An assessment of 24-hour ambulatory EEG/ECG monitoring in a neurology clinic.

The relative merits of 24-hour ambulatory EEG/ECG monitoring and routine EEG recording have been compared in a group of 62 patients attending a neurological clinic because of episodes of loss of consciousness. Overall, ambulatory EEG abnormalities were detected in 21 cases (34%) compared with 16 cases (26%) for routine EEG. Ambulatory EEG mainly improved the detection of generalised paroxysmal activity, but in some cases lateralised abnormalities were detected which were not present on the routine record. Patients who reported clinical attacks once a week or more frequently showed an improved yield of diagnostic abnormalities on ambulatory EEG, but the technique did not prove superior to routine EEG if attacks were less frequent. The indications for, and limitations of, ambulatory EEG monitoring are discussed.