Overview of Dementia

From Primary Care RAP:

Rob Orman MD and Heidi James MD
● Contrary to popular belief, dementia is not a normal part of aging. It affects approximately 5.2 million Americans over the age of 65. After the age of 65, the lifetime risk of developing dementia is roughly 20%.
● The DSM-5 renamed dementia; it is now referred to as major neurocognitive disorder. This new definition has a much broader reach, to include younger patients, such as someone with a brain injury or another disease process that can impair cognition.It is generally dened as a decline in cognition involving one or more of the following domains:
     ○ Learning and memory. This includes free recall, cued recall, recognition memory, and autobiographical long-term memory.      ○ Language. Object naming, word finding, fluency, grammar/syntax, and receptive language are elements of this domain.
     ○ Executive functioning. Planning, decision-making, working memory, responding to feedback, inhibition, and mental exibility are examples.
     ○ Complex attention. This includes sustained, divided, or selective attention and information processing speed.
     ○ Perceptual motor function. Such as visual perception, visual constructional reasoning, and perceptual motor coordination.      ○ Social recognition. Recognition of emotions or insight.
● What is unique to dementia is that deficits must cause two major changes:
     ○ It must be a decline in the individual’s previous level of functioning.
     ○ It must interfere with the ability to perform activities of daily living.
● The onset of neurocognitive deficits is both insidious and progressive. It exists in a continuum, from mild to severe depending on the impact it has on one’s independence
Dementia should be distinguished from delirium (which is of more acute onset) and should not be attributable to another mental disorder.
Alzheimer’s is the most common form of dementia, causing approximately 70% of cases.
     Other common forms include Lewy body dementia, vascular dementia, frontotemporal dementia, and Parkinson’s disease. There can be overlap between some of these dementias; this is particularly common with vascular dementia and Alzheimer’s disease. Rarer causes of neurocognitive disorder include normal pressure hydrocephalus, prion disease, HIV-related changes, alcohol, traumatic brain injury, and medication-induced.
     ● Normal pressure hydrocephalus (NPH) is one of the few reversible causes of dementia. Its symptoms may include cognitive decline, incontinence, and gait disturbance. NPH is reversible with an intracranial shunt.
● There are numerous risk factors for neurocognitive disorders.
     ○ Age is the biggest risk factor. 40% of those who live to be 90 meet the diagnostic criteria.
     ○ Other risk factors include family history, lower education level, cardiovascular comorbidity, chronic anticholinergic use, apolipoprotein E4 genotype, and Down syndrome.
● While there is no protective shield against the development of dementia, lifelong learning, a healthy diet, exercise, and the maintenance of social connectedness are believed to lessen the risk, particularly of Alzheimer’s. When a patient reports a plan to retire, encourage him/her to take up a few hobbies and make sure the patient has a good social network. A wide network of friends has the added benefit of enabling people with dementia to live at home for a longer period of time.
● Many people present to a primary care clinic concerned about memory loss. More often than not, they only have mild cognitive impairment (MCI) and do not meet criteria for major neurocognitive disorder. Each yearly, roughly 10-15% of those with MCI will go on to meet the dementia diagnostic criteria. Typically, those with Alzheimer’s are unaware of their own memory loss; it is friends or family who encourage the clinic visit for evaluation.
● Given its prevalence and morbidity, should primary care providers be screening patients for dementia if asymptomatic? No.
     ○ Both the United States and Canadian Preventive Services Task Forces agree that screening is unnecessary.
     ○ Since dementia is not treatable or reversible, screening has little benefit.
● When a patient schedules an appointment due to concern about memory loss, Dr James usually arranges a two visit evaluation.      ○ On the first visit, she takes a thorough collateral history from the patient and his/her family members, does a physical exam, and arranges for diagnostic testing (laboratory and neuroimaging).
          ■ The history focuses on details regarding the onset and progression of symptoms. It includes family history, past medical history, medication history, and mental health history.
          ■ Alcohol and drug use are discussed.
          ■ James does not do screening tests for dementia on the first visit, as she feels that family concern is a sufficient reason to embark on a full workup.
          ■ The physical exam includes a complete neurologic exam.
          ■ Diagnostic testing is done to rule out reversible causes. Standard labs can include a CBC, electrolytes, creatinine, TSH, folate, liver function tests, B12, syphilis screen, and an HIV test. Head CT scans are typically adequate for neuroimaging.
     ○ On the second visit, Dr James does a screening test for dementia. There are several validated tests from which to choose.
          ■ The mini-mental status exam (MMSE) takes about 5 minutes. A perfect score is 30, and any result less than 25 is generally indicative of dementia. The clock-drawing test can be added as part of the MMSE assessment.
          ■ The Montreal Cognitive Assessment Test is another option.
          ■ All tests should be graded with the patient’s education level in mind.
          ■ The tests evaluate the various domains affected by dementia: recall, orientation, ability to follow multi-step instruction, and visuo-spatial ability.
○ If the diagnosis of dementia is highly suspected, patients can be referred to a neurologist or geriatrician if the services are available. Most, however, can be well managed by their primary provider. The greatest service the primary provider can provide is supporting the patient’s family and connecting them with community resources as they journey through dementia together.

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