As a rule, in hospital practice there’ is little urgency for a rapid diagnosis in idiopathic epilepsy to be effected, and doubtful cases can be submitted to prolonged observation until an actual seizure has resulted. There are, however, certain occasions when the necessity arises for the establishment of a definite diagnosis as early as possible. In the average hospital case, the period of observation necessary will be a matter of days or, at the most, a week or so, but in cases of irregular seizures at infrequent intervals, this period may have to be extended into months before any opinion can be offered. It is with a view to curtailing this period of observation that an attempt has been made in this investigation to determine a method whereby the condition can be diagnosed with a degree of certainty in the absence of seizures.