Contribution of stereotactic brain biopsies to the diagnosis in several cases of dementia.

Early detection and precise diagnosis of dementias are important since they determine subsequent medical care. Presently the only way to classify these syndromes is by neuropathological examination. Between 1972 and 1988, 246 stereotactic serial brain biopsies were performed in 28 selected demented patients. Comparison between preoperative clinical diagnosis and histological finding gives the following results: the diagnosis has been confirmed in 32%, corrected or specified in 67% and stereotactic brain biopsies only showed unspecific pathological gliosis in 8%. This emphasizes the difficulties to assess precisely the diagnosis. This must be kept in mind when evaluating drug trials.