Pre- and postganglionic vasomotor dysfunction causes distal limb coldness in multiple system atrophy

Area of Science:

• Neurology
• Autonomic Neuroscience
• Vascular Physiology

Background:

• The pathophysiology of limb coldness in multiple system atrophy (MSA) remains poorly understood.
• Investigating autonomic dysfunction is crucial for understanding MSA symptoms.

Purpose of the Study:

• To evaluate cutaneous vasomotor neural function in MSA patients with and without limb coldness.
• To compare autonomic function between MSA patients and healthy controls.

Main Methods:

• Assessed skin sympathetic nerve activity (SSNA) and skin vasomotor reflex (SVR) in 18 MSA patients and 20 controls.
• Measured resting SSNA, SSR, SVR, and their responses to electrical stimulation.
• Analyzed SSNA frequency, reflex burst amplitude, SVR changes, recovery time, and blood flow velocity.

Main Results:

• MSA patients exhibited significantly lower resting SSNA frequency and SSNA reflex burst amplitude compared to controls.
• Skin blood flow velocity was significantly slower in MSA patients.
• Recovery time of SVR was significantly prolonged in MSA patients with limb coldness.

Conclusions:

• Limb coldness in MSA may result from impaired peripheral circulation due to prolonged vasoconstriction.
• Combined pre- and postganglionic sympathetic vasomotor dysfunction contributes to reduced skin blood flow velocity.
• Autonomic dysfunction significantly impacts peripheral circulation in MSA patients.