Effect Of Exercise Training On Cerebrovascular Impedance In Amnestic Mild Cognitive Impairment Patients

Abstract

Cerebrovascular hypoperfusion is associated with cognitive impairment in older adults. PURPOSE: To test the hypotheses that 1) patients with amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer’s disease, have higher cerebrovascular impedance than age-matched cognitively normal individuals; 2) 1-year endurance exercise training reduces cerebrovascular impedance in aMCI patients. METHODS: In the cross-sectional study arm, cerebrovascular impedance was estimated in 58 patients with aMCI (67±7 years) and 25 normal control subjects (65±6 years) with cross-spectral analysis between dynamic changes in cerebral blood flow velocity (CBFV) in the middle cerebral artery (via transcranial Doppler) and carotid arterial blood pressure (via applanation tonometry). In the longitudinal study arm, cerebrovascular impedance was evaluated in randomly-assigned 37 aMCI patients who completed 1-year endurance (n=17) or stretching exercise (n=20). RESULTS: After adjustment for age and sex, aMCI patients exhibited higher impedance modulus in the range of the first harmonic oscillations (0.78-1.56 Hz, Z1) than NC (1.18±0.34 vs. 1.01±0.35 mmHg/cm/s, P=0.037). There was an inverse correlation between Z1 and mean CBFV (r=-0.673, P<0.0001). Linear mixed model analysis of exercise training revealed that Z1 was significantly decreased after 1-year exercise intervention irrespective of exercise modes (time effect: P=0.001; interaction between time and exercise modes: P=0.410). CONCLUSION: Our findings suggest that aMCI is associated with higher cerebrovascular impedance when compared to cognitively normal older adults, and that regular physical activity ameliorates cerebrovascular impedance in patients with aMCI. Supported by the NIH (5R01AG033106-01, RZ) and JSPS (16KK0011, JS).