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Ages & Stages: Alzheimer's & Parkinson's
from the National Women's Health Report, "Women & Neurologic Conditions"
http://www.wistv.com/global/story.as...Type=Printable

Here's something you never would have a heard a neurologist say about Alzheimer's 10 years ago: "This is a really exciting time." Or about Parkinson's disease: "We're doing really well."

Yet that's just what Carol Lippa, MD, of Drexel University's College of Medicine in Philadelphia, and Jayaraman Rao, MD, of the Oschner Clinic Foundation in New Orleans, had to say about their respective specialties.

Let's start with Alzheimer's disease.

More women than men are diagnosed with Alzheimer's, a disparity that's long been attributed to the fact that women live longer than men. But above and beyond age, says Dr. Lippa, it appears that women are slightly more susceptible to the disease. "It's likely related to estrogen in some way," she says-either low levels of estrogen as women get older or the sudden drop in estrogen that occurs during menopause. Does that mean that supplemental estrogen is the answer?

Probably not. The Women's Health Initiative (WHI) study found that estrogen, alone or with progestin, increased the rate of dementia, including Alzheimer's disease, in women 65 and older. It also didn't protect against mild cognitive decline.

Those findings have led some experts to suggest maybe it isn't estrogen that's to blame for the gender disparity in Alzheimer's, but luteinizing hormone, which regulates estrogen in the body. Postmenopausal women and older men have much higher levels of this hormone, and people with Alzheimer's have levels twice as high as those without the disease. Plus areas of the brain most likely to be destroyed in Alzheimer's disease have large numbers of receptors for luteinizing hormone.

This is important because it provides another clue to the underlying causes of the disease, which we need to develop treatments.

The reason Dr. Lippa is so excited about Alzheimer's today is that she sees exciting new treatments coming in the next few years. For instance, several trials of vaccines are ongoing that stimulate the immune system to view beta amyloid plaques-the hallmark of the disease-as foreign bodies and attack them. However, no definitive results have been shown so far.

We're also learning more about preventing Alzheimer's. For instance, there appear to be clear links between high blood sugar and the disease. So some studies are investigating whether existing diabetes drugs might help improve the way the brain uses glucose, reducing the risk of the disease. Plus, observational studies suggest that anything that reduces the risk of heart disease also reduces the risk of Alzheimer's, including following a healthy diet, reducing cholesterol and blood pressure levels, losing weight and getting more physical activity. "A heart-healthy diet is a brain-healthy diet," Dr. Lippa said.

Parkinson's disease has also reached a watershed in terms of our understanding and treatment of the disease, says Dr. Rao. Parkinson's disease is the second most common neurological degenerative disease after Alzheimer's, affecting about 1 million Americans. The disease results from the loss of dopamine-producing brain cells in selected brain areas.

The primary symptoms of Parkinson's are loss of motor control, resulting in tremors, muscle stiffness, slow gait and the inability to control certain muscular movements. Like Alzheimer's, Parkinson's is a disease of aging, with the number of people affected expected to double over the next 20 years. Unlike Alzheimer's, however, it is more prevalent in men than women.

Today, in addition to a plethora of medications to treat the underlying lack of dopamine and Parkinson's symptoms (including rigidity, restless legs and insomnia, etc.), there are several nondrug approaches. The most exciting one is deep-brain stimulation, in which electrodes are implanted in the area of the brain responsible for the movement disorders. The electrodes are connected to a device about the size of a half dollar called a pulse generator that is programmed to electrically stimulate the brain. These electrical signals block the abnormal nerve signals that cause tremor and other Parkinson's symptoms.

However, most treatments only address the symptoms of the disease, says Dr. Rao. What he's excited about are new treatments focused on arresting its progression. "If you slow the progression even marginally, the quality of life we can give these patients for a longer time is really improved."

References

Shumaker SA, Legault C, Rapp SR, et al. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health InitiativeMemory Study: a randomized controlled trial. JAMA. May 28, 2003;289(20):2651-62.

Webber KM, Casadesus G, Atwood CS, Bowen RL, Perry G, Smith MA. Gonadotropins: a cohesive gender-based etiology of Alzheimer disease. Mol Cell Endocrinol. Jan 2, 2007;260-262: 271-5. Epub Oct 18, 2006.

Nutt JG, Wooten GF. Clinical practice. Diagnosis and initial management of Parkinson's disease. N Engl J Med. Sep 8, 2005;353(10):1021-7.