Is overwork weakness relevant in Charcot-Marie-Tooth disease?

Area of Science:

• Neurology
• Clinical Muscle Physiology
• Rehabilitation Science

Background:

• Overwork weakness (OW) is muscle weakening from exertion, known in some neuromuscular disorders.
• Its occurrence in Charcot-Marie-Tooth disease (CMT) is debated, with prior studies yielding conflicting results.
• Previous research focused on hands and did not assess lower limb muscles.

Purpose of the Study:

• To investigate the overwork weakness (OW) hypothesis in Charcot-Marie-Tooth disease type 1A (CMT1A).
• To compare bilateral muscle strength in hands and legs of CMT1A patients.
• To determine if dominant limb muscles weaken more than non-dominant ones in CMT1A.

Main Methods:

• Bilateral intrinsic hand and leg muscle strength were assessed in 271 adult CMT1A patients.
• Manual testing and manual dexterity evaluations were employed.
• Muscle strength was compared between dominant and non-dominant sides.

Main Results:

• No significant side-to-side strength differences were found for intrinsic hand muscles (first dorsal interosseous, abductor pollicis brevis) or leg muscles (anterior tibialis, triceps surae).
• Dominant muscles did not weaken with increased age or disease severity (CMT Neuropathy Score).
• The dominant triceps surae showed slightly greater strength with advancing age and disease severity.

Conclusions:

• The study data do not support the overwork weakness (OW) hypothesis in Charcot-Marie-Tooth disease type 1A (CMT1A).
• Exercise and physical activity are not detrimental and should be encouraged for CMT1A patients.
• Rehabilitation remains the primary effective treatment for managing CMT1A.