Understanding the Screening and Diagnosis of Dementia in the Elderly

Many people mistakenly assume that dementia can occur as a natural result of aging. However, dementia is a specific medical disorder defined as cognitive impairment that causes a decline in one's ability to function. Most forms of dementia are more common in the elderly, thus the screening and diagnosis of dementia in this population deserves particular attention.

General screening for cognitive impairment should be conducted in all individuals who are greater than 80 years of age, as well as in elderly individuals who are undergoing elective surgery or were recently discharged from the hospital, in elderly with an unexplained decline in functional status, sleep difficulties or behavioral disturbances, and in older adults with poor adherence to prescribed medical regimens.

A rapid way to screen for the possibility of dementia is to use the mini-cog exam. This exam consists of a three item recall test and a clock face drawing test. This easy dementia screening test can help a health care provider determine if further work up to formally diagnose dementia is necessary in an elderly individual.

There are very specific criteria that must be met before an individual is formally diagnosed with dementia. According to the DSMIV, there are four criteria for diagnosing dementia:

1. Memory impairment

2. One or more of: aphasia (difficulty finding words), apraxia (difficulty executing movements), agnosia (failure to recognize objects), and/or decreased executive functioning.

3. Impairment of functioning that is a decline from the previous level of functioning.

4. The deficits must not appear exclusively during the course of delirium. Delirium is acute in onset and has a fluctuating course of disorganized thinking and difficulty maintaining one's focus.

In order to determine if an individual meets the above criteria for dementia, the diagnosing physician will need to obtain an accurate history by speaking to both the patient and the patient's family or caregivers. A physician will also perform a full physical exam with a complete neurological evaluation. In addition, the mental status exam (MSE) should be conducted. A score of less than 20 on the MSE indicates significant cognitive impairment.

Certain lab tests should be performed in order to rule out a medical condition that may be causing the symptoms of dementia. Labs to consider when concerned about dementia in a patient include B12 and folate levels, RPR to rule out syphilis, an alcohol and drug screen, TSH and thyroid hormone levels, HIV test, and a complete blood count.

Imaging should also be considered in an individual with a potential new diagnosis of dementia. A CT or MRI of the head may be done to rule out vascular dementia, Alzheimer's disease, multiple sclerosis, head trauma, Pick's disease, and normal pressure hydrocephalus.

It is important for health care providers to know how and when to screen for dementia in the elderly. It is also crucial that physicians are familiar with the medical work up and specific criteria required for the diagnosis of dementia in order to avoid missing a reversible cause of cognitive impairment in elderly individuals.

Source: Diagnostic and Statistical Manual of Mental Disorders IV.