Dementia and cognitive impairment in the oldest old in the community. Prevalence and comorbidity.

BACKGROUND

The study focuses on the prevalence of dementia in the oldest old.

METHOD

A community sample (n = 402) of the oldest old in Munich (> or = 85 years) was assessed with different methods. Four instruments and a clinical examination were used for case identification: (a) the Geriatric Mental State Interview (GMS-A); (b) the Structured Interview for the Diagnosis of Dementia (SIDAM); (c) the Global Deterioration Scale (GDS); and (d) the Mini Mental State Examination (MMSE). The clinical examination was performed by the interviewing physicians, who made their diagnoses according to ICD-10 and DSM-III-R.

RESULTS

The structured interviews (GMS-A: 25.4%; SIDAM/SISCO: 28.0%; SIDAM/DSM-III-R: 27.8%; SIDAM/ICD-10: 16.1%) gave lower point prevalence rates of dementia than physicians' clinical diagnoses (43.1%). The rates were 21.2% based on the MMSE. Depressive syndromes and anxiety syndromes were the most frequent psychiatric disturbances associated with dementia in the very old.

CONCLUSION

Dementia rates were high in the oldest old, showed an increase with age but no sex differences. Interview methodology has a major impact on results.