Deep brain stimulation in Parkinson disease: new scale assesses effect

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  • The Deep Brain Stimulation Impairment Scale (DBS-IS) may help assess the effect of this treatment for Parkinson disease.

Why this matters

  • Conventional tools for assessing Parkinson disease do not fully capture specific symptoms or impairments that may remain unaffected by, worsen after, or be induced by bilateral deep brain stimulation of the subthalamic nucleus.

Key results

  • The new scale has 22 questions and 6 subscales (postural instability and gait difficulties, cognition, speaking, apathy, impulsivity, and difficulties related to the deep brain stimulation device).
  • The scale has high reliability on all subscales (Cronbach alpha, 0.71-0.90) and high construct validity (r>0.50; P<.001).

Study design

  • A scale development and validation study among 215 patients and 391 patients, respectively, with Parkinson disease in Germany who underwent surgery for bilateral deep brain stimulation of the subthalamic nucleus and some of their caregivers.
  • The main outcomes were the scale and its performance.
  • Funding: The German Parkinson’s Disease Foundation.


  • Findings may not apply to patients having stimulation of other brain targets.
  • The scale developed was based on outcomes in only the first year after surgery.
  • Patient and caregiver experiences were collected by anonymous surveys.