Oct 17 2012
By Liam Davenport, medwireNews Reporter
Cognitive dysfunction in Parkinson's disease (PD) is linked to neurocirculatory abnormalities such as orthostatic and supine hypertension, suggesting early treatment of such abnormalities may slow cognitive decline, say researchers.
The team writes in Neurology: "In general, our results fit with the view that myriad episodes of cerebral hypo- and hyperperfusion… contribute to vascular brain injuries and thereby to dementia in PD.
Joong-Seok Kim, from the Catholic University of Korea, in Seoul, and colleagues performed a comprehensive set of neuropsychologic tests, recorded orthostatic vital signs and ambulatory 24-hour blood pressure, and obtained brain magnetic resonance scans, for 87 patients with early PD.
In all, 25 patients had normal cognition, 48 had mild cognitive impairment, and 14 had dementia. Orthostatic hypertension (OH) was detected in 36.8% of patients, while 20.7% had supine hypertension (SH), with supine systolic blood pressure higher than 150 mmHg; and 79.3% of patients were defined as nondippers, because their blood pressure did not decrease at night.
Patients with OH had more severe impairment in verbal intermediate/delayed memory than those without, and had a trend toward higher Cholinergic Pathways Hyperintensive Scale (CHIPS) scores. Furthermore, 71.4% of dementia patients had OH, compared with just 20% of those with normal cognition.
All SH patients had some form of cognitive dysfunction and had more severe defects on most neuropsychologic test domains than those without SH. While 78.6% of patients with dementia had SH, none of those with normal cognitive function had SH. Mean CHIPS scores were higher in SH patients than those without SH, and all SH patients were nondippers.
Patients with both OH and SH had more severe cognitive impairment and higher CHIPS scores than those with neither OH nor SH. None of the OH plus SH patients had normal cognition, and 69% had dementia.
The team also reports that frontal executive functions were negatively related to the standard deviation of systolic blood pressure, and changes in nocturnal blood pressure were linked to visuospatial memory function.
Furthermore, mean CHIPS scores were significantly higher in patients with dementia than in those with normal cognition or mild cognitive impairment, at 24.5 versus 14.0. However, dipper and nondipper patients did not differ in terms of cognitive status.
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