Effects of Sleep Extension on Sleep Physiology and Behavior of Young Children
Phase: NA
Conditions: Attention Deficit Hyperactivity Disorder
Sponsor: University of Massachusetts, Amherst

 
 
 
 
 
Sleep Extension and Behavior of Young Children 
 
 
 
 
University of Massachusetts, Amherst Protocol Record 2015-2739 
 
Protocol first approved: 11/9/15 
 
Submitted to ClinicalTrials.gov: 2/20/18 
 

Study Protocol 
 
Sleep Measures 
Actigraphy. Actiwatch Spectrum wristwatches (Spectrum 2; Philips Respironics) were used to 
measure sleep and wake onset times and confirm that experimental manipulations were 
followed. The Actiwatch has off-wrist detection and a triaxial accelerometer that samples activity 
at 32Hz, with a sensitivity of <0.01g. Activity was stored in 15-second epochs. Actigraphy is a 
reliable index of time spent asleep and awake in developmental populations.  
 
Polysomnography (PSG). Polysomnography electrode caps (EasyCap) were used to record 
overnight sleep physiology. Data was collected from 24 EEG electrodes, 2 electrooculogram 
electrodes, and 2 electromyogram electrodes (affixed to the chin) referenced to a mid-forehead 
ground (FPz) and referenced to Cz and contralateral mastoids.  
 
Sleep Diary. Sleep diaries were used to validate scoring of actigraphy data. Caregivers logged 
their child’s sleep latency, sleep onset time, and morning wake onset time each day of the 
experimental protocol.  
 
Behavioral Measures 
Go/No-Go Task. A developmentally appropriate Go/No-Go task was used to assess inhibitory 
control. In Go trials (75% of trials), images of various animals (e.g., giraffe, elephant, panda) 
were presented. In No-Go trials (25% of trials), a chimpanzee was presented.  Displayed 
images were 3 inches in height and 4 inches in length, centered on a 14-inch computer screen 
positioned approximately 15 inches from participants. 
 
Each trial began with the presentation of an animal image for 500 ms. Children were instructed 
to respond, via a button press on a computer mouse, for all of the animals (Go trials) except for 
the chimpanzee for which they were to inhibit their response (No-Go trials). A blank screen was 
presented for 500 ms between trials. Children were given 12 practice trials to ensure they 
understood task instructions. Subsequently, test trials were presented in 2 blocks of 60 trials 
each. Two pseudo-random trial orders were used for all participants (for evening and morning 
sessions). Trial order was counterbalanced across sessions (morning and evening), conditions 
(baseline and extension), and participants.  
 
Procedure 
Procedures were approved by the local Institutional Review Board. Accordingly, researchers 
described the procedures and caregiver consent was obtained at an in-home visit. During this 
initial visit, the sleep diary was given to the caregiver. Child assent was obtained and the 
Actiwatch was fitted to child’s non-dominant wrist. Children and caregivers were shown how to 
use the Actiwatch and an instruction sheet was provided for future reference. Caregivers were 
asked to oversee the child’s use of the Actiwatch and complete the sleep diary each day. 
Children and caregivers were instructed that the child must maintain their habitual wake time 
across the two 5-day testing periods. For consistency, maintaining habitual wake time was 
intended to ensure that sleep extension was a product of earlier sleep onset time and not 
delayed wake time. Children’s wake time is also often constrained by bus schedules and school 
start times. 
 
There were two conditions, a baseline condition and a sleep extension condition. During the 
baseline condition, children followed their normal bedtime routine for five consecutive nights. 
During the extension condition, caregivers were instructed to put their child to bed 90 minutes 
earlier than their habitual bedtime for five consecutive nights. Caregivers were provided a list of 

tips to aid in implementing the earlier bedtime. 
 
On the last night of the baseline and extension conditions, children, accompanied by a 
caregiver, arrived at the sleep laboratory approximately one hour before their habitual (baseline 
condition) or extended (extension condition) bedtime. After settling in, children completed a 
baseline assessment of the Go/No-Go task. Children were then fitted with a PSG cap. Children 
and caregivers slept in the lab (in separate beds in the same room) overnight. The following 
morning, children woke at their habitual wake time. The PSG cap was removed and children 
were given time to complete their normal morning routine. Children then completed the morning 
assessment of the Go/No-Go task. This concluded the overnight visit. At the end of each in-lab 
visit, the Actiwatch and sleep diaries were collected. Caregivers were provided monetary 
compensation and children chose an age-appropriate prize. 
 
There was approximately one week between the baseline and extension conditions. The order 
of conditions was counterbalanced across participants. Whenever possible, the conditions were 
matched for the day of the week they took place.  
 
Statistical Analyses 
Statistical analyses were performed in SPSS, and an alpha of 0.05 was used to determine 
significance. 
 
Sleep 
Actigraphy data was used to assess the efficacy of the sleep extension intervention in extending 
sleep time from baseline. Children and their caregivers were instructed to press an event 
marker on the Actiwatch when the child went to sleep and woke up each day. Event markers 
and sleep diary entries were used to confirm the start and end time of each sleep bout. Actiware 
software (Philips Respironics) was then used to differentiate intervals of sleep and wake. Sleep 
onset time was set at the first of three consecutive minutes of sleep and wake onset time was 
set at the last of five consecutive minutes of sleep. Total sleep time was defined as the total 
minutes scored as sleep between sleep onset and wake onset.  
 
A repeated-measures ANOVA was used to compare sleep-timing variables (i.e., sleep onset 
and total sleep time) between the baseline and extension conditions across groups. In these 
models, sleep-timing variables were independently entered as outcome variables. Condition 
(baseline and extension) was entered as a within-subjects factor and group (ADHD and TD) 
was entered as a between-subjects factor.  
 
Polysomnography was scored according to the revised American Academy of Sleep Medicine 
manual by a trained researcher. Due to recording error, five participants in the TD group did not 
have usable PSG data.  
 
Repeated-measures ANOVAs were used to compare PSG outcome variables (i.e., total sleep 
time and time spent in distinct sleep stages) between conditions and groups. Here too, condition 
was entered as a within-subjects factor and group as a between-subjects factor.  
 
Inhibitory Control 
To determine whether sleep extension improved inhibitory control in children with and without 
ADHD, a repeated-measures ANOVA was used. In this model, inhibitory control, as measured 
by accuracy (% correct) on No-Go trials, was entered as the outcome variable. Condition and 
time (evening and morning) were entered as within-subject factors and group was entered as a 
between-subjects factor. Separate repeated-measures ANOVAs were then run independently 

for each group to assess group-specific changes in inhibitory control following the sleep 
manipulation.