Visual and brainstem auditory evoked potentials in hereditary motor-sensory neuropathy

Area of Science:

• Neuroscience
• Clinical Neurology
• Electrophysiology

Background:

• Hereditary motor-sensory neuropathy (HMSN) encompasses a group of genetic disorders affecting peripheral nerves.
• Subclinical involvement of central sensory pathways in HMSN is not fully understood.
• Evoked potentials are valuable tools for assessing the functional integrity of sensory pathways.

Purpose of the Study:

• To investigate subclinical involvement of visual and auditory pathways in patients with HMSN types I and II.
• To compare electrophysiological findings in HMSN patients with healthy controls and Guillain-Barré syndrome (GBS) patients.

Main Methods:

• Recorded visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) in 57 HMSN patients (37 type I, 20 type II).
• Included 12 GBS patients and 40 healthy controls for comparison.
• Focused on latency and interpeak latency measurements, excluding patients with central nervous system involvement.

Main Results:

• Over 30% of HMSN I patients exhibited delayed VEP latency, less frequent in HMSN II.
• Nearly 50% of HMSN patients (both types) showed abnormal BAEP, primarily prolonged I-III interpeak latency (IPL).
• Abnormalities were more common in adults and could occur simultaneously or separately for VEP and BAEP.

Conclusions:

• VEP and BAEP abnormalities suggest subclinical involvement of optical and auditory pathways in HMSN.
• HMSN type I appears more susceptible to these electrophysiological changes than type II.
• Evoked potentials are sensitive indicators for detecting early sensory pathway dysfunction in HMSN.