Dementia is a general term for memory loss and decline in mental ability that is severe enough to interfere with the activities of daily living. Dementia can result from a variety of irreversible and potentially reversible causes. Reversible causes of dementia can include depression, vitamin B12 deficiency, hypothyroidism, side effects from medications, and infections. It is obviously important to know if the diagnosis can identify one of these reversible causes.
85-95% of dementias are due to irreversible causes. It is important to diagnose which particular disease may be causing the problems. Just like not all cancer medications work for all the different forms of cancers, medications and treatments for the different forms of dementia can vary widely, highlighting the need for an accurate diagnosis.
This is also important because 1 in 8 individuals over 65 will have a dementia and currently over 70% of them do not ever receive a clear diagnosis. Most older adults receive their medical care from primary care and other community physicians who often lack the clinical diagnostic information necessary to accurately determine the type of dementia afflicting the patient.
The most common form of irreversible dementia among the elderly is Alzheimer’s disease, which accounts for approximately 60% of all cases. More than 35 million people in the world suffer from Alzheimer’s disease, including 5.3 million in the USA. The scourge of Alzheimer’s disease adversely impacts California as 600,000 residents are affected, including over 60,000 individuals in Orange County.
The remaining 40% of dementia cases are caused by a variety of different disorders. These include Lewy body dementia, frontotemporal dementia, vascular dementia, Parkinson’s disease dementia, Huntington’s disease dementia, Creutzfeldt-Jacob dementia and a number of other very rare disorders.
Mild Cognitive Impairment (MCI) and Alzheimer’s Disease
It is important to get an accurate diagnosis of dementia and to get that diagnosis as early as possible. Studies show that a diagnosis is undetected in up to 91% of persons with mild symptoms and undetected in 76% of persons with moderate to severe symptoms. Families struggle to get a diagnosis, spending more than two years and seeing more than two doctors in the process. Families often battle over what is “normal” with their misinterpretations leading to stress and conflict. The actual diagnosis often provides relief for many. An early diagnosis gives families time to plan, to maximize safety, to participate in clinical trials and to experience benefits of the medications available today that are most effective when started early.
People who experience normal aging find that it takes a longer time to process new information and more effort to learn, organize and store new information. There is a greater susceptibility to distraction. They are slower to recall information, but the ability able to retrieve it remains intact. It is harder to quickly switch mental gears between several tasks.
There is a new and emerging area in the course of aging that is called the Preclinical period in which the individual may complain of problems with recent memory, concentrating or other cognitive abilities, but scores within the normal range on objective tests assessing these abilities. This is referred to as “a stage where the person knows – but the doctor doesn’t.”
Mild Cognitive Impairment (MCI) is diagnosed when the cognitive decline exceeds that expected for a person’s age and education, but the impairment does not interfere significantly with the activities of daily living. Multiple studies indicate that 8-15% of people with MCI progress to Alzheimer’s disease each year, compared to only 1-2% of older adults in general. Not all individuals with MCI progress to Alzheimer’s disease or another form of dementia, and a sizable number may actually return to normal levels of functioning. Curiously, men are more likely to be diagnosed with MCI.
Individuals with MCI may also experience behavioral changes that involve depression, anxiety, aggression and emotional apathy; these can be due to the awareness of and frustration related to his or her condition. Anti-depressants are often prescribed to treat these problems. Medications approved for treatment for Alzheimer’s disease may help with symptoms but do not ultimately halt the progression of the disease.
Vascular dementia is caused by poor blood flow to the brain, depriving brain cells of the nutrients and oxygen they need to function normally. Vascular dementia can result from any number of conditions that narrow the blood vessels, including stroke, diabetes and hypertension. Post stroke dementia has a sudden onset and a stepwise progression and the cognitive profile is highly variable, depending on the location of the stroke. After a stroke the risk of dementia doubles. Controlling hypertension, weight, diabetes and heart disease are vitally important to helping prevent vascular dementia.
Lewy Body Dementia
Lewy Body dementia is characterized by accumulation of abnormal protein deposits called Lewy bodies, which we typically associate with Parkinson’s disease. Most cases of Lewy body dementia occur in adults older than 60 and it appears to be more common in men. Common symptoms include visual hallucinations, fluctuating levels of attention (clear days and confused days), cognitive and motor dysfunction, sleep behavior disorder and severe sensitivity to anti-psychotic drugs.
The symptoms can closely resemble and overlap with Alzheimer’s and Parkinson’s making Dementia with Lewy bodies widely under-diagnosed. In fact, some patients start out with a movement disorder leading to a diagnosis of Parkinson’s, then develop dementia and other symptoms of Lewy body dementia. Others present with cognitive dysfunction that may look like Alzheimer’s initially, but with time, hallucinations, motor impairments and fluctuating attention appear. A third smaller group of patients present first with neuropsychiatric symptoms such as hallucinations, behavioral problems or difficulty with complex mental activities and later develop other symptoms. Drugs that are effective for Lewy body dementia include cholinesterase inhibitors which increase the levels of chemical messengers that are important for memory, thought and judgment and may help with hallucinations. Parkinson’s disease medications which help with motor problems can also cause increased confusion and hallucinations. Antipsychotic medications may improve hallucinations, but at least a third of Lewy body dementia patients can exhibit dangerous sensitivity to neuroleptics.
Frontotemporal dementia (FTD) causes damage to brain cells in the frontal and temporal lobes. FTD affects the individual’s personality significantly, usually resulting in a decline in social skills, coupled with emotional apathy. The emotional deficits are extremely problematic and include lack of concern for a loved one’s illness, cruelty to children, animals and the elderly, lack of concern when others are sad, rude comments, loss of respect for intrapersonal space, socially inappropriate behaviors, and diminished response to pain. Repetition, indifference to boredom, perseveration and focus on unimportant issues are some of the behaviors of patients with FTD. Unlike other types of dementia, FTD typically results in behavior and personality changes manifesting before memory loss and speech problems. It is more common than Alzheimer’s in people younger than 60 years old. Anti-psychotics and cholinesterase inhibitors are not appropriate for these patients although anti-depressants such as SSRI’s and the drug memantine may be helpful.
Parkinson’s Disease Dementia
Parkinson’s disease is a chronic, progressive neurological condition, and in its advanced stages, the disease can affect cognitive functioning. Not all people with Parkinson’s disease will develop dementia. Parkinson’s symptoms include tremors, rigidity, akinsesia (immobility) and postural instability, muscle stiffness and reduced muscular power. Reasoning, memory, speech, and judgment are usually affected. Parkinson’s is often accompanied by depression, hallucinations, anxiety, delusions, delirium, apathy and compulsive behaviors, some of which may be related to medications.
Performance may fluctuate during the course of a day or from day to day. The characteristics of executive functioning such as initiation, planning concept formation, rule finding and mental speed may be affected. Visuo-spatial functions such as orientation, perception and construction may be affected, causing a concern about driving. Memory may be affected in recall of recent events or learning new material although memory usually improves with cueing. Language is usually preserved although word finding difficulties and impaired comprehension of complex sentences may be present.
Huntington’s disease is an inherited progressive dementia that affects the individual’s cognition, behavior and movement. Huntington’s disease does not skip generations. Each child of a parent with Huntington’s has a 50/50 chance of inheriting the defective gene. If a child does not inherit the gene, he or she cannot pass it on. If the child does inherit the gene, he or she can pass it on and will develop the disease.
The cognitive and behavioral symptoms of dementia due to Huntington’s include memory problems, impaired judgment, problems with short-term memory, organizing, coping, concentrating, mood swings, depression and speech problems (especially slurred speech). Delusions and hallucinations may occur. In addition, the individual may experience fidgety behavior, lack of coordination, difficulty ambulating, and uncontrollable jerking movements of the face and body. Symptoms that may also occur are irritability, anxiety, aggressive outbursts and social withdrawal.
The average lifespan after onset is 10-25 years and the younger the age of onset, the more rapid the progression of the disease. Symptoms generally appear between the ages of 30 and 50, but can strike children and young adults.
The gene discovery has made possible a predictive test for Huntington’s from a blood sample allowing those at risk to find out whether or not they will develop the disease. Pre-and post-test counseling is critical.
Institute for Memory Impairments and Neurological Disorders
University of California, Irvine