A laboratory validation study of a portable system for remote recording of sleep-related respiratory disorders

This study represents the validation of an out-of-laboratory recording system for screening sleep disorders by comparing it to an in-laboratory system which accomplishes complete polysomnography. Forty patient cases were collected. Each patient slept in the sleep laboratory with the simultaneous monitoring of eight channels from the Sleep I/T (CNS, Inc), as well as complete polysomnographic monitoring comparable to that which accomplishes routine patient evaluations utilizing the Sleeplab (CNS, Inc) system. The data collected on the Sleeplab system were analyzed in a computer-assisted manner followed by manual overreading of the raw data. The Sleep I/T data analysis was performed automatically using default parameters. The results revealed no significant differences in the determination of sleep efficiency, respiratory disturbance index (RDI), periodic leg movement (PLM) index, or the desaturation index. For the RDI, the sensitivity was 100 percent and the specificity was 93 percent for correctly detecting an RDI of 15 per hour, and the PLM index had a sensitivity of 89 percent and specificity of 97 percent in detecting episodes greater than 20 per hour. These data demonstrate excellent agreement between this out-of-laboratory system and polysomnography in its ability to detect accurately RDI, PLM index, and saturation levels.