Lower Extremity Neuromuscular Alteration During Dual Cognitive Standing Balance Tasks In Adults Diagnosed With Hiv

Abstract

Individuals diagnosed with human immunodeficiency virus (HIV) often present with impaired postural control as a consequence of proprioceptive alteration, due to secondary effects of prescription medication. PURPOSE: This study seeks to evaluate lower extremity neuromuscular activation during dual postural control tasks in individuals living with HIV. METHODS: Twenty-three participants of Hispanic-latino origin diagnosed with HIV (18 male and 5 female, average age 55± 1.7 years) with an average CD4 count of 698.8 (22 years of HIV diagnosis) enrolled in this study. Surface electromyography (EMG) on the tibialis anterior (TA) and gastrocnemius (GA) muscles was used on the participant’s dominant leg. Each task took approximately 15 seconds to finish. Each participant was instructed to quietly stand in a bi-pedal posture on a balance foam. Four single balance and dual cognitive-balance tasks (count backwards from 100 in increments of 3) were performed on the balance foam. RESULTS: The variables of interest in this study were 1) time to peak, 2) decay and, 3) duration of muscle activation for TA and GA. A repeated measure ANOVA analysis was used to compare all variables of interest. No significant difference is indicated between duration and decay of muscle activation for TA and GA across the various tasks assessed. Throughout the cognitive balance task, GA time to peak activation was slower (P< 0.001) during eyes closed (EC) head movements (HUD) ( 7.7 +/- 0.7 seconds) when compared to HUD with eyes open (EO) (0.3+/-0.2 secs) and, eyes open (EO 0.5+/-0.2 secs). CONCLUSIONS: As the GA plays a major role in static balance, an increased fall risk could be resultant of this delay in time to peak onset. As such, our research recommends lower extremity electromyography and strength assessment in this population to forestall or decrease fall hazards.