Poster W4 - Optimizing Electrical Stimulation for Tremor Suppression: Efficacy of 2 vs. 6 Electrode Configurations

Introduction: Tremors are involuntary muscle contractions that cause shaking movements. They most commonly affect hands making it difficult to do daily activities for many individuals. Effective tremor suppression can enhance the independence of patients with various neurological conditions that cause tremors such as Parkinson's disease and essential tremor. Recent research has demonstrated electrical stimulation as a promising method for tremor suppression, offering an alternative to pharmacological treatments and surgical interventions. This study aims to investigate the parameters for optimizing electrical stimulation for tremor suppression, specifically examining the efficacy of using 2 versus 6 electrodes by stimulating both antagonist and agonist muscles out of phase.In this study, it was determined if the greater spread of electrical stimulation contributes to better tremor suppression or if focused approach yields superior results.

Materials and

Methods: The study involved five subjects who participated in two different experiments. In one experiment, subjects were required to draw within the lines of a spiral. Three trials were conducted using both 2 and 6 electrodes at 150 Hz and 200 Hz, with a 5-minute recovery period between each trial. In the second experiment, subjects were required to hold a cup. Three trials were conducted using both 2 and 6 electrodes at 200 Hz, with a 5-minute recovery period between each trial. The subjects included three with essential tremor and two with Parkinson's disease. The electrodes were placed equally on antagonist and agonist muscles of the forearm. An IMU device was used to track and record the tremor activity. Each session lasted for 55 seconds, beginning with a 10-second baseline period with no electrical stimulation to establish a control measurement.

Results, Conclusions, and Discussions: The results demonstrated a significant difference in tremor suppression between the 2-electrode and 6-electrode configurations. For subjects with Parkinson's disease, the 6-electrode configuration did not reduce or increase tremor, while the 2-electrode configuration showed some suppression in the y and z directions but an increase in tremor in the yaw direction. For subjects with an essential tremor, both 2 and 6 electrodes reduced tremor, with the 6-electrode configuration providing more significant tremor suppression (Table 1,2,3).

The study concludes that the effectiveness of tremor suppression varies based on electrode configuration and the type of tremor disorder. The 6-electrode arrangement reduced tremors more significantly than the 2-electrode arrangement for subjects with essential tremor. The two-electrode setup for Parkinson's disease demonstrated some directional suppression, but overall efficacy was inconsistent. These results underline the necessity of customized electrode positioning and stimulation settings based on the unique tremor type and patient attributes.

The findings have important implications for the development of non-invasive treatments for tremor suppression. The variability in data collected also indicates the potential influence of task-specific factors, such as grip changes during the cup holding task or unforeseen movement of the hand during the writing task. Future research should explore personalized approaches to electrode placement and stimulation parameters, potentially incorporating adaptive systems that adjust in real-time to the patient's needs. Additionally, long-term studies are needed to establish the sustainability and reliability of these findings.

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