Portable computerized polysomnography in attended and unattended settings

Study objective: We compared the validity of a new portable polysomnographi c recorder against a laboratory-based polysomnographic system from the same manufacturer. Design and patients: Simultaneous, full polysomnographic recordings from th e portable device (PSGP) and the laboratory-based system (PSGL) were obtain ed using separate sets of sensors on 20 patients referred for investigation of sleep apnea, Setting: After initial optimization of signals, the portable device was lef t unattended in 10 of the patients (to simulate home studies), while in the other 10 the signals were reviewed on a laptop computer screen and adjustm ents to electrode or sensor placement made as needed during the studies. Re cordings were manually scored by a technologist blinded to the origin of th e data, Measurements and results: The quality of signals was comparable between the PSGP and PSGL studies, apart from a slight decrease in respiratory signal quality dating PSGP studies that led to reduced confidence in respiratory e vent scoring. SaO(2) signal loss was also greater in unattended PSGP, There was good agreement between PSGP and PSGL for sleep variables and the apnea -hypopnea index (r = 0.99). The periodic limb movement index was slightly l ower during unattended PSGP, Blinded physician assessment of the records le d to a recommendation for repeat studies due to poor signal quality in one (10%) attended and one (10%) unattended per-table recording. There was no s ignificant discordance between PSGP and PSGL in the final diagnostic formul ations, Conclusion: Portable polysomnography is a viable alternative to laboratory- based polysomnograph! and may be improved further by better sensor attachme nt.