The first line of therapy for cervical dystonia patients is botulinum toxin injections, however injection parameter determination and optimization are challenging for physicians to do. In addition, some patients receiving this treatment long-term experience short duration of relief. Thus, Dysport (Ipsen Biopharmaceuticals), another BoNT-A formulation, may increase the duration of clinical benefit. The objective of this study is to compare the wearing off time of their original BoNT-A formulation (same injection parameters for at least 3 cycles) and the optimized treatment of Dysport (after 2 injection cycles). Ideally, the clinical benefits should last 2.5 - 3 months as injections are administered every 3 months. Conversion to Dysport will be conducted and optimization of Dysport dosing will be done using our sensor-technology assessment. It is unclear whether there are differences in the neurophysiological effects between BoNT-A formulations, such as blocking spinal afferent signals from proprioceptive mechanoreceptors of the injected muscles contributing to CD or the modulation of cortical activity \[8\]. The underlying pathophysiology of impaired motor control in CD is theorized to be caused by abnormal somatosensory processing that affects proprioceptive and tactile function \[8\]. By altering the processing of proprioceptive signals from the muscles to the cortical somatosensory-motor areas, proprioceptive perception can be modulated and possibly normalize activity of the somatosensory-motor areas in CD. Thus, it is hypothesized that BoNT-A may indirectly modulate these cortical pathways and Dysport may have a longer modulatory effect to produce a longer lasting clinical response.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
33
Dysport injections optimized using kinematics
London Health Sciences Centre
London, Ontario, Canada
waning effect
telephone call report of when participant perceives benefit of treatment is wearing off
Time frame: within 12 weeks of treatment
objective measures of CD severity
Kinematic sensor technology is used to measure CD symptoms (neck pulling and/or tremor). Sensors coupled with computer-assisted analysis can measure degrees of deviation from neutral head/neck position and angular root mean square tremor/dystonic jerks amplitude in each plane of motion (vertical, lateral, rotational).
Time frame: 4-weeks and 12-weeks post-treatment
changes in TMS measures
changes in brain activity (inhibitory and excitatory pathways) using paired pulse TMS. Using established techniques
Time frame: 4-weeks and 12-weeks post-treatment
visual-motor performance
speed, reaction time and accuracy in completing upper limb target reaching choice tasks using a robotic haptic device
Time frame: 4-weeks and 12-weeks post-treatment
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