Differences In Motor And Cognitive Outcomes Between Healthy Controls And Individuals With Persistent Post-Concussion Symptoms

It has been reported that 10-15% of individuals who sustain a mild traumatic brain injury experience persistent post-concussion symptoms (PPCS) lasting greater than three months post-injury. Individuals experiencing PPCS have reported greater number and severity of symptoms, and have greater corticospinal inhibition, lower gait scores, and worse neurocognitive performance compared to healthy controls. However, these separate findings come from different studies, as few studies have quantified this multifaceted condition across multiple domains of functional and physiological outcomes. PURPOSE: To determine the effects of PPCS on motor and cognitive performance compared to healthy controls. METHODS: A cross-sectional design was employed. Twelve individuals with PPCS (19.5 ± 21.2 months post injury, 25.6 ± 5.5 years; 8 F) were recruited from Parkwood Institute’s Acquired Brain Injury Outpatient program. Twelve uninjured individuals who were age-, height-, and weight-matched (23.4 ± 3.2 years; 7 F) also participated in the study as controls. Outcome measures included i) symptom reporting - Rivermead Post-Concussion Symptoms Questionnaire, ii) neurophysiology - transcranial magnetic stimulation (TMS), iii) neurocognitive status - Repeatable Battery for the Assessment of Neuropsychological Status, and iv) gait - Functional Gait Assessment. RESULTS: The PPCS group reported a significantly greater number (13.6 ± 3.0) and severity (34.0 ± 14.9) of symptoms compared to the control group (1.92 ± 4.2 and 3.83 ± 9.1, respectively; p < 0.001). The PPCS group had significantly greater corticospinal inhibition (150.5 ± 38.3 ms), measured through TMS, compared to controls (90.7 ± 18.0 ms; p = 0.006). There were no significant differences in overall neurocognitive scores between groups (PPCS: 89.6 ± 15.4; Control: 97.8 ± 10.3; p = 0.14). Finally, functional gait scores were significantly lower in the PPCS group (26.8 ± 3.4) compared to controls (29.3 ± 0.7; p = 0.03). CONCLUSION: As expected, the PPCS group demonstrated a greater number and severity of symptoms compared to the control group. Although cognitive scores showed no significant differences between groups, the PPCS group showed more marked deficits in motor function, as demonstrated by greater corticospinal inhibition and lower gait scores. Lawson Internal Research Fund (IRF-25-20); Parkwood Institute Research-Student Endowment (PIRSE#:LRI7764458)