DETECTION OF PERIODIC LEG MOVEMENTS WITH A STATIC-CHARGE-SENSITIVE BED

We evaluated the performance of the static-charge-sensitive bed (SCSB) , a noninvasive movement sensor, in detecting nocturnal periodic movem ent activity using simultaneous bilateral anterior tibialis electromyo graphy (EMG(at)) as a reference. Two different study setups were used, one with 500 random record extracts, another with 10 continuous recor dings. The inter-rater reliability between two independent scorers was 0.92 in scoring EMG(at) and 0.91 in scoring SCSB. In an epoch based a nalysis, depending on the study setup and scorer, the sensitivity of t he SCSB to detect periodic leg movements was 0.81-0.94 whereas the spe cificity was 0.84-0.89. In a movement-by-movement analysis, despite in complete concordance between the two methods the total number of movem ents per hour were comparable. Our findings support the use of the SCS B as a non-invasive alternative to anterior tibialis EMG recordings to reveal the presence of nocturnal periodic movement activity and estim ate its frequency.