Idiopathic epilepsy in 125 dogs: a long-term study. Clinical and electroencephalographic findings.

Well-documented cases of confirmed idiopathic epilepsy in 125 dogs were evaluated retrospectively. Forty-six breeds (each with no sex predisposition) were examined. Although dogs of all ages were affected, the peak value for the onset of first seizure was between one and five years. Approximately 75 per cent of animals had generalised grand mal type seizures with loss of consciousness. Preictal and postictal phases were present in the majority of dogs. Interictal electroencephalographic recordings of 37 anaesthetised dogs were statistically analysed. High frequency and low amplitude paroxysmal discharges with either a focal or generalised distribution were found in the majority of these dogs. Possible causes for this variation from dog to dog were analysed. It was concluded that, despite anaesthesia, electroencephalographic features were consistent and unique in dogs with idiopathic epilepsy.