[Cognitive impairment in very elderly patients: a retrospective study in a neurology service]

A considerable proportion of very elderly patients with cognitive impairment are attended in the general neurology offices. There are few studies about the clinical characteristics of these patients.

To describe the background and clinical features of very elderly patients who come to the general neurology clinic due to cognitive complaints or suspected cognitive impairment.

We retrospectively studied 336 patients (296 patients < 85 years vs. 40 patients >= 85 years of age) who had been mostly referred by primary care physicians. Cognitive performance was measured by the Mini-Mental State Examination and the overall (i.e., cognitive and functional) clinical situation was measured by the Clinical Dementia Rating scale.

Older patients had more frequently cognitive impairment (mild cognitive impairment or dementia), both at the first visit and at the one-year follow-up visit (p < 0.0005). No differences were found in symptom duration (2.0 ± 2.1 vs. 1.5 ± 1.4 years), type of symptoms, or comorbidity. Alzheimer's disease was the most frequent etiological diagnosis in both age groups (82.4% vs. 75.0%; p > 0.05).

Very elderly patients studied in the neurology office have a higher risk of presenting cognitive impairment, despite being comparable in terms of symptoms and time of evolution. These results could be explained from the hypotheses of brain reserve and combined brain pathology.