Erica Sharpe, PhD 
 
Co-Investigator(s): 
Alison Lacombe, PhD 
Matthew Butler, PhD 
Doug Hanes, PhD 
Ryan Bradley, ND, MPH  
 
IRB#: ES62018 
Version #: 3 
Initial Document Approval Date:  
 
A.0 ABSTRACT: Extended sleep onset latency (SOL), more simply described as difficulty falling asleep or 
“sleep onset insomnia” can increase risk for a variety of health conditions. Regular early start times for work in 
industrialized nations lead to shortened total sleep time for those who have trouble falling asleep at night. This 
shortened sleep duration leads to increased risk of: death from coronary heart disease (48% for those sleeping less 
than 5 hrs per night as compared to 6-8hrs); fatal and non-fatal strokes (15%); and all-cause mortality (12%), [1]. 
Sleep disorders persist in the US, despite existing pharmaceutical and behavioral remedies, with 10-15% of our 
total population suffering from insomnia symptoms and 6-10% having clinically diagnosable insomnia [1, 2]. 
Mind/body therapies offer additional solutions to this problem. Select studies have correlated meditation with 
decreased SOL[3], however there is a need for more research on the use of such techniques as possible therapeutic 
alternatives or supplements to the standard of care. The guided meditation practice of yoga nidra (literally 
translating as “yogic sleep”) is a promising intervention for treatment of sleep disorders, due to its purported 
ability to induce a deep state of mental, physical and emotional relaxation. Reputed to be four times more restful 
than sleep, this practice has effects on the brain and body that are thus worthy of exploration. In this pilot study 
we address feasibility questions including: acceptability of our intervention conditions, credibility of yoga nidra 
as a possible treatment for insomnia, and appropriateness of our selected measurement systems to monitor effects 
of yoga nidra on the brain and body. We further aim to investigate the impact of yoga nidra on autonomic nervous 
system (ANS) tone as a potential mechanism through which SOL may be reduced. Changes in ANS tone will be 
measured via heart rate variability (HRV) parameters and respiratory rate.  Changes in brainwave activity 
associated with yoga nidra and sleep onset will be measured using electroencephalography (EEG). Our study 
sample includes twenty-two adults between the ages of 18 and45 who report difficulty falling asleep. Our study 
sample includes twenty-two adults between the ages of 18 and 45 who report difficulty falling asleep but do not 
reach criteria for “severe” clinical insomnia and do not take sleep medications. Each participant will visit our 
clinic twice: the first visit will include “lying quietly” for 30 minutes followed by 1 additional hour of continued 
monitoring in case sleep onset occurs. The second visit will include randomization into one of two groups: (1) 
intervention: 30 minutes of listening to a standardized recording of yoga nidra and 1 additional hour of continued 
monitoring in case sleep onset occurs; or (2) “lying quietly” for 90 minutes (baseline control). Feasibility 
outcomes as well as changes in parameters associated with SOL detected herein will be used to inform the design 
of future clinical studies of yoga nidra and its impact on SOL.

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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B.0 SPECIFIC AIMS  
B.1 Specific Aim 1: to measure patterns of electrical brain activity via electroencephalography (EEG) (Thought 
Technologies® EEG device attached to frontal lobe, central lobe, occipital lobe, eyes and chin sites) before, during, 
and after the practice of yoga nidra, compared to a control condition of lying quietly, in order to determine: 
B.1.a: If yoga nidra induces changes in brainwave activity measurable by our EEG system 
H0: There are no differences in patterns of brain electrical activity between yoga nidra and control, indicating 
that (a) the EEG system we have selected is not sensitive enough for use in this intervention, (b) changes 
produced do not occur in the electrode sites we have selected, or (c) yoga nidra does not induce changes in 
brainwave activity 
H1: There are mean differences in EEG power in alpha, theta, beta and/or delta bands originating in the frontal, 
occipital and/or central lobes between yoga nidra/control. 
B.1.b:If sleep can be detected using our EEG measurement system and analysis of raw data by registered sleep 
study scoring technologists at Sleep Strategies™ 
H0: Sleep is not detected, indicating (a) our system is not capable of detecting sleep, or (b) our intervention does 
not induce sleep. 
H1: Sleep is detected in the intervention group and/or the control condition 
B.1.c: If time to sleep onset (sleep onset latency SOL: minutes from the start of the intervention to when a persistent 
NREM 2 brainwave pattern begins) differs between intervention and control 
H0: There is not a significant difference in mean SOL between intervention and control 
H1: Mean SOL is decreased with the intervention, relative to the control. 
 
B.2 Specific Aim 2: to measure patterns of respiratory rate (RR) via the wireless Spire® device; and heart rate 
variability (HRV) via the wireless Bodyguard 2® electrocardiogram (ECG) device before, during, and after yoga 
nidra, compared to a control condition of lying quietly, in order to determine: 
B.2.a: If yoga nidra induces changes in HRV and RR that are measurable by our selected system 
H0: There are no differences in patterns of RR or HRV between yoga nidra and control indicating that (a) 
yoga nidra produces no changes to RR or HRV, or (b) our measurement system is not sensitive enough.  
H1: Mean RR decreases, high frequency (HF) HRV parameters increase and/or root mean square of successive 
differences (RMSSD) in HRV parameters increase with intervention vs. control 
B.2.b: If it is feasible to use these devices in our clinic, to measure changes in HRV and RR during and after yoga 
nidra; and if data from these devices can be successfully extracted and analyzed. 
H0: One or both of these devices pose challenges that cause them to be impossible to use for collection of data; 
or impossible to use due to challenges in retrieving or analyzing the data gathered.  
H1: Both devices can be successfully applied and used for measurement during this study; and our study team 
is able to retrieve and analyze relevant data from these devices. 
 
B.3. Specific Aim 3: to assess feasibility of our intervention, in order to determine: 
B3.a:If our intervention is viewed as credible for supporting healthy sleep within our population, indicated in the 
Post-Intervention Survey by experience of benefit ratings on a slider scale (range: not beneficial to very beneficial)  
H0: The intervention is not credible for the proposed use, indicated as all ratings below 50% 
H1: The intervention is viewed as credible for use in decreasing SOL in our selected population, indicated 
through 1 or more ratings above 50% 
B3.b: If intervention conditions are acceptable, as indicated by recruitment and retention rates. 
H0: Conditions are not acceptable, as indicated by an inability to recruit twenty-two participants for our proposed 
study within one three months and/or a dropout rate greater than 50%. 
H1: Conditions are acceptable, indicated by a dropout rate below 50% and ability to recruit twenty-two 
participants within three months. 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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C.0 BACKGROUND AND SIGNIFICANCE: Up to 15% of the US population has difficulty falling asleep at 
night [2]. This disorder, known as “sleep onset insomnia”, combined with early work start times in industrialized 
nations can lead to significantly shortened nightly sleep durations. Short sleep durations lead to increased risk of: 
death from coronary heart disease (48%), fatal and non-fatal strokes (15%), and all-cause mortality (12%)[1]. 
Current approaches to decreasing sleep onset latency (SOL), or the time it takes to fall sleep, include prescription 
drugs, supplements, and behavioral change. Hypnotic sleeping pills (e.g. benzodiazepine, Z hypnotic or 
barbiturate) which offer little benefit [4, 5]can be costly, and carry risks including death from overdose (with 
hypnotics causing thousands of deaths per year and increasing risk of opioid overdose), depression (respiratory 
and mood: causing cardiac arrest and suicide), and automobile crashes (with hypnotics involved in over half of 
reported intoxication/dangerous driving deaths)[4, 6, 7]. Melatonin supplements, which are not recommended for 
pregnant/breastfeeding women, carry unknown long-term side effects (especially for children and adolescents), 
may interact with drugs (e.g. caffeine and birth control) processed by the CYP liver enzyme that increase plasma 
melatonin, and additionally interact with hypnotics to cause psychomotor and memory impairment[8]. Behavioral 
approaches, which include diet and lifestyle change (e.g. modifying caffeine and alcohol consumption, practicing 
sleep hygiene, and increasing exercise) [9, 10], require significant will power, commitment, and time-investment 
[11, 12]. Mind/ body techniques such as yoga, may offer additional remedies [11, 13-15], yet few of these methods 
have been subjected to formal research[2].A meditative practice that is seemingly most appropriate for addressing 
insomnia but which has yet to be studied, is yoga nidra (literally translated to mean “yogic sleep”); a practice that 
naturally induces a hypnogogic state without use of hypnotics. 
 
Yoga nidra is a scripted and reproducible, guided relaxation technique that facilitates the transition between 
waking and sleeping. It is estimated that the average person actually sleeps during 10-50% of a yoga nidra practice 
[6]. Traditionally, yoga nidra has been used to treat insomnia by practicing before bed. Treatment includes basic 
sleep hygiene [16], and physical postures (called asanas) before yoga nidra, in order to reduce restlessness, pain, 
stiffness and tension that could prevent focus during the practice. In similarity to other meditative and progressive 
relaxation techniques, the practice of yoga nidra is said to produce significant physical relaxation (clinically 
characterized by increased parasympathetic (PNS) response[17-19] and decreased muscle tension [19]). Unique 
to yoga nidra, however, is the additional release of mental and emotional tensions. During yoga nidra, mental 
tension is released by rotating awareness throughout the body, following the mapping of the motor homunculus 
[6, 20, 21]. It is proposed that by sending a signal from body to brain, following the same pattern as this neuronal 
map, the mind is progressively relaxed [6]. Emotional release is then evoked through systematic arousal of feeling, 
sensation and experience. Further mental relaxation is achieved during a guided visualization practice to follow. 
Yoga nidra additionally involves techniques such as sense withdrawal, breath awareness, and the creation of a 
resolve; all practices with may encourage physical relaxation and decrease anxieties before sleep. Practitioners of 
yoga nidra state that although everyone sleeps, many of us hold onto anxieties, pain, and emotions throughout the 
night that cause us to wake feeling unrested. Yoga nidra creates a period of true restfulness: free of mental, 
physical and emotional tension. Performed while lying down, this practice is described as “sleep after throwing 
off the burdens”. Little formal research on yoga nidra has been done in the US and most claims are anecdotal. 
However, unpublished studies from India have shown that during yoga nidra, alpha brainwave activity increases: 
a change that also occurs during the process of falling asleep[6]. Increased alpha brainwave activity has been 
reported during other forms of meditation as well in studies that also note decreased respiratory rate (RR) [3, 22-
25]. One study has shown yoga nidra to increase heart rate variability (HRV) when practiced after hatha yoga, 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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but also when practiced without hatha yoga movements beforehand[26]. Individuals with insomnia have 
chronically elevated RR[27], as well as sympathetic nervous system (SNS) activity [18, 27], both of which may 
contribute to their difficulties falling asleep. It is possible that yoga nidra may decrease SOL by lowering both 
RR and SNS activity while also facilitating the transition into an alpha brainwave state that immediately precedes 
sleep. 
 
The goal of our proposed research is to investigate the effects of yoga nidra on brainwave patterns, heart rate 
variability (HRV), and respiratory rate (RR) as possible indicators of the ability of this practice to induce sleep 
onset. We also address feasibility questions including: acceptability of our intervention conditions, credibility of 
yoga nidra as a possible technique to support healthy sleep and reduce symptoms of sleep onset insomnia, and 
appropriateness of our selected measurement systems to monitor effects of yoga nidra on the brain and body. Our 
population includes 22 adults between the ages of 18 and 45 who suffer from insomnia and do not take sleeping 
medications. Each participant will visit our clinic twice. At each visit we will take two hours of measurements: 
capturing the yoga nidra practice as well as a resting period afterwards. The first visit will involve lying quietly 
as a baseline control to replace yoga nidra. At the second visit, half of the population will participate in yoga nidra 
and the other half will continue to practice the baseline control of lying quietly. This design will unveil and 
account for any “first night” effects, wherein a participant may feel more comfortable at the second visit, due to 
familiarization with the environment. Feasibility outcomes and physiological changes detected during this study 
will be used to inform future research designs related to yoga nidra and sleep onset. 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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D.0 PERSONNEL AND PRELIMINARY DATA  
D.1  
Erica Sharpe, PhD 
 
Alison Lacombe, PhD 
 
 
Matthew Butler, PhD 
 
 
Doug Hanes, PhD 
 
Ryan Bradley, ND, MPH 
 
D.2 Preliminary Data: The purpose of this intervention is to gather preliminary data for our future 
clinical pilot study on yoga nidra and insomnia in adults. 
 
E.0 RESEARCH DESIGN AND METHODS STUDY FLOW  
 
E.1. Overview: In this intervention we will explore the physiological effects of yoga nidra. We will 
measure patterns in brainwave activity, respiration and heart rate variability using EEG, and two wireless 
devices: the Spire® breath monitor and the Bodyguard® HRV monitor. We also address feasibility 
questions related to credibility and acceptability, using self-report surveys, drop-out rates, and participant 
feedback. Twenty-two participants will be recruited using digital and paper advertisements throughout 
Portland and NUNM. Interested individuals will call or email our clinic. Our study coordinator will set up 
a screening call with all potential participants. She will ask general questions and use standardized surveys 
to exclude participants based on criteria described below. Those who pass the telephone screening will 
then be invited for two visits to our clinic where they will undergo two hours of measurements each. Each 
visit will involve completion of a consent form and a few intake surveys. The measurement periods will 
involve: 10 minutes of baseline data collection, thirty minutes of lying quietly or listening to a recording 
of yoga nidra, and then 1 hour of resting comfortably. Participants will be allowed to fall asleep during 
this time and they will be left alone in the room with the lights out during the entire intervention (after 
baseline data collection). When finished, participants will complete a few short questionnaires before their 
departure. The first visit will involve lying quietly as a baseline control At the second visit, half of the 
population will be randomly selected to do yoga nidra and half will complete the baseline control 
measurements again. See Tables 1-3 for a detailed description. 
 
 
 
 
 
 
 
 
 
 
 
 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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Table 1. Recruitment/Screening. If potential participants pass all surveys shown in this table, they will be scheduled for two clinic visits. 
 
 
Telephone Screening Surveys 
Insomnia Severity Index 
(ISI) 
Baseline-Intake 
Requirements to pass 
8-21 (subclinical insomnia 
to clinical insomnia, 
moderate severity) 
Age 18-45, limited substance use, 
no diagnosed fibromyalgia, no use 
of sleeping pills. See Table 4 for 
more. 
 
 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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Table 2. Intervention Outline 
 
Schedule 
Consent 
Arrival Surveys 
Physiological 
Measurements 
Exit Surveys 
CF 
*STOP-BANG, PreI, *PHQ-2 to 
PHQ-9, , *GAD-7, *PSQI, 
*PROMIS-29, PANAS, STAIY-6 
RR 
EEG 
ECG 
PANAS 
STAIY-6 PE 
Clinic Visits 
 
Visit 1: V1 
Visit 2: V2 
Check-In 
V1 only 
*V1 only. Exclude participants and 
give medical referral if PHQ-9 score 
is 10 or more, and/or if they answer 
“yes” 3 or more times on STOP-
BANG survey. 
 
 
 
 
 
 
Pre-Practice Baseline: 
5 min eyes open 
5 min eyes closed 
 
 
 
 
 
 
 
 
#During Practice: 
Visit 1: 30 min lying quietly 
^Visit 2: 30 min yoga nidra 
or 30 min lying quietly 
 
 
 
 
 
 
 
 
Nap-time: 
1 hour of rest or sleep 
 
 
 
 
 
 
 
 
Check-out 
 
 
 
 
 
 
 
 
#Study Coordinator will turn out the lights and leave the room for the practice and nap time. A sound monitor will be in the room, in case there is need for assistance. 
^ Participants will be randomized using the attached randomization plan, generated using the website: www.randomization.com, one block and 22 subjects.  
 
Table 2 Abbreviations: Consent Form (CF), Pre-Intervention Survey (PreI), Positive Negative Affect Schedule (PANAS), State Trait Anxiety Inventory 
(STAI Y-6), Patient Health Questionnaire (PHQ-9), Sleep Apnea Survey (Snoring, Tiredness, Observations, Pressure, BMI, Age, Neck, Gender (STOP-BANG), 
Generalized Anxiety Disorder (GAD-7) Survey, Pittsburgh Sleep Quality Index (PSQI), Patient Reported Outcome Measurement Information System 
Tool-29 (PROMIS-29), Respiratory Rate (RR), electroencephalogram (EEG), electrocardiogram (ECG), Post Intervention Exit Survey (PE). 
 
 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
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IRB #: ES62018 
Approval Date: August 29th, 2018 
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Table 3. Measurement Tools/Forms and their Purpose 
Name of measurement tool 
Abbreviation 
Standardize
d  
Recall 
Period 
Purpose 
Patient Health Questionnaire  
PHQ2/ PHQ9 
Y 
2 weeks 
Depression screener used in recruitment. 
Insomnia Severity Index 
ISI 
Y 
14 days 
Insomnia assessment 
Baseline Intake 
- 
N (in house) 
General  
To gather: contact information; demographics (age, gender, 
menopause, ethnicity, language, ability to hear); and information 
on substance use (alcohol, stimulants, sleeping pills, cannabis), 
lifestyle (disruptions to sleep, shift work, mind/body practice), 
and comorbidities(a diagnosis for any of the following:  
fibromyalgia, sleep apnea, insomnia or depression) 
Sleep Apnea Screener 
STOP-BANG 
Y 
General 
To predict sleep apnea based on:  
Snoring, Tiredness, Observations of interrupted breathing, blood 
Pressure, BMI, Age, Neck circumference, Gender (STOP-
BANG) 
Positive/Negative Affect Schedule 
PANAS 
Y 
Moment  
Assessment of mood (20Q’s) before/after visit.  
State Trait Anxiety Inventory Y-6 
STAI Y-6 
Y 
Moment 
Anxiety measurement (7 Q’s) before/after visit 
Consent Form 
CF 
N (in house) 
General 
To confirm participant willingness to participate in the study 
Pre-Intervention Survey 
PreI 
N (in house) 
Moment 
Assessment of participant perceptions about the intervention 
before they experience it. 
One day 
Documentation of behavior and substance use in the last 24 hours 
(exercise, alcohol, caffeine intake, sleep quality, tiredness and 
restedness) 
Generalized Anxiety Disorder Survey 
GAD-7 
Y 
2 weeks 
Anxiety assessment (7 Q’s) used in recruitment 
Pittsburgh Sleep Quality Index 
PSQI 
Y 
30 days 
Sleep quality assessment 
Patient-Reported Outcomes 
Measurement Information System 
PROMIS-29 
Y 
7 days  
Assessment of disturbed sleep, depression, anxiety, pain, and 
other health outcomes 
Respiratory Rate Monitor, Spire® 
RR 
- 
Real-Time To gather data on breathing rate 
Electroenchephalograph, ProComp 
Infiniti,  
EEG 
- 
“ 
To gather data on brainwave patterns 
Electrocardiograph, BodyGuard2® 
ECG 
- 
“ 
To gather data on heart rate variability (HRV) 
Post-Intervention Exit Survey 
PE 
Y 
2 hours 
Documentation of participant perceptions of the intervention after 
experiencing it, and feedback about intervention conditions 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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E.1.1 Subjective Outcome Questionnaires: 
 
Patient Heath Questionnaire (PHQ-2 and PHQ-9): Validated surveys used 
during Visit 1 to determine depression as perceived over the past two weeks. 
Individuals with scores indicating possible depression (3 or more points on the two-
question PHQ-2 survey), will be asked the remaining 7 questions on the PHQ-9 
survey. Those with scores indicating moderate depression (10 or more on the PHQ-
9) will be excluded from the study. This survey correlates well (r=0.75) [28]to the 
popular 21-question Beck Depression Index, which assesses depression in the 
present moment, however the PHQ-9 provides a more general assessment of 
depression during the past two weeks, using just nine questions. Cronbach’s alpha 
score: 0.89 ([29]. If participants indicate moderate depression (score of 10 or more), 
they will be advised to contact their primary care physician. They will also be 
provided with a resource list of affordable options for care. If suicidality is 
perceived, they will immediately be given the number for a help-line.  
Insomnia Severity Index (ISI): Validated survey used during the phone screening 
to determine insomnia severity. Here, we ask participants to recall sleep during the 
past two weeks, to determine if they may have insomnia. Individuals with scores 
indicating insomnia in the range of sub-clinical to moderately severe clinical insomnia as 
measured by the Insomnia Severity Index (score between 8 and 21). will be included. 
Cronbach’s alpha score: 0.90 [30]. Those who score above 21 on the phone 
screening will be read a medical referral. 
 
Baseline Intake: In-house survey used during the phone screening, to gather 
information on gender, age, socioeconomic status, education, languages spoken and 
ethnicity. We will assess use of cigarettes, cannabis, sleeping pills, stimulants, and 
other drugs. Participants will also be asked if they do shift work, have a regular 
mind/body practice within the last six months, or have any clinically diagnosed 
comorbidities including: fibromyalgia, sleep apnea, deafness or depression; all of 
which are exclusion criteria. 
STOP-BANG: Validated survey used at Visit 1 to determine likelihood of having 
sleep apnea. Participants will be excluded for the likelihood of having sleep apnea, 
if they answer yes to 3 or more questions (involving: snoring, tiredness, observed 
interrupted breathing, blood pressure, BMI, age, neck circumference and gender). 
Analysis of this instrument revealed that with minimal information requested, it is 
adequate for use in informal diagnosis. Chronbach’s alpha score of 0.74[31].  
Positive/Negative Affect Schedule (PANAS): Validated survey used to determine 
mood as perceived in the moment. This survey will be used before and after each 
visit to determine if the practice has any effect on positive or negative affect, which 
are independent of one another and may also affect sleep. Cronbach’s alpha score: 
NA of 0.87 and PA of 0.88[32]. 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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State Trait Anxiety (STAI): Validated survey used to determine anxiety as 
perceived in the moment. This survey will be used before and after each visit to 
determine if the practice has any effect on anxiety, which may also affect sleep. 
Cronbach’s alpha score: 0.89 for total scores [33] 
Pre-Intervention Survey (PrI): In-house survey taken before each visit. 
Participants will use a slider scale to indicate how credible they view the upcoming 
intervention to be, as a method for reducing symptoms of insomnia and as a 
relaxation technique (mental, physical and emotional). They will also be asked 
about exercise, caffeine intake and alcohol/substance use during the 24 hours prior 
to the intervention, as well as about their sleep quality the night before and how 
they feel at the moment (how tired or rested they are). 
Generalized Anxiety Disorder (GAD-7) Survey: Validated survey administered 
at the start of the first visit, to determine anxiety as perceived over the past two 
weeks. This survey correlates moderately with the widely used Penn State Worry 
Questionnaire (r=0.51-0.71). Cronbach’s alpha score: 0.79-0.91 [34]. 
Pittsburgh Sleep Quality Index (PSQI): Validated survey administered at the 
start of the first visit, asking to recall sleep during the past month, to determine the 
quality of sleep. Scores of 5 or more indicate poor sleep quality. This survey 
correlates with other surveys used herein: the PHQ-9 (0.49), and the GAD-7 (0.46). 
Cronbach’s alpha score: 0.57[35].   
Patient-Reported 
Outcome 
Measurement 
Information 
System 
Tool 
(PROMIS-29): Validated survey administered at the start of the first visit, asking 
to recall the past 7 days to assess sleep quality, anxiety, depression, pain, and more. 
Cronbach’s alpha score: 0.87-0.97[36]. 
Post Intervention Exit Survey (PE): In-house survey. Participants will use a slider 
scale to indicate how credible they now view this intervention to be, as a method 
for reducing symptoms of insomnia and as a relaxation technique. They will also 
be asked about intervention acceptability/tolerability (comfort, challenges, 
comments, etc.), and about how they feel (rested or tired). 
 
 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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E.1.2 Objective Outcomes: 
 
Respiratory Rate (RR): respiratory rate will be measured using a portable device 
(the Spire®) worn on the belt. This device is popularly used and attracting research 
interest[37]. 
 
Electroencephalogram (EEG): brainwave patterns will be measured using a 
Thought Technologies ProComp Infiniti System® for EEG measures, with 
electrodes attached to one frontal lobe location (F3), a central lobe location (C3), 
an occipital lobe location (O1), both eyes (EOD), and the chin. A grounding 
electrode will be attached to the ears, and a reference will be placed on one mastoid 
bone (M2, behind the ear).This device has been used in research for measurement 
of various physiological parameters [38, 39]. For our study, we will look at mean 
EEG power, calculated from frequency and amplitude of brainwaves originating 
from the frontal, central and occipital lobes of the brain. Electrodes for brainwave 
monitoring will be placed on detection sites for frontal, central and occipital lobes. 
One electrode will be placed on the chin for assessment of muscle tone during REM 
sleep. Electrodes placed near the eyes will be used to detect slow eye rolling during 
sleep onset. This EEG set-up or “montage” complies with the American Academy 
of Sleep Medicine guidelines for detecting sleep using EEG[40]. 
 
Electrocardiogram (ECG): heart rate variability will be measured using a portable 
wire-less device called the FirstBeat Bodyguard 2 ®. This device has been validated 
against a clinical ECG with off-line R-wave detection. It was found that the 
Bodyguard 2 has a high beat detection rate and provides accurate HRV analysis in 
many conditions (i.e. siting, lying, standing, walking, etc.)[41]. For our study, we 
will focus on detection of high frequency (HF) HRV parameters, as well as root 
mean square of successive differences (RMSSD) in HRV values, to determine 
parasympathetic response, or more simply, relaxation[42].  
 
 
 

 
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Study Title: A Closer Look at Yoga Nidra: Sleep Lab Analyses 
PI: Erica Sharpe, PhD 
IRB #: ES62018 
Approval Date: August 29th, 2018 
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E.2 Recruitment: Twenty-two study participants will be recruited using online advertising, flyers, 
and newspapers distributed throughout the NUNM campus and the city of Portland. Other 
advertising methods will be used as needed. A telephone screening will be used to select the most 
appropriate participants for our study. We also have a list of individuals who expressed interest in 
a recent NUNM Study (the PYAMA study), and who stated that they would be willing to be 
contacted again for future studies. Our study coordinator will send the attached email to them, 
asking if they would like to participate in our study. 
 
E.2.1 Sample Size Calculation: We have calculated our sample size considering changes 
in EEG power for alpha frequency bands measured by other researchers studying 
meditation and brainwave activity. In one study of thirty-four novice meditators exposed 
to mindfulness meditation and then a non-meditative condition, a 10% increase in alpha 
power was observed in the occipital lobe (29 (µV)2/Hz with a 6% pooled standard deviation 
of 19(µV)2/Hz)[22] during meditation as compared to the control condition. This increase 
in alpha activity during meditation and yoga nidra agrees with previous reports [6, 22, 23]. 
Assuming our intervention will at least match the power observed by Ahani (29 (µV)2/Hz), 
and allowing for the same measurement error (6%), a 90% power, and a 5% alpha, our 
sample size equation is as follows: N= 2((1.96 + 1.2816)2(19)2)/(29)2. This yields a sample 
size of 9 individuals per study arm. With a predicted 20% dropout rate, we plan to recruit 
11 individuals into each of two study arms, requiring 22 participants. Visit 1 will be the 
same for all 22 participants, and involve lying quietly and getting adjusted to the 
environment. At Visit 2, the participants will be randomized into two groups (lying quietly 
vs. yoga nidra). It should be noted that change in theta power has also been largely observed 
during meditation [3, 23, 43]. The above referenced study [22]detected a 70% increase in 
theta power during mindfulness meditation in novice meditators. Using our proposed 
sample size of 11 per arm, and the pooled standard deviation for theta values found by 
Ahani, et.al. 2014 (13%, [22]), a change as low as 66% theta power could be detected using 
an 80% power. With this sample size, we are well powered to detect clinically significant, 
previously observed changes in EEG power in the alpha and theta bands generated from 
the occipital lobe during meditation and yoga nidra. 
 
E.3 Description of Participant Population:  
E.3.1 Inclusion Criteria Participants must be between the ages of 18-45. They must speak 
English and be able to listen to a recording while resting comfortably. Participants must 
report disrupted sleep that indicates insomnia in the range of sub-clinical to moderately severe 
clinical insomnia as measured by the Insomnia Severity Index (score between 8 and 21). 
E.3.2 Exclusion Criteria If a participant does not speak English or cannot hear they must  
be excluded from this intervention. We will exclude candidates with co-morbidities 
including sleep apnea (clinically diagnosed or classified using a STOP-BANG survey score 
of 3 or more), and moderatedepression (indicated by a score of 10 or more on the Patient 
Health Questionnaire (PHQ-9). See Table 4, Exclusion Criteria for other exclusions, and 
Table 1 for surveys used in recruitment. 
 

 
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E.3.3 Considerations: Participants who are unable to lie on their back can assume another 
comfortable position. General anxiety will be documented in our population using the 
Generalized Anxiety Disorder (GAD-7) survey, upon intake. Comorbidities including any 
diagnosed disease/disorder will be documented, along with any regular substance use that 
is not grounds for exclusion from this study (alcohol use, caffeine use, medications, etc.). 
 
Table 4. Exclusion criterion and rationale 
Exclusion 
Rationale 
Regular Mind/ Body Practice (within last 6 
months) 
My affect response to yoga nidra 
Younger than 18 or older than 45 
Non-minors and pre-menopausal women 
Sleep Apnea (STOP-BANG survey) 
Interference with sleep quality 
Sleeping pills 
Possible masking of intervention effect 
Moderate Depression (PHQ-9) 
Interference with sleep 
Unavoidable disruptions to sleep (e.g. new baby, 
pet or other dependent) 
Insomnia may not be the issue 
Stimulant use  
Disrupted sleep 
Opioid/illegal drug use 
Disrupted sleep 
Cannabis use within the last 30 days 
Possible masking of intervention effect 
Shift work 
Irregular sleep patterns/ disturbed circadian 
rhythms/insomnia may not be the issue 
Alcohol (> 14 drinks per week) 
Interference with REM sleep 
Smoke cigarettes 
May interfere with relaxation effects of yoga nidra 
 
E.4 Screening for Eligibility: Prospective participants will call or email our study coordinator 
using information advertised on the flyer, on the NUNM webpage, and using other available 
advertising methods (online, newspaper, TV, etc.). Our study coordinator will them set up a phone 
call with them. She will use screening tools that inquire about age, demographics, comorbidities, 
lifestyle and more (as seen in Tables1-4) to determine eligibility for our study. Two additional 
surveys will be administered at Visit 1, to confirm eligibility. One of these two surveys requires 
the study coordinator to take measurements such as neck circumference and blood pressure, and 
thus must be completed in person. 
 
E.5 Screening Visit: The telephone screening is our first requirement to join the study. Once 
individuals pass the phone screening they will be scheduled for two clinic visits. See Tables1-
Further screening will occur using two additional questionnaires, as well as measurements taken 
by the study coordinator, at the beginning of Visit 1.  
 
E.5.1 Procedures during the telephone screening: The following surveys and questions 
will be used for determining eligibility. All surveys and questions are built directly into 
Redcap. The study coordinator will enter all information into this secure server during the 
phone screening. 

 
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Insomnia Severity Index (ISI): This survey score will be used as our exclusion criteria 
for insomnia. It will be scored using the instructions found on the survey footer. Poor sleep) 
will be identified using a score of 8-21, indicating a range of insomnia symptoms that 
correlate with subclinical to moderately severe clinical insomnia . Only those participants 
who score in this range during the telephone screening will be invited to schedule their 
clinic visits. Participants with scores of 22 or more will be referred to see a medical 
professional. 
Baseline Intake Survey: Demographic data will be analyzed by gender, ethnicity, 
socioeconomic status, and education. All parameters will be presented as percentages. Age 
will be used as a recruitment filter, with only those individuals ages 18-45 being included 
in our study. Additionally, we will ask if potential participants can understand English and 
if they can hear. Answering yes to both questions will be required for inclusion, as our 
intervention is a recording in English. Substance Use and Lifestyle: Individuals who do 
any of the following will be excluded: consume more than 14 alcoholic drinks per week; 
regularly use cannabis (within past 30 days); regularly use restricted substances, or abuse 
drugs (stimulants, depressants/opioids, etc.); use sleeping pills; have a regular mind/body 
practice (within past 6 months). Comorbidities: Participants will be excluded if they answer 
yes to having fibromyalgia. Sleep apnea, and depression will be screened for at visit 1 as 
sleep may be affected by these conditions.  
In order to determine if prospective participants have un-diagnosed depression or 
sleep apnea, we will ask them to complete the two surveys below at Visit 1. These 
surveys will be completed after signing the consent form and completing the pre-
intervention expectancy survey. Once these two surveys are complete, the study 
coordinator will make a decision to continue the visit or exclude the participant based 
on these results. 
Patient Heath Questionnaire (PHQ-9): This survey score will be used as our exclusion 
criteria for depression. It will be scored using the instructions found in the PHQ-9 
instructions from the Stable Resource Toolkit. Individuals with moderatedepression 
(indicated by a score of 10 or higher) will be excluded from the study. Participants with a 
score below 10 will be allowed to continue on with their two scheduled clinic visits. 
STOP-BANG: Using this questionnaire, the likelihood of having sleep apnea will be 
determined, based on snoring, tiredness, observation of apnea, blood pressure, BMI, age, 
neck circumference, and gender. The study coordinator will complete the survey by asking 
the participant questions as well as taking measurements at the beginning of Visit 
1.Measurements taken by the study coordinator at this time will include: blood pressure, 
height, weight, BMI, and neck circumference. Scoring will be accomplished using 
directions on the survey itself. If the answer is “yes” for three or more criteria, they are 
high-risk for having sleep apnea, and they will be excluded. These participants with scores 
indicating likely sleep apnea will be referred to see a medical professional. 
E.6 Experimental Groups (or Cohorts) 

 
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E.6.1 Control Condition: Participants will act as their own baseline control by lying 
quietly for 90 minutes during Visit 1. 
 
E.6.2 Experimental Condition: Half of the participants will be part of the experimental 
group by listening to a yoga nidra recording during the first 30 minutes of the 90 minute 
measurements taken  Visit 2. Participants will be randomized according to the 
Randomization Plan (in Appendix 1) upon their arrival at Visit 2. 
 
Note: In all cases and at all visits, before the 90 minute measurement period, an impedance 
check will be performed and sensors will be adjusted as needed to insure that all EEG 
electrodes are collecting high quality data. Then baseline measurements (5 minutes eyes 
open and 5 minutes eyes closed) will be taken. Accounting for these activities, participants 
will be prepared for two hour measurement periods. 
 
E.7 Informed Consent: At the beginning of Visit 1, participants will be given a consent form that 
outlines the research and the information we aim to gain from this study. They will be given ample 
time to read this form and offer their signature if they wish to participate. The study coordinator 
or a PI, to the best of their abilities, will answer any questions. Further questions about participant 
data or safety will be forwarded to the IRB. 
 
E.8 Data Collection and Sources 
5.8.1 Confidentiality and Data Storage: All participants will be assigned a number when 
they join the study. This number will be used on all forms and all electronic data. Names, 
assigned numbers, and contact information will be stored in an Excel sheet, saved only by 
the study coordinator on an encrypted computer. All paper surveys, questionnaires, and 
PHI will be stored in a secure location at the Helfgott Research Institute. All digital surveys 
will be administered through the secure RedCap server. 
5.8.2 Data Integrity: Every effort will be made to ensure confidentiality and to keep any 
shared personal health information confidential. We will protect PHI by limiting use of 
identifying data. Names will be replaced by numerical codes on all study documents. We 
will make an effort to ensure confidentiality by limiting where names and identifiers are 
stored. Identifiers will only be recorded in necessary locations such as our file matching 
names to numerical codes used in the study.  
 
The first time the “Participant ID” (the code that will replace the name) appears is on the 
telephone survey. The study coordinator will assign the code at the very end, once the 
participant passes the screening. This document will thus contain the only connection 
between identifying information and the ID code. It will not be shared outside of our study 
team, and will only be accessed on a case-by-case basis; for withdrawals for example. We 
have additionally added “Participant ID” boxes to the beginning of each RedCap survey. 
This ID will be used to organize surveys for analysis without use of identifiers.  
 

 
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E.9 Risks and Benefits:  
E.9.1 Risks: Although we will make every effort to protect your identity, there is a minimal 
risk of loss of confidentiality. Yoga nidra is a mind/body meditative practice, which 
involves mental, physical and emotional release and relaxation. Risks may include bringing 
up possibly upsetting memories, or emotions. If suddenly woken, participants may become 
startled, dizzy upon standing, and/or disoriented. Measurements will involve the placement 
of EEG sensors on the participants’ heads using gel as an adhesive. There may be minimal 
discomfort from the gel and electrodes, worn on the top and back of head, the eyes, and the 
chin, with a grounding electrode on the ear, and a reference electrode behind the ear. HRV 
will be monitored using an adhesive sensor on the chest. Though this sensor is small and 
wireless, there may be minimal discomfort or distraction from wearing the device or from 
the adhesive used. There could be additional risks that we are unaware of at the time of the 
study. If you experience any side effects while participating in the study, please contact 
Erica Sharpe at esharpe@nunm.edu as soon as possible.   
E.9.2 Benefits: There is no guarantee that participants will receive any benefit from this 
study. However, participation will help us learn more about yoga nidra as a possible 
intervention to address insomnia in adults, and will also be useful for assessing feasibility 
of this intervention as a whole. It is possible participants may receive benefit from the 
practice of yoga nidra. These practices may have mental, physical and emotional benefits 
including relaxation, emotional release, and mental relaxation.  
 
 

 
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E.10 Data Analysis: Quantitative data collected from all digital and paper surveys will be analyzed 
by our biostatistician. Digital RedCap surveys will be exported as de-identified data (using 
numbers instead of names) to Excel, analyzed and stored in an encrypted computer at Helfgott. 
Information attained from the telephone screening visits will be documented by the study 
coordinator and stored on an encrypted Helfgott computer. Objective measurements of RR, EEG, 
and ECG will be exported to a local, encrypted computer, de-identified and analyzed.  
 
E.10.1 Specific Aim 1: Electroencephalogram (EEG) Analysis: All EEG data will be 
exported and sent to Sleep Strategies for detailed analysis. This company will be able to 
determine time to sleep onset, as well as other aspects of sleep architecture (stages of sleep 
including NREM1-3 and REM, waking after sleep onset, and sleep duration).  
 
Data Pre-Processing: For each frequency band (beta: 13-35 Hz; alpha: 8-12 Hz; theta: 4-
7.5 Hz, and delta: 0.5-3.5 Hz) the amplitude of all waves in that category are automatically 
averaged by our ProComp Infinity software during each of several steps in the yoga nidra 
practice (i.e.: introduction and resolve, rotation of consciousness, awareness of breath, 
feelings and sensations, visualization, repetition of resolve and end of practice). The 
instrument will output mean EEG amplitude for each frequency band (alpha, beta, theta, 
and delta) for each step of the practice, and for each matched time interval during the 
baseline control of lying quietly. All amplitude measurements will then be converted to 
power by squaring the amplitude and dividing by the median frequency of the brainwave 
band we are interested in (alpha, beta, theta or delta).Artifact removal will be performed 
by eliminating data points above a 200uV threshold (representing high voltage durations) 
and below 2uV (representing flat channel effects)[22].These EEG power values will be 
used for the following analyses. 
 
Specific Aim 1, Outcome 1: We will determine the change in EEG power in the 
alpha, beta, theta, and delta bands for the (1) frontal lobe, (2) central lobe and (3) 
occipital lobe, during the practice of yoga nidra, and afterward, as compared to a 
baseline control (lying quietly). To measure this change, collected EEG frequency 
and amplitude (Hertz, Hz and microvolts, µV, respectively) values will be analyzed 
for our intervention as compared to our baseline control condition, where each 
subject serves as their own control in Visit 1.  
 
The following procedure will be applied for analysis of the alpha theta, beta and 
delta bands originating from each of three locations: the frontal, central and 
occipital lobes. Thus, in total, the process described below will be carried out 
twelve times (once for each of four frequency bands (alpha, theta, beta, delta) 
coming from three locations (frontal, central and occipital lobes)). In this 
description, analysis of EEG power in the alpha frequency band is described. The 
same methods will be applied to the other bands. 
 
Whole Practice Comparison (Primary Outcome): the mean alpha EEG power 
throughout the entire yoga nidra practice will be compared to that of the baseline 

 
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control period. We will compare all alpha EEG power values recorded during the 
entire 30 minute baseline of lying quietly (visit 1) to those values recorded during 
the entire yoga nidra practice(visit 2), in a paired two-sided t-test. Our study is 
powered to be capable of determining at least a 9% change in mean alpha EEG 
power during the practice, using a 90% power and 5% alpha. 
 
Step by Step Comparison: For the two baseline steps (5 min eyes open; 5 min 
eyes closed), and for each step of yoga nidra, all participant alpha EEG power 
values will be compared in a paired, two-tailed t-test to the alpha EEG power for 
matched time intervals taking place during the baseline control period of lying 
quietly. With this analysis, we will determine if there was a significant change in 
EEG power in the alpha band during any step of yoga nidra. We will also determine 
if there were any significant changes in the participant’s brainwave patterns at 
baseline for visits 1 and 2. 
 
Post Practice (Exploratory Outcome):To determine sustained effects of the yoga 
nidra practice during the hour following the intervention, measurements will 
continue, and alpha EEG power will be automatically averaged by the instrument 
during 12 regular 5-minute intervals. A similar Step-by-Step comparison will be 
made between baseline and intervention groups, wherein the mean alpha EEG 
power for each 5-minute interval during the hour following yoga nidra will be 
compared to that of matched 5-minute intervals during the hour following the 
baseline control of lying quietly. Additionally, the mean alpha EEG power 
representing the entire hour following yoga nidra will be compared the mean 
alpha EEG power representing the hour following the baseline control (using the 
same method described above). In this way, we will determine if the mean alpha 
EEG power during the hour following yoga nidra was significantly higher than that 
determined during the baseline control. We will also be able to see which 5-minute 
time intervals, if any, displayed particularly increased EEG power. 
 
Ultimately, we will report changes seen in each brainwave frequency originating 
from the frontal, central and occipital lobes throughout the practice of yoga nidra 
and the hour following, as compared to a baseline control. Changes reported will 
detail the differences seen in each frequency band during each step of yoga nidra 
and the hour following; and also as an average throughout the entire practice and 
during the hour after. 
 
All measures will be assessed for normality and transformed prior to analysis as 
required.  If any extreme outliers are detected, we will attempt to determine whether 
these might have been due to measurement errors or movement artefacts, and 
discard the outlier if this is the case.  If no cause for the outlier can be detected, then 
we will compare the main analysis with a sensitivity analysis conducted without 
the outlier. 
 

 
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Specific Aim 1, Outcome 2: We will document whether or not each participant fell 
asleep during each visit. Sleep and sleep stages (NREM and REM) will be 
identified by Sleep Strategies experts, following analysis of our raw EEG data. We 
will calculate percentage of participants who fell asleep during any point of their 
measurement period for each visit (baseline and intervention). Using only those 
individuals who fell asleep, we  will also calculate: (1) average percent time spent 
in REM, NREM 1, NREM 2 and NREM 3 for each visit, and (2) percentage of 
people who first fell asleep during the intervention (yoga nidra or lying quietly) vs. 
during the hour afterwards. Mean (SD) total sleep time will be also be computed 
for each of two visits, for those who fell asleep. 
 
Specific Aim 1, Outcome 3: We will compare time to sleep onset (i.e. sleep onset 
latency, SOL) for baseline and intervention. SOL is measured from the start of the 
measurement period to persistent NREM 2 sleep (as determined using our raw EEG 
data, by experts at Sleep Strategies). SOL is measured in minutes and will be 
presented in terms of mean and standard deviation for each visit (baseline vs. 
intervention). To determine statistical significance of differences between groups, 
a paired, two-tailed t-test will be performed. This outcome will be examined more 
closely in a larger future clinical trial investigating the effects of yoga nidra on sleep 
latency. 
 
E.10.2 Specific Aim 2: Respiratory Rate and Heart Rate Variability 
 
Respiratory Rate (RR): Respiratory rate data will be attained by contacting the 
Spire® Company to retrieve raw data attained by one device, used by all twentytwo 
participants throughout the course of our trial. Clinic visit times (including start 
time for each measurement) will be carefully noted in an Excel sheet, in order to 
accurately extract RR data for each step of our intervention. Mean respiratory rate 
will be determined for each time interval measured during the yoga nidra practice 
and each matched time interval measured during the control. It will also be 
determined for each 5-minute interval during the hour of measurements occurring 
post-intervention/control. Intervention and baseline values will be compared, in a 
statistically similar manner to EEG power data, wherein average RR for each time 
interval during and after yoga nidra will be compared to average RR for each 
matched time interval during and after the baseline control. A paired, two-tailed t-
test will be used for this analysis. This comparison will reveal whether or not a 
significant decrease in respiratory rate can be detected at any point during yoga 
nidra, or during the hour afterwards. Similar to the EEG data, mean RR throughout 
the entire 30 minute yoga practice will be compared using the same two tailed, 
paired t-test to the mean RR throughout the entire 30 minutes baseline period. This 
analysis will tell us if RR significantly decreased when comparing the entire yoga 
nidra experience to the entire baseline experience. The same grouped statistical 
analysis will be done for the entire hour following the intervention vs. the hour 

 
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following the baseline control. Our analysis will determine whether or not there is 
a statistically detectable decrease in RR during the whole of the hour following 
yoga nidra as compared to control. The primary outcome here is mean RR changes 
during yoga nidra. Comparison of changes in RR during the hour post-practice, and 
during each time interval of intervention/control will be exploratory. The same 
comparison described above will also be made for measurements taken during the 
10 minutes prior to the intervention (eyes open/eyes closed baseline) for 
intervention and baseline control groups. This comparison will determine if there 
are any significant changes in RR at baseline between visit 1 and 2. 
 
Electrocardiogram (ECG): Autonomic tone will be assessed using HRV data 
attained from the portable, wireless Bodyguard 2® device. Raw data will be 
uploaded using FirstBeat Uploader and then processed and analyzed using with 
Kubios, MatLab and Excel as our data analysis software. High frequency (HF) 
HRV parameters, and root mean square of successive differences in HRV 
(RMSSD) will be our primary measurements extracted from our HRV data. 
Generally, these values directly correlate with increased parasympathetic nervous 
system (PNS) response, or more simply, physical relaxation [42]. For our analysis, 
the mean HF and RMSSD during each indicated time interval representing steps in 
yoga nidra and 5-min increments of the hour following will be determined for each 
participant. All values from each time increment at Visit 2 (intervention) will be 
compared (using a paired, two-tailed t-test where p is less than 5%) to those values 
attained during the matched time intervals occurring during Visit 1(baseline). This 
analysis will determine whether or not there is significant increase in 
parasympathetic response (indicating relaxation) during any point of the yoga nidra 
practice or the hour afterwards, as compared to baseline control of lying quietly. 
The same comparison will be made for measurements taken during the 10 minutes 
prior to the intervention (eyes open/eyes closed baseline). This comparison will 
determine if there are any significant changes in HRV at baseline between visit 1 
and 2. As described in analysis of EEG and RR data, mean HF and RMSSD HRV 
values representing the entire yoga nidra practice will be compared again to those 
values representing the entire baseline control of lying quietly (using the same 
statistical method). This comparison will also be made for the entire 1-hour period 
following yoga nidra vs. the entire 1-hour period following baseline control. These 
last two analyses will tell us if there was a significant change in PNS response 
during yoga nidra as a whole, or the hour post-yoga nidra as whole, compared to 
our baseline controls. The primary outcome here is mean changes in HRV 
parameters during yoga nidra. Comparison of changes during the hour post-
practice, and during each time interval of intervention/control will be exploratory. 
 
 
 
 

 
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E.10.3Specific Aim 3: Feasibility (Credibility and Intervention Conditions) 
Specific Aim 3, Outcome 1: Feedback given using the continuous slider scale 
questions on the pre/post intervention surveys will be converted to a quantifiable 
value between 1 and 100 automatically, by Redcap. Results will reveal how positive 
our population was that they would experience mental, physical or emotional 
relaxation and whether it could help them fall asleep. Results will be presented 
using average and standard deviation values of % positive expectancy before and 
after each visit. A graphical representation of results of expectancy analysis will be 
presented using a bar graph that shows % positive expectancy before our 
intervention vs. afterwards. Four bars will appear, representing expectancy for 
mental, physical and emotional relaxation, as well as for ability of the practice to 
help them fall asleep at night.  
Specific Aim 3, Outcome 2: In addition to expectancy, intervention acceptability 
will be assessed using recruitment and retention outcomes.  If we can recruit our 
target sample size within three months, we will conclude that our proposed 
intervention is perceived as acceptable to potential participants. Dropouts will also 
be monitored to measure acceptability of the intervention. If more than 50% of our 
participants drop out, we will conclude that the intervention was not acceptable, 
and changes should be made. Participants will also be asked about tolerability as 
part of their post-intervention questionnaire. Slider scales will be used to assess 
comfort level during the intervention, as well as intervention tolerability. Slider 
scale questions will be scored and reported in the same way as the expectancy 
questions above (SA 3, Outcome 1). Multiple choice options are provided for 
questions inquiring about challenges and distractions appearing during each visit. 
Results will be presented as % of the sample that answered in each way. An open-
ended comment box is also included in the post-intervention survey. These 
responses will be analyzed using qualitative approaches to determine trends and 
take into consideration any areas that could be improved in our future study designs.  
Expectancy and Outcomes (Exploratory): In order to track how conscious 
expectancy correlates with outcomes, we will look at participants who report a 
expectancy of 50% or more on one or more slider scales used in the pre-intervention 
expectancy survey. For these participants, we will report results from our primary 
outcome (mean differences in EEG power originating in the frontal, occipital and 
central lobes during yoga nidra as compared to control). We will report the same 
analysis for those who report less than 50% expectancy on all scales in their pre-
intervention survey. We will additionally look at the relationship between 
expectancy and sleep. We will report the percentage of high-expectancy individuals 
who fell asleep, as compared to the percentage of low-expectancy individuals who 
fell asleep.  
 
 

 
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E.10.4 Acute Changes at Each Visit: 
Pre/Post Intervention State Trait Anxiety (STAI Y-6): Momentary anxiety will 
be analyzed before and after the measurement period of each visit. We will use the 
six question version of the STAI survey, found to be reliable and valid[44]. Data 
will be analyzed using directions on the survey. The normal range is between 34-
36 points. Mean pre-intervention STAI Y-6 scores will be compared to mean post-
intervention STAI Y-6 scores using a two tailed paired t-test. 
Generalized Anxiety Disorder (GAD-7) – Visit 1 only: This survey (recalling 
anxiety symptoms during the past two weeks) will be scored using the instructions 
found in the survey instructions. Scores will describe our sample at entry and help 
us to understand changes seen in the pre/post analysis of momentary STAI 
responses. This data will be presented as a score (mean and standard deviation) 
representing our entire sample at Visit 1.  
Pre/Post Intervention Positive/Negative Affect Schedule (PANAS): Momentary 
mood (positive and negative affect) will be analyzed using PANAS survey. This 
survey will only be administered during visit 2. Responses will be scored using 
directions on the survey. Mean pre-intervention positive affect scores will be 
compared to mean post-intervention positive affect scores using a two tailed paired 
t-test. The same analysis will be done for the negative affect scores. This analysis 
will determine whether or not yoga nidra is capable of increasing positive affect 
and/or decreasing negative affect.  
 
 

 
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E.10.5 Sample Statistics: 
At each visit, statistics will be gathered using a Pre-Visit Survey, asking 
participants how they feel about the intervention they are about to experience, as 
well as about their behaviors within the past 24 hours. Using results from this 
survey, the following descriptions of our sample will be calculated and presented. 
Exercise: % of participants who exercised within 2 hours of the intervention 
Alcohol: % of participants who consumed alcohol within 24 hours. 
Caffeine: % of participants who consumed caffeine that day.  
A sub-analysis of caffeine intake will also include a rough estimate of milligrams 
(mg) of caffeine consumed by our sample within 7 hours of the intervention. 
Caffeine quantity will be determined by asking participants how many cups they 
consumed and what type of caffeinated beverage(s) they had. The average 
concentration of caffeine in coffee or tea (mg/cup) made available by the Mayo 
Clinic, will be multiplied by number of cups consumed of each, to determine a 
rough estimate of caffeine consumed for each participant. All values will be 
averaged together to represent our entire sample. These results will be presented as 
an independent bar graph showing average and standard deviation of mg caffeine 
consumed by our sample group per visit (baseline vs. intervention). We expect there 
to be no significant difference between visits. Ref, Mayo Clinic caffeine resource: 
(https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-
depth/caffeine/art-20049372). 
Sleep Quality:% of participants reporting better than average sleep the night before 
(indicated by assigning their own sleep quality a score above 50 on a slider scale). 
Additionally, Mean reported sleep quality will be compared for Visits 1 and 2 using 
a paired, two-tailed t-test to determine if there was a significant difference in our 
sample from visit to visit. We do not expect there to be a difference.  
Tiredness: as part of the pre/post intervention surveys, participants will be asked 
about their degree of tiredness, using a slider scale in Redcap. Mean and SD will 
be calculated in order to determine average day-time sleepiness from our sample 
population before and after the intervention and control. Mean tiredness before the 
intervention for visits 1 and 2, and after the intervention for visits 1 and 2 will also 
be compared using a t-test, to define our sample. 
Rested-ness: as part of the pre/post intervention surveys, participants will be asked 
about how rested they feel, using a slider scale in Redcap. Mean and SD will be 
calculated in order to determine how rested our sample population is before the 
intervention/control and afterwards. Mean restedness before the intervention for 
visits 1 and 2, will also be compared, along with mean restedness after the 
intervention for visits 1 and 2. Paired, two-tailed t-tests will be applied to determine 
if these differences are statistically significant. 
 

 
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E.10.6: Exploratory Data Analysis: Correlation of PROMIS tool with the popular ISI 
and PSQI for sleep; the GAD-7 for anxiety, and the PHQ-9 for depression. This is an 
exercise in methods of validation to prepare us for validation of the PROMIS tool in a 
larger future clinical trial. 
Procedures used in other papers validating the PSQI and ISI surveys [45], [46] as 
well as the PROMIS-29 tool [47] (for systemic sclerosis) will be considered as 
guidelines for validating the PROMIS-29 instrument as a tool for assessment of 
sleep, depression and anxiety. Each scale used here in this comparison provides a 
“cut-off point” differentiating mild or non-existing sleep disturbance, anxiety or 
depression from moderate symptoms that may require medical attention. For this 
reason, a dichotomous value of yes or no will be the final outcome for these scales, 
based on Table 5. Scoring information for the PSQI and PROMIS-29 is seen below. 
Details about the ISI and PHQ-9 can be seen in the recruitment section, and details 
about the GAD-7 are seen in the acute changes section.  
Table 5. Yes/No Thresholds for Survey Tools  
 
Y/N 
Threshold: 
Moderate 
Depression 
Y/N 
Threshold: 
Moderate 
Anxiety 
Y/N 
Threshold:  
Poor Sleep 
Quality 
PROMIS-29 
>60 
>60 
>50 
PSQI 
 
 
>5 
ISI 
 
 
>8 
GAD-7 
 
≥10 
 
PHQ-9 
≥10 
 
 
 
If 50-70% of participants identified as having a particular disorder using our 
primary exclusion criteria survey (e.g. PHQ-9 for depression) are also identified by 
the PROMIS-29 tool as having the particular disorder, the PROMIS tool for that 
disorder will be considered to correlate moderately with our reference survey. If 
this survey agreement is above 70%, high correlation will be established. It should 
be noted that all participants in the study will have already been identified as having 
poor sleep, according to the ISI.  
Patient-Reported 
Outcome 
Measurement 
Information 
System 
Tool 
(PROMIS-29) – Visit 1 only: Scoring will be done using the PROMIS adult profile 
instruments scoring manual from the PROMIS Assessment Center. Depression and 
anxiety domains will both be classified here using a score above 60. This value is 
selected because it is one standard deviation (sd=10) from the mean of 50, which 
represents average level of depression and/or anxiety in the general population. 
Poor sleep will be classified by a score above 50, as the PROMIS scoring manual 

 
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indicates that for this survey, the average score of 50 represents slightly poorer than 
average sleep[48].  
Pittsburgh Sleep Quality Index (PSQI) – Visit 1 only: This survey will be scored 
using the instructions found on the survey footer. Poor sleep quality will be 
identified as having a score above 5 points. 
E.10.7 Blinding: our biostatistician, Doug Hanes, PhD, will analyze the data after the trial 
is complete, without knowledge of which visit (1 or 2: baseline or yoga nidra) that data 
came from.  
 
F.0 Conclusion, Summary and/or Benefits of the Knowledge Gained: With this study we will 
gain useful information that will help inform our study design for larger pilot studies that will 
investigate the effects of yoga nidra on sleep. Information gleaned will include: the effects of yoga 
nidra on brainwave patterns, respiratory rate and heart rate variability during and after the practice, 
as compared to a baseline control of laying quietly. This will be novel information, as no published 
studies in the US have simultaneously measured brainwave patterns, respiration rate, and heart 
rate variability during the practice of yoga nidra. Appropriate groundwork has been set, however, 
with several studies reporting other forms of meditation to affect brainwave activity, RR, and 
HRV[23]. One study reported brainwave changes during yoga nidra[43], and one other study 
reported HRV increase during yoga nidra[26]. Our study will expand upon research into the effects 
of mind/body practices on brainwave activity and respiration, while also looking closely at HRV 
as an indicator of ANS response. For our population, ability of this intervention to increase PNS 
response could be highly therapeutic. Other researchers have shown that throughout all wake and 
sleep stages, individual with insomnia exhibit elevated sympathetic nervous system (SNS) activity 
(observed as increased LF and decreased HF components of HRV [18, 27]) which is associated 
with their increased risk of coronary artery disease. Increasing PNS response may help them sleep, 
but may also help balance underlying ANS imbalances that maybe causing insomnia. Aside from 
physiological measurements, this study will also give us valuable information on the feasibility of 
this study (with respect to instrument selection, intervention acceptability and credibility). We will 
use these findings to inform future study designs. Moving forward, we aim to carry out a larger 
trial involving the practice of yoga nidra before bed as a potentially self-administered treatment 
for insomnia. This future study will evaluate yoga nidra and the feasibility of testing our yoga nidra 
intervention and its impact on SOL utilizing actigraphy, sleep journals, and self-report surveys. 
The mind/ body practice of yoga nidra is an approachable technique, with a history of use in 
reducing sleep onset latency. We propose that this practice can be easily integrated into a sleep 
routine to produce immediate and measurable effects in the general American population. 
 
 
 

 
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