Feasibility of evoked potentials as a probe for exploring sleep

Sleep studies concerning auditory evoked potentials (AEPs) elicited by high stimulation rates are infrequent due to limitations in AEP extraction methods. Stages of sleep are conventionally determined by visual scoring of electroencephalography (EEG) signals. The regulatory mechanisms of the sleep-cycles may help us explore how sleep affects AEPs and, in the future, may be suitably implemented as dynamic probes for the neurophysiological monitoring of sleep. In this study we implemented deconvolution methods to extract AEPs, and extend the scoring method by incorporating quantitative EEG descriptors. Data were collected according to a protocol approved by the Institutional Review Board at the University of Miami. Subjects were recorded under two conditions: sleep and resting-wakefulness. For each condition, three auditory stimulus regions were delivered in series: 5 Hz low-rate (control), 30 Hz high-rate stimuli region, and silence region (control). To assess the underlying sleep stages, EEG was collected and scored according to the American Academy of Sleep Medicine (AASM) guidelines and further analyzed with quantitative descriptors. Preliminary results demonstrated changes in the AEPs components that correspond to the changes of sleep depth. In conclusion, this methodology appears feasible to monitor sleep and investigate underlying brain processing changes in sleep.