title: A portable device for intensive care brain function monitoring with event-related potentials.
abstract: Monitoring level of consciousness or depth of sedation is essential in modern intensive care units and emergency rooms. Current methods are based on spontaneous EEG providing only indirect information on the reactivity of the brain. Measurement of auditory event-related potentials (ERPs) has been shown to have additional potential for evaluation of the level of consciousness. Unfortunately, compact and easy-to-use devices are not commercially available. In this study a portable battery-powered device for clinical auditory ERP measurements was designed, constructed and validated. The device consists of a five-channel data logger and a 16-bit stereo audio stimulator. The signals are digitized with a 22-bit sigma-delta analogue-to-digital converter and stored to a PC Card hard disk. Prior to the in vivo application, the device was validated with extensive technical tests. Importantly, the RMS noise amplitude of the EEG channels was found to be less than 1 mivroV and the delivered auditory stimulus intensity corresponded accurately the settings (mean difference 0.2+/-0.5 dB). In addition to technical tests the device was successfully validated in vivo. To summarize, a novel portable instrument for measurement of auditory event-related potentials in intensive care environment is introduced.
authors: Department of Clinical Neurophysiology, Kuopio University Hospital, University of Kuopio, P.O. Box 1777, FIN-70211 Kuopio, Finland. Pekka.Tiihonen@kuh.fi
authors: Pekka
authors: P
authors: Tiihonen
authors: Jukka
authors: J
authors: Kinnunen
authors: Juha
authors: J
authors: Töyräs
authors: Esa
authors: E
authors: Mervaala
authors: Ari
authors: A
authors: Pääkkönen
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D003243:Consciousness; D003422:Critical Care / Q000706:statistics & numerical data*; D054810:Deep Sedation / Q000295:instrumentation / Q000706:statistics & numerical data; D004558:Electric Stimulation; D004867:Equipment Design; D005071:Evoked Potentials; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000706:statistics & numerical data; D012984:Software