Pilot study of autonomic and cardiovascular responses to orthostatic stress among young adults with visual and hearing impairments

Abstract

Individuals with visual and hearing impairments often experience reduced physical activity and limited participation in daily activities, which may affect autonomic regulation and cardiovascular risk. However, impairment-specific physiological characteristics in young adults remain poorly understood. This exploratory and hypothesis-generating cross-sectional pilot study investigated autonomic modulation during an acute orthostatic stress test in 35 university students divided into three groups: healthy controls, individuals with visual impairments, and individuals with hearing impairments. Indicators of arteriosclerosis, physical function, autonomic nervous system activity assessed by heart rate variability (HRV), physical activity level, and quality of life were evaluated and compared among groups. The primary outcomes of this study were vascular and autonomic responses during the acute orthostatic stress test, specifically the Arterial Velocity Pulse Index (AVI), Arterial Pressure-volume Index (API), and heart rate variability (HRV) indices. Secondary outcomes included baseline body composition, motor performance, daily physical activity levels, and quality of life (QOL) scores. Although no significant group × time interactions were observed for HRV parameters during the acute orthostatic stress test, a significant main effect of group was observed for HF, whereas no significant group effects were observed for the other HRV parameters. Significant group differences were observed for both API and AVI, with post hoc comparisons indicating higher values in the hearing impairment group than in healthy controls. These preliminary findings may suggest potential impairment-specific cardiovascular profiles that warrant further investigation in larger studies. No significant differences were observed in physical function or quality of life among the groups. Overall, the findings should be interpreted cautiously because of the exploratory design and small sample size. These exploratory findings may suggest possible differences in vascular characteristics in young adults with sensory impairments, with exploratory observations regarding autonomic modulation. However, these observations require confirmation in larger adequately powered studies.