EFFECT OF HYPERTENSION ON PREFRONTAL CORTEX ACTIVATION IN OLDER ADULTS DURING INSTRUMENTED TRAIL WALKING TASKS

Abstract

Abstract Hypertension (HTN) can lead to non-amnestic cognitive impairment. However, it is unclear if this cognitive impairment affects dual task walking in older adults with HTN. The objective of this study was to evaluate the differences in prefrontal cortex (PFC) oxygenated hemoglobin (HbO2) levels during comfortable walking (CW) and an instrumented trail walking task (TWT) in older adults with HTN. We hypothesized that older adults with HTN would show decreased activation, or lower PFC HbO2 using functional near-infrared spectroscopy, during TWT in comparison to older adults without HTN. There were 15 adults in HOA group (11 females; 65±9 years old), and 9 adults in HTN group (3 females; 68±8 years old). The experimental paradigm consisted of three tasks (CW, TWT-A, TWT-B) in each of two blocks, with difficulty increasing from TWT-A to TWT-B through the inclusion of task-switching. A linear mixed effect model was conducted to investigate the effects of cohort, task, block and interaction between them on HbO2. We found that: 1) HTN adults exhibited lower HbO2 levels compared to HOA (p< 0.001), during TWTs but not CW; and 2) increased HbO2 levels were observed in TWTs relative to CW. During TWTs, HTN adults showed decreased activation compared to HOA, which shows that their ability to focus on dual task execution is limited. The hypertensive adults face difficulty in matching the attentional demands of the dual task, similar to cognitively impaired older adults, which may be partly explained by capacity sharing theory.