Kinematic Technology Helps Treat Patients with Tremors

The data helps alleviate functional disability caused by essential tremor by objectively individualizing and personalizing injection parameters for botulinum toxin type A (BoNT-A).

The researchers conducted a 38-week open label study of 24 people injected with BoNT-A. The participants performed two postural and two weight-bearing scripted tasks with TremorTek motion sensors placed over the wrist, elbow, and shoulder joints. The sensors captured angular tremor amplitude and acceleration joint motion that was segmented into directional components: flexion-extension (F/E) at the elbow, F/E and adduction-abduction at the shoulder, pronation-supination, and radial-ulnar F/E at the wrist.

The multi-joint biomechanical recordings allowed individualized selection and determination of which muscles would contribute to specific upper limb tremor biomechanics and subsequent dosing per participant. The results showed that by week 38, the patients showed a significant decrease in tremor amplitude in the wrist and shoulder joints; 40% participants self-reported mild weakness in injected muscles, but had no interference in arm function. The study was published on April 21, 2016, in PLOS One.

“Very few clinicians inject for tremor because before now, it just didn't work. The injections would only cause weakness,” said senior author Professor Mandar Jog, PhD, of the LHRI department of clinical neurological sciences. “We realize now that was because they didn't know where to inject. The uniqueness of our development is the simplicity of it. It records from multiple joints in a straightforward way.”

BoNT-A intramuscular injections are commonly used to treat various movement disorders, such as focal dystonias, and may provide modest beneficial effects in essential tremor patients who are unresponsive to conventional drugs. The therapy has not been widely adopted due to risk of significant hand and wrist weakness causing functional limb impairment, and therefore proper identification of the dynamics of the tremulous joints is necessary to optimize injection pattern and outcomes.

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Lawson Health Research Institute
University of Bonab