None listed
Conditions
Brief summary
Dystonia is a neurological disorder causing involuntary muscle contractions, and is thought to be caused by abnormal firing of specific brain networks. There are a number of types of dystonia, each defined by the body region/s that are affected. For example, and relevant to the present application, cervical dystonia (CD) affects the muscles of the neck. The current ‘gold standard’ treatments for CD are the injection of botulinum toxin type A (botox) into the affected muscles, or deep brain stimulation via brain surgery in more severe cases. However, injections only treat patients’ symptoms, rather than the underlying substrate of the disorder, and include side effects such as muscle wasting, while surgery is invasive and can be risky. As such, new treatments for CD are needed. Repetitive transcranial magnetic stimulation (rTMS) has shown some promise in patients with CD, however, overall results have not yet been compelling enough to carry rTMS forward as an approved treatment method. rTMS in CD has been hindered by the fact that the particular brain region that should be stimulated is still unknown. This is because previous neuroimaging findings have identified many different brain regions as abnormal in CD. This research will build upon findings by Corp et al. (2019), who demonstrated that the somatosensory cortex is abnormal in CD patients. Thus, this will be the first study to investigate whether a form of rTMS (called continuous theta-burst stimulation, or cTBS) to this brain region can effectively relieve CD symptoms. Aim 1 of the project is to investigate whether cTBS is an effective treatment for CD symptoms. It is hypothesised that there will be a significant overall reduction in CD symptoms post-intervention, as measured by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). Aim 2 of this study is to investigate neurophysiological and kinematic changes, due to the application of cTBS. It is hypothesised that there will be significant changes in the excitability of the somatosensory cortex and the corticospinal pathway after the application of real cTBS in comparison to sham stimulation. Further, it is hypothesised that there will be a correlation between these changes in excitability, and reductions in CD symptom scores (as measured by the TWSTRS). CD symptoms will also be measured through kinematic testing using a custom-made device to measure head and neck angle, tilt, and position.
Interventions
Participants will undergo 2 weeks (10 sessions) of continuous theta-burst stimulation (cTBS) to the somatosensory cortex (S1). Participants will be randomised before beginning the trial to receive either the intervention (cTBS) or a sham/placebo in the first block of sessions, and then the opposite form of stimulation in the second block of sessions (i.e., 20 sessions in total, separated into two blocks). The order of stimulation will be counterbalanced amongst participants. A washout period of
Participants will undergo 2 weeks (10 sessions) of continuous theta-burst stimulation (cTBS) to the somatosensory cortex (S1). Participants will be randomised before beginning the trial to receive either the intervention (cTBS) or a sham/placebo in the first block of sessions, and then the opposite form of stimulation in the second block of sessions (i.e., 20 sessions in total, separated into two blocks). The order of stimulation will be counterbalanced amongst participants. A washout period of approximately 2 weeks will separate the two blocks of sessions. A Magventure Magpro R30 machine will be used to apply cTBS to the S1 bilaterally, which takes approximately 40 seconds each side. The cTBS intervention will consist of three pulses delivered at 50Hz every 200 milliseconds, for a total of 600 pulses. The first, sixth, and last sessions in the intervention block are expected to take approximately 3 hours, due to the extra outcome measures collected (such as interhemispheric inhibition and single pulse TMS). The rest of the sessions are expected to take less than 30 minutes. The intervention will take place at Deakin University's Cognitive Neuroscience Unit (Burwood). The intervention will be delivered by a student researcher and the principal investigator, who has over 5 years experience in TMS application.
Sponsors
Deakin University - Australian Government Research Training Program Scholarship
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
To be included in the study participants must be cervical dystonia patients aged 18 to 85, diagnosed by a physician with cervical dystonia 12 or more months ago. Participants must have had a subjective response to botulinum toxin treatment at some point, with their last botulinum toxin injection 2 or more months ago.
Exclusion criteria
Severe head tremor, trauma to head or neck < 12 months prior to onset of dystonia, acquired dystonia (i.e., dystonia as a result of a traumatic brain injury, drug-induced, or as a result of another neurological condition), or pronounced head or neck tremor when lying down with neck supported.
Outcome results
None listed