Autonomic nervous function assessment using thermal reactivity of microcirculation

Area of Science:

• Neurology
• Clinical Neurophysiology
• Peripheral Nerve Disorders

Background:

• Current methods for diagnosing peripheral neuronal damage, like nerve conduction velocity, detect changes only in severe cases when therapeutic options are limited.
• Small nerve fibers are affected earlier than large fibers in most peripheral neuropathies (PNP), highlighting the need for sensitive diagnostic tools.
• Axonal degeneration begins distally, affecting the longest C-fibers first, particularly in the lower extremities.

Purpose of the Study:

• To evaluate the utility of heat-induced laser Doppler flowmetry (HLDF) for assessing early C-fiber dysfunction in peripheral neuropathy.
• To investigate the correlation between HLDF measurements of skin blood flow regulation and established electrophysiologic tests.

Main Methods:

• Utilized laser Doppler flowmetry to measure skin blood flow regulation in response to heat stimulation.
• Assessed the function of afferent and efferent sympathetic C-fibers by analyzing microcirculation response.
• Compared HLDF results with traditional electrophysiologic tests and sudomotor function tests.

Main Results:

• Heat-induced laser Doppler flowmetry (HLDF) demonstrated advantages in assessing early C-fiber dysfunction.
• The method showed a close correlation between microcirculation response to heat and electrophysiologic tests.
• Sudomotor function tests did not achieve the same level of correlation.

Conclusions:

• HLDF is a valuable, objective method for assessing early C-fiber dysfunction in peripheral neuropathy.
• This technique offers a reliable way to evaluate microcirculation regulation, reflecting sympathetic C-fiber function.
• HLDF shows promise as a complementary diagnostic tool in the management of peripheral nerve damage.