Devices to Manage Tremor in Parkinson’s Disease and Essential Tremor

On June 25, 2025, the Centers for Medicare & Medicaid Services (CMS) will convene a panel of the Medicare Evidence Development and Coverage Advisory Committee (MEDCAC). The MEDCAC panel will examine what clinical endpoints should be of interest to CMS in studies of devices for management of tremor in patients with Parkinson’s Disease or essential tremor. By voting on specific questions, and through discussion, MEDCAC panel members will advise CMS about the ideal clinical endpoints to measure in research studies on this topic, as well as appropriate measurement instruments, definitions of minimal clinically important differences and adequate follow-up duration.

This need has arisen because Parkinson's and essential tremor are common among Medicare beneficiaries and because potential clinical endpoints are wide-ranging. Input from the MEDCAC panel will be used by CMS in future relevant National Coverage Analyses (NCAs) of new devices.

Studies have often focused on shorter term data with greater reliance upon intermediate and surrogate outcomes. Although these endpoints may help in answering certain questions, they are generally less helpful for CMS, whose focus is on the more ultimate health outcomes associated with the technologies and particularly for older adults. As a result, there are more frequent evidence gaps in the research literature with respect to the clinically meaningful health outcomes for CMS beneficiaries in assessments of these kinds of medical interventions.

For these reasons, CMS commissioned a Clinical Endpoints Review (CER) of the literature to identify endpoints that should be considered when designing studies of devices for management of Parkinson’s Disease and essential tremor. The CER revealed many potential clinical endpoints that were used with varying frequency across the studies. Most of these clinical endpoints can be assessed with formal instruments. Definitions of minimal clinically important difference (MCID) could not be identified for some of the instruments, and useful guidance on follow-up duration was not available from the CER. A neurosurgeon and two neurologists reviewed the completed CER and submitted written responses to review questions. These three physicians also had special expertise in movement disorders.

The MEDCAC panel members will make use of the CER as well as their own professional expertise in considering recommendations for CMS. A subcommittee of the full MEDCAC panel reviewed the CER along with responses from the three physician specialists who read the completed CER. The subcommittee then assisted CMS in formulating voting questions and a discussion guide for the full panel meeting.

By voting on specific questions, and through discussion, MEDCAC panel members will advise CMS on these issues: 1) clinical endpoints considered important for older adults and suggested instruments for measuring those endpoints, 2) MCIDs, and 3) the duration of patient follow-up necessary to demonstrate effectiveness and safety, device durability, and patient adherence.

April 24, 2025

03/26/2025 - MEDCAC subcommittee (Devices to Manage Tremor in Parkinson’s Disease and Essential Tremor)

After presentations of background information and a time for public comments, the Panel will be asked to provide feedback that CMS will subsequently use to draft a technical report on this topic. To that end, the remainder of the Panel meeting after public comments will be structured as follows:

• An electronic poll to determine how Panelists rate the importance of 3 clinical endpoint domains under which important clinical endpoints have been organized.
• A brief statement from each Panelist regarding his or her vote.
• Open discussion of each endpoint domain. Panelists will be asked to very briefly:
  • Identify the most important and perhaps least important clinical endpoints within the domain
  • Provide guidance regarding minimal clinically important differences (MCIDs) where none have been identified in the literature
  • Suggest an appropriate duration of follow-up when endpoints in these domains are used in clinical studies

Panelists may find it helpful to print this document or plan to have it open on their laptops for reference during Panel discussions.

VOTING

The following endpoint domains and suggested clinical endpoints pertain to studies evaluating medical devices to manage tremor in older adults who have Parkinson’s Disease or essential tremor. These domains and endpoints have been identified through a systematic literature review (the Clinical Endpoints Review [CER} document). The review included input from an external neurologist. Completion of the CER document was followed by feedback from three other external expert reviewers (two neurologists and one neurosurgeon) and deliberations of a Panel Subcommittee on March 26, 2025. In the June 25 full MEDCAC Panel meeting, Panelists will use rating scales, as shown, to indicate the importance of each clinical endpoint within each endpoint domain.

1.      Clinician-Assessed Health Outcomes Domain

Specific Clinical Endpoints, Parkinson’s Disease

Global change in motor symptom severity
Motor-related activities (experiences) of daily living
Gait function, postural instability, balance and/or falls
Global change in nonmotor symptoms
Motor complications (motor fluctuations, dyskinesia)
Speech function and swallowing
Cognitive function

Specific Clinical Endpoint, Essential Tremor

Reduction in tremor

2.      Patient-Reported Outcomes Domain

Specific Clinical Endpoints, Parkinson’s Disease

Parkinson’s Disease-related quality of life
Sleep quality

Specific Clinical Endpoint, Essential Tremor

Tremor-related quality of life or tremor-related activities (experiences) of daily living

3.       Device-Related Safety Domain

Several adverse events are possible following device-related treatments of Parkinson’s Disease and essential tremor. The nature and seriousness of these possible adverse events vary by device type.

DISCUSSION

Please be prepared to discuss the following issues as they apply to each endpoint domain.

1. The importance of specific clinical endpoints within each domain and how importance may differ by device type or patient subpopulation
2. Ideal and minimum duration of follow-up required for detection of an impact within each domain
3. Thresholds for defining an MCID for clinical endpoints identified for studies of devices for patients with essential tremor. No MCIDs were identified for these endpoints in the literature reviewed by the CER, nor were any suggested by the expert reviewers. Panel input can be qualitative and need not be instrument-specific.