Evaluation of Sensory and Motor Function in Spinal and Bulbar Muscular Atrophy Using Quiet Stance and Reactive...

Area of Science:

• Neurology
• Biomedical Engineering
• Rehabilitation Science

Background:

• Spinal and bulbar muscular atrophy (SBMA) is an X-linked neuromuscular disorder causing progressive muscle weakness and sensory neuropathy.
• Previous studies indicate SBMA patients have deficits in dynamic balance and quiet stance postural control.
• Automatic postural reactions in SBMA have not been previously reported.

Purpose of the Study:

• To expand on existing knowledge of sensory postural control in SBMA.
• To investigate automatic postural reactions in individuals with SBMA.
• To examine the correlation between muscle strength and balance capabilities in SBMA.

Main Methods:

• A cross-sectional study design was employed.
• Fifty male individuals diagnosed with SBMA participated.
• Balance was assessed using the modified Clinical Test of Sensory Interaction on Balance (mCTSIB) and the Motor Control Test (MCT); strength was measured via isometric dynamometry.

Main Results:

• Participants demonstrated significantly increased sway velocity during quiet stance across most mCTSIB conditions.
• Automatic postural reactions were significantly slower in SBMA patients compared to normative data on the MCT.
• Plantarflexor weakness strongly correlated with poorer performance on both balance tests.

Conclusions:

• SBMA patients show abnormal sensory postural control, with a notable reliance on visual input.
• Automatic postural corrections are impaired in SBMA, indicating slower responses to perturbations.
• Plantarflexor weakness is associated with both sensory and automatic balance deficits, increasing fall risk and highlighting a potential therapeutic target.