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| Name | Class |
|---|---|
| KU Leuven | OTHER |
| Research Foundation Flanders | OTHER |
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An extended replication of Jaen & Dalton (2014), the investigators aim to investigate the role of odors and associated trigger beliefs on symptom perception and airway inflammation in individuals with asthma
Participants with asthma are randomly assigned to a 15-min (phenylethyl alcohol) odor inhalation, accompanied by either an asthmogenic suggestion (nocebo), or a therapeutic suggestion (placebo). Airway inflammation, lung function, and asthma symptoms are measured in response to the odor/suggestion, up to 24 hours after odor inhalation. The investigators are also measuring worry and heart rate variability as potential mediators of the response.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Odor+ Positive belief | Experimental | Participants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor improves asthma symptoms (therapeutic suggestion) |
|
| Odor + Negative belief | Experimental | Participants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor worsens asthma symptoms (asthmogenic suggestion) |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Therapeutic Suggestion | Behavioral | suggestions about potential beneficial effects of the odor are given |
|
| Measure | Description | Time Frame |
|---|---|---|
| Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction | Fraction of exhaled nitric oxide | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction |
| Measure | Description | Time Frame |
|---|---|---|
| asthma symptoms | measured using the Asthma Symptom Checklist | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction |
| Forced Expiratory Volume at one second (FEV1) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Thomas Janssens, PhD | KU Leuven | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| UZ Leuven | Leuven | 3000 | Belgium |
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| ID | Term |
|---|---|
| D001249 | Asthma |
| D007249 | Inflammation |
| ID | Term |
|---|---|
| D001982 | Bronchial Diseases |
| D012140 | Respiratory Tract Diseases |
| D008173 | Lung Diseases, Obstructive |
| D008171 | Lung Diseases |
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| ID | Term |
|---|---|
| D013404 | Suggestion |
| D000431 | Ethanol |
| D009812 | Odorants |
| ID | Term |
|---|---|
| D006990 | Hypnosis |
| D026441 | Mind-Body Therapies |
| D000529 | Complementary Therapies |
| D013812 | Therapeutics |
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| Asthmogenic Suggestion | Behavioral | suggestions about potential negative effects of the odor are given |
|
|
| Phenylethyl Alcohol odor | Other | Over the course of 15 minutes, participants, receive 15 short sniffs of Phenylethyl Alcohol odor |
|
Measured using Jaeger Masterscreen Spirometer, according to ERS-ATS guidelines
| baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction |
| Worry | measured using worry Visual Analog Scales | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction |
| Cortisol | cortisol awakening response (AUC), and changes in cortisol (AUC) will be measured using saliva sampling | baseline, immediately after odor induction, 2 hours after odor induction, at awakening, 30 min after awakening, 24 hours after odor induction |
| Change in Heart rate and Heart Rate Variability (HRV) | 24 hour heart rate data will be recorded using an ambulatory ECG monitor, and analyzed in 1 hour epochs, extracting mean of successive differences (MSD) as a variable of interest. | change from baseline to 24 hours after odor induction |
| Change in Respiratory rate | respiratory rate (breaths/min) is recorded continuously, and changes between baseline and odor presentation periods will be analysed | change from baseline to 15 min odor presentation |
| change in Fraction of end-tidal carbon dioxide (FetCO2) | FetCO2 (plateau %CO2 in exhaled air) is recorded continuously, and changes between baseline and odor presentation periods will be analysed | change from baseline to 15 min odor presentation |
| D012130 |
| Respiratory Hypersensitivity |
| D006969 | Hypersensitivity, Immediate |
| D006967 | Hypersensitivity |
| D007154 | Immune System Diseases |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D011613 |
| Psychotherapy |
| D004191 | Behavioral Disciplines and Activities |
| D000438 | Alcohols |
| D009930 | Organic Chemicals |
| D004777 | Environment |
| D055669 | Ecological and Environmental Phenomena |
| D001686 | Biological Phenomena |
| D004778 | Environment and Public Health |