Latest Updates on the Evaluation of Suspected Dementia

The percentage of Americans older than 65 years of age is likely to double over the next decade, from just over 10% currently to 20% in 2020. The primary cause of dementia is Alzheimer's disease which is responsible for 70% of all cases of dementia. Other major causes are vascular dementia (17%), Lewy Body disease, Parkinson-related dementia, and frontal lobe dementia. The good news is that people are living longer, however, one of the side-effects is a greater number of people with dementia. Fortunately new research and diagnostic technology has enabled earlier detection of cognitive dysfunction and better treatment.

For people with suspected dementia or early cognitive decline, the medical workup is initiated with obtaining a history from family members or care givers since the person with the condition is likely to be unable to give an accurate history. Important considerations in the differential diagnosis of dementia are depression, substance abuse (primarily alcohol), medication side-effects, nutritional deficiency, and hypothyroidism.

Screening tests can be performed in the clinic, and at least one should be done during the initial visit. These tests are the verbal fluency test, the mini-cognitive assessment, and the Sweet 16. The most sensitive and specific test is the verbal fluency test. Ask the patient to name as many animals as possible in 1 minute. A score of less than 15 is suggestive of dementia. In people with 7 years of education or less, the cut-off score may need to be lowered to 12 or even 9 for people with no education.

In people who test positive, further testing is initiated and includes the mini-mental status exam and clock drawing test. A formal test for depression such as the geriatric depression scale should also be done. Helpful laboratory tests include a metabolic panel, folate and B-12 levels, TSH, CBC, and calcium. An MRI (or CT) of the brain is helpful, and FDG PET scanning can improve management in some cases. Also consider an HIV test, Lyme titer, rapid plasma reagin test (for syphilis) or cerebrospinal fluid analysis in appropriate patients.

Management is directed at the underlying cause. Acetylcholinesterase inhibitors such as donepezil may help slow down the progression of Alzheimer's Disease. Antihypertensives and other cardiovascular agents may help delay the progression of vascular dementia. Depression is very common in the elderly and pharmaceutical therapy can be effective for these patients.

REFERENCES

Evaluation of suspected dementia. Simmons BB, Hartmann B, Dejoseph D. Am Fam Physician. 2011 Oct 15;84(8):895-902. Review.

Pharmacologic treatment of Alzheimer's disease: an update. DeLaGarza VW. Am Fam Physician. 2003 Oct 1;68(7):1365-72. Review.

The 36-Hour Day. Mace NL and Rabins PV [2006].