Is rapid eye movement sleep behavior disorder a marker of Parkinson's disease severity?

Parkinson's disease (PD) is characterized by motor and non-motor features. There are several proposed clinical markers to define disease severity. However, if rapid eye movement sleep behavior disorder (RBD) is associated with worse prognosis of both motor and non-motor findings in PD is unknown.

To determine whether RBD is a marker of PD clinical severity.

We cross-sectionally compared patients according to the presence of RBD and used Hoehn Yahr, Schwab and England (ADL), MDS-UPDRS, brain magnetic resonance, polysomnography and autonomic reactivity tests to evaluate PD stage and disability. Pairwise comparisons and regression techniques were used to investigate the association of PD clinical markers with RBD.

We enrolled 120 PD patients. RBD was present in 46 % (n = 55; median age 65 years; 67 % male), who were compared to PD patients without RBD (n = 65, median age 62 years, 64 % male). There was also a healthy control group comprising 48 subjects (median age 57 years, 54 % male). Comparing PD patients with and without RBD, RBD was associated with higher MDS-UPDRS Part II scores [15(11-21) x 12(7-16), p = 0.02], higher frequency of abnormal gait (43,6 % x 21,5 %; p = 0.01), greater use of walking aids (21,8 % x 4,6 %; p = 0.005), greater dysautonomia (56,4 % x 47,7 %, p = 0.002) and osteoporosis [PR 1,64(1.37-1.96), p < 0.001) and lower ADL scores [80(80-90) x 90(80-90); p = 0.002], CONCLUSION: The presence of RBD in PD patients was associated with indirect indicators of motor impairment, lower independence in ADL, possibly a higher frequency of dysautonomia and with a higher frequency of osteoporosis.