Lumbomuscular proprioceptive reflexes in body equilibrium.

Area of Science:

• Neuroscience
• Biomechanics
• Physiology

Background:

• Proprioceptive reflexes originating from lumbar erector muscles play a crucial role in maintaining body equilibrium.
• Understanding these reflexes is vital for diagnosing and treating balance disorders, particularly those associated with spinal injuries.

Observation:

• Unilateral procainization of lumbar erector muscles in healthy subjects induced eye nystagmus, disrupted righting reflexes, and altered lower limb stepping reactions, indicating induced imbalance.
• In patients with traumatic vertigo and lumbar pain, unilateral procaine injections into tender spots reduced eye nystagmus, improved righting reflexes, and corrected lower limb drift, alleviating vertigo and ataxia.

Findings:

• The study revealed contrasting effects of lumbar proprioceptor manipulation on equilibrium in healthy individuals versus vertigo patients.
• Procainization in healthy subjects led to increased imbalance, possibly due to heightened asymmetry between left and right proprioceptive input.
• Conversely, in vertigo patients, procainization resulted in decreased imbalance, suggesting a reduction in existing asymmetry and contributing to improved stability.

Implications:

• These findings support a biphasic model of proprioceptive reflexes, analogous to Fukuda's two-phase labyrinthine reflex theory.
• This biphasic concept, involving stages of disturbance and coordination, offers a new framework for interpreting lumbar proprioceptive reflexes in relation to body equilibrium.
• The results highlight the potential therapeutic implications of modulating lumbar proprioception for managing balance disorders and vertigo.