Expert insight on Alzheimer’s causes, diagnosis & treatment
Alzheimer’s disease is a chronic brain disease that gradually erodes an individual’s memory, intellectual abilities and personality.
As of 2012, an estimated 5.2 million Americans — one in eight people age 65 or older — have Alzheimer’s, according to the Alzheimer’s Association, and this number is expected to increase rapidly as America’s baby boomers reach retirement age. Already, it’s the sixth leading cause of death in the United States.
4 questions for Alzheimer’s expert Glenn E Smith, PhD
To explain more about Alzheimer’s, the American Psychological Association asked Glenn E Smith, PhD, to share his knowledge about this mental illness. Dr Smith is a consultant in the Division of Neurocognitive Disorders, Department of Psychiatry & Psychology at the Mayo Clinic in Rochester, Minnesota, and is the clinical director of Alzheimer’s disease resources on MayoClinic.com.
1. News about Alzheimer’s frequently focuses on the use of medications to treat the disease. Are there behavioral treatments that can help without medication?
Outcomes of clinical trials with medications for treating Alzheimer’s have been disappointing.
Historically, these clinical trials involved patients with dementia, because the presence of dementia was required for the diagnosis of Alzheimer’s disease. There is a growing concern that by the time dementia is present, the brain may be so ravaged that treatment at that point cannot be effective.
Recently, substantial progress has been made in the ability to detect Alzheimer’s before dementia is present. For example, we can now reliably diagnose mild cognitive impairment. This ability has given rise to secondary prevention strategies that seek to prevent or delay progression to full dementia.
A variety of behavioral treatments show promise as secondary prevention strategies. At the Mayo Clinic, we have launched an intensive multicomponent intervention that combines daily physical activity, cognitive exercise, a memory compensation strategy, wellness education and support groups. We’ve observed that this intervention produces short-term improvement and longer-term stabilization of a patient’s ability to function.
2. What is early-onset Alzheimer’s, and do the symptoms differ between early-onset and when it occurs at a later age?
In normal aging, processing speed declines and word finding may worsen, but memory is relatively spared.
By contrast, the hallmark first sign of Alzheimer’s disease is forgetting. Indications of the illness first appear in brain structures that are critical for new learning and delayed recall of information. The disease soon spreads to regions supporting more complex understanding of language and executive function, which covers basic mental tasks such as planning, strategizing, organizing and setting goals. Simple attention (including processing speed), visual-spatial reasoning and other aspects of speech and language are generally spared early on.
In distinction, with another form of dementia known as Lewy Body disease, organizing visual information and understanding how it can change if movement occurs and other aspects of attention are impaired early. Attention is also compromised early in vascular-based cognitive impairment. By recognizing these cognitive differences, neuropsychological assessment can contribute to early diagnosis among the various types of dementia.
Early-onset dementia is a label applied when the diagnosis is before age 65. Clinically, Alzheimer’s disease presents pretty much the same at age 63 as at age 83. But Alzheimer’s disease is highly associated with advancing age.
For other causes of dementia, like fronto-temporal dementia and Lewy Body disease, peak incidence is at a younger age. So, early-onset dementia has a greater probability of not being caused by Alzheimer’s. Thus, differences between early- and late-onset dementias are based more in the different age-specific incidences of the various causes for dementia.
3. If someone has parents and grandparents diagnosed with Alzheimer’s, is it inevitable that person will someday also suffer from the disease? In other words, what is the role of genetics in the development of Alzheimer’s?
There are three major genes known to cause dementia, and these genes follow what is known as the Mendelian inheritance pattern, in which the genetic trait displayed results from one parent’s gene dominating over a gene inherited from the other parent. But these three genes are present in less than 5 percent of all dementia cases.
There are also genes that increase susceptibility to develop Alzheimer’s. The most notable of the susceptibility genes is the Apolipoprotein E (ApoE) gene. Carrying one copy of the ε4 form of the ApoE gene increases your risk up to four times. But you can carry the risky form of this gene and still not develop dementia, and many people develop the disease without carrying the ε4 gene.
Finally, a family history of Alzheimer’s irrespective of ε4 status does increase your risk of developing the disease. Yet even with a family history, the chances are still greater that you will die without developing Alzheimer’s disease than with the disease, provided you do not carry a causative gene.
4. What are the most important steps a person can take to prevent onset of the disease?
Physical and mental inactivity, smoking, obesity, diabetes, hypertension and depression (each modifiable by behavioral intervention) have been shown to be risk factors for the development of Alzheimer’s disease. Barnes and Yaffee, (Lancet Neurology, 2011) suggest that 25 percent improvement in these conditions among the general population would prevent as many as 16.5 percent of Alzheimer’s disease cases in the United States.
To ensure timely and accurate diagnoses, psychologists, especially those who specialize in aging or cognition science, are particularly well positioned to recognize, formally assess and explain the implications of cognitive changes associated with the diagnosis of mild cognitive impairment.
Additionally, as more people find themselves in the role of caregiver for a family member with Alzheimer’s, psychologists are responding by developing state-of-the-art interventions to enhance caregiver resilience.