Low enrollment

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

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.

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

Essential Tremor participants with and without ataxia

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.

Data will be available within 6 months of study completion.

Data access requests will be reviewed by an external Independent Review Board. Requestors will be required to sign a data access agreement.