Transcranial Doppler and Lower Extremity Function in Older Adults: Einstein Aging Study.

OBJECTIVES: To determine whether transcranial Doppler ultrasound (TCD) measures of mean blood flow velocity (MBFV) in the major cerebral arteries are associated with measures of lower extremity function in community-dwelling older adults.

DESIGN: Cross-sectional study.

SETTING: Community sample.

PARTICIPANTS: Individuals aged 70 and older (mean 79.5, 54% female) without dementia participating in the Einstein Aging Study (N = 200).

MEASUREMENTS: All participants underwent TCD assessments and tests of lower extremity function at an annual clinic visit. Average MBFV for anterior (left and right anterior and middle cerebral arteries (MCAs)) and posterior (vertebral (VA) and basilar (BA) artery) circulation was measured using a standardized TCD protocol. Lower extremity function was characterized according to gait speed (cm/s) measured using an instrumented walkway, balance according to unipedal stance time (UPST, seconds), and lower extremity strength according to timed repeated chair rise (seconds).

RESULTS: Multiple regression models adjusted for age, sex, race, education, and medical comorbidities showed that lower MBFV in the MCA was associated with slower gait speed and chair rise time but not with UPST. Ordinal regression models showed that lower MBFV in the VA and BA is associated with shorter UPST.

CONCLUSION: Low MBFV in the anterior and posterior cerebral circulation was associated with worse lower extremity function and balance in older adults. This might be indicative of the importance of age-related changes in cerebral hemodynamics in the function of brain regions involved in specific aspects of physical performance.