Normal range for H-reflex recording from the calf muscles

Area of Science:

• Neurophysiology
• Clinical Electrophysiology

Background:

• The H-reflex is a valuable electrophysiological measure.
• Establishing normative data is essential for accurate clinical interpretation.
• Previous studies have had limited sample sizes or demographic diversity.

Purpose of the Study:

• To determine the normal range for H-reflex latency in the calf muscle.
• To investigate the influence of demographic factors on H-reflex latency.
• To establish normative values for side-to-side H-reflex latency variability.

Main Methods:

• Recruitment of 251 asymptomatic subjects.
• Bilateral H-reflex latency recordings from the calf.
• Statistical analysis using repeated measures ANOVA to assess demographic influences (age, height, race, gender, BMI).
• Analysis of side-to-side variability using simple ANOVA.

Main Results:

• Age and height were significantly associated with H-reflex latency (P < 0.01).
• Race, gender, and BMI did not show significant associations with H-reflex latency.
• Mean H-reflex latency was 30.3 ± 2.4 ms.
• Upper limits of normal (mean + 2 SD) ranged from 30.0 to 38.2 ms.
• Mean side-to-side variability was 0.2 ± 1.0 ms, with an upper limit of normal of 2.2 ms (mean + 2 SD).

Conclusions:

• Normal H-reflex latency ranges were established for a large, diverse population.
• Age and height are key demographic factors influencing H-reflex latency.
• The derived normative data are critical for diagnosing peripheral nerve disorders.