VRT as a Biomarker of Cerebellar Dysfunction in Chronic Cannabis Use

Completed

• Conditions: Healthy; Cannabis Use; Alcohol Use Disorder
• Interventions: Diagnostic Test: Visuomotor adaptation task

• Registration Number: NCT03662737
• Lead Sponsor: Hospital Clinic of Barcelona

Brief Summary

Chronic cannabis consumption has been associated with poor psychosocial functioning that could be associated to cerebellar dysfunction. The cerebellum has a relevant role in adaptation processes and has a high density of cannabinoid 1 receptor (CB1R). Implicit motor learning is a cerebellum dependent function that can be measured with a visuomotor rotation task (VRT).

The project aims to identify a sensitive and specific biomarker of cerebellum dysfunction in chronic cannabis users. The investigators would like to demonstrate that the visuomotor rotation paradigm is valid to measure and quantify such a dysfunction.

A longitudinal prospective study with a 3 month follow-up is proposed. 3 groups will be included: 1) chronic cannabis users; 2) individuals with an alcohol use disorder; and 3) healthy controls. All groups will be matched by sex and age. Forty individuals will be included in each group. Individuals will be assessed at baseline, at first month and at 3-months of follow-up. Sociodemographic and clinical data will be recorded. Information on cannabis consumption will be registered using an App.

Participants will do the visuomotor rotation task and answer three questionnaires: the Intrinsic Motivation Inventory, the Scale for the assessment and rating of ataxia (SARA) and the Harris tests for lateral dominance.

The biomarker developed by this project will facilitate the detection of cerebellar alterations in chronic cannabis users, and will permit to quantify and monitor such alteration over time. The team's intention is to patent the proposed model and disseminate it in order to use it in clinical practice at both primary and specialized health centres.

Detailed Description

The subjects have to realize movements towards a target, at a digitizing tablet, holding a digitizing pencil. Visual feedback is projected on a screen surface in front of the subject, which hides the sight of actual movements from the latter. In the experimental condition of rotation, the experimenter introduces a rotation of 45 grades between the movement realized by the subject and the visual feedback that is provided on the screen. Then, the subject is provided with a strategy in order to overcome this perturbation: that is, to make the movement aiming 45 grades to the opposite direction from the introduced rotation. This explicit strategy leads to immediate correction of the error, but as the time passes subjects tend to commit more and more errors due to implicit motor adaptation. This happens because the motor control system tends to correct the perceived perturbation between the anticipated and the actual location of the hand in an automatic and unconscious way. The conflict between the implicit and explicit strategies has the surprising consequence of a persistent and accumulative deterioration of performance that can only be resolved when the participants abandon the explicit strategy. Subjects with cerebellar damage show deficits in implicit motor learning and for this reason they do not show this progressive deterioration of performance. Given that chronic cannabis abuse can lead to cerebellar damage, the investigators hypothesize that subjects from the experimental group 1 (cannabis use) will have a significant smaller directional error on the rotation condition than controls. A second hypothesis is that this effect will be cannabis-specific, due to the high CB1R concentration on the cerebellum, so the alcohol dependence group is expected to perform similarly to control group

Study Timeline

• Study First Submitted: 2018-09-03
• Study First Submitted QC: 2018-09-06
• Study First Posted: 2018-09-07
• Study Start: 2019-09-01
• Primary Completion: 2021-12-31
• Study Completion: 2021-12-31
• Status Verified: 2023-09
• Last Update Submitted: 2023-09-27
• Last Update Posted: 2023-09-28

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 61

Inclusion Criteria

• 18-50 years old
• Right-handed
• Daily consumption of cannabis for at least 2 years (cannabis group) or diagnosed Alcohol Use Disorder (alcohol group)

Exclusion Criteria

• Non-corrected visual deficits
• Regular consumption of other drugs except nicotine
• Other Axis I or neurological diagnosis

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Group 2 - Alcohol dependence	Visuomotor adaptation task	Individuals between 18 and 50 years old diagnosed with alcohol use disorder according to DSM-V criteria and have been consuming alcohol for at least 3 years. Individuals who are diagnosed with another substance use or severe mental disorder will be excluded (except tobacco use).
Control Group	Visuomotor adaptation task	Individuals matched in gender and age with the experimental groups and with no diagnosis of substance use or severe mental disorder (except tobacco use)
Group 1 -Chronic cannabis use	Visuomotor adaptation task	Individuals between 18 and 50 years old who have been using at least 2 joints per day for at least 3 years. They should have used cannabis during the last 24h but not during the 3h prior to participation to the study and they should test positive for cannabis in their urine. Individuals with another substance use or severe mental disorder will be excluded (except tobacco use)

Primary Outcome Measures

Name	Time	Method
Change in directional error between baseline and after cessation of cannabis use	The visuomotor adaptation task duration will not exceed 20 minutes and subjects are expected to realize it at three different time points: baseline, 1 month, 3 months	Directional error of hand movement trajectories towards the target object on the rotation condition of the visuomotor rotation task.

Trial Locations

Locations (1)

Hospital Clínic; 🇪🇸 Barcelona, Catalonia, Spain