[Study of mapped slow auditory evoked potentials in Alzheimer's disease]

Alzheimer's disease affects around 500,000 persons in Italy and its diagnosis remains essentially clinical. Our aim was to contribute to the diagnosis of Alzheimer's disease by mapping auditory evoked potentials (AEP). Evoked potentials represent the electric response of the CNS to an external stimulus and can be represented as a sequence of waves. Brain mapping allows a chromotopogram to be compiled showing chromatic maps.

A group of 12 patients were studied aged between 68 and 84 years old who were referred to our attention at the Department of Geriatrics and Gerontology at Catania University and the A.O. Cannizzaro, Geriatrics Unit. All patients completed an assessment form (MM-SE, ADAS) and underwent brain NMR and AEP.

These tests enabled us to identify two types of patients (Group A and Group B) based on the responses shown. The overall evaluation of results revealed that patients with Alzheimer-type dementia present an anomalous cortical neurogenic response to mapped AEP, and that patients in Group A showed anomalous wave morphology, latency and localisation and asymmetric impregnation. The data gathered in this study did not confirm any specific characteristics of AEP given that similar anomalies are found in metabolic dysfunction syndromes and demyelination pathologies.

However, while it does not constitute a specific technique for screening against Alzheimer's disease, the mapping of AEP may contribute to the diagnosis of this disease.