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A research team made up of HMS neurologists at Beth Israel Deaconess Medical Center and neuropsychologists at Boston University has found that when patients with Parkinson’s disease experience a drop in blood pressure upon standing up—a condition known as orthostatic hypotension—they also exhibit significant cognitive deficits. These deficits reverse when patients lie down and their blood pressure returns to normal. These findings were reported on January 3 in Neurology.
Although these cognitive impairments can go unnoticed by physicians assessing patients with Parkinson’s who are lying down or seated, the impairments could lead to difficulty in daily activities performed while standing and walking, such as tracking conversations, counting change, and interpreting traffic signals.
Marked by characteristic tremor, rigidity, and slowness of movement, Parkinson’s disease is a progressive degeneration of parts of the nervous system. It affects many aspects of movement and can cause a masklike, expressionless face; rigid limbs; and problems with walking and posture. Parkinson’s is also associated with cognitive defects attributed to breakdowns in connectivity between regions of the brain. Up to 50 percent of people with Parkinson’s disease may also have orthostatic hypotension (OH).
The research team divided fifty-five volunteers into three study groups: eighteen patients with both Parkinson’s and OH, nineteen patients with Parkinson’s but without OH, and eighteen control participants with neither Parkinson’s nor OH.
When the three groups’ relative performances were compared with each other, participants with both Parkinson’s and OH were far more susceptible to posture-related impairment on several tests, including those that measured math skills and abilities such as producing words easily, keeping information in mind while working on it, paying sufficient attention so that later memory is efficient, and searching for items quickly and accurately.
“Based on the results of this study,” says co-senior author Roy Freeman, an HMS professor of neurology and director of the Center for Autonomic and Peripheral Nerve Disorders at Beth Israel Deaconess, “we encourage clinicians to include cognitive testing in a variety of postures in their assessments of patients.”
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