An Investigation of Physiological System Impairments in Individuals 4 Weeks to 6 Months Following Mild Traumatic Brain Injury.

OBJECTIVE

The Buffalo Concussion Treadmill Test (BCTT) was developed to identify potential physiological system impairment (PSI) underlying persistent symptoms post-mild traumatic brain injury (mTBI). This study evaluates PSI in individuals 4 weeks to 6 months post-mTBI using the BCTT "failure" criteria, and additional exploratory measures of test duration and heart rate (HR) response.

SETTING

Tertiary hospital and university.

PARTICIPANTS

Participants included 73 individuals 4 weeks to 6 months post-mTBI and a comparison group of 39 healthy controls (HCs). The mTBI group was further subgrouped at screening into those considering themselves asymptomatic (Asymp mTBI) ( n = 35) or symptomatic (Symp mTBI) ( n = 36).

DESIGN

Observational cohort study.

MAIN MEASURES: BCTT; failure rate (%), test duration (minutes), HR responses.

RESULTS

: Thirty percent of the mTBI group (including 50% of the Symp and 9% of the Asymp subgroups) failed the BCTT. BCTT duration and associated overall HR change was significantly lower in the mTBI group and Symp subgroup compared with HCs. Compared with HCs maximal HR percentage was higher for the first 4 minutes of the test in the mTBI group, and for the first 2 minutes of the test for the Symp subgroup.

CONCLUSIONS

Individuals post-mTBI demonstrated PSI impairment subacutely. In some individuals this was despite an initially reported absence of symptoms. The study also showed some preliminary evidence that BCTT duration and HR responses may be additionally informative post-mTBI.