To investigate the diagnostic value of electroencephalography (EEG) in dogs with epilepsy, applying human criteria for EEG abnormalities observed with this disorder. Twenty-six dogs with a clinically established diagnosis of epilepsy were investigated with electroencephalography (EEG) in order to evaluate the diagnostic yield of EEG in canine epilepsy. Of 23 dogs with evaluable EEGs 15 (65%) demonstrated abnormal activity. The most common abnormalities were focal low frequency patterns without spikes (48%), followed by focal epileptiform activity (22%) and generalized epileptiform activity (17%). The distribution between focal and generalized activity were 73% and 27%, respectively. Consistency were demonstrated between the clinical- and the EEG-diagnosis in 13 dogs (87%). A relationship was demonstrated between the number of abnormal EEGs and the proximity of a seizure to the EEG examination. A marked consistency was demonstrated between the clinical diagnosis of seizure type and the type of abnormalities observed in the EEG, thus indicating that EEG is a valuable diagnostic aid in confirming the diagnosis of epilepsy in dogs. EEG findings in dogs with epilepsy and humans with this disorder were markedly similar.
