OPERATIONAL CRITERIA FOR THE CLASSIFICATION OF CHRONIC-ALCOHOLICS - IDENTIFICATION OF WERNICKE ENCEPHALOPATHY

Objectives-To establish better operational criteria for the diagnosis Wernicke's encephalopathy. Current criteria for diagnosing Wernicke's encephalopathy require the presence of three clinical signs (oculomoto r abnormalities, cerebellar dysfunction, and an altered mental state), although it has often been reported that most patients do not fulfil all these criteria. Methods-The clinical histories of 28 alcoholics wi th neurological and neuropsychological assessments and definitive neur opathological diagnoses were examined to determine clinical signs for use in a screening schedule. Operational criteria were then proposed f or differentiating patients with Wernicke's encephalopathy alone or in combination with Korsakoff's psychosis or hepatic encephalopathy. The new criteria for Wernicke's encephalopathy require two of the followi ng four signs; (1) dietary deficiencies, (2) oculomotor abnormalities, (3) cerebellar dysfunction, and (4) either an altered mental state or mild memory impairment. Reproducibility and validity testing of these criteria were performed on 106 alcoholics screened from a large necro psy sample. Results-Despite rater variability with regard to specific symptoms, within and between rater reliability for diagnostic classifi cation using the criteria retrospectively on patient records was 100% for three independent raters. Validity testing showed that Wernicke's encephalopathy was underrecognised only when occurring with hepatic en cephalopathy (50% sensitivity). Conclusions-By contrast with current c riteria, the proposed operational criteria show that the antemortem id entification of Wernicke's encephalopathy can be achieved with a high degree of specificity.