A review on epilepsy in the horse and the potential of Ambulatory EEG as a diagnostic tool.

Epilepsy in the horse is diagnosed based on clinical signs, but diagnosing can be difficult if a grand mal is not present. The future prospects of the horse and potentially the safety of the owner depend on an accurate diagnosis. This review presents information on epilepsy and focuses on the diagnostic potential of (Ambulatory) electroencephalography ((A) EEG). An epileptic seizure is a brain disorder, which expresses itself as a recurrent episode of involuntary abnormal behaviour. The aetiology can originate from inside or outside the brain or is idiopathic. Besides those categories, seizures can be classified as generalised or partial. A typical generalised tonic-clonic seizure is characterised by the prodrome, the ictus and the post-ictal phase. EEG is the graphic recording of rhythmic bioelectric activity which originates predominantly from the cerebral cortex. In human medicine, the 10/20 international basis system for electrode placement is used. This makes comparison more reliable and consistent. The normal human brainwaves recorded are alpha, beta, theta and delta waves. In the horse, fewer descriptions of normal signals are available. In humans suffering from epilepsy, spikes, complexes, spike-and-wave discharges and rhythmical multi-spike activity are seen. In horses suffering from epilepsy, spikes, sharp waves and spike-and-wave discharges are seen. In humans, AEEG has numerous advantages above short-duration EEG in diagnosing epilepsy or intracranial pathology. In future, AEEG might be useful to record brain signals in awake horses expressing their behaviour under natural circumstances.