The Effect of Odors on Asthma Symptoms
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Therapeutic Suggestion, Asthmogenic Suggestion, Phenylethyl Alcohol odor.
- Who it may be relevant to
- Registry conditions: Asthma. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Belgium
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
The Effect of Suggestion of Harmful/Beneficial Effects of Odors on Asthma Symptoms
Overview
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
Detailed description
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.
Interventions
- Behavioral Therapeutic Suggestion
suggestions about potential beneficial effects of the odor are given - Behavioral Asthmogenic Suggestion
suggestions about potential negative effects of the odor are given - Other Phenylethyl Alcohol odor
Over the course of 15 minutes, participants, receive 15 short sniffs of Phenylethyl Alcohol odor
Primary outcome measures
- Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction [Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction]
Secondary outcome measures (7)
- asthma symptoms [Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction]
- Forced Expiratory Volume at one second (FEV1) [Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction]
- Worry [Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction]
- Cortisol [Time frame: 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) [Time frame: change from baseline to 24 hours after odor induction]
- Change in Respiratory rate [Time frame: change from baseline to 15 min odor presentation]
- change in Fraction of end-tidal carbon dioxide (FetCO2) [Time frame: change from baseline to 15 min odor presentation]
Eligibility criteria
Inclusion criteria
- A physician diagnosis of asthma
Exclusion criteria
- FEV1 lower than 60% predicted
- clinical condition other than asthma
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
Belgium · 1 center
- UZ Leuven — Leuven
Identifiers
NCT: NCT02624362 · S57940