Orthostatic hypotension acutely impairs executive functions in Parkinson's disease

Orthostatic hypotension is a frequent non-motor symptom of Parkinson's disease, with negative prognostic role on cognitive functions. Here we measured the acute effects of orthostatic hypotension on executive functions in Parkinson's disease patients devoid of hypertension, carotid artery stenosis, and significant chronic cerebrovascular pathology. Measurements were carried out during regular visits in outpatient setting. Twenty-eight Parkinson's disease patients were recruited and studied along scheduled outpatient visits. They were divided into two groups (n = 14 each) based on the presence or lack of orthostatic hypotension. This was diagnosed according to international guidelines. All patients were submitted to the Stroop's test and to the phonological and semantic verbal fluency test after 10-min resting in supine position and immediately upon standing in upright position. Testing lasted less than 5 min in either position. In upright position, subjects with orthostatic hypotension displayed significantly worse performances at the Stroop's test word reading time (22.1 +/- 4.1 vs. 14.9 +/- 4.0 s), interference time (56.1 +/- 12.3 vs. 41.4 +/- 11.8 s), and number of errors at the interference section (5.8 +/- 3.2 vs. 1.3 +/- 2.1) as compared to those without orthostatic hypotension. These results demonstrate that worsening of attentive function upon standing can be measured in Parkinson's disease patients with orthostatic hypotension during routine outpatient visits. These findings suggest that clinically asymptomatic orthostatic hypotension in Parkinson's disease patients may acutely worsen neuropsychological performances with possible negative impact on daily functioning.