Sensory testing as a predictor of short vs. long term trajectory of recovery from concussion

Abstract

There have been numerous reports of neurological assessments of post-concussed athletes. However, the majority of the methods commonly deployed are either qualitative assessments that are simply symptom based or are psycho-social questionnaires. The information provided from those studies does not provide insight into the neural mechanisms impacted by concussion, and more importantly, does not contribute to a prognostic view of overall brain health that would facilitate or predict the recovery of the concussed individual. Cortical metrics are measures that were designed to probe brain function via the somatosensory system (i.e., with high fidelity tactile inputs) and have been demonstrated to be both objective, quantifiable and physiologically based. The methods have also been recently reported to parallel findings in a neurophysiological animal model of brain injury (Challener et al, 2020) that support the concept that these metrics parallel alterations in specific neural mechanisms post-injury. In this report, the battery of tactile based measures are reaction time (RT), reaction time variability (RTvar), sequential and simultaneous amplitude discrimination, temporal order judgement (TOJ) and duration discrimination (DD). These methods are administered with a computer mouse sized tactile stimulator (the Brain Gauge) that delivers sinusoidal stimuli to digits 2 and 3 with precision control of both amplitude and frequency. The results obtained during the first week of observation post-injury predict the recovery trajectory of the concussed individual. Interestingly, some of the metrics of the individuals who take longer to recover from injury obtained during the first week outperform the metrics of individuals that recover quickly, and these findings parallel the findings from the animal model.