Time-Frequency Analysis of Somatosensory Evoked High-Frequency (600 Hz) Oscillations as an Early Indicator of Arousal Recovery after Hypoxic-Ischemic Brain Injury

Ze Ou, Yu Guo, Payam Gharibani, Ariel Slepyan, Denis Routkevitch, Anastasios Bezerianos, Romergryko G. Geocadin, Nitish V. Thakor

Research output: Contribution to journalArticlepeer-review

Abstract

Cardiac arrest (CA) remains the leading cause of coma, and early arousal recovery indicators are needed to allocate critical care resources properly. High-frequency oscillations (HFOs) of somatosensory evoked potentials (SSEPs) have been shown to indicate responsive wakefulness days following CA. Nonetheless, their potential in the acute recovery phase, where the injury is reversible, has not been tested. We hypothesize that time-frequency (TF) analysis of HFOs can determine arousal recovery in the acute recovery phase. To test our hypothesis, eleven adult male Wistar rats were subjected to asphyxial CA (five with 3-min mild and six with 7-min moderate to severe CA) and SSEPs were recorded for 60 min post-resuscitation. Arousal level was quantified by the neurological deficit scale (NDS) at 4 h. Our results demonstrated that continuous wavelet transform (CWT) of SSEPs localizes HFOs in the TF domain under baseline conditions. The energy dispersed immediately after injury and gradually recovered. We proposed a novel TF-domain measure of HFO: the total power in the normal time-frequency space (NTFS) of HFO. We found that the NTFS power significantly separated the favorable and unfavorable outcome groups. We conclude that the NTFS power of HFOs provides earlier and objective determination of arousal recovery after CA.

Original languageEnglish (US)
Article number2
JournalBrain Sciences
Volume13
Issue number1
DOIs
StatePublished - Jan 2023

Keywords

  • cardiac arrest
  • continuous wavelet transform
  • high-frequency oscillations
  • hypoxic-ischemic injury
  • somatosensory evoked potentials

ASJC Scopus subject areas

  • General Neuroscience

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