Electroencephalographic patterns of clinically normal, sedated, and tranquilized newborn foals and adult horses.
Abstract: To establish a clinically practical procedure for recording the equine EEG, 25 healthy adult horses and 6 newborn foals were used. Recordings were taken with the animals alert and tranquilized, confined in metal stocks, or physically restrained. The dominant alert waveforms of adult horses were fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV-dominant 10 to 15 microV). Underlying this fast activity was slower (0.5 to 4.0 Hz) activity with medium-to-low voltages (10 to 40 microV). Twelve of the 25 adult horses had EEG frequencies in the alpha frequency range (10 to 15 Hz, 10 to 50 microV). Eight horses were given xylazine and 17 were given acetylpromazine. Those given xylazine had generalized slowing with several distinct frequency patterns (25 to 40 Hz, 5 to 30 microV; 10 to 15 Hz, 10 to 80 microV; and 0.5 to 4.0 Hz, 10 to 90 microV). Horses given acetylpromazine had fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV). Underlying this activity were slower waveforms (1 to 4 Hz) with medium-to-low voltages (5 to 10 microV). Occasional well-formed spindle activity was observed (10 to 14 Hz, 10 to 50 microV). Acetylpromazine had little effect on the EEG recording, whereas xylazine exerted a substantial effect. All leads were synchronous with lower voltages in the left frontal, right frontal, and transfrontal leads. The alert pattern of a newborn foal was characterized by low frequency (2 to 6 Hz) with medium-to-high voltages (20 to 90 microV).(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1985-01-01 PubMed ID: 3970440
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- Comparative Study
- Journal Article
Summary
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This research established a practical method to record electroencephalogram (EEG) in horses and newborn foals, under both alert and tranquilized conditions, by observing dominant EEG patterns and how different tranquilizing drugs influenced these readings.
Methodology and Participants
- 25 healthy adult horses and 6 newborn foals were involved in the study
- They were either kept alert, sedated, confined within metal stocks or physically restrained during EEG recordings
- Two types of drugs, xylazine and acetylpromazine, were given to 8 and 17 horses respectively in order to study the effects of sedation on EEG patterns
Findings – Adult Horses
- Adult horses demonstrated a dominant waveform when alert, which was fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV). Alongside this, a slower activity was recorded of 0.5 to 4.0 Hz with voltages of 10 to 40 microV.
- Notably, 12 of the 25 adult horses tested demonstrated waveforms in the alpha frequency range (10 to 15 Hz, 10 to 50 microV)
- Effects of sedation on EEG varied significantly based on the drug administered. In horses given xylazine, multiple distinctive frequency patterns emerged – all slower than when in an alert state. Horses given acetylpromazine had fast activity similar to their alert state, but with a presence of slower waveforms as well.
- Overall, acetylpromazine seemed to have a negligible effect on EEG patterns, while xylazine caused prominent alterations
Findings – Newborn Foals
- In newborn foals, the alert EEG pattern was characterized by low frequencies (2 to 6 Hz) with medium-to-high voltages (20 to 90 microV)
- However, the study does not provide specific findings on the impact of tranquilizers on the EEG readings of foals
Implications
- The study establishes a practical procedure for taking equine EEG readings under various conditions, which could be crucial for neurological evaluations
- The effects of different tranquilizers on EEG readings emphasize the need to account for these effects when interpreting EEG results
Cite This Article
APA
Mysinger PW, Redding RW, Vaughan JT, Purohit RC, Holladay JA.
(1985).
Electroencephalographic patterns of clinically normal, sedated, and tranquilized newborn foals and adult horses.
Am J Vet Res, 46(1), 36-41.
Publication
Researcher Affiliations
MeSH Terms
- Acepromazine / pharmacology
- Age Factors
- Animals
- Animals, Newborn
- Brain / drug effects
- Brain / physiology
- Electroencephalography / veterinary
- Female
- Horses / physiology
- Male
- Restraint, Physical / veterinary
- Thiazines / pharmacology
- Xylazine / pharmacology
Citations
This article has been cited 8 times.- Zanker A, Wöhr AC, Reese S, Erhard M. Qualitative and quantitative analyses of polysomnographic measurements in foals. Sci Rep 2021 Aug 11;11(1):16288.
- Lacombe VA. Seizures in horses: diagnosis and classification. Vet Med (Auckl) 2015;6:301-308.
- Rochais C, Sébilleau M, Menoret M, Oger M, Henry S, Hausberger M, Cousillas H. Attentional state and brain processes: state-dependent lateralization of EEG profiles in horses. Sci Rep 2018 Jul 5;8(1):10153.
- Cousillas H, Oger M, Rochais C, Pettoello C, Ménoret M, Henry S, Hausberger M. An Ambulatory Electroencephalography System for Freely Moving Horses: An Innovating Approach. Front Vet Sci 2017;4:57.
- Tünsmeyer J, Hopster K, Kästner SB. Clinical Use of a Multivariate Electroencephalogram (Narcotrend) for Assessment of Anesthetic Depth in Horses during Isoflurane-Xylazine Anesthesia. Front Vet Sci 2016;3:25.
- Lewis MJ, Williams DC, Vite CH. Evaluation of the electroencephalogram in young cats. Am J Vet Res 2011 Mar;72(3):391-7.
- Steiss JE. A survey of current techniques in veterinary electrodiagnostics: EEG, spinal evoked and brainstem auditory evoked potential recording. Vet Res Commun 1988;12(4-5):281-8.
- Short CE, Räihä JE, Räihä MP, Otto K. Comparison of neurologic responses to the use of medetomidine as a sole agent or preanesthetic in laboratory beagles. Acta Vet Scand 1992;33(1):77-88.
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