Performance on three cognitive tasks by patients with dementia, depression or Korsakov's syndrome

Perception, attention and recall were measured in geriatric subjects and patients suffering from dementia, Korsakov's psychosis or depression. Dementia patients were unable to perceive, attend and recall; depressed patients were unable to attend; and patients with Korsakov's psychosis were unable to attend and recall. Perception, attention and recall were correlated in the normal group but not in any one patient group. Traditional assumption of the interdependence of these functions may not be applicable to these patients. Demented patients show a different pattern of cognitive disability than age-matched controls.