ESSENTIALS OF DIAGNOSIS
Progressive decline of intellectual function.
Deficits in one or more cognitive domains severe enough to cause impairment of function.
Not due to delirium or another mental disorder.
Dementia is an acquired, persistent, and progressive impairment in intellectual function, with compromise of one or more cognitive domains. The Diagnostic and Statistical Manual, 5th edition identifies these domains (with example deficits) as: (1) complex attention (easily distracted, difficulty performing calculations), (2) executive function (poor abstraction, mental flexibility, planning, and judgment), (3) learning and memory (difficulty recalling items from a list, forgetting recent events), (4) language (word finding and object naming difficulty), (5) perceptual-motor function (difficulty navigating in known environments, copying a drawing), and (6) social cognition (change in personality, trouble reading social cues). The diagnosis of dementia requires a significant decline in function that is severe enough to result in the loss of independence in IADLs.
While dementia prevalence doubles every 5 years in the older population, reaching 30–50% at age 85, the prevalence among US adults 65 years or older has been declining. This improvement has been attributed to higher education levels and better control of cardiovascular risk factors. Women suffer disproportionately, both as patients and as caregivers. Alzheimer disease accounts for roughly two-thirds of dementia cases in the United States, with vascular dementia (either alone or combined with Alzheimer disease) and dementia with Lewy bodies accounting for much of the rest. Some risk factors for Alzheimer disease are older age, hyperlipidemia, hypertension, family history, lower education level, and female sex. Approximately one-third of Alzheimer disease cases worldwide might be prevented by addressing nine risk factors throughout life. Education, cognitive "exercises," and social support may be protective. Risk factors for vascular dementia are those for stroke, ie, older age, hypertension, cigarette use, atrial fibrillation, diabetes mellitus, and hyperlipidemia.
Depression and delirium are also common in elders, may coexist with dementia, and may also present with cognitive impairment. Depression is a common concomitant of early dementia. A patient with depression and cognitive impairment whose intellectual function improves with treatment of the mood disorder has an almost fivefold greater risk of suffering irreversible dementia later in life. Delirium, characterized by acute confusion, occurs much more commonly in patients with underlying dementia.
According to the US Preventive Services Task Force (USPSTF), there is insufficient evidence to recommend for or against screening all older adults for cognitive impairment. While there is logic in the argument that early detection may improve future planning and patient outcomes, empiric evidence that demonstrates a clear benefit for either patients or caregivers is lacking. It is important to note, however, that the Medicare Annual Wellness Visit mandates that clinicians assess patients for cognitive impairment based on the clinician’s observations and reports ...