<unk>  (from Latin de- "apart, away" + mens (genitive mentis) "mind") is the progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal ageing.
Particularly affected areas may be memory, attention, language, and problem solving. Especially in the later stages of the condition, affected persons may be disoriented in time (not knowing what day of the week, day of the month, month, or even what year it is), in place (not knowing where they are), and in person (not knowing who they are).
Symptoms of<unk>  can be classified as either reversible or irreversible depending upon the etiology of the disease. Less than 10 percent of cases of<unk>  have been reversed.<unk>  is a non-specific term encompassing many disease processes, just as fever is attributable to many etiologies. We do not routinely screen asymptomatic older adults for cognitive impairment. However, cognitive difficulty observed in a patient encounter, and family or patient concerns for memory and cognition, require thorough evaluation.
Without careful assessment, delirium can easily be confused with<unk>  and a number of other psychiatric disorders because many of the signs and symptoms are also present in<unk>  (as well as other mental illnesses including depression and psychosis). Screening for depression in patients with<unk>  is recommended because depression is a common treatable comorbidity that may also masquerade as<unk> . Cognitive deficits may be pronounced and similar to<unk> . However, both depressive symptoms and cognitive impairment respond to treatment with antidepressants, distinguishing these patients from those with Alzheimer disease and secondary depression. Late-life depression remains underdiagnosed and inadequately treated
Dementia
Orientia
Parkinsonism
Multi-infarct dementia
Semantic dementia
Early-onset Alzheimer's disease
Delirium
Alzheimer's disease