[Amnestic episodes].
Amnesic episodes, by no means infrequent occurrences, are likely to trigger off anxiety in the patient and to evade adequate diagnostic interpretation. They consist of an isolated disturbance of short-term memory, manifesting itself as a permanent memory gap. The clinical features may vary from a conspicuous behaviour with stereotype repetition of questions to a completely inconspicuous picture with flawless execution of even highly differentiated behaviour patterns. The vegetative state may either be completely undisturbed or vary from mild impairment with nausea and vertigo to marked vegetative disorder. We are advocating a classification in 3 groups: a) "Genuine" amnesic states as symptoms of impaired blood flow in the basilar system in the absence of other etiological clues. b) "Symptomatic" amnesic episodes with tangible pathogenic factors, such as injury of the head and cervical spine, epilepsy, intoxication with various agents. The "genuine" amnesic states can also be regarded as transitory ischemic attacks of the basilar system. They show the following criteria: preponderance in females beyond middle age, duration of several hours, relatively high frequency of vascular risk factors and degenerative changes in the cervical spine, often triggered off by stress on the cervical spine, low tendency towards recurrence, general clinical benignity. In consequence, we stress the importance of etiological clarification before the onset of therapy. After the diagnosis of "genuine" amnesic state has been established, treatment has to be in accordance with the principles of basilar stroke therapy with subsequent vascular prophylaxis. Nevertheless, because of possible therapeutic or forensic consequences, the "symptomatic" states have to be kept in mind.