Dexamphetamine effects on the perceptions of visual, auditory, tactile and multimodal illusions in healthy volunteers

• Register: ANZCTR
• Last refreshed on: 13 January 2020
• Main ID: ACTRN12615000619549
• Date of registration: 15/06/2015
• Prospective Registration: Yes
• Primary sponsor: Mathew Martin-Iverson
• Public title: Dexamphetamine effects on the perceptions of visual, auditory, tactile and multimodal illusions in healthy volunteers
• Scientific title: Dexamphetamine effects on healthy volunteers in a cross-over design on the perceptions of visually, auditory, tactile and multimodal illusions
• Date of first enrolment: 27/07/2015
• Target sample size: 72
• Recruitment status: Completed
• URL: https://anzctr.org.au/ACTRN12615000619549.aspx
• Study type: Interventional
• Study design: Purpose: Treatment; Allocation: Non-randomised trial; Masking: Blinded (masking used);Assignment: Crossover;Type of endpoint: Efficacy;
• Phase: Not Applicable

Countries of recruitment

Australia

Contacts

• Name: Prof Mathew Martin-Iverson

• Name: Prof Mathew Martin-Iverson

Key inclusion & exclusion criteria

Inclusion criteria: Healthy people >17 and <60 years of age
Exclusion criteria: 1. Heart or severe blood vessel disease,
2. High blood pressure (> 180/90 mm Hg),
3. Glaucoma,
4. Hyperthyroidism (overactive thyroid),
5. Tics (muscle twitching usually in the face or shoulders),
6. Sensitivity to dexamphetamine or sympathomimetic amines,
7. Any degenerative disease of the nervous system,
8. Epilepsy, or other neurological disorder, including head injury.
9. Tourette's syndrome or a family history of this disorder,
10. A psychiatric or psychological problem for which they are receiving treatment (schizophrenia, depression, anxiety, etc),
11. A serious medical problem for which they are receiving treatment (cardiovascular disorders, respiratory disorders, etc),
12. Had or are currently receiving treatment for substance abuse,
13. A family history of schizophrenia in first-degree relatives (parents, children or siblings),
14. Previously experienced hypersensitivity to dexamphet-amine,
15. Used any drug including alcohol or any illicit drug within 24 hours of each testing session,
16. Used caffeine on the day of each testing session,
17. Current prescription medication that you are taking other than contraceptives or acne medication
18. Used over-the-counter medication in the 48 hours before each testing session


Age minimum: 18 Years
Age maximum: 59 Years
Gender: Both males and females

Health Condition(s) or Problem(s) studied

Mental Health - Schizophrenia

This is a dexamphetamine challenge study in healthy volunteers as a model for studying dopaminergic mechanisms in psychoses;
This is a dexamphetamine challenge study in healthy volunteers as a model for studying dopaminergic mechanisms in psychoses

Intervention(s)

dexamphetamine (0.45 mg/kg, by mouth with gelatine capsules) once only, and placebo: gelatine capsules filled with glucose. The two treatments are given about a week apart (minimum 5 days). Dexamphetamine levels determined from five saliva samples taken throughout the day, at about 70 min intervals.

Primary Outcome(s)

Visual Flash illusions. The experience of illusions related to the number of light flashes observed in the presence of additional light flashes or brief sounds will be measured by recording the number of flashes that the participant says that they see, along with a record from the participant pressing a number key on a computer keyboard or joystick representing the number of flashes observed.
[This will be measured on both days of testing (placebo and dexamphetamine days) for about 15 minutes 60 minutes after consuming the capsules and again for 25 minutes 125 minutes after consuming the capsules.]

Tactile funnelling illusion. This illusion is produced by touching a person's arm at points with callipers, while the arm is obscured from vision with a barrier. It is measured by recording the number points felt, and by the participant pointing to where they felt the touch with their hand.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 15 minutes 225 minutes.]

Phantom Word Illusion. Participants' experience of hear words will be measured while listening to sounds through stereo headphones and repeating any words heard. The number of different words heard and the time from the beginning of the sounds to when the words are heard will be measured by recording the words spoken by the participants, as well as by measuring joystick presses each time a different word is heard.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 10 minutes 80 minutes after consuming the capsules.]

Secondary Outcome(s)

This is a primary outcome.
McGurk effect. This illusion is produced by watching a video of a person's face while that person makes the sound of a syllable. At the same time, the participant listens to syllables uttered by that person through stereo headphones. What syllables are heard and when are measured by recording the participants' saying out loud what syllables they hear.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 15 minutes 60 minutes after consuming the capsules and again for 25 minutes 275 minutes after consuming the capsules.]

Dexamphetamine saliva levels. About 1-2 ml of saliva are collected 5 times each of the two days, and are used to measure dexamphetamine levels, measured by high performance liquid chromatography with ultraviolet detection.[These samples are collected on both test days just before consuming the capsules and at about 70 min intervals thereafter, until 5 samples are taken.]

Brief Psychiatric Rating Scale. This is measured by one of the experimenters asking questions of the participants.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 8 minutes 95 minutes after consuming the capsules ]

Magical Ideation Scale. This is measured by the participants' filling out a brief yes/no questionnaire.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 5 minutes 90 minutes after consuming the capsules ]

This is a primary outcome:
Marble hand illusion. This illusion is produced by tapping the hand gently with an automated tapper, while listening to the sound of the hand being tapped through a headset. Gradually, the sound of the tapping is changed, and with it so does the feeling of the hand. The feeling of the hand is assessed with the Senna et al. (2014) questionnaire (Senna I, Maravita A, Bolognini N and Parise CV (2014) The marble-hand illusion. PLoS One 9:e91688.)[This will be measured on both days of testing (placebo and dexamphetamine days) for about 30 minutes 240 minutes after consuming the capsules.]

Amphetamine scale. This is measured by the participants' filling out a very brief visual analog scale about how they are feeling at that moment in time.[Amphetamine-like feelings are measured on both test days just before consuming the capsules and at about 70 min intervals thereafter, until measured 5 times.]

Heart rate is measured using an automated blood-pressure device.[Heart rate is measured in triplicate on both test days just before consuming the capsules and at about 70 min intervals thereafter, until 5 triplicates are measured.]

blood-pressure. This is measured using an automated blood-pressure device[Blood pressure is measured in triplicate on both test days just before consuming the capsules and at about 70 min intervals thereafter, until 5 triplicates are measured.]

Scale for the Assessment of Positive Symptoms. This is measured by the participants filling out a brief questionnaire, and by an experimenter also filling out a brief questionnaire.[This will be measured on both days of testing (placebo and dexamphetamine days) for about 5 minutes 103 minutes after consuming the capsules ]

Secondary ID(s)

Nil

Source(s) of Monetary Support

University of Western Australia

Secondary Sponsor(s)

Dr Joseph Lee

Dr Rajan Iyyalol

Ethics review

Status: Approved
Approval date:
Contact:

University of Western Australia Human Research Ethics Committee

Results

• Results available: Yes
• Date Posted: 09/01/2019
• Date Completed: 28/09/2017