Perceptual Olfactory BiasPRSNCT02845700
Perceptual Retraining to Reduce Suicide Risk
A study testing Perceptual Retraining Treatment in people with Perceptual Olfactory Bias, run by Florida State University at 2 sites in United States.
Trial summary
The study will use a prospective design consisting of three phases. The phases are: 1. the development of the perceptual retraining treatment (PRT), 2. the evaluation of the treatment's feasibility and acceptability, and 3. an assessment of its efficacy. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Perceptual Olfactory Bias
- What is being tested?
- Perceptual Retraining Treatment
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 13 participants
- Where
- 2 sitesUnited States
- Study dates
- Sep 2015to Sep 2016
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- evidence of olfactory perceptual bias toward military-relevant stimuli (e.g., burning rubber, decay, fuel).
- military combat exposure in Operation Iraqi Freedom, Enduring Freedom, or New Dawn.
- Age 18-60.
Who cannot join
- Significant medical illness that compromises olfactory perception or tolerance (e.g., significant olfactory disease or dysfunction, cardiovascular disease, respiratory disorders, renal disease, epilepsy, stroke, and uncontrolled hypertension or migraines).
- Evidence of imminent suicidal intent
- Evidence of current or past psychotic-spectrum disorders, or uncontrolled bipolar disorder.
- English speakers.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Southeast Louisiana Veterans Health Care System
New Orleans, Louisiana, 70112
Florida State University
Tallahassee, Florida, 32306
About this study
The study will use a prospective design consisting of three phases. The phases are:
- the development of the perceptual retraining treatment (PRT),
- the evaluation of the treatment's feasibility and acceptability, and
- an assessment of its efficacy.
During the third phase, a pilot study will be conducted in which participants will be randomly assigned to either PRT or a waitlist control group in order to assess efficacy. Diagnostic information and eligibility criteria will be assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual (DSM) 4th ed. (SCID) and the Clinician Administered PTSD Scale for DSM-5 (CAPS-5).
Read the detailed description
This study will use clinical interviews, self-report measures, and behavioral assessments to evaluate the efficacy of the PRT protocol. The study will recruit approximately 30 veterans. The primary inclusionary criterion will be that participants must show some evidence of olfactory perceptual bias toward military-relevant stimuli (e.g., burning rubber, decay, fuel). Investigators are not requiring current suicidal ideation as an entry criterion because investigators believe that a fair percentage of veterans will have some suicidal ideation/intent but making this an entry requirement will limit the investigators ability to recruit given the tight timeline for the study.
The study will consist of the development and evaluation of a novel intervention. The essential feature of this intervention is the use of a gradient of triggering smells (e.g., burning rubber, decay, fuel, etc.), to which participants will be systematically exposed in an effort to facilitate habituation to these odors. The PRT protocol will be administered over two 1-hour sessions. Participants will return 1 month after their final PRT protocol session to complete a battery of follow-up measures, as well as the CAPS-5.
The primary outcome measures of interest are: olfactory perceptual bias (as measured by the olfactory bias assessment), suicidal ideation and behaviors (as measured by the Beck Suicide Scale and Depressive Symptom Inventory- Suicidality Subscale), and symptoms related to suicide, such as anxiety and trauma (as measured by the Beck Anxiety Inventory and PTSD Checklist for DSM-5, respectively).
- Conditions
- Perceptual Olfactory Bias
- Being tested
- Perceptual Retraining Treatment, Sham Neutral training
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Perceptual Retraining TreatmentBehavioural
Perceptual retraining involves the systematic presentation of diluted malodors (i.e., odors perceived as threatening). For each individual, vials on either side of a pre-determined and ideographic detection threshold will be presented. During the retraining, participants will be given feedback to shift their bias away from the malodorous target stimuli. For example, in the context of diluted solutions participants will be given the feedback that they are "correct" when a "neutral" response is given to solutions that are above the starting threshold (stronger malodor) and "incorrect" when a target is endorsed that is below the starting threshold (weaker malodor).
Sham Neutral trainingBehavioural
Control condition using systematic presentation of diluted neutral-neutral odor pairs.
| Study group | Role | What they receive |
|---|---|---|
| Perceptual Retraining Treatment (PRT) | Active comparator | The Perceptual Retraining Treatment will involve systematic presentation of diluted malodors. For each individual, vials on either side of their initial ideographic detection threshold will be presented. During the retraining, participants will be given feedback to shift their bias away from the malodorous target stimuli. For example, in the context of diluted solutions participants will be given the feedback that they are "correct" when a "neutral" response is given to solutions that are above the starting threshold (stronger malodor) and "incorrect" when a target is endorsed that is below the starting threshold (weaker malodor). Each training session will consist of 4 training blocks. Receives: Behavioral: Perceptual Retraining Treatment |
| Sham Neutral Training (SNT) | Placebo comparator | Approximately half of the participants will be randomized to the SNT condition designed to control for the effects of time and learning. In the SNT condition, participants will complete the same assessments (including the olfactory bias assessment), as well as a sham training consisting of neutral/neutral odor pairing dilutions, rather than the combat/neutral odor pairings as in the PRT. Following the one-month assessment, they will be given the option to complete the PRT. Receives: Behavioral: Sham Neutral training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percent Change in Olfactory Perceptual Bias
A participant's ability to detect an array of threatening malodor in neutral dilution gradients will be tested at baseline and after the second and final intervention session (one week after baseline). Perceptual bias is calculated as the percentage of correct responses (i.e., yes or no to detecting the malodor) on an odor over 6 trials for each of the 8 odors, at 25% and 33% dilution (i.e., over 96 trials). Larger positive percentages indicate greater habituation to the malodor, and therefore a training effect toward reducing threat bias (i.e., a positive effect on intervention outcomes).
Measured: Baseline, Week 1
Secondary outcomes (4)
Change From Baseline in Mean Clinician Administered PTSD Scale for DSM-5 (CAPS-5) at 1 Month
The Clinician Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 (CAPS-5) was administered at the baseline appointment and 1-month follow-up appointment to assess PTSD symptom severity. All 20 of the CAPS-5 items are scored 0-4 and summed to calculate a total score, which ranges from 0-80. Higher scores indicate greater PTSD symptom severity. A difference score was calculated by subtracting the CAPS-5 score at 1-month from baseline, and averaged across each condition; thus, higher (positive) change scores are indicative of increases in PTSD symptom severity, whereas lower (negative) change scores are indicative of decreases in PTSD symptom severity.
Measured: Baseline, month 1
Change in Suicidal Ideation Assessed Using the Depressive Symptom Inventory - Suicidality Subscale
The Depressive Symptom Inventory - Suicidality Subscale (DSI-SS) was administered at the baseline appointment and 1 month follow-up appointment to assess the severity of thoughts related suicidal ideation. All four items of the DSI-SS are scored on a 0-3 scale, with total possible sum scores ranging from 0-12; higher scores indicate greater severity of suicidal ideation. For the outcome measure reported, a difference score was calculated by subtracting DSI-SS scores at 1 month from DSI-SS scores at baseline, and averaged across conditions. DSI-SS change scores of zero reflect no change from baseline to 1 month.
Measured: Baseline, month 1
Change in Beck Suicide Scale Scores From Baseline to 1 Month
The Beck Suicide Scale (BSS) was administered at the baseline appointment and 1-month follow-up appointment to assess thoughts and behaviors related to suicidal ideation, desire, and attempts. The BSS comprises 21 items rated on a 0-3 scale. The first 19 items are sum scored with total possible scores ranging from 0 - 38, with higher scores indicating greater severity of suicide risk. A difference scores was calculated by subtracting the BSS score at 1 month from BSS scores at baseline. Mean change scores of 0 reflect no change in BSS scores from baseline to 1 month.
Measured: Baseline, month 1
Change in the Beck Anxiety Inventory-II From Baseline to 1 Month
The Beck Anxiety Inventory-II (BAI) was administered at the baseline appointment and 1-month follow-up appointment to assess symptom severity associated with anxious arousal. The BAI comprises 21 items rated on a 0-3 scale, which can be sum scored to calculate total scores ranging from 0 - 63. Higher scores on the BAI are indicative of greater anxious arousal. A difference scores was calculated by subtracting the BAI score at 1 month from BAI scores at baseline; thus, higher (positive) change scores are indicative of increases in anxious arousal, whereas lower (negative) change scores are indicative of decreases in anxious arousal.
Measured: Baseline, month 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Jul 2016 (estimated)
- Study startSep 2015
- Primary completionSep 2016
- Study completionSep 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Perceptual Olfactory BiasStudies of the same condition, open and under way.
- More trials run by Florida State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 13 participants (actual)
Sponsor and investigators
- Lead sponsor
- Florida State University
- Sponsor type
- University, hospital or other
- Collaborators
- United States Department of Defense, Southeast Louisiana Veterans Health Care System
- Responsible party
- Principal investigator, Wen Li, Florida State University
- Investigators
- Wen Li, PhD, Principal investigator, Florida State UniversityLaurel Franklin, PhD, Principal investigator, Southeastern Louisiana Veterans Health Care System
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02845700
- Sponsor's protocol ID
- A-16054.13a
- Acronym
- PRS
- Status last verified
- Aug 2017
- First submitted
- 6 Jul 2016
- Last updated
- 14 Jan 2019
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Jan 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Perceptual Retraining to Reduce Suicide Risk
- ClinicalTrials.gov ID
- NCT02845700
- Acronym / sponsor ID
- PRS / A-16054.13a
- Conditions
- Perceptual Olfactory Bias
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 13 participants (actual)
- Lead sponsor
- Florida State UniversityUniversity, hospital or other
- Collaborators
- United States Department of Defense, Southeast Louisiana Veterans Health Care System
- Study start
- Sep 2015
- Primary completion
- Sep 2016 (actual)
- Study completion
- Sep 2016 (actual)
- First posted
- 27 Jul 2016 (estimated)
- Results
- Posted 14 Jan 2019
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study will use a prospective design consisting of three phases. The phases are:
- the development of the perceptual retraining treatment (PRT),
- the evaluation of the treatment's feasibility and acceptability, and
- an assessment of its efficacy.
During the third phase, a pilot study will be conducted in which participants will be randomly assigned to either PRT or a waitlist control group in order to assess efficacy. Diagnostic information and eligibility criteria will be assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual (DSM) 4th ed. (SCID) and the Clinician Administered PTSD Scale for DSM-5 (CAPS-5).
Detailed description
This study will use clinical interviews, self-report measures, and behavioral assessments to evaluate the efficacy of the PRT protocol. The study will recruit approximately 30 veterans. The primary inclusionary criterion will be that participants must show some evidence of olfactory perceptual bias toward military-relevant stimuli (e.g., burning rubber, decay, fuel). Investigators are not requiring current suicidal ideation as an entry criterion because investigators believe that a fair percentage of veterans will have some suicidal ideation/intent but making this an entry requirement will limit the investigators ability to recruit given the tight timeline for the study.
The study will consist of the development and evaluation of a novel intervention. The essential feature of this intervention is the use of a gradient of triggering smells (e.g., burning rubber, decay, fuel, etc.), to which participants will be systematically exposed in an effort to facilitate habituation to these odors. The PRT protocol will be administered over two 1-hour sessions. Participants will return 1 month after their final PRT protocol session to complete a battery of follow-up measures, as well as the CAPS-5.
The primary outcome measures of interest are: olfactory perceptual bias (as measured by the olfactory bias assessment), suicidal ideation and behaviors (as measured by the Beck Suicide Scale and Depressive Symptom Inventory- Suicidality Subscale), and symptoms related to suicide, such as anxiety and trauma (as measured by the Beck Anxiety Inventory and PTSD Checklist for DSM-5, respectively).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Perceptual Retraining Treatment (PRT) | Active comparator | Behavioral: Perceptual Retraining TreatmentThe Perceptual Retraining Treatment will involve systematic presentation of diluted malodors. For each individual, vials on either side of their initial ideographic detection threshold will be presented. During the retraining, participants will be given feedback to shift their bias away from the malodorous target stimuli. For example, in the context of diluted solutions participants will be given the feedback that they are "correct" when a "neutral" response is given to solutions that are above the starting threshold (stronger malodor) and "incorrect" when a target is endorsed that is below the starting threshold (weaker malodor). Each training session will consist of 4 training blocks. |
| Sham Neutral Training (SNT) | Placebo comparator | Behavioral: Sham Neutral trainingApproximately half of the participants will be randomized to the SNT condition designed to control for the effects of time and learning. In the SNT condition, participants will complete the same assessments (including the olfactory bias assessment), as well as a sham training consisting of neutral/neutral odor pairing dilutions, rather than the combat/neutral odor pairings as in the PRT. Following the one-month assessment, they will be given the option to complete the PRT. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- evidence of olfactory perceptual bias toward military-relevant stimuli (e.g., burning rubber, decay, fuel).
- military combat exposure in Operation Iraqi Freedom, Enduring Freedom, or New Dawn.
- Age 18-60.
Key exclusion criteria (4 listed)
- Significant medical illness that compromises olfactory perception or tolerance (e.g., significant olfactory disease or dysfunction, cardiovascular disease, respiratory disorders, renal disease, epilepsy, stroke, and uncontrolled hypertension or migraines).
- Evidence of imminent suicidal intent
- Evidence of current or past psychotic-spectrum disorders, or uncontrolled bipolar disorder.
- English speakers.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Perceptual Retraining TreatmentPerceptual retraining involves the systematic presentation of diluted malodors (i.e., odors perceived as threatening). For each individual, vials on either side of a pre-determined and ideographic detection threshold will be presented. During the retraining, participants will be given feedback to shift their bias away from the malodorous target stimuli. For example, in the context of diluted solutions participants will be given the feedback that they are "correct" when a "neutral" response is given to solutions that are above the starting threshold (stronger malodor) and "incorrect" when a target is endorsed that is below the starting threshold (weaker malodor). | Behavioural | Perceptual Retraining Treatment (PRT) |
| Sham Neutral trainingControl condition using systematic presentation of diluted neutral-neutral odor pairs. | Behavioural | Sham Neutral Training (SNT) |
Primary outcome
Percent Change in Olfactory Perceptual Bias
Time frame: Baseline, Week 1
A participant's ability to detect an array of threatening malodor in neutral dilution gradients will be tested at baseline and after the second and final intervention session (one week after baseline). Perceptual bias is calculated as the percentage of correct responses (i.e., yes or no to detecting the malodor) on an odor over 6 trials for each of the 8 odors, at 25% and 33% dilution (i.e., over 96 trials). Larger positive percentages indicate greater habituation to the malodor, and therefore a training effect toward reducing threat bias (i.e., a positive effect on intervention outcomes).
4 secondary outcomes
Change From Baseline in Mean Clinician Administered PTSD Scale for DSM-5 (CAPS-5) at 1 Month
Time frame: Baseline, month 1
Change in Suicidal Ideation Assessed Using the Depressive Symptom Inventory - Suicidality Subscale
Time frame: Baseline, month 1
Change in Beck Suicide Scale Scores From Baseline to 1 Month
Time frame: Baseline, month 1
Change in the Beck Anxiety Inventory-II From Baseline to 1 Month
Time frame: Baseline, month 1
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jan 2019.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Wen Li, PhD principal investigator
Florida State University
Laurel Franklin, PhD principal investigator
Southeastern Louisiana Veterans Health Care System
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Perceptual Retraining Treatment in people with Perceptual Olfactory Bias, run by Florida State University at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 14 Jan 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 14 Jan 2019). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percent Change in Olfactory Perceptual Bias (time frame: Baseline, Week 1). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Jan 2019.