Clinical features of Alzheimer's disease

The preclinical stage of Alzheimer's disease is inconspicuous and there are - almost by definition - no reliable and valid symptoms and signs which wo uld allow a very early diagnosis before the manifestation of irreversible d eficits. For a clinical diagnosis of dementia, cognitive impairment has to be severe enough to compromise the activities of daily living. In the mild dementia stage,difficulties with declarative memory are usually prominent; depressive symptoms are not infrequent, but the patient usually manages to live alone. Supervision is needed in the moderate dementia stage, when othe r cognitive domains are affected in a more obvious manner and non-cognitive disturbances of thought, perception, affect, and behavior put increasing s tress on the caregivers. Complete dependence of the patients, who frequentl y develop neurological disturbances, is typical of the late stage of illnes s. The life expectancy of patients with a clinical diagnosis of Alzheimer's disease is significantly reduced, but to date there is hope that the perio d of relative well-being and not of suffering can be prolonged with modern symptomatic treatment interventions.