Circadian activity rhythm in Parkinson's disease: findings from the PHASE study

Circadian disruptions in Parkinson's disease (PD) are characterized as amplitude reduction rather than as phase shift; however, large-scale studies evaluating circadian rhythms between PD patients and non-PD older adults have not been performed. The present study aimed to compare the circadian activity rhythm (CAR) between PD patients and non-PD older adults.

In this cross-sectional study on 157 PD outpatients and 1111 community-dwelling older adults (controls), physical activity was measured using actigraphy at 1-min intervals over 6 days in PD patients and 2 days in non-PD older adults. Data were base-10 log-transformed and regretted to the sigmoidally transformed cosine curve.

The mean amplitude (log counts/min) and acrophase were 1.85 (SD, 0.52) and 14:19 (SD, 1:15), respectively, in the controls (n = 1111); 1.42 (0.48) and 14:24 (1:20), respectively, in the early-stage (Hoehn-Yahr I and II) PD patients (n = 95); and 1.23 (0.54) and 13:41 (1:56), respectively, in the late-stage (Hoehn-Yahr III-V) PD patients (n = 62). Multivariable analysis revealed significantly lower amplitude in the early-stage and late-stage PD groups than in the controls. The acrophase significantly advanced in the late-stage PD group than in the controls. With the advancement of PD stage, amplitude and peak significantly decreased; trough increased; acrophase and active offset advanced; and robustness weakened.

Compared with non-PD older adults, PD patients exhibited a phase advance in CAR, along with amplitude reduction. With an advanced stage of PD, a phase advance in CAR also occurred, along with amplitude reduction and weakened robustness.