Reflex mechanisms in CRPS-related dystonia

Complex Regional Pain Syndrome (CRPS) is a disabling syndrome associated with sensory (e.g., burning pain, allodynia, hyperalgesia), autonomic (e.g., edema, skin color and temperature changes), and motor impairments (e.g., tremor, myoclonus, dystonia). Approximately 25% of the patients with CRPS develop fixed dystonia which is characterized by abnormal sustained muscle contractions and abnormal postures. No definitive pathophysiology of CRPS and related dystonia exists. Neurophysiological studies have found evidence of impaired inhibition at the spinal cord and motor cortex. In this thesis, a computational neuromuscular model has been developed to explain the movement disorder fixed dystonia through disturbed proprioceptive reflexes. To validate the model, methods have been developed to quantify proprioceptive reflexes in vivo during postural control of patients with fixed dystonia. The prime goal of this thesis is to gain insight into the pathophysiology of fixed dystonia and develop a diagnostic protocol. Although the mechanisms behind fixed dystonia are still elusive, the evidence implicating involvement of aberrant muscle force feedback is compelling. Aberrant muscle force feedback successfully mimicked dystonia in the neuromuscular model while experiments demonstrated involvement of muscle force feedback in fixed dystonia.BioMechanical EngineeringMechanical, Maritime and Materials Engineerin