Transcranial magnetic stimulation treatment for focal hand dystonia

Unmet Need

Focal hand dystonia (FHD) is an involuntary movement disorder that occurs in an estimated 15 out of 1 million people. It causes sustained or intermittent muscle contractions that make it painful for people perform tasks such as writing. Current commercial treatments for FHD include botulinum toxin injections and neurostimulator devices. New brain stimulation therapies are currently being researched as a treatment for FHD. However, these therapies can only be performed when patients are at rest. Following a treatment, evaluation techniques, such as the Burke-Fahn-Marsden dystonia scale and writer’s cramp rating scale, are used to measure the efficacy of an intervention. These evaluation techniques are highly susceptible to variability because it depends on a physician’s ability to adequately rate a patient’s symptoms. There is a need for comprehensive FHD treatment that improves a patient’s symptoms, incorporates patient activity during treatment, and accurately evaluates the treatment efficacy.

Technology

Duke inventors have developed a treatment for focal hand dystonia (FHD). This is intended to use neurostimulation, including evaluation techniques, to improve the quality-of-life for people with FHD. Specifically, the treatment uses repetitive transcranial magnetic stimulation (rTMS) to deliver magnetic pulses to the basal ganglia and cerebellum, deep regions of the brain responsible for motor control, motor learning, executive function, behaviors, and emotion. Inventors deliver rTMS at a 10 Hz frequency, a novel methodology in TMS treatments, and subjects perform writing tasks interleaved with the rTMS. This approach of alternating between task performance and TMS activates the subjects’s brain motor network. To bypass limitations from current evaluation scales, the inventors use accessible kinematic and hand recognition software to automatically measure a subject’s ability to perform writing tasks. The results of this treatment demonstrated that FHD subjects had reduced writing dysfluency, reduced cortical activity at the primary somatosensory and premotor cortical regions, reduced basal ganglia and increased cerebellar activity, and greater behavioral improvement. A preliminary study demonstrated that two key measures of the evaluation software distinguished FHD and were significantly correlated with other clinical determinants.

Advantages

• A non-surgical treatment procedure for FHD using rTMS
• Personalized targeting using subjects own brain scan and electric field modeling
• Automated measures for assessing FHD that can be used in clinical research settings and are consumer accessible.
• Clinically proven to improve subject’s ability to perform writing tasks.