Clinical trial NCT03769961: Ataxia in Essential Tremor: Describing the Differences Between Disease Process and Treatment Effect
Official title: Ataxia in Essential Tremor: Describing the Differences Between Disease Process and Treatment Effect (ATAX)
Study type: OBSERVATIONAL
Overall status: TERMINATED
Conditions: Essential Tremor
Deep Brain Stimulation
Ataxia
Cerebellar Diseases
Keywords: essential tremor
dbs
Lead sponsor: Oregon Health and Science University
Sponsor class: OTHER
Collaborators: name: Portland VA Medical Center
First posted: 2018-12-10
Enrollment: 6
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_CONTROL
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Essential Tremor participants with and without ataxia

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

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.

Eligibility criteria: 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

Primary outcomes:
measure: Ataxia Differences between DBS and no DBS
timeFrame: Visit 2 (after DBS has been turned off for 3-10 days)
Secondary outcomes:
measure: Balance Confidence
timeFrame: Visit 2 (after DBS has been turned off for 3-10 days)
Other outcomes:
Locations:
city: Portland
country: United States
facility: Oregon Health & Science University
state: Oregon
city: Portland
country: United States
facility: VA Portland Health Care System
state: Oregon
Study officials:
References:
citation: 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.
citation: 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.
citation: 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.
citation: 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.