Validation of the Brazilian Portuguese version of the Rapid Eye Movement Sleep Behavior Disorder Screening...

A diagnosis of rapid eye movement sleep behavior disorder (RBD) currently requires confirmation with polysomnography (PSG). However, PSG may not be sufficiently available. In these situations, a clinical diagnostic measure might be useful.

To validate the Brazilian Portuguese version of RBD screening questionnaire (RBDSQ) for patients with Parkinson's disease (PD).

Using detailed clinical interviews and PSG analysis (diagnostic gold standard), a convenience sample of 69 subjects was divided into the following subgroups: patients with PD and RBD (PD+RBD; n=50) and patients with PD alone (PD-RBD; n=19).

RBDSQ-BR showed adequate internal consistency (Cronbach's α=0.809) and, except for item 8, adequate item-test correlation. The retest performed in a second sample (n=13, consecutive) showed high agreement for total score (intraclass correlation coefficient, ICC=0.863) and acceptable agreement for items 2, 3, 6.2, 6.3, 7, and 8 (K>0.60). The receiver operating characteristic (ROC) curve analysis had an area under the curve (AUC) of 0.728. A cut-off score of 4 enabled the correct diagnosis of 76.8% subjects and provided the best balance between sensitivity (84%) and specificity (57.9%), with a 2.0 likelihood ratio of a positive result (LR+) and a 0.3 likelihood ratio of a negative result (LR-). Items 2 and 6.2 had 84.2% specificity and 3.2 LR+. Combined items 1+2+6.2, 2+6.1, and 6.1+6.2 increased the specificity to 94.7%, with LR+ ranging from 6.1 to 7.6.

RBDSQ-BR is a reliable instrument, which may be useful for RBD diagnosis of Brazilian patients with PD. The instrument is also valid and may help in a better selection of cases for a more detailed clinical evaluation or even PSG analysis.