Qualitative and quantitative characteristics of the electroencephalogram in normal horses during spontaneous drowsiness and sleep

D. Colette Williams, Monica R Aleman, T. A. Holliday, D. J. Fletcher, B. Tharp, Philip H Kass, Eugene Steffey, Richard A Lecouteur

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Background: The influence of sleep on the equine electroencephalogram (EEG) has not been well documented. Hypothesis: The objectives were to develop a noninvasive method of electrode placement for recording the EEG in horses and to establish normal EEG parameters for the various states of vigilance. Findings are compared with previously published reports on equine sleep based on electrocorticography (ECoG). Animals: Five neurologically normal horses. Methods: Overnight EEGs were recorded digitally in association with simultaneous videotaping of the horses' behavior. Data were analyzed by visual inspection, states of vigilance were identified, and representative segments were quantitatively processed. Transient EEG events were examined. Results: Slow wave sleep (SWS) was significantly different (P < .05) in frequency and power from drowsiness and rapid eye movement (REM) sleep. Second-degree heart block was associated with SWS as were transient events commonly recognized in EEGs of humans. Drowsiness and REM sleep were similar. In both, background activity was low-amplitude β activity admixed with prominent activity of approximately 4 Hz. Standing REM sleep was associated with numerous partial collapses in 1 horse. Conclusions and Clinical Importance: Normative data for several states were described and probable benign variants identified. This information will serve as control data for sedative and anesthetic studies in this species. The sleep patterns observed during this study are those of horses removed from their usual surroundings, and thus may represent those encountered in a clinical environment.

Original languageEnglish (US)
Pages (from-to)630-638
Number of pages9
JournalJournal of Veterinary Internal Medicine
Volume22
Issue number3
DOIs
StatePublished - May 2008

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electroencephalography
Sleep Stages
sleep
Horses
Electroencephalography
Sleep
horses
REM Sleep
eyes
Heart Block
sedatives
Hypnotics and Sedatives
anesthetics
electrodes
Anesthetics
Electrodes
heart

Keywords

  • Equine electroencephalography
  • Rapid eye movement sleep
  • Slow wave sleep
  • Wakefulness

ASJC Scopus subject areas

  • veterinary(all)

Cite this

Qualitative and quantitative characteristics of the electroencephalogram in normal horses during spontaneous drowsiness and sleep. / Williams, D. Colette; Aleman, Monica R; Holliday, T. A.; Fletcher, D. J.; Tharp, B.; Kass, Philip H; Steffey, Eugene; Lecouteur, Richard A.

In: Journal of Veterinary Internal Medicine, Vol. 22, No. 3, 05.2008, p. 630-638.

Research output: Contribution to journalArticle

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