When Parkinson’s disease patients experience a drop in blood pressure upon standing up—known as othostatic hypotension (OH)—they can exhibit significant cognitive defects, according to a recent study.

With this in mind, neurologists at Beth Israel Deaconess Medical Center, who conducted the study, which appeared in the journal Neurology, urge physicians to conduct cognitive testing of their patients in a variety of postures in their Parkinson’s disease assessment.

The neurologists note that the cognitive deficits in patients with OH reverse when the patients lie down and their blood pressure returns to normal. As such, these cognitive impairments may go unnoticed by physicians assessing patients with Parkinson’s who are lying down or seated, and could lead to difficulty in daily activities performed while standing and walking, according to a media release from Beth Israel Deaconess Medical Center.

“Cognitive impairment is a common symptom of Parkinson’s disease,” says co-senior author Roy Freeman, MD, director of the Center for Autonomic and Peripheral Nerve Disorders at BIDMC and a professor of neurology at Harvard Medical School (HMS).

“In this study, we demonstrated that the upright posture in patients with Parkinson’s disease exacerbated cognitive deficits, and that this effect is transient and reversible. Based on these results, we encourage clinicians to include cognitive testing in a variety of postures in their assessments of patients.”

Freeman and his team divided 55 volunteers into three study groups: 18 patients with both PD and OH, 19 patients with PD but without OH, and 18 control participants with neither PD nor OH. All participants were given a series of cognitive tests, with the tests administered while supine and again while tilted to 60 degrees. Researchers measured and recorded the participants’ blood pressure before and during each round of cognitive testing to ensure that participants were never at risk for fainting, the release explains.

When the three groups’ relative performances were compared to each other, postural changes had no significant impact on participants with PD but without OH, compared to the control group. However, Participants with PD and OH were far more susceptible to posture-related impairment on several tests, including those that measured math skills, the ability to produce 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, the release continues.

“As we suspected, people with both Parkinson’s disease and orthostatic hypotension showed posture-related impairments when upright relative to supine on nearly all measures of cognition,” says lead author Justin Centi, who notes that study participants with Parkinson’s disease without orthostatic hypotension demonstrated deficits on only two cognitive tests. There was no difference between upright and supine scores for the control group.

Cognitive deficits in PD result, at least in part, from neurodegeneration, the authors explain. But transient blood pressure changes when upright may indeed play a contributing role. Clinical providers might miss an important target for intervention when not considering OH as a contributor to cognitive impairment, the release notes.

[Source(s): Beth Israel Deaconess Medical Center, Science Daily]