Impairment of cerebral hemodynamic response to the cold pressor test in patients with Parkinson's disease.
OBJECTIVE
Disturbance of the autonomic nervous system (ANS) is frequently encountered in Parkinson's disease (PD). In this study, we examined changes in systemic and cerebral hemodynamics during the cold pressor test (CPT) to determine whether cerebrovascular reactivity, controlled by the sympathetic nervous system, is intact or impaired in patients with PD.


METHODS
Forty-nine patients with PD and 49 sex- and age-matched non-PD subjects were evaluated. Measurements were performed in the resting state and over a period of 1min of CPT. The cerebral blood flow velocity (CBFV) and pulsatility index (PI) of the middle cerebral artery (MCA) were recorded by transcranial color-coded Doppler ultrasonography (TCCS). Mean arterial blood pressure (MAP), heart rate (HR), and end-tidal CO(2) (Et-CO(2)) were investigated simultaneously. The resistance of the cerebrovascular bed (CVR) was calculated as the ratio of mean arterial blood pressure to mean cerebral blood flow velocity (Vm). Changes of Vm, PI and CVR in response to the cold pressor test were evaluated.


RESULTS
Baseline values for control and PD subjects showed no statistical difference. CPT induced a significant increase in MAP, HR, and Vm in both groups. Pulsatility index (PI) and CVR were decreased in both groups during CPT. Percent increases of Vm (P<0.001) and MAP (P=0.011) were significantly higher while the percent decreases of PI (P=0.002) and CVR (P=0.007) were significantly decreased more in the non-PD group.


CONCLUSIONS
This study indirectly shows that ANS-mediated cerebrovascular reactivity is impaired in patients with PD. Further investigations are needed to confirm the hypothesis that using the cold pressor test to evaluate cerebrovascular reactivity might be beneficial in early diagnosis of impairment of ANS-mediated cerebrovascular autoregulation in patients with PD.
Tsai
Shih-Jei
SJ
Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; School of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Chen
Shiuan-Chih
SC
Leu
Tsong-Ming
TM
Chen
Chiu-Mei
CM
Chou
Hsi-Hsien
HH
Peng
Hsien-Yu
HY
Liao
Jiuan-Miaw
JM
Lin
Tzer-Bin
TB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology; D003080:Cold Temperature; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D017585:Ultrasonography, Doppler, Transcranial; D014655:Vascular Resistance / Q000502:physiology