Cognitive-Sensorimotor Function in Long-COVID

As many as one in seven COVID-19 survivors will experience symptoms that persist more than two months after their acute illness has resolved. Growing evidence estimates that up to 30% of people who experience this chronic post-COVID disorder (aka post-acute sequelae of SARS-CoV-2 infection (PASC)) will exhibit gait and balance dysfunction. The consequences of impaired mobility are of considerable concern for the Veterans Health Administration (VHA) given that mobility is closely related to quality of life for older adults and almost half of Veterans are 65 years or older. There currently is no established VHA standard-of-care for PASC. The critical first step towards development of comprehensive clinical protocols to identify and treat PASC-related gait and balance dysfunction is understanding the contributing factors. PASC is characterized by diverse multi-organ system effects that has made it difficult to identify the causes of dysfunction. However, new data suggests frequently reported neurologic issues related to cognitive and sensorimotor impairment may be potential contributors to gait and balance dysfunction. While cognition, sensation, and muscle function can be measured in isolation, the effects of cognitive and sensory impairment on gait and balance are best detected using dual task tests (e.g., count backward by 7's while walking) that pair cognitive and motor function or tasks performed in complex environments that limit sensory feedback and/or stress sensory-motor integration (e.g., maintaining standing balance with eyes closed). However, such assessments are not included in the current recommended PASC gait and balance screening guidelines, thereby leaving a clinical gap in knowledge when evaluating and treating Veterans and non-Veterans with PASC-related gait and balance dysfunction. Therefore, the proposed project will evaluate the effect of PASC on isolated cognitive-sensorimotor function (Aim 1), and cognitive-sensorimotor contributions to gait (Aim 2) and balance (Aim 3) dysfunction in COVID-19 survivors through an observational cross-sectional study design. Aim 1 will assess cognition, vision, proprioception, and muscle strength independent of functional task in COVID-19 survivors with and without PASC using established methods. Aim 2 will perform an instrumented assessment of gait performance of participants under a dual task scenario to stress cognition. Aim 3 will perform an instrumented assessment of postural balance under different conditions that challenge sensorimotor integration by compromising certain sensory modalities (vision, vestibular, somatosensory). A non-instrumented clinical outcome measure will also be performed as a secondary measure to evaluate a potential clinical screening tool. Based on emerging evidence, the investigators hypothesize that COVID-19 survivors with PASC will exhibit worse cognitive-sensorimotor function, dual task gait performance, and sensory-interaction balance performance than those without PASC when accounting for age, sex, and time since acute infection. PASC-induced gait and balance dysfunction has significant clinical implications as it could compromise mobility, long-term health, and quality of life of Veterans if left unaddressed.