Organic brain disease in psychogeriatric patients: impact of symptoms and screening methods on the diagnostic process

Psychogeriatric patients are mentally affected by a heterogeneous group of diseases, traditionally classified as functional or organic brain disorders (OBDs). Here, we evaluate screening procedures with respect to revelation of underlying OBD. Fifty consecutive patients admitted to a psychogeriatric unit dedicated to late-onset psychiatric disease were included. Diagnosis at admission, symptoms, and time of onset of disease were determined blindly by an independent, experienced psychiatrist on the basis of referral documents and the interview written at admission. Subsequently, consensus established a clinical diagnosis (after psychiatric and neurologic evaluations) and a final diagnosis after the screening procedures (Cognistat and MMS-tests, electroencephalograms, computed tomography, and SPECT). Conventional criteria (ICD-10, ICPC) were used for diagnostic classification. Only 10 of the 50 patients were diagnosed with OBD at admission and an additional 7 patients following full clinical evaluations. At final diagnosis, 34 (of 46) patients were diagnosed with significant OBD. The Cognistat test had the largest diagnostic impact, with sensitivity/specificity values of 81%/60% for OBD.