Focal changes to human electrocorticography with drowsiness: A novel measure of local sleep

Jeremy D. Slater, Mircea I. Chelaru, Bryan J. Hansen, Charles Beaman, Giridhar Kalamangalam, Nitin Tandon, Valentin Dragoi

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Drowsiness may be defined as the progressive loss of cortical processing efficiency that occurs with time passing while awake. This loss of cortical processing efficiency is reflected in focal changes to the electroencephalogram, including islands of increased delta power concurrent with drop-offs in neuronal activity (i.e., focal cortical inactivity). The authors hypothesized that these focal changes are evidenced at individual electrodes by combination of increased instantaneous amplitude in delta band and decreased instantaneous frequency in theta-alpha band, permitting their categorization as “active” and “inactive.” An analysis of records from six patients with refractory epilepsy undergoing video-electrocorticographic monitoring was conducted. Feature extraction and state classification on multiple recordings revealed focal changes consistent with the hypothesis, as well as progressively increased numbers of inactive electrodes with time awake. The implications of these findings on the study of sleep, and particularly local sleep, are discussed.

Original languageEnglish (US)
Pages (from-to)236-247
Number of pages12
JournalJournal of Neuropsychiatry and Clinical Neurosciences
Volume29
Issue number3
DOIs
StatePublished - Jun 1 2017

ASJC Scopus subject areas

  • General Medicine

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