Validation of a polysomnographic score for REM sleep behavior disorder.
OBJECTIVE
Rapid eye movement (REM) sleep behavior disorder (RBD) was described more than 2 decades ago, but only 1 report on 5 patients and 5 normal subjects has tested the effectiveness of a method by which relevant polysomnographic findings can be quantified. We sought to validate this method in a larger sample of patients and control subjects.


METHODS
Cross-sectional.


METHODS
Academic hospital.


METHODS
A clinician interviewed 17 patients at risk for RBD secondary to neurodegenerative disorders and 6 controls to assess whether RBD was present by history. Bed partners completed a questionnaire that quantified RBD symptom severity. From 2 consecutive nocturnal studies in each patient, 2 different polysomnographic RBD scores were generated: the percentage of 30-second REM epochs with at least 15 seconds of tonically maintained electromyographic activity, and the percentage of 3-second REM mini-epochs that contained phasic electromyographic bursts.


RESULTS
The tonic and phasic measures, combined together, were higher in patients with clinical determinations of probable or possible RBD (n=9) than in patients judged unlikely to have RBD (n=4, P = .023). The overall polysomnographic measure correlated with the symptom scores (rho = 0.42, P = .048). Specific polysomnographic RBD measures on night 1 correlated highly with those on night 2 (rho > 0.70, P < .0001).


CONCLUSIONS
This quantitative method to assess the severity of RBD polysomnographic features appears to be both valid and reliable in patients at risk for RBD because of neurodegenerative disorders.
Consens
Flavia B
FB
University of Michigan, Ann Arbor, MI, USA. fconsens@umich.edu
Chervin
Ronald D
RD
Koeppe
Robert A
RA
Little
Roderick
R
Liu
Suyu
S
Junck
Larry
L
Angell
Karen
K
Heumann
Mary
M
Gilman
Sid
S
D000368:Aged; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods*; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires