title: Multichannel wearable system dedicated for simultaneous electroencephalography∕near-infrared spectroscopy real-time data acquisitions.
abstract: Functional neuroimaging is becoming a valuable tool in cognitive research and clinical applications. The clinical context brings specific constraints that include the requirement of a high channel count to cover the whole head, high sensitivity for single event detection, and portability for long-term bedside monitoring. For epilepsy and stroke monitoring, the combination of electroencephalography (EEG) and functional near-infrared spectroscopy (NIRS) is expected to provide useful clinical information, and efforts have been deployed to create prototypes able to simultaneously acquire both measurement modalities. However, to the best of our knowledge, existing systems lack portability, NIRS sensitivity, or have low channel count. We present a battery-powered, portable system with potentially up to 32 EEG channels, 32 NIRS light sources, and 32 detectors. Avalanche photodiodes allow for high NIRS sensitivity and the autonomy of the system is over 24 h. A reduced channel count prototype with 8 EEG channels, 8 sources, and 8 detectors was tested on phantoms. Further validation was done on five healthy adults using a visual stimulation protocol to detect local hemodynamic changes and visually evoked potentials. Results show good concordance with literature regarding functional activations and suggest sufficient performance for clinical use, provided some minor adjustments were made.
authors.affiliation: Ecole Polytechnique de Montreal, Department of Electrical Engineering, Montreal, Quebec, H3C-3A7 Canada.
authors.forename: Etienne
authors.initials: E
authors.lastname: Lareau
authors.forename: Frederic
authors.initials: F
authors.lastname: Lesage
authors.forename: Philippe
authors.initials: P
authors.lastname: Pouliot
authors.forename: Dang
authors.initials: D
authors.lastname: Nguyen
authors.forename: Jerome
authors.initials: J
authors.lastname: Le Lan
authors.forename: Mohamad
authors.initials: M
authors.lastname: Sawan
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D003020:Clothing; D004569:Electroencephalography / Q000379:methods*; D006801:Humans; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D010775:Photic Stimulation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014793:Visual Cortex / Q000502:physiology