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Motor control deficits outlasting self-reported symptoms are often reported following mild traumatic brain injury (mTBI). The exact duration and nature of these deficits remains unknown. The current study aimed to compare postural responses to static or dynamic virtual visual inputs and during standard clinical tests of balance in 38 children between 9 and 18 years-of-age, at 2 weeks, 3 and 12 months post-concussion. Body sway amplitude (BSA) and postural instability (vRMS) were measured in a 3D virtual reality (VR) tunnel (i.e., optic flow) moving in the antero-posterior direction in different conditions. Measures derived from standard clinical balance evaluations (BOT-2, Timed tasks) and post-concussion symptoms (PCSS-R) were also assessed. Results were compared to those of 38 healthy non-injured children following a similar testing schedule and matched according to age, gender, and premorbid level of physical activity. Results highlighted greater postural response with BSA and vRMS measures at 3 months post-mTBI, but not at 12 months when compared to controls, whereas no differences were observed in post-concussion symptoms between mTBI and controls at 3 and 12 months. These deficits were specifically identified using measures of postural response in reaction to 3D dynamic visual inputs in the VR paradigm, while items from the BOT-2 and the 3 timed tasks did not reveal deficits at any of the test sessions. PCSS-R scores correlated between sessions and with the most challenging condition of the BOT-2 and as well as with the timed tasks, but not with BSA and vRMS. Scores obtained in the most challenging conditions of clinical balance tests also correlated weakly with BSA and vRMS measures in the dynamic conditions. These preliminary findings suggest that using 3D dynamic visual inputs such as optic flow in a controlled VR environment could help detect subtle postural impairments and inspire the development of clinical tools to guide rehabilitation and return to play recommendations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Romeas, Greffou, Allard, Forget, McKerral, Faubert and Gagnon.)

To compare the visual memory performance of uncomplicated and complicated mild TBI (mTBI) groups with that of a control group on the Rey Complex Figure Test (RCFT). We also aimed to explore the influence of factors such as age, gender, education, occupation, and intellectual functioning on visual memory in individuals with mTBI. The RCFT and the Wechsler Abbreviated Scale of Intelligence (WASI-II) were administered to 138 participants (90 uncomplicated mTBI patients, 19 complicated mTBI patients, and 29 controls). The mTBI patients demonstrated significantly lower scores than control participants on both immediate and delayed RCFT recall conditions, with performance in the low average and borderline range. However, there was no difference in performance between the two mTBI groups on the recall conditions. In addition, no significant differences were observed across the three groups on the recognition condition. The WASI-II Performance and Verbal IQ scales explained most of the variance in the immediate and delayed RCFT recall conditions but were not associated with performance on the recognition condition. In contrast with the recognition processes involved in visual memory, recall processes seem to be more vulnerable following mTBI and both verbal and performance IQ seem to be related to visual memory performance.

Although atypical motor behaviors have been associated with autism, investigations regarding their possible origins are scarce. This study assessed the visual and vestibular components involved in atypical postural reactivity in autism. Postural reactivity and stability were measured for younger (12-15 years) and older (16-33 years) autistic participants in response to a virtual tunnel oscillating at different frequencies. At the highest oscillation frequency, younger autistic participants showed significantly less instability compared to younger typically-developing participants; no such group differences were evidenced for older participants. Additionally, no significant differences in postural behavior were found between all 4 groups when presented with static or without visual information. Results confirm that postural hypo-reactivity to visual information is present in autism, but is contingent on both visual environment and development.