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Relationship between interictal epileptiform discharges under medetomidine sedation and clinical seizures in canine idiopathic epilepsy
  1. Shinichi Utsugi,
  2. Miyoko Saito,
  3. Toshikazu Sato and
  4. Maki Kunimi
  1. Department of Small Animal Surgery (Neurology), School of Veterinary Medicine, Azabu University, Kanagawa, Japan
  1. Correspondence to Dr Miyoko Saito; msaito{at}


Background Electroencephalography (EEG) is required for the diagnosis of canine idiopathic epilepsy as a highest confidence level of diagnosis by the International Veterinary Epilepsy Task Force; however, EEG is seldom used and a standardised assessment method has not been reported.

Methods Interictal EEG was performed under medetomidine sedation in dogs with idiopathic epilepsy and in control dogs. Epileptiform discharge (ED) frequency was compared between dogs with more severe and less severe seizures during one month before EEG and control dogs.

Results All 10 dogs with more severe seizures had ED, as had 7 of 11 with less severe seizures. All epileptic dogs without ED had good long-term outcomes. ED frequency (number of ED per five minutes) was significantly higher in dogs with more severe (median, 4.5) than with less severe seizure (median, 0.46) and in the control dogs (median, 0.15). An ED frequency greater than 0.8 was considered to indicate epilepsy.

Conclusion Interictal EEG in a light sleep state under medetomidine sedation had a high detection rate of ED, and ED frequency had a positive correlation with the recent severity of epileptic seizures. This allows interictal EEG recordings to be used as a simplified and objective test that may help to diagnose epilepsy and to assess the recent severity of the disease in dogs.

  • canine
  • visual analysis of EEG
  • epileptiform discharge frequency
  • severity of seizure
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  • MS and SU contributed equally.

  • Funding The study was supported in part by JSPS KAKENHI Grant Number JP17H01507.

  • Competing interests None declared.

  • Ethics approval This study was approved by the Institutional Research Committee at Azabu University, and all procedures were conducted in accordance with the guidelines approved by this committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article.

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