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Trial registered on ANZCTR


Registration number
ACTRN12617000652370
Ethics application status
Approved
Date submitted
24/03/2017
Date registered
5/05/2017
Date last updated
16/04/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
The impact of Sulpiride (600mg; a dopamine antagonist) on behavioural and electrophysiological measures of visuospatial attention and inhibition
Scientific title
A DAT1 genotype and DRD2 Taq1A genotype, placebo controlled, randomised, double blind, crossover designed study of the effect of Sulpiride (600mg) on visuospatial attention and cognitive control measures (recorded with electroencephalography (EEG) and behavioural tasks) in a sample of 50 healthy adults
Secondary ID [1] 291157 0
Therapeutic good administration (TGA), Australian Govt, Dept of Health - Clinical Trials Notification (CTN) scheme - Protocol Number: 2016000821
Universal Trial Number (UTN)
U1111-1192-8304
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Spatial Attention Deficits 302108 0
Inhibitory Control Deficits 302163 0
Condition category
Condition code
Neurological 301728 301728 0 0
Studies of the normal brain and nervous system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants will attend 2 separate sessions, one week apart (on the same day and time). On each occasion, the participant will be given a capsule to swallow containing either 600mg sulpiride or a placebo sugar pill, according to a randomised, double blind procedure. Participants will commence the study tasks after 180 minutes have elapse (to coincide with peak drug levels) and will complete the tasks within 330 minutes. Observation will occur for a further 30 minutes.
Intervention code [1] 297205 0
Treatment: Drugs
Comparator / control treatment
The placebo will be a capsule containing microcrystalline cellulose (trade name Avicel).
Control group
Placebo

Outcomes
Primary outcome [1] 301124 0
Lateral differences in mean reaction time to visuospatial targets (reaction time asymmetry) assessed using a computer based Bilateral Perceptual Decision Making Paradigm that compares response times to stimulus presented in the left and right visual hemifields
Timepoint [1] 301124 0
Between 3 and 5.5 hours following administration of sulpiride and placebo (testing occurs over a 2-2.5 hour period and includes the Bilateral Perceptual Decision Making Paradigm and 3 other tasks, with the order of the tasks changed for each participant)
Primary outcome [2] 301125 0
Hemispheric differences in alpha power assessed using EEG
Timepoint [2] 301125 0
This will be assessed at the same time as participants undertake the Bilateral Perceptual Decision Making Paradigm (between 3 and 5.5 hours following administration of sulpiride and placebo)
Primary outcome [3] 301357 0
Laterality index for spatial distribution of attention weighting assessed using a computer based task called the "Combi-TVA" (based on Bundesons Theory of Visual Attention). This task requires participants to report as many letters as they can recall from a briefly presented array of letters and to also report as many target letters as they can recall from a briefly presented array of target and distractor letters (eg. red targets and blue distractors)
Timepoint [3] 301357 0
Between 3 and 5.5 hours following administration of sulpiride and placebo (testing occurs over a 2-2.5 hour period and includes the CombiTVA and 3 other tasks, with the order of the tasks changed for each participant)
Secondary outcome [1] 331789 0
Mean stop signal reaction time (SSRT) and response time variability assessed using a Response Inhibition Task
Timepoint [1] 331789 0
Between 3 and 5.5 hours following administration of sulpiride and placebo (testing occurs over a 2-2.5 hour period and includes the Response Inhibition Task and 3 other tasks, with the order of the tasks changed for each participant)
Secondary outcome [2] 332414 0
Amplitude and latency of the event related potential (ERP) component N2, assessed using EEG
Timepoint [2] 332414 0
This will be assessed at the same time as participants undertake the Bilateral Perceptual Decision Making Paradigm and the Response Inhibition Task (between 3 and 5.5 hours following administration of sulpiride and placebo)
Secondary outcome [3] 334299 0
Amplitude and latency of the event related potential (ERP) component P2, assessed using EEG
Timepoint [3] 334299 0
This will be assessed at the same time as participants undertake the Bilateral Perceptual Decision Making Paradigm and the Response Inhibition Task (between 3 and 5.5 hours following administration of sulpiride and placebo)
Secondary outcome [4] 334300 0
Amplitude and latency of the event related potential (ERP) component (CPP - centro-parietal positivity), assessed using EEG
Timepoint [4] 334300 0
This will be assessed at the same time as participants undertake the Bilateral Perceptual Decision Making Paradigm and the Response Inhibition Task (between 3 and 5.5 hours following administration of sulpiride and placebo)

Eligibility
Key inclusion criteria
Inclusion Criteria: Participants must be right handed, aged between 18 and 45, caucasian (all four grandparents of European descent) and neurologically healthy. Females must not be pregnant or breastfeeding and must be taking the combined progesterone/oestrogen oral contraceptive pill.
Minimum age
18 Years
Maximum age
45 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants are ineligible for the study if any of the following apply: current smokers or have smoked more than 5 cigarettes a week in their lifetime; alcohol dependence; any current or history of neurological or psychiatric illness; any current or history of psychotropic drug use; illicit drug use in the last 6 months; any history of significant illicit drug use or more than monthly cannabis use, pregnant or breastfeeding.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation (to either "placebo first" or "sulpiride first" conditions) is generated by computer sequence and managed by an off-site service provider who informs an off-site pharmacist of the allocation. The off-site pharmacist maintains the allocation schedule.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Block randomisation according to a computerised sequence generated by the automated Griffith University Randomisation Service
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Phase 1
Type of endpoint/s
Efficacy
Statistical methods / analysis
Each measure will be analysed using a Mixed Model ANOVA and will be run twice. The first analysis will involve the within-subjects factor consisting of the conditions placebo and sulpiride and the between subjects factor consisting of DAT1 genotype group. Those with zero or one copy of the 10-repeat allele (non 10/10 group) will be compared with those with two copies of the 10-repeat allele (10/10 group) on each. The second analysis will involve the within-subjects factor consisting of the conditions placebo and sulpiride and the between subjects factor consisting of Taq1A genotype group. Homozygous carriers of the C[A2] allele will be compared with carriers of the minor allele T[A1] on each of the measures. In both instances, we are looking for the main effect of drug, main effect of gene group and an interaction of drug and gene group. Analyses will be undertaken to examine whether shifts in posterior alpha hemispheric asymmetry are in the same direction as shifts in spatial bias behaviour.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
11/11/2016
Date of last participant enrolment
Anticipated
30/11/2018
Actual
Date of last data collection
Anticipated
21/12/2018
Actual
Sample size
Target
50
Accrual to date
24
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 295595 0
Government body
Name [1] 295595 0
Australian Research Council
Country [1] 295595 0
Australia
Primary sponsor type
Individual
Name
Professor Mark Bellgrove
Address
Director of Research, Institute of Cognitive and Clinical Neurosciences
Australian Research Council (ARC) Future Fellow, Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University, Building 17, Clayton Campus, Wellington Road, Monash University, VIC, 3800 Australia, Australia
Country
Australia
Secondary sponsor category [1] 294427 0
University
Name [1] 294427 0
Monash University
Address [1] 294427 0
Wellington Road, Monash University, Clayton, VIC, 3800 Australia, Australia
Country [1] 294427 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296916 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 296916 0
Monash University
Room 111, Chancellery Building E
24 Sports Walk, Clayton Campus, Wellington Rd, Clayton VIC 3800, Australia
Ethics committee country [1] 296916 0
Australia
Date submitted for ethics approval [1] 296916 0
11/05/2016
Approval date [1] 296916 0
16/08/2016
Ethics approval number [1] 296916 0
CF16/1572 - 2016000821

Summary
Brief summary
This study will investigate whether temporarily reducing dopamine transmission in the healthy brain affects an individual’s spatial selective attention, that is, the direction in space (left or right) in which an individual’s visual attention naturally falls. By combining this investigation with measures of electrical activity in the brain and genetic testing, we hope to gain a deeper understanding of the mechanisms involved in spatial attention and the influence on these mechanisms of genes implicated in the structure and function of the dopamine system in the brain. Uncovering the mechanisms of spatial attention may help us better understand and treat disorders involving spatial attention deficits, including Attention Deficit Hyperactivity Disorder, which involves an impaired awareness of, and ability to respond to, objects and information in a particular area of visual space.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 72422 0
Prof Mark Bellgrove
Address 72422 0
Monash Institute of Cognitive and Clinical Neurosciences
School of Psychological Sciences
Monash University
Building 17, Clayton Campus
18 Innovation Walk
Wellington Road,
Monash University, VIC, 3800
Australia
Country 72422 0
Australia
Phone 72422 0
+61 3 9902 4200
Fax 72422 0
Email 72422 0
[email protected]
Contact person for public queries
Name 72423 0
Keri Stevens
Address 72423 0
Building 17, Clayton Campus
18 Innovation Walk
Wellington Road,
Monash University, VIC, 3800
Australia
Country 72423 0
Australia
Phone 72423 0
+61 412 371 924
Fax 72423 0
Email 72423 0
[email protected]
Contact person for scientific queries
Name 72424 0
Mark Bellgrove
Address 72424 0
Monash Institute of Cognitive and Clinical Neurosciences
School of Psychological Sciences
Monash University
Building 17, Clayton Campus
18 Innovation Walk
Wellington Road,
Monash University, VIC, 3800
Australia
Country 72424 0
Australia
Phone 72424 0
+61 3 9902 4200
Fax 72424 0
Email 72424 0
[email protected]

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