Forgetfulness occurs more frequently with aging. Memory functions less efficiently with aging, more noticeably after the age of 50. However, this is not dementia. Forgetfulness does not interfere with activities of daily living (you still remember to eat and to get your clothes on straight). A typical statement would be, "Do you know where I left the car keys?" The best way to retain mental sharpness with aging is to remain mentally active and continue to learn. However, dementia is NOT a normal aging process.

The acute events of the past week are typical for delirium, not dementia, which is a chronic process. Delirium is an acute confusional state with loss of attention, clouding of consciousness, decreased short-term memory, anxiety, irritability, and mental status fluctuation. Patients who already have dementia may exhibit 'sundowning' with mild to moderate delirium at night, often brought on by drugs. Benzodiazepines are a common cause for delirium. Changes in sleep patterns occur with aging. The amount of REM sleep does not change, but there is a marked decrease in stage 3 and 4 sleep, with an increase in wakeful periods.

Alzheimer disease accounts for 90% of cases of dementia. Dementia affects activities of daily living. Persons with dementia can no longer remember how to do routine tasks. Two simple questions can reveal the extent of the problem: (1) can the affected person find the bathroom in the house? (2) does the affected person recognize family members? Persons affected by dementias are not themselves anymore, and it is no use to get angry over this situation. No amount of nagging or repetition will change things. In the earlier stages of a dementia, when some higher mental functions are still retained, it can be a very frustrating situation for the affected person (e.g., an accountant who can no longer use a calculator).

Short term memory loss can occur from pathologic conditions. The hippocampi are the regions where short term memories are formed, and selective damage to these structures can be manifested, not as dementia, but as short term memory loss. Such affected persons retain all long-term memories and can perform activities of daily living. However, they form new memories poorly. The hippocampal neurons are very sensitive to hypoxia, so diseases that could lead to hypoxic episodes (such as heart disease) could affect the brain in this way. A classic statement from the family member of an affected person would be, "What did I just say?" The loss of neurons is permanent, so affected persons will have difficulty forming new memories, though older memories and activities of daily living are not affected.

A clinical diagnosis is typically made. Laboratory testing can help rule out metabolic diseases (e.g., hypothyroidism). Brain biopsy is not done. Radiographic procedures such as MRI and PET scans can indicate whether there are lesions (with MRI) or brain activity patterns typical for dementia (with PET). [PET scans for non-malignant conditions may not be reimbursed.]

There is little that can be done to alter the course of a dementia such as Alzheimer disease. Research is continuing in this area. Family members must learn to cope with the nature of the illness. Decisions regarding long-term care need to be made.