Ataxia in Essential Tremor: Describing the Differences Between Disease Process and Treatment Effect (ATAX)

Ataxia in Essential Tremor: Describing the Differences Between Disease Process and Treatment Effect (ATAX)

The proposed study aims to characterize ataxia occurring in essential tremor and essential tremor with DBS.

Study Overview

• Status: Terminated
• Conditions: Ataxia; Essential Tremor; Cerebellar Diseases; Deep Brain Stimulation
• Intervention / Treatment: Other: No intervention

Detailed Description

Objectives: In recent years, there has been a growing amount of evidence tying Essential Tremor (ET) to cerebellar dysfunction. This has been clinically observed, demonstrated through specific gait measures of ataxia (often involving tandem gait), and confirmed through Positron emission tomography (PET) imaging. Deep Brain stimulation for ET has become a widely utilized therapeutic intervention for patients, and the bilateral thalamic ventralis intermedius (VIM) is most commonly implanted. However, it has been noted that in some patients gait ataxia significantly worsens post-op. This initially was thought to be a result of disease progression, but recent studies have in fact shown that this is a DBS related phenomenon.

Methods: Participants will have two visits to either the Portland VA or Oregon Health & Science University (OHSU). At each visit, several assessments of balance, tremor, gait and balance, and DBS settings will be made. The gait and balance assessments will be performed by a unblinded and a blinded rater.

• Study Type: Observational
• Enrollment (Actual): 6

Contacts and Locations

Study Locations

• United States
  • Oregon
    • Portland, Oregon, United States, 97201
      • Oregon Health & Science University
    • Portland, Oregon, United States, 97239
      • VA Portland Health Care System

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Essential Tremor participants with and without ataxia

Description

Inclusion Criteria:

• Essential Tremor diagnosis at least 3 years duration
• Absence of other neurological signes (such as dystonia, ataxia, or Parkinsonism)
• Patients must be able to walk 2 minutes unassisted.
• Patients must be able to understand and consent to be in the study.

Exclusion Criteria:

• Patients who have had changes in DBS settings within the last 3 months.
• Patients who have had no initial improvement or response to DBS.
• ET medication changes in the last month.
• Actively abusing alcohol.
• A neurologic diagnosis other than ET that in the investigator's opinion could affect gait and/or balance.
• Atypical tremor disorder including by not limited to tremor due to multiple sclerosis, medication-induced tremor, Parkinson's disease, or parkinsonian syndrome.
• Dementia

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
ET (DBS-, Ataxia+); Essential Tremor without DBS with Ataxia on examination	Other: No intervention; No interventions - Observational study
ET (DBS-, Ataxia-); Essential Tremor without DBS and without Ataxia on examination	Other: No intervention; No interventions - Observational study
ET (DBS+, Ataxia+); Essential Tremor with DBS with Ataxia on examination	Other: No intervention; No interventions - Observational study
ET (DBS+, Ataxia-); Essential Tremor with DBS without Ataxia	Other: No intervention; No interventions - Observational study

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ataxia Differences between DBS and no DBS	Compare the Scale of the Assessment and Rating of Ataxia (SARA) total score between DBS and no DBS participants with essential tremor. This 8-item scale rates gait (0-8 points), stance (0-6 points), sitting (0-4 points), speech disturbance (0-6 points), finger chase (0-4 points), nose-finger test (0-4 points), fast alternating hand movements (0-4 points), and heel-shin slide (0-4 points). Motor activists of the four extremities (items 5-8) assessments are performed bilaterally, mean values to obtain a total score. Cumulative score ranges from 0 (no ataxia) to 40 (most severe ataxia).	Visit 2 (after DBS has been turned off for 3-10 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Balance Confidence	The Activities-Specific Balance Confidence Scale (ABC) is a subjective measure of confidence in performing various ambulatory activities without falling or experiencing a sense of unsteadiness. The ABC scale is a 16-item self-report measure in which participants rate their balance confidence on a 0-100 scale (0 = 0 no confidence, 100 = 100 complete confidence). Overall score is calculated by adding item scores and dividing by the total number of items.	Visit 2 (after DBS has been turned off for 3-10 days)

Collaborators and Investigators

• Sponsor: Oregon Health and Science University
• Collaborators: Portland VA Medical Center

Publications and helpful links

General Publications

• Ramirez-Zamora A, Boggs H, Pilitsis JG. Reduction in DBS frequency improves balance difficulties after thalamic DBS for essential tremor. J Neurol Sci. 2016 Aug 15;367:122-7. doi: 10.1016/j.jns.2016.06.001. Epub 2016 Jun 2.
• Nazzaro JM, Lyons KE, Pahwa R. Deep brain stimulation for essential tremor. Handb Clin Neurol. 2013;116:155-66. doi: 10.1016/B978-0-444-53497-2.00013-9.
• Kronenbuerger M, Konczak J, Ziegler W, Buderath P, Frank B, Coenen VA, Kiening K, Reinacher P, Noth J, Timmann D. Balance and motor speech impairment in essential tremor. Cerebellum. 2009 Sep;8(3):389-98. doi: 10.1007/s12311-009-0111-y. Epub 2009 May 19.
• Fasano A, Herzog J, Raethjen J, Rose FE, Muthuraman M, Volkmann J, Falk D, Elble R, Deuschl G. Gait ataxia in essential tremor is differentially modulated by thalamic stimulation. Brain. 2010 Dec;133(Pt 12):3635-48. doi: 10.1093/brain/awq267. Epub 2010 Oct 5.

Study record dates

Study Major Dates

• Study Start (ACTUAL): December 1, 2018
• Primary Completion (ACTUAL): September 14, 2020
• Study Completion (ACTUAL): September 14, 2020

Study Registration Dates

• First Submitted: December 6, 2018
• First Submitted That Met QC Criteria: December 6, 2018
• First Posted (ACTUAL): December 10, 2018

Study Record Updates

• Last Update Posted (ACTUAL): September 17, 2020
• Last Update Submitted That Met QC Criteria: September 15, 2020
• Last Verified: September 1, 2020

More Information

Terms related to this study

• Keywords: essential tremor; dbs
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Movement Disorders; Dyskinesias; Ataxia; Tremor; Essential Tremor; Cerebellar Ataxia; Cerebellar Diseases
• Other Study ID Numbers: 18608

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Post data entry and verification, data and specimens will be de-identified (no 18 HIPAA identifiers and age aggregated for those > 89 years old) and transferred to the Neurological Disorder Repository (MIRB # 3129). This repository is maintained at the Portland VA Health Care System. Verification of the coded data set creation and the absence of the identifiers will be created and retained in the study files. The research coordinator will be responsible for the creation and verification process. The key to the code will be maintained by the study and will not be released to the repository. The recipient investigator must present the data use agreement, documentation of an Institutional Review Boar (IRB) approved protocol and Informed Conset Form (ICF) allowing the release of the identifiable specimens/data, or the release of coded specimens/data.
• IPD Sharing Time Frame: Data will be available within 6 months of study completion.
• IPD Sharing Access Criteria: Data access requests will be reviewed by an external Independent Review Board. Requestors will be required to sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No