Title: Measuring balance deficits in chronic inflammatory demyelinating polyneuropathy
Supervisors: Dr. Mark Carpenter
Committee members: Dr. Michael Berger, Dr. J. Timothy Inglis
Abstract: Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated peripheral neuropathy leading to progressive loss of strength, sensation, and balance. A common treatment method for CIDP is intravenous immunoglobulins (IVIg), most often administered once every 3-4 weeks. Most balance research on CIDP patients to date has used either subjective clinical balance assessments or static balance measures only, and the effects of treatment on balance in CIDP remain unclear. Therefore, the proposed research has two main goals: (1) to characterize balance in CIDP, and (2) to determine if/how treatment affects balance in CIDP.
CIDP patients (proposed n=20) will complete one visit approximately halfway between doses, when their medication is at its peak effect (‘Mid-Cycle’), and one visit soon before receiving a dose, when their medication is beginning to wear off (‘End-Cycle’). Healthy controls will also complete 2 visits, approximately 4 weeks apart. During each visit, participants will complete: (1) strength/sensory tests and clinical balance measures, (2) a series of stance and gait tasks while wearing a SwayStar (a box worn around the waist, containing 2 angular velocity transducers to measure trunk sway), (3) maximal voluntary contractions (MVCs), recorded from several muscles of the leg and trunk using surface electromyography (EMG), and (4) a series of dynamic balance perturbations in 4 directions while standing on a multi-directional tilting platform. Responses to these perturbations will be measured by calculating onset latencies and amplitudes of EMG activity.
Based on previous work with CIDP patients and other clinical populations, it is hypothesized that CIDP patients will exhibit abnormal balance performance overall compared to the control group. This will be characterized by increased trunk sway during the stance and gait tasks, and smaller, delayed muscle responses to the perturbations. Additionally, we hypothesize that both of these balance measures will improve with treatment in the CIDP group.