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Background: According to Braak staging of Parkinson's disease (PD), detection of autonomic dysfunction would help with early diagnosis of PD. Objective: To determine whether the autonomic nervous system is involved in the early stage of PD, we evaluated cardiovascular and sudomotor function in early untreated PD patients. Methods: Orthostatic blood pressure regulation, heart rate variability, skin vasomotor function, and palmar sympathetic sweat responses were examined in 50 early untreated PD patients and 20 healthy control subjects. Results: The mean decrease in systolic blood pressure during head-up tilt in PD patients was mildly but significantly larger than in controls (p = 0.0001). There were no differences between the 2 groups in heart rate variability, with analysis of low frequency (LF; mediated by baroreflex feedback), and high frequency (HF; mainly reflecting parasympathetic vagal) modulation. However, LF/HF, an index of sympatho-parasympathetic balance, was lower in the PD group than in controls (p = 0.02). Amplitudes of palmar sweat responses to deep inspiration (p = 0.004), mental arithmetic (p = 0.01), and exercise (p = 0.01) in PD patients were lower than in controls, with negative correlations with motor severity. Amplitudes of palmar skin vasomotor reflexes in PD patients did not differ from controls. Conclusions: Our study indicates impairment of sympathetic cardiovascular and sudomotor function with orthostatic dysregulation of blood pressure control, reduced LF/HF and reduction in palm sweat responses even in early untreated PD patients.

Objective. Spinal cord injury (SCI) results in disruption of descending tonic activation of sympathetic circuits in the spinal cord. The authors determined whether different stimuli that increase sympathetic activity induced cutaneous vasoconstriction (skin vasomotor reflex, SkVR) above and below the level of lesion in subjects with clinically complete SCI.Methods. Baseline skin blood flow (SkBF) and SkVR reduction rate in the pulp of the finger and great toe was measured by laser Doppler probes in chronic complete SCI and in controls.Results. In the finger, baseline SkBF was similar in SCI and controls. The SkVR was elicited by all stimuli in controls but was significantly diminished to gasp, mental arithmetic, tactile stimulation, cutaneous cold, and deep breathing in high SCI compared to controls. In the toe, baseline SkBF was less stable in both controls and SCI. SkVR trends were identified in controls, and responses were not present or greatly reduced in high and low SCI.Conclusions. Measurements of skin vasomotor reflexes to physiological stimuli may be a noninvasive method to evaluate the extent of sympathetic adrenergic pathways in chronic SCI. This is of clinical relevance in monitoring recovery of sympathetic adrenergic function either spontaneously or following repair interventions.

PINK1was recently found to be associated with PARK6 as the causative gene. We performed mutation analysis in eight inbred families whose haplotypes link to the PARK6 region. We identified six pathogenic mutations (R246X, H271Q, E417G, L347P, and Q239X/R492X) in six unrelated families. All sites of mutations were novel, suggesting that PINK1may be the second most common causative gene next to parkinin parkinsonism with the recessive mode of inheritance. Ann Neurol 2004;56:424–427

Introduction. Patients with Parkinson’s disease (PD) showed reduced myocardial 123I-MIBG uptake, which may affect autonomic regulation. We investigated correlation between MIBC accumulation and cardiovascular autonomic function in PD. Methods. We performed myocardial MIBG scintigraphy, heart rate variability (HRV) analysis, and the head-up tilt test (HUT) in 50 PD patients (66.4±7.8 years; duration 5.5±5.9 years). Autonomic function tests were also performed in 50 healthy controls (66.5±8.9 years). As HRV parameters, a high-frequency power (HF, 0.15–0.4 Hz), a low-frequency power (LF, 0.04–0.15 Hz), and LF/HF ratio were used. Results. Our PD patients had a significant reduction in LF and HF compared with the controls (P=0.005 and P=0.01). In HUT, systolic and diastolic blood pressure falls in the PD group were significantly greater than those in the controls (P=0.02 and P=0.02). The washout rate of MIBG was negatively correlated with blood pressure changes during HUT. Conclusion. Our PD patients showed reduced HRV, blood pressure dysregulation, and reduced MIBG accumulation, which was correlated with blood pressure dysregulation. Orthostatic hypotension in PD may be mainly caused by sympathetic postganglionic degeneration.