Steroid Nasal Irrigation for Flavor Evaluation and Detection (SNIFFED) Study
Phase: NA
Conditions: Olfactory Disorder
Sponsor: Washington University School of Medicine

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Title:  Steroid Nasal Irrigation for Flavor Evaluation and Detection Study  
 
Name and Department of Proposed Faculty Mentor: Jay Piccirillo, MD, Department of 
Otolaryngology and Sam Klein, Professor, Center for Human Nutrition, Department of Medicine 
and Dorina Kallogjeri, MD, MPH  
 
NCT number: 201608163 
 
Document Date: 05/22/2019   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Abstract: Olfaction is the ability to perceive smell. Gustation is the ability to perceive taste. 
Anosmia is the inability to detect smell. Ageusia is the inability to detect taste. The senses of 
olfaction and gustation are often confused in people with olfactory disturbance. Despite being 
two different sensations, they both coincide within the human central processing system to 
provide the perception of “flavor.” Therefore, it is common for many individuals who suffer 
from anosmia to also complain of deficits in taste perception. In this project, our aims are 
threefold: 1) to assess the efficacy of a 30-day treatment of budesonide nasal irrigation to 
improve the sense of smell and taste 2) to determine the impact of a 12-week period of olfactory 
training on patients with olfactory dysfunction who fail to improve after budesonide nasal 
irrigation treatment 3) to understand what, if any, neural network changes occur following 
olfactory training as measured by resting-state functional connectivity MRI (rs-fcMRI).  
 
We will first identify study subjects with olfactory dysfunction based on predefined inclusion 
and exclusion criteria. Next, we will measure baseline perception of smell and taste using a 
battery of tests: University of Pennsylvania Smell Identification Test (UPSIT) and Sniffin Sticks 
for smell; NIH Taste Intensity Test with general Labeled Magnitude Scale (gLMS) and PROP 
Taster Test for taste. If subjects have hyposmia/anosmia defined by an abnormal UPSIT and/or 
Sniffin Sticks score, they will be treated with budesonide nasal saline irrigation for 30 days and 
their perception of smell and taste retested following completion of nasal irrigation using the 
same assessments described above. Subjects who do not improve from baseline measurements of 
these composite tests will undergo a 12-week smell training intervention program, after which 
they will repeat the battery of smell and taste tests. While several studies have demonstrated the 
utility of smell training intervention in the improvement of anosmia, there have not been any 
studies showing how much improvement budesonide nasal irrigation provides to patients with 
olfactory dysfunction. Upper respiratory conditions, such as rhinosinusitis, often cause patients 
to have a diminished sense of smell and/or taste. Budesonide is an anti-inflammatory agent that 
is frequently used to treat rhinosinusitis and improves olfaction in patients with upper respiratory 
illnesses. Similarly, budesonide may increase olfaction in individuals with olfactory dysfunction. 
The significance of our project will be to provide a novel way to treat olfactory dysfunction. The 
possible success of budesonide will manifest in the improvement in quality of life in those with 
olfactory dysfunction, who will hopefully experience an enhanced sense of smell, taste, and 
“flavor”.  
 
The olfactory system is unique in its high degree of neuroplasticity, with ongoing neurogenesis 
of olfactory tract cells throughout life.  Because of the regenerative properties of the olfactory 
system, olfactory training has emerged as a promising intervention to modulate neuroplasticity in 
patients with smell disorders. In this study, our second and third aims will be to validate the 
efficacy of olfactory training and to use rs-fcMRI to evaluate changes in functional connectivity 
in olfactory related networks in individuals with olfactory dysfunction undergoing olfactory 
training, respectively.  

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Statement of Research Problem: We wish to determine the effect of budesonide nasal saline 
irrigation on the ability to smell and/or taste in a cohort of patients who complain of 
anosmia/hyposmia. It is well known that people frequently misidentify olfactory disturbances as 
taste disturbances.1 Although smell and taste are separate senses, they both integrate and interact 
in the brain (in addition to other senses) to provide us with the perception of flavor. The intimate 
intertwining of these two chemical senses, combined with the erroneous use of “flavor” as a 
synonym for “taste,” may contribute to this common confusion between symptoms arising from 
olfactory dysfunction as if they were caused by taste dysfunction. While literature has supported 
the intervention of a 12-week smell-training program in improving olfactory function12, none 
have investigated the role of budesonide nasal saline irrigation in treating olfactory dysfunction 
and the biologic mechanism of olfactory training is not well understood. We will assess taste and 
smell function in subjects before and after treatment with budesonide nasal saline irrigation.  
Those who fail to show improvement will undergo a baseline resting state functional 
connectivity MRI (rs-fcMRI) and undergo 12 weeks of olfactory training while continuing the 
budesonide nasal irrigation. Once more, we will assess post-intervention smell and taste function 
in patients undergoing the smell training program to see if they display any improvement and 
obtain a post-intervention rs-fcMRI. 
 
Specific Aims: The aims of our study will be 
1) To assess the ability of a 30-day treatment with budesonide nasal irrigation to impact sense of 
smell.  
2) To assess whether a 12 week smell training intervention is effective for subjects with anosmia 
or hyposmia who fail to improve after budesonide nasal irrigation treatment. 
3) To determine whether improved olfaction is the result of changes in functional connectivity in 
one or more olfactory related networks.  
 
Background : We will be using a battery of tests to measure subjects’ baseline sensation of 
smell and taste before and after a 30-day trial of budesonide nasal saline irrigation and, if 
deemed necessary, a 12-week smell training program. The tests for each of these components are 
outlined below. For each test, subjects will receive a set of instructions to follow. The tests will 
be administered by a trained expert so that every individual experiences the tests in a uniform 
manner. Olfactory dysfunction affects up to fifteen percent of the general population and can 
cause significant psychosocial distress including decreased appetite, reduced self-hygiene, and 
mood disturbances. 3,4 Most causes of olfactory dysfunction are acquired and include 1) nasal 
inflammatory conditions, such as chronic sinusitis and viral upper respiratory tract infections; 2) 
traumatic brain injury and; 3) neurodegenerative disorders, such as Alzheimer’s or Parkinson’s 
disease.  The pathophysiology behind olfactory dysfunction is complex and poorly understood. 
As a result, treatment options are limited.  
 

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The olfactory system is unique in its neuroplasticity with ongoing neurogenesis of olfactory bulb 
cells throughout life.  Because of the neuro-regenerative properties of the olfactory system, 
olfactory training has emerged as a promising treatment for olfactory loss. With olfactory 
training, patients with olfactory dysfunction are exposed to various stimulating odors, such as 
resinous, fruity, spicy, or flowery scents over several weeks to months. In a large randomized, 
controlled multicenter trial, Damm et al. demonstrated that patients with post-infectious olfactory 
loss had improved olfactory function following 18 weeks of olfactory training as measured by 
threshold, discrimination, and identification scores. 20 While several other clinical studies have 
also examined the effectiveness of olfactory training with promising findings, the biologic 
mechanism of olfactory training is not well understood.   
 
We hypothesize that olfactory training is associated with dynamic modulation in neural activity 
in the olfactory and somatosensory networks. A recent neuroimaging study by Kollndorfer et al. 
suggests that olfactory training enhances functional connectivity in chemosensory processing 
networks in anosmic patients. In their case study, seven patients with anosmia secondary to 
upper respiratory tract infections underwent twelve weeks of olfactory training followed by post-
training fMRI. Although anosmic patients were unable to consciously detect odors, specific seed 
regions with increased functional connections were identified following olfactory training, which 
included the anterior entorhinal cortex, inferior prefrontal gyrus, and the primary somatosensory 
cortex. These findings suggest that olfactory related networks are capable of reorganization with 
training and that olfactory training may be a promising therapeutic treatment for olfactory 
dysfunction.27 
Olfactory function - The olfactory portion of our testing is comprised of two exams: the 
UPSIT and Sniffin Sticks. The UPSIT is a test of olfactory identification and consists of four 10-
page booklets, with a total of 40 items. On each page, there is a different “scratch and sniff” strip 
and four choice options. Subjects are asked to scratch each strip with a pencil to release the 
scents, detect the smell, and identify the smell from the four choice options. The UPSIT comes 
with a scoring rubric that identifies the normalcy benchmark based on age and gender. The 
UPSIT is commercially available, takes a few minutes to complete, and is the gold standard test 
to assess smell identification in people. 1,2 Sniffin Sticks are commercially-available felt-tip pens 
filled with liquid odorants or odorants dissolved in propylene glycol. Subjects are presented with 
odors by uncapping the pens and placing them approximately 2 cm away from each nostril for 
about 3 seconds. By presenting odors in this fashion, the subject’s baseline identification and 
discrimination score can be determined. Odor threshold intensity will be assessed by using a 
staircase method: 3 sticks will be presented in a random order - two with a solvent (controls) and 
one with the test odorant at a particular dilution (variable). Subjects will be asked to indicate 
which of the three sticks is the odorant. Presentation of each pen in this triplet set of Sniffin 
Sticks will occur every 20 seconds. The end result will be to determine the threshold at which the 
subject can detect odors. Starting at a lower concentration, we will present the test pen (with the 
two controls) at increasing concentrations until the subject is able to first detect the scent. Then, 

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we will present pens at continually lower concentrations until they cannot detect a scent. This 
will continue back and forth until we have 7 “reversals” in detection. A reversal is when the 
subject goes from being able to detect a scent, to being unable to detect a scent, and vice versa. 
The quantity we are observing is the dilution factor of the pen. At the end, we will average the 
dilution factors of the last 4 reversals to calculate the subject’s baseline threshold for smell 
intensity. Following completion of the three tests, a composite threshold, discrimination, and 
identification (TDI) score can be determined. Use of the Sniffin Sticks have been shown to be a 
safe and reliable way to assess olfactory performance.3  
Gustatory function - Subject’s gustatory function will be evaluated using the NIH Taste 
Intensity Test and the PROP Taster Test. NIH Taste Intensity Test examines taste identification 
by determining subjects’ perception of salty, sweet and bitter solutions on the tip of the tongue 
and in the whole mouth. Salty taste will be identified as the predominant taste quality from 150 
mM sodium chloride, sweetness as the predominant quality from 300 mM sucrose and bitterness 
as the predominant quality from 0.5 mM quinine hydrochloride.  One concentration of each of 
the 3 taste compounds will be presented in two test series (one for tip of the tongue and one for 
whole mouth taste sensation).  For assessment of taste function at the tip of the tongue, solutions 
will be presented on a cotton swab.5 Between each exposure to the cotton swab, subjects will 
rinse with distilled water to prevent adaptation or interference between samples. After a 3-minute 
break, the test will be repeated with samples presented in medicine cups (whole mouth 
procedure). Subjects will sip and expectorate each sample and rinse with distilled water between 
samples. The rationale behind using both a regional (tip of the tongue) and whole mouth taste 
test is intensity perception evaluated using a whole mouth procedure may fail to detect damage 
to the taste component perceived by the anterior portion of the tongue due to the central release 
of inhibition from other oral sensory cranial nerves.5 However, the regional application of taste at 
the tip of the tongue isolates taste perception that is carried solely by the chorda tympani nerve, 
and therefore allows detection of specific nerve damage, which can occur due to early history of 
frequent ear infections, some dental procedures, and viral illness. The NIH Taste Intensity Test 
has been shown to adequately assess the patient’s ability to identify tastants.5 The ability to taste 
PROP and phenylthiocarbamide (PTC), both bitter compounds, is an inherited trait present in 
70% of the US adult Caucasian population.11 We will use the PROP Taster Test to evaluate 
subjects’ taster classification. After rinsing with distilled water, subjects will be asked to place 10 
mL of 0.32 mM PROP in their mouth, expectorate it, and rate the intensity of the sensation. They 
will then rinse three times with distilled water and wait 45 seconds. After this break, subjects will 
be asked to place 10 mL of 0.1 M NaCl in their mouth, expectorate it, and rate the intensity of 
the sensation. Non-tasters are classified as those who rate the sensation of NaCl as higher than 
that of PROP, medium tasters are those who rate the two sensations similarly, and supertasters 
are those who rate the intensity of the PROP sensation higher than that of NaCl. The PROP test 
has been proven to be a valid and reliable means to test PROP taster status.14 The general 
Labeled Magnitude Scale (gLMS) will be used to rate sensations for both the NIH Taste 
Intensity Test and the PROP Taster Test. This is a psychophysical tool that requires subjects to 

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rate the perceived intensity along a vertical axis lined with adjectives that are spaced semi-
logarithmically based upon experimentally determined intervals to yield ratio-quality data.6 
Seven anchor labels are provided: no sensation, barely detectable, weak, moderate, strong, very 
strong, and strongest sensation of any kind. Each of the labels will correspond to a predominant 
taste sensation - bitter, salty, sweet. Before using the gLMS scale to assess taste intensity and 
quality, subjects will be trained on the use of the gLMS.7 That is, at their baseline visit, subjects 
will be first familiarized with the use of the gLMS by rating the intensity of 10 oral and non-oral 
sensations (e.g. the tingling of a carbonated beverage, the warmth of lukewarm water) and then 
being told how intense the average individual perceives these stimulants. That way, subjects will 
have a standardized comparison model for quantifying their detection of taste intensity. 
Clinical Global Impression, Questionnaire for Olfactory Dysfunction, and ODOR 
questionnaire: At each phase of the study, subjects will be asked to fill out an intervention-
specific form rating how they feel they’ve responded to treatment as well as a Questionnaire for 
Olfactory Dysfunction, which is a validated quality of life questionnaire for patients with 
olfactory disorders. Together, these two forms will provide a subjective measurement to go along 
with our objective measures of smell and taste test performance. With the results from the 
UPSIT, Sniffin Sticks ,Clinical Global Impression forms and Questionnaire for Olfactory 
Dysfunction, we hope to have a well-rounded sense of the utility of budesonide nasal irrigation 
in affecting olfactory and gustatory sense for phase one of the study. In phase two, the smell 
training program will be initiated in the group of subjects who have abnormal results on either 
the Sniffin Sticks or UPSIT tests after 30 days of budesonide nasal saline irrigation. Subjects will 
smell 4 odors (phenyl ethyl alcohol, eucalyptus, lemon, eugenol) twice a day for 12 weeks. The 
odors will be placed in separate jars at the same concentration in each jar. Each jar will be 
labeled with the specific odor. Subjects will be advised to sniff each of the jars for 10 seconds 
(~30-second interval in between) twice a day. This will continue for 12 weeks. During this 
period, the subjects will continue the budesonide nasal irrigation. After the intervention, they will 
be asked to return and be retested with the aforementioned battery of tests along with completing 
an additional quality of life questionnaire (ODOR).  The ODOR questionnaire will be completed 
during a telephone call or via a link sent by email. The smell training program has been 
performed and shown to be safe and successful in a previous study of patients with olfactory 
dysfunction without sinonasal disease.12  
 
 
Resting-state functional connectivity MRI: We propose to study changes in functional 
connectivity in the olfactory and somatosensory networks in patients with olfactory dysfunction 
following olfactory training. We hypothesize that olfactory training is associated with dynamic 
modulation in neural activity in the olfactory and somatosensory networks. A recent 
neuroimaging study by Kollndorfer et al. suggests that olfactory training enhances functional 
connectivity in chemosensory processing networks in anosmic patients. In their case study, seven 
patients with anosmia secondary to upper respiratory tract infections underwent twelve weeks of 
olfactory training followed by post-training fMRI. Although anosmic patients were unable to 

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consciously detect odors, specific seed regions with increased functional connections were 
identified following olfactory training, which included the anterior entorhinal cortex, inferior 
prefrontal gyrus, and the primary somatosensory cortex (Figure 1). 27 These findings suggest that 
olfactory related networks are capable of reorganization with training and that olfactory training 
may be a promising therapeutic treatment for olfactory dysfunction.  
 
  
Fig. 1. Functional connectivity during chemosensory stimulation in anosmic patients before 
(A/B/C) and after the olfactory training (D/E/F), overlaid on an axial template in MNI space (p = 
0.005, uncorrected). The green dot represents the selected ROI (A/D (olfactory network): 
−14,14,2 (caudate nucleus); B/E (integrative network): −34,22,10 (insular cortex); C/F 
somatosensory network: −58,−42,36 (supramarginal gyrus)); the red dots capture the statistically 
significant functionally connected brain areas. 27 
 
A Siemens 3 Tesla PRISMA MRI scanner will be used to capture resting-state blood 
oxygenation level-dependent (BOLD) fc-MRI and structural scans. The rs-fcMRI acquisition 
procedure will take advantage of state-of-the-art sequences (developed originally for the Human 
Connectome Project(HCP) that provide unprecedented spatial and temporal resolution, which 
should increase the sensitivity and power of network-based methods:  use of a 32-channel head 
coil with multiband EPI, 8-fold acceleration (repetition time [TR] = 800 ms, echo time [TE] = 33 
ms, flip angle = 90º, 2 × 2 × 2 mm voxels). Scans take place while participants are awake in the 
scanner performing no task (i.e., eyes open, no music, headphones and earplugs in place). The rs-
fcMRI activity of predefined cortical networks of interest will be measured before the 
intervention and after the completion of the intervention. Preprocessing steps include best 
practices for rs-fcMRI (again primarily developed at Washington University), including motion 

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correction, atlas registration, and temporal filtering. Critically, we will identify time periods of 
high motion and model these out of the analysis to avoid spurious connectivity results. 
 
Methods 
Overview of design: This is a single pre- and post-intervention study. Potential participants will 
be identified from recruiting methods described below.  After an initial screening for inclusion 
and exclusion criteria, potential participants will be scheduled for an in-person assessment. 
Consent will be obtained. The UPSIT and Sniffin Sticks test will then be conducted to determine 
if the participant has a composite score of less than 33/34 (male/female) and/or 30.5, 
respectively, and thus qualifies for the study.  A limited nasal cavity exam will be conducted by a 
licensed physician (the Nasal Exam Form will be completed by the physician) and the rest of the 
battery of smell and taste function tests will be performed.  Phase 1 of the study will consist of 
30-days of budesonide saline nasal irrigation treatment.  All subjects will be provided with the 8-
ounce (240 ml) NeilMed Sinus Rinse Regular Bottle Kit and a one-month supply of USP Grade 
Sodium Chloride & Sodium Bicarbonate Mixture (pH balanced, Isotonic & Preservative & 
Iodine Free) commercially prepared packettes. Subjects may substitute the NeilMed Sinus Rinse 
Regular Bottle Kit for a nasal irrigation system, which in the opinion of the Principal 
Investigator, is similar to the NeilMed system and embodies the low-pressure, high-volume 
concept of nasal irrigation.  Examples of such systems include, but are not limited to, ceramic or 
plastic neti pot or nasal douch (Nasendusche). Subjects will need to purchase distilled water or 
boil tap water for five minutes for use with the saline irrigation. Subjects will be required to 
dissolve the contents of two capsules into the 8-ounce (240 ml) NeilMed Sinus Rinse Regular 
Bottle along with the saline rinse. All subjects will be instructed to irrigate both right and left 
nasal cavity with one-half of the contents of the nasal rinse once daily. After this treatment has 
been completed, participants will return for a follow-up appointment, at which time the same 
battery of smell and taste tests will be performed. We will compare the results of these tests 
before and after 30 days of budesonide.  
 
The primary purpose of budesonide nasal irrigation in our study is to rule out inflammation as a 
reversible cause of olfactory dysfunction. Evaluating otolaryngologists at our institution and in 
the community sometimes prescribe budesonide nasal irrigation to patients with post-viral 
olfactory dysfunction as part of their initial work-up. As a result, if patients are referred to our 
study having already completed budesonide nasal irrigation and have no improvement on smell 
with objective smell testing, we will enroll participants directly into olfactory training. 
 
If the participant scores abnormally on  the Sniffin Sticks or UPSIT test, they will be eligible to 
continue the second phase of the study, the smell training program. Participants who obtain 
normal scores on the UPSIT and Sniffin Sticks at follow-up will be excluded from Phase 2. Prior 
to starting the 12 week smell training program subjects will have a baseline rs-fcMRI.  At the 
conclusion of the 12 week smell training subjects will return for the third and final sitting of the 

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smell and taste function tests and final MRI. During this period, the subjects will continue the 
budesonide nasal irrigation. We will examine: a) whether olfactory training improves conscious 
smell through intervention-based assessments; b) differences in functional networks in patients 
with olfactory dysfunction before and after 12 weeks of olfactory training. 
 
In addition, 20 age- and gender-matched healthy controls with normal smell will also undergo 
baseline rs-fcMRI. Control participants will have their smell assessed using the UPSIT to 
confirm normosmia and will be given a baseline questionnaire regarding overall health and 
smell. Control participants will be compensated $50.00 for the MRI scan. 
 
Study subjects: Subjects include adults age 18-70 with post-infectious smell loss only. Age (+/- 
5 yrs) - and gender-matched healthy controls with normal smell will also be recruited. 
 
Sampling criteria: Inclusion criteria are adults age 18-70 with anosmia or hyposmia, or 
normosmia. Exclusion criteria are inability to speak/understand English, current smoking or 
history of smoking within the past 6 months, nasal polyps, phantosmia, exposure to head and/or 
neck radiation, exposure to chemotherapy, neurologic disorder, magnetic implantation devices 
(e.g. pacemaker, cochlear implant) that would preclude the use of MRI, pregnancy, prior smell 
training, and current cold or rhinitis.  
 
Plans for recruitment: We will recruit subjects using a variety of means. Patients scheduled in 
the Barnes-Jewish ENT clinic with complaints of trouble smelling will be introduced to the study 
during their clinic appointment and, if they meet the criteria, consented to participate. 
Advertisements will be posted in Barnes-Jewish ENT clinic for patients with complaints of 
anosmia/hyposmia to enroll in the study as well, if they meet the criteria above.  The ads will 
briefly describe the concept of the study. Lastly, we will recruit subjects from the Washington 
University Volunteers for Health Research Participant Registry and the Otolaryngology Research 
Participant Registry via telephone by using a uniform script delivered by a trained researcher.  
 
Measurements 
Main predictor variables include baseline olfactory and gustatory identification and intensity 
perception. Baseline olfactory ability will be determined by the subjects’ performance on the 
UPSIT and Sniffin Sticks; Baseline gustatory identification will be determined by subjects’ 
performance of detecting the correct flavor during the NIH Taste Intensity Test; gustatory 
intensity will be determined by their ratings on the gLMS; PROP taster status will be determined 
by their rating on the gLMS. 
 
Main outcome variables include the objective pre- and post-intervention differences within and 
between subject performance on the UPSIT and Sniffin Sticks tests before and after budesonide 
(Phase 1) and within and between changes in network connectivity between the olfactory and 

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somatosensory network post smell intervention training (Phase 2). We will also evaluate a 
subjective response by having subjects complete an intervention-specific Clinical Global 
Impression form after each intervention. To determine subjects eligible for phase 2 of the study, 
we will only select subjects with scores that fall below normal on either the UPSIT or Sniffin 
Sticks tests. For the UPSIT, subject scores will be compared to a rubric containing normal age- 
and gender-based scores. For the Sniffin Sticks, patients whose composite score remains below 
the normal cutoff of 30.5 will be eligible for Phase 2. Upon completion of the smell training 
program, subjects will once again complete the UPSIT, Sniffin Sticks, NIH Taste Intensity and 
PROP Taster tests. We will use results on the UPSIT, Sniffin Sticks, Clinical Global impression 
form and Questionnaire for Olfactory Dysfunctionto gather information on the objective and 
subjective differences in smell before and after smell training.  
 
Materials  
Olfaction: UPSIT: 4 different 10-page booklets, with a total of 40 items. On each page, 
there is a different “scratch and sniff” strip and four choice options. Sniffin Sticks: A triplicate 
set of 16 felt-tip pens filled with liquid odorants or odorants dissolved in propylene glycol at 
different concentrations. We will use a blindfold and cloth gloves to protect against the 
incidental detection of external olfactory stimuli.  
Gustation: NIH Taste Intensity Test solutions: 1.0 M sucrose (sweet), 1.0 M NaCl 
(salty),10 and 0.001M Quinine hydrochloride (bitter)5. PROP Taster Test: 0.320 mM Prop and 0.1 
M NaCl.  Stimuli will be prepared in the metabolic kitchen of the Clinical Research Unit at 
Washington University School of Medicine. 
 
Approach to statistical analyses: We will use standard descriptive statistics to describe the 
study population and distribution of pre- and post-intervention test scores on the UPSIT and 
Sniffin Sticks, for both Phase 1 (Specific Aim 1) and Phase 2 (Specific Aim 2). Paired-sample t-
tests or its non-parametric equivalent, the Wilcoxon signed rank test, will be used to compare 
pre- and post-intervention changes. Effect size and 95% confidence interval will be calculated 
and reported. The impact of any potential confounders will be explored through mixed model 
analysis. 
 
Our primary analyses of the resting state will be network-based approaches that quantify 
properties of network organization based on nodes (brain regions) and the connections between 
them (identified by correlations in their time series). To define the nodes, we will use a recently-
developed multimodal atlas of human cerebral cortex produced for the HCP20, the most current 
parcellations of brain areas based on a large number of participants’ resting state data. Having 
extracted time series data from each brain region, we will then capitalize on recent applications 
of graph theoretic approaches to identifying and characterizing network connectivity.21 To 
analyze the functional networks in terms of their integration and segregation, four graph 

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measures will be computed: global efficiency, network modularity, characteristic path length, 
and clustering coefficient. 22,23  
 
Our primary focus will be on the integration of the olfactory and somatosensory networks, which 
is most strongly reflected in the global efficiency measure (intuitively, an integrated network will 
have a higher number of short paths between nodes; the other measures will be used to provide 
convergent support). 24 We will also conduct exploratory analyses using these measures on 
whole-brain functional connectivity maps, to detect more general network effects we may have 
missed.  
 
To supplement these graph theoretic analyses, we will also conduct more conventional seed-
based analyses as we have done in our prior work, placing seeds in included the anterior 
entorhinal cortex, inferior prefrontal gyrus, and the primary somatosensory cortex regions to 
produce whole-brain voxelwise functional connectivity maps. Doing so helps foster continuity in 
our research program and comparison of our new results to prior published work. 20-24 
 
A strength of our network analysis of the rs-fcMRI data is that we are able to numerically 
quantify network properties (e.g., global efficiency) in a way that can be easily combined with 
our behavioral and clinical data. We will include our measures of neural network processing in 
the statistical models described above in order to see whether degree of clinical improvement is 
related to changes in neural network processing. 
 
We predict that both olfactory training will be associated with increased integration between the 
olfactory and somatosensory networks, and that the degree of improved integration will correlate 
with clinical outcomes. We will also investigate changes in cortical connectivity by comparing 
integration changes within subjects, and whether certain signatures of network organization 
before intervention predicts whether olfactory training will be effective.  
 
In secondary analyses, we plan to explore the relationship between our two main networks of 
interest and the anterior entorhinal cortex, inferior prefrontal gyrus, and the primary 
somatosensory cortex region networks. Each of these additional networks has been hypothesized 
to contribute to olfaction, and by broadening our network analyses we hope to increase our 
understanding of the large-scale brain changes associated with anosmia/hyposmia.  
 
Hypotheses, sample size and power: Our hypothesis is if individuals with persistent complaints 
of anosmia or hyposmia, who fit our inclusion and exclusion criteria, are given a 30-day 
treatment of budesonide nasal saline irrigation, then they will demonstrate an improvement in 
their sense of smell and thus, perception of taste and flavor. We also predict that those who do 
not experience improvement with the budesonide treatment will experience improvement after 
the smell training intervention program.  

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Sample size: As this is a pilot study and there is no previous research to guide our sample 
size calculation, we derived our planned sample size of 125 subjects as follows:  
For the imaging portion of the study, we would like to have 20 participants with post-
viral olfactory dysfunction and 20 age- and gender-matched healthy controls with normal smell. 
In this way, we should have a minimum number of subjects for neuroimaging and behavioral 
analyses to obtain more robust sample size estimates for future definitive studies.  Studies using 
12 weeks of OT in patient populations similar to ours report improvement in 30% to 85% of the 
subjects undergoing training. 12, 21, 26 Therefore, in order to obtain 20 subjects who do not 
experience improvement, we will need to have 96 subjects complete budesonide therapy. 
Assuming a 20% drop-out rate, we will need to enroll 120 subjects. As this is a pilot study, we 
will use the data herein to power our next study.  Stopping rule: If after treating with budesonide 
and assessing the first 25 subjects, we observe 100% improvement of smelling and identify no 
need for smell training, we will stop the study and report the results. 
 
Limitations and issues: Possible experimental issues include subject compliance in returning 
for retesting; subject ability to successfully use the gLMS scale after training; proper use of 
budesonide nasal irrigation; possible interference between samples during smell and taste battery 
testing; and compliance in performing the daily smell training intervention.  Inability to use nasal 
irrigation seems unlikely, as Dr. Piccirillo has treated hundreds of patients with budesonide nasal 
saline irrigation and has experienced few patients who have difficulty. 
 
Ethical considerations: Each of the tests (UPSIT, Sniffin Sticks, NIH Taste Intensity Test, 
PROP Taster Test) and the smell training intervention have been safely administered in previous 
studies. They are all non-invasive and pose no harm to the subjects. The budesonide nasal 
irrigation has been previously used in another study without harm to human subjects. Each test is 
commercially available and there are no financial conflicts of interest.  Limited identifying 
information will be collected to protect patient confidentiality. 
 
References 
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2       Doty, R. L., Frye, R. E. & Agrawal, U. Internal consistency reliability of the fractionated 
and whole University of Pennsylvania Smell Identification Test. Percept Psychophys 45, 381-384 
(1989). 
3       Hummel, T., Sekinger, B., Wolf, S. R., Pauli, E. & Kobal, G. 'Sniffin' sticks': olfactory 
performance assessed by the combined testing of odor identification, odor discrimination and 
olfactory threshold. Chem Senses 22, 39-52 (1997). 
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