Personalized Bilateral Upper Limb Essential Tremor Therapy with Botulinum Toxin Using Kinematics

Area of Science:

• Neurology
• Biomedical Engineering
• Pharmacology

Background:

• Essential tremor (ET) presents significant variability, complicating visual assessment for botulinum toxin type A (BoNT-A) treatment.
• Previous kinematic analysis guided unilateral ET treatment effectively.

Purpose of the Study:

• To evaluate the efficacy and safety of bilateral arm BoNT-A injections guided by automated kinematic tremor analysis for essential tremor.
• To assess improvements in tremor amplitude, quality of life, and functional interference.

Main Methods:

• An open-label study involving 31 ET participants receiving three bilateral arm BoNT-A injection cycles over 30 weeks.
• Automated kinematic whole-arm tremor assessment determined muscle selection and dosage, removing clinician variability.
• Efficacy measured by Fahn-Tolosa-Marin tremor scale, quality of life (QoL) questionnaire, and grip strength.

Main Results:

• BoNT-A injections significantly reduced tremor amplitude by 47.7% bilaterally, persisting from week 6 to week 30 (p < 0.005).
• Quality of life improved by 26.5% (p < 0.005), and functional interference decreased by 30% (p < 0.005).
• Maximum grip strength showed a transient reduction at week 6 (p = 0.001) but without functional impairment.

Conclusions:

• Computer-assisted kinematic analysis provides a standardized, effective method for personalized bilateral BoNT-A injections in ET.
• This approach overcomes clinical assessment variability, leading to improved bimanual upper limb functionality and patient-reported outcomes.