VRT as a Biomarker of Cerebellar Dysfunction in Chronic Cannabis Use

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.

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Key information

Conditions

Cannabis Use Alcohol Use Disorder Alcohol-Related Disorders Alcoholism Chemically-Induced Disorders Healthy Mental Disorders Substance-Related Disorders

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hospital Clínic

Barcelona, Catalonia, 08036, Spain

About this study

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

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Visuomotor adaptation task

Diagnostic Test

We will measure performance of the subjects of each group on the visuomotor adaptation task, especially in the rotation condition, in which a perturbation will be induced between the anticipated location of the hand and the provided visual feedback, and in the washout condition, in which the rotation will be removed. We expect that subjects with cannabis use disorder will not show the expected implicit motor adaptation to the perturbation and consequently no deterioration of performance on the task, due to cannabis-induced cerebellar damage. In other words, we want to show that this visuomotor task is a cheap and quick biomarker of cerebellar dysfunction in chronic cannabis users.

Primary outcomes

Change in directional error between baseline and after cessation of cannabis use

Time frame: 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.

Sponsors and collaborators

Lead sponsor

Hospital Clinic of Barcelona

Other

Registry information

Official study title

A Visuomotor Rotation Task as a Biomarker of Cerebellar Dysfunction in Chronic Cannabis Use

Important dates

Study start: 2019
Primary completion: 2021
Study completion: 2021
First posted: Sep 7, 2018
Registry last updated: Sep 28, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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