The Combined Effect of Chronic Cannabis Use and Subconcussive Head Impacts on Brain Health

Summary

The purpose of this pilot study is to better understand the effects of chronic cannabis (THC) use on the neural responses to subconcussive head impacts, as a form of repetitive soccer headings. The study is designed to identify the physiological changes of cannabis using cohort (THC) and compare it to a nonusing cohort in order to see if the responses to 20 controlled bouts of soccer headings are exacerbated by the chronic cannabis use, diminished to less of a response, or unchanged, through an array of neurologic measures, including cognitive function, ocolar-motor function, autonomic function, and blood biomarkers. The hypothesis is that repetitive subconcussive head impacts will impair cognitive function in worse memory, attention span, and visual and verbal problem solving; this impairment will be greater in the chronic cannabis use groups than non-using group. The blood and salivary biomarkers neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) will be measured in plasma, with the hypothesis that repetitive subconcussive head impacts will significantly increase plasma NFL and GFAP level at 24 hours-post heading and decrease by 72 hours-post heading, while remaining undetectable at 2 hours-post heading; the chronic cannabis use groups will see more severe effects on ocular-motor function than the non-using group. The study aims to determine the differences in acute effects of subconcussive head impacts on eye movement, attention, and language function between chronic cannabis use subjects and non-using subjects by evaluating ocular-motor function with near point of convergence and King-Devick tests. The hypothesis is that repetitive subconcussive head impacts will significantly increase impairments of eye movements, attention, and language function, as well as near point of convergence; the chronic cannabis use groups will see more severe effects on hampered ocular-motor function than the non-using group. Lastly, there is a cold pressor test to assess autonomic nerve function, with the hypothesis that repetitive subconcussive head impacts will decrease autonomic nerve function in chronic cannabis use patients to a greater degree than non-using subjects.

Conditions

• Concussion, Mild

Interventions

OTHER

Soccer heading

A standardized and reliable soccer heading protocol will be used for the experiment. A triaxial accelerometer embedded in a head-band pocket and positioned directly below the external occipital protuberance (inion) to monitor linear and rotational head accelerations. A JUGS soccer machine will be used to simulate a soccer throw-in with a standardized ball speed of 25mph. The ball speed is similar to when soccer players make a long throw-in from the sideline to mid-field. Soccer players frequently perform this maneuver during practice and games. Subjects will stand approximately 40ft away from the machine to perform the heading. Participants perform 20 standing headers with 1 header per 30 seconds. The subjects will be instructed to direct the ball back toward the JUGS soccer machine in the air.

Sponsors & Collaborators

• Indiana University

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

26 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-10-30

Primary Completion

2021-10-01

Completion

2021-12-01

Countries

• United States

Study Locations