Ataxia Prevalence in Primary Orthostatic Tremor

Tremor Other Hyperkinet Mov (N Y). 2020 Dec 16:10:54. doi: 10.5334/tohm.570.

Abstract

Background: The exact pathophysiology of primary Orthostatic Tremor (OT) is unknown. A central oscillator is assumed, and previous imaging studies show involvement of cerebellar pathways. However, the presence of ataxia on clinical exam is disputed. We set out to study ataxia in OT prospectively.

Methods: EMG-confirmed primary OT subjects and spousal controls received a neurological exam with additional semiquantitative evaluations of ataxia as part of a multinational, prospective study. These included detailed limb coordination (DLC), detailed stance and gait evaluation (DS), and the Brief Ataxia Rating Scale (BARS). Intra- and inter-rater reliability were assessed and satisfactory.

Results: 34 OT subjects (mean age = 67 years, 88% female) and 21 controls (mean age = 66 years, 65% male) were enrolled. Average disease duration was 18 years (range 4-44). BARS items were abnormal in 88% of OT patients. The OT subjects were more likely to have appendicular and truncal ataxia with significant differences in DLC, DS and BARS. Ocular ataxia and dysarthria were not statistically different between the groups.

Discussion: Mild-to-moderate ataxia could be more common in OT than previously thought. This is supportive of cerebellar involvement in the pathophysiology of OT. We discuss possible implications for clinical care and future research.

Highlights: Previous studies of Primary Orthostatic Tremor (OT) have proposed pathophysiologic involvement of the cerebellar pathways.However, presence of ataxia has not been systematically studied in OT.This is a prospective comprehensive ataxia assessment in OT compared to controls. Mild-to-moderate appendiculo-truncal ataxia was found to be common in OT.

Keywords: ataxia; balance; cerebellum; coordination; orthostatic tremor; tremor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Ataxia / epidemiology
  • Ataxia / physiopathology*
  • Case-Control Studies
  • Dizziness / epidemiology
  • Dizziness / physiopathology*
  • Electromyography
  • Female
  • Gait Analysis
  • Humans
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Tremor / epidemiology
  • Tremor / physiopathology*

Supplementary concepts

  • Primary orthostatic tremor

Grants and funding

This research was supported in part by the University of Nebraska Foundation’s Orthostatic Tremor Research and Education Fund, and by the UNMC/Nebraska Medicine Clinical and Translational Research Support Fund, both to Dr. Torres-Russotto. There was no specific funding for this project obtained by other authors. Dr. Bertoni has received support for clinical research trials/lectures/or has served on advisory boards for the following: Abbvie, Acadia, Aventis, Boehringer Ingelheim, Cephalon, Eisai, Elan Pharmaceuticals, KGaA, Kyowa, Merck, Novartis, Pharmacia, Schwarz Pharma, SKB (Smith Kline Beecham), Solvay, TEVA, and UCB Pharma. Dr. Bhatti has done speaking/consulting for Teva neurosciences, Abbvie, Adamas, Accadia, Allergan Pakistan, Merz, Medtronic, Boston Scientific, Abbott, PharmEvo Pakistan, Amneal and Accorda in the past. He has done research funded by Abbvie, NIH, Ipsen, Revance, Prilenia and global kinetics. Dr. Doss declares to have received in the past funding from Actelion for unrelated projects and speaker honoraria, Teva Pharmaceuticals for unrelated projects. Dr. Hellmann declares speaking engagements paid by Teva. Dr. Torres-Russotto has received consultation honoraria from AbbVie, Acorda, Adamas, Allergan, Global Kinetics Corporation, Ipsen, Kyowa-Kirin, Sunovion and Teva. Dr. Torres-Russotto has participated in clinical trials sponsored by AbbVie, Ipsen and Revance. The other authors have no financial disclosures.