Body mass index effect on common nerve conduction study measurements

Area of Science:

• Neurology
• Clinical Electrophysiology
• Human Physiology

Background:

• Nerve conduction studies (NCS) are essential for diagnosing neuropathies.
• The influence of body composition, specifically body fat, on NCS parameters is not fully understood.
• Body Mass Index (BMI) is a common metric for assessing body fat percentage.

Purpose of the Study:

• To investigate the relationship between body mass index (BMI) and various nerve conduction study (NCS) measures.
• To determine if increased body fat affects nerve conduction parameters.

Main Methods:

• Two hundred fifty-three subjects underwent comprehensive NCS, including motor, sensory, mixed nerve studies, and H-reflex.
• Body Mass Index (BMI) was calculated and analyzed both continuously and by dividing subjects into thirds (upper, middle, lower).
• Repeated measures analysis of variance was employed, adjusting for age, sex, and height.

Main Results:

• Significant correlations (P < or = 0.01) were found between BMI and sensory/mixed nerve amplitudes for all tested nerves.
• Obese subjects exhibited 20-40% lower mean amplitudes compared to thinner subjects.
• No significant correlation was observed between BMI and nerve conduction velocity, H-reflex latency, or most other motor/sensory/mixed measures.

Conclusions:

• Increased BMI is associated with reduced sensory and mixed nerve amplitudes.
• Clinicians should consider the impact of elevated BMI on NCS results, particularly amplitude measures.
• These findings highlight the importance of body composition in the interpretation of electrodiagnostic tests.