Safety and effectiveness of frameless linac-based stereotactic radiosurgery on tremor in patients with essential tremor or Parkinson’s disease (TREMOR study)

Trial summary:

In this study, we are trying to find out if using stereotactic radiosurgery to treat tremor is safe and effective in patients who have tremor dominant Parkinson’s or essential tremor and are unable to undergo conventional therapy.

Receptor status / problem studied:

Tremor in essential tremor, Tremor in Parkinson's disease

Inclusion criteria

  • Age great than or equal to 18 years.
  • Clinical diagnosis of essential tremor or tremor dominant Parkinson’s disease made by a
  • Tremor of at least one upper limb resulting in significant disability despite medical treatment
  • Medication refractory tremor or intolerant to medications
  • Not a suitable surgical candidate or declined surgery
  • Assessed as able to tolerate MRI scan and treatment session(s) with light sedation
  • Has been reviewed and approved for enrolment by the multidisciplinary study team

In addition, the following criteria will apply (to be assessed by the study movement disorders

  • For patients with essential tremor:
    • tremor refractory to adequate trials of at least two medications, one of which should
      be a first line therapy of either propranolol or primidone (an adequate medication
      trial is defined as a therapeutic dose of each medication or the development of side
      effects as the medication dose is titrated)
      postural and intention tremor severity score of greater than or equal to 2 in the
      extremity marked for treatment as measured by the FTMRS while stable on
    • significant disability due to essential tremor despite medical treatment (FTMRS score
      of 2 or above in any one of the items 16-21)
    • may have bilateral appendicular tremor
  • For patients with tremor dominant Parkinson’s Disease:
    • will have a tremor dominant and postural instability/gait difficulty (TD/PIGD) ratio >
      1.5 in the medicated [ON] state as calculated from the Unified Parkinson’s Disease
      Rating Scale (UPDRS) formula as described by Jankovic et al. (Jankovic et al. 1990)
    • tremor remains disabling when medical therapy is optimal or not tolerated for the treatment of other cardinal signs of Parkinson’s disease (bradykinesia, rigidity, etc.), as determined by a neurologist at the site
    • a resting tremor severity score of greater than or equal to 3 in the hand/arm as measured by the medicated (ON) UPDRS question #20 or a postural/action tremor greater than or equal to a 2 for question #21
    • subject exhibits a significant disability from their PD tremor despite medical treatment where a significant disability is defined as a Parkinson’s disease tremor with at least a score of 3 on #16 of the medicated (ON) UPDRS

Exclusion criteria

  • Presence of head tremor that would interfere with treatment delivery
  • Patients with central neurodegenerative disease other than Parkinson’s disease
  • Drug-induced parkinsonism
  • Unable to undergo MRI due to the presence of a metallic implanted device such as a pacemaker or defibrillator or cochlear implant
  • Prior cranial irradiation
  • Change in medication(s) in the four weeks prior to enrolment or plans to change medication(s) during the 12-month follow-up period
  • Presence of significant cognitive impairment as determined by meeting the DSM-5 criteria for Major Cognitive Disorder
  • Unstable psychiatric disease, defined as active uncontrolled depressive symptoms, psychosis, delusions, hallucinations, or suicidal ideation. Subjects with stable, chronic anxiety or depressive disorders may be included provided their medications have been stable for at least 60 days prior to study entry and if deemed appropriately managed by the site neuropsychiatrist
  • Unable to provide informed consent
  • Unable or unwilling to attend follow-ups or comply with protocol requirements
  • Pregnant or planning to become pregnant

View more trial information

Open for recruitment

Trial Title



Neurological conditions

Type of trial

Investigator Initiated

Type of treatement

Radiation Oncology Radiation Medicine





Principal Investigator
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