H-reflex recovery curve in syringomyelia

Area of Science:

• Neuroscience
• Neurology
• Clinical Electrophysiology

Background:

• Cervical syringomyelia is a neurological disorder characterized by cyst formation within the spinal cord.
• Understanding motor neuron excitability is crucial for diagnosing and managing neurological conditions.
• Previous studies have explored motor neuron excitability in various neuropathies, but specific data for syringomyelia are limited.

Purpose of the Study:

• To assess motor neuron excitability in patients with cervical syringomyelia.
• To compare motor neuron excitability in cervical syringomyelia with that in spasticity due to stroke and healthy controls.
• To investigate the characteristics of H-reflex recovery curves in cervical syringomyelia.

Main Methods:

• H-reflex recovery curves were measured in 13 patients with cervical syringomyelia.
• Median nerve stimulation at the elbow and H-reflex recording from the flexor carpi radialis muscle were performed.
• Double pulses with varying interstimulus intervals (75-900 ms) were used to analyze reflex recovery.

Main Results:

• H-reflex was unobtainable in two patients with advanced cervical syringomyelia and sensory loss.
• Patients with syringomyelia demonstrated marked H-reflex facilitation at interstimulus intervals of 150-300 ms.
• This facilitation was significantly higher compared to patients with stroke-induced spasticity.

Conclusions:

• Cervical syringomyelia is associated with increased motor neuron excitability.
• H-reflex recovery curves provide valuable insights into the pathophysiology of cervical syringomyelia.
• The findings differentiate the neurophysiological profile of syringomyelia from other conditions causing spasticity.