The value of long-term EEG recordings for diagnosis and differential d
iagnosis of epilepsy is described. It is emphasized that long-term EEF
monitoring increases the scope of EEG techniques and improves the dia
gnostic value of standard EEG recordings providing up to 90% positive
diagnostic information. In particular, the value of ambulatory cassett
e recording is stressed. Allowing quantification of epileptic activity
recorded in real-life situation, useful information not available by
means of standard EEG recordings can be obtained. Recording and scorin
g all-night sleep, it enables studying abnormalities of sleep patterns
. In addition the value of long-term EEG recordings in therapy and con
trol of epileptic patients is pointed out and discussed.