The purpose of this research study is to examine the efficacy of a 12-week smell training intervention for participants with olfactory dysfunction following an infection of the upper respiratory tract.
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. This study aims to study the efficacy of smell training for patients with olfactory dysfunction following a viral upper respiratory tract infection. Eligible participants will complete a 30-day course of budesonide nasal saline irrigation. Participants who do not show improvement in their olfaction based on composite smell and taste tests will be eligible to receive a baseline resting-state fMRI (rs-fMRI) and complete a 12-week smell training intervention program. Smell training involves participants smelling 4 odors (phenyl ethyl alcohol, eucalyptus, lemon, and eugenol) twice a day for 12 weeks. Following completion of smell training, participants will undergo repeat smell and taste tests as well as rs-fMRI to ascertain the efficacy of smell training.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
51
Participants will be provided with 4 vials of essential odors. Participants will sniff each scent for 20-30 seconds, twice daily, for 12 weeks. The participant will take 30 seconds of rest between each scent. All participants will undergo this smell training regimen for 12 weeks.
Washington University
St Louis, Missouri, United States
Pre- and Post-intervention Difference in Functional Connectivity Before and After Smell Training.
Baseline and post-intervention connectivity within and between regions of interest in the olfactory and olfactory related networks using resting state fMRI will be obtained. Resting-state connectivity was analyzed using the CONN toolbox version 18b (https://web.conn-toolbox.org/) and SPM12, version 7487 (Wellcome Trust Centre for Neuroimaging). Functional connectivity values (Fisher z-transformed Pearson correlation coefficients) were compared using a paired, 2-tailed t test and corrected for multiple comparisons. p\<0.05 was considered to be significant.
Time frame: 12 weeks
Pre- and Post-intervention Difference in Smell Testing Before and After Budesonide Treatment
Objective pre- and post-intervention differences of participant performance on the UPSIT and Sniffin Sticks tests before and after budesonide saline nasal irrigation. University of Pennsylvania Identification Test (UPSIT) consists of 4 odor-impregnated booklets that participants scratch and sniff to identify various odors, and scores account for differences in sex. Hyposmia is defined as a score of 19 to 34 for females and 19 to 33 for males. Anosmia for either sex is defined as a score below 18. Possible scores range from 0 to 40 with higher scores indicating better sense of smell. Sniffin' Sticks are odor-encapsulated markers that are used to measure odor detection threshold, discrimination, and identification (TDI). Normosmia is defined as a TDI score \>30.5. An increase by 5.5 points or more from baseline is considered meaningful improvement. Possible scores range from 1 to 48 with higher values indicating better sense of smell.
Time frame: 30 days
Subjective Response to Smell Training Intervention
Participants subjective sense of smell following intervention is measured using a visual analogue scale from 0 to 100 with 0 representing no sense of smell and 100 representing best possible sense of smell.
Time frame: 12 weeks
Comparison of Olfactory Network in Healthy Controls to Study Participants
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Baseline functional connectivity within and between the olfactory and associated networks of healthy controls will be compared to that of study participants prior to smell intervention treatment as measured by rs-fMRI.Resting-state connectivity was analyzed using the CONN toolbox version 18b (https://web.conn-toolbox.org/) and SPM12, version 7487 (Wellcome Trust Centre for Neuroimaging). Functional connectivity values (Fisher z-transformed Pearson correlation coefficients) were compared using a paired, 2-tailed t test and corrected for multiple comparisons . P \< .05 was considered statistically significant.
Time frame: 1 week
Pre- and Post-intervention Difference in Smell Testing Before and After Smell Training
Objective pre- and post-intervention differences of participant performance on the UPSIT and Sniffin Sticks tests before and after budesonide saline nasal irrigation. University of Pennsylvania Identification Test (UPSIT) consists of 4 odor-impregnated booklets that participants scratch and sniff to identify various odors, and scores account for differences in sex. Hyposmia is defined as a score of 19 to 34 for females and 19 to 33 for males. Anosmia for either sex is defined as a score below 18. Possible scores range from 0 to 40 with higher scores representing better sense of smell. Sniffin' Sticks are odor-encapsulated markers that are used to measure odor detection threshold, discrimination, and identification (TDI). Normosmia is defined as a TDI score \>30.5. An increase by 5.5 points or more from baseline is considered meaningful improvement. Possible scores range from 1 to 48 with higher values indicating better sense of smell.
Time frame: 12 weeks
Pre and Post Difference in QOD-NS After Smell Training
The QOD-NS is a validated 17-item questionnaire that pertains to olfactory-specific quality of life domains adversely impacted by olfactory dysfunction and is inversely scored (maximum score of 51), with higher scores reflective of more impaired quality of life.
Time frame: 12 weeks