Deep Brain Stimulation for Essential Tremor

Essential Tremor Breakthrough: Can Stimulation Pulse-Width Improve Gait?

Lena Kashyap in Health & Wellness August 2025 • 4 min read.

"A new study explores how adjusting the pulse width of thalamic deep brain stimulation can alleviate gait ataxia in essential tremor patients, offering a potential path to better treatment outcomes."

Essential tremor (ET) is a common neurological disorder characterized by involuntary shaking, which can significantly impact a person's quality of life. While deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become a well-established treatment for disabling and drug-refractory ET, it can sometimes lead to delayed onset cerebellar syndrome, including gait ataxia.

Gait ataxia, a condition characterized by impaired balance and coordination during walking, can be a challenging side effect of DBS for ET. Researchers have been exploring ways to mitigate this issue, with a focus on refining stimulation parameters to optimize therapeutic benefits while minimizing adverse effects.

A recent study delved into the impact of stimulation pulse-width on gait ataxia in ET patients who had undergone thalamic DBS. The study hypothesized that using short pulse-widths could selectively stimulate fast-conducting dentate-thalamic myelinated fibers, potentially reducing gait disturbances without compromising tremor suppression.

Short Pulse-Width Stimulation: A Promising Solution for Gait Ataxia?

Deep Brain Stimulation for Essential Tremor

The study enrolled seven patients (two males, average age 73) with pharmacologically intractable ET and gait progressive ataxia, all of whom had bilateral DBS implants in the STN area. The participants underwent two stimulation conditions: their usual stimulation parameters (baseline) and a reduced pulse-width of 30 µs after a two-week follow-up period.

The research protocol included a comprehensive clinical evaluation using the Fahn-Tolosa-Marin tremor rating scale (TRS) and the SARA scale for ataxia (specifically items 1-3). Kinematic assessments of locomotion were also conducted, with participants performing at least five walking trials (8 meters each) in a gait laboratory environment, walking barefoot at their preferred speed.

Clinical Evaluations: The Fahn-Tolosa-Marin tremor rating scale (TRS) assessed tremor severity, while the SARA scale focused on evaluating ataxia.
Kinematic Assessments: An optoelectronic system (SMART DX, BTS) captured detailed movement data, which was then processed using custom Matlab algorithms to calculate gait spatio-temporal parameters.
Statistical Analysis: The researchers used the coefficient of variation (CV) to quantify parameter variability and compared baseline and ataxic conditions using the Wilcoxon matched pairs test (JMP13).

The results of the study indicated that short pulse-width (30 µs) stimulation remarkably improved gait ataxia, as demonstrated by the clinical scale (SARA 1-3 baseline score: 6.8 ± 2.8; follow-up score: 3.0 ± 2.0; p<0.01) and kinematic parameters. Importantly, tremor control was maintained with DBS (TRS baseline score: 10.2 ± 9.5; follow-up score: 4.8 ± 4.2; p = n.s.).

Implications and Future Directions

The study's findings suggest that DBS-induced gait ataxia in ET patients can be effectively managed by reducing the stimulation pulse-width to 30 μs. This short pulse-width approach may selectively stimulate fast-conducting dentate-thalamic myelinated fibers, which are the appropriate target for tremor control. This prevents current spread, which is responsible for cerebellar side effects. The pulse-width reduction did not compromise tremor suppression, offering a well-controlled therapeutic outcome. Further research is warranted to validate these findings in larger cohorts and explore the long-term effects of short pulse-width stimulation on gait and overall quality of life in ET patients.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.gaitpost.2018.07.147, Alternate LINK

Title: Effects Of Short Pulse-Width Stimulation On Gait Ataxia Of Essential Tremor Patients Implanted With Thalamic Deep Brain Stimulation

Subject: Rehabilitation

Journal: Gait & Posture

Publisher: Elsevier BV

Authors: C. Palmisano, M. Reich, J. Volkmann, C.A. Frigo, I.U. Isaias

Published: 2018-10-01

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Everything You Need To Know

1

What is essential tremor?

Essential tremor (ET) is a neurological disorder that causes involuntary shaking, which can severely impact daily life. This involuntary shaking distinguishes it from other movement disorders and is a primary reason for seeking treatment. The study focuses on individuals with ET, for whom current treatments, such as Deep Brain Stimulation (DBS), are not fully effective, particularly concerning gait ataxia.

2

What is Deep Brain Stimulation, and why is it relevant?

Deep Brain Stimulation (DBS) is a treatment where electrodes are implanted in the brain to deliver electrical stimulation. The study focuses on thalamic DBS, which is applied to the subthalamic nucleus (STN). While effective for tremor, thalamic DBS can sometimes lead to side effects, like gait ataxia. The significance lies in the potential to improve the quality of life for ET patients. By refining the stimulation parameters, like pulse-width, researchers aim to maximize the benefits of DBS while minimizing adverse effects like gait ataxia.

3

What is gait ataxia and why does it matter?

Gait ataxia is characterized by impaired balance and coordination when walking. In the context of this study, it is a side effect of Deep Brain Stimulation (DBS) for Essential Tremor (ET). The importance of understanding gait ataxia is that it helps to define the negative consequences that DBS can have for some patients. The study explores the impact of stimulation pulse-width on reducing this condition, indicating the need for careful adjustment of stimulation parameters to optimize treatment outcomes and improve patient quality of life.

4

What is stimulation pulse-width and what are its implications in this context?

The study uses stimulation pulse-width, a parameter of Deep Brain Stimulation (DBS), which refers to the duration of the electrical pulse delivered to the brain. The study suggests that using a shorter pulse-width (30 µs) can reduce gait ataxia in Essential Tremor (ET) patients. This is significant because it offers a method to specifically target the therapeutic benefits of DBS while minimizing side effects. By adjusting the pulse-width, researchers aim to stimulate the fast-conducting dentate-thalamic myelinated fibers more selectively, potentially improving gait without compromising tremor control.

5

What methods were used to assess the outcomes of the study?

The Fahn-Tolosa-Marin tremor rating scale (TRS) and the SARA scale are used to evaluate the effectiveness of treatments. The TRS measures the severity of tremor, and the SARA scale evaluates ataxia, specifically items 1-3. Kinematic assessments and statistical analysis are additional tools to evaluate the patients. The significance of these assessments is that they provide objective measurements to determine if the intervention (short pulse-width DBS) is effective at reducing tremor and gait ataxia. The outcomes of the study, measured using these scales, showed that the short pulse-width stimulation improved gait ataxia and maintained tremor control.