Effects of Deep Brain Stimulation for the Treatment of Parkinson's Disease
Condition: Parkinson
MeSH terms: Parkinson Disease
Study type: Observational

Summary: 
      The purpose of this study is to assess the effects of unilateral deep brain stimulation on
      upper and lower extremity motor function in advanced Parkinson's disease patients. It is
      hypothesized the unilateral stimulation will lead to improvements in bilateral motor
      functioning.
    

Detailed description: 
      Parkinson's disease (PD) is a chronic progressive degenerative illness in which dopaminergic
      neurons in the substantia nigra pars compacta deteriorate resulting in a reduction in
      striatal dopamine. Decreased levels of dopamine in PD patients results in varying
      combinations of akinesia, bradykinesia, tremor, rigidity and gait\postural instability.
      Parkinson's disease is the second most common neurodegenerative disorder, affecting nearly
      1.2 million Americans with annual treatment costs approaching $25 billion. Deep brain
      stimulation (DBS) is a surgical approach developed for the treatment of advanced PD that
      provides promise in alleviating its motor deficits. The most common stimulation site for the
      treatment of advanced PD is the subthalamic nucleus (STN). Nearly 90 percent of patients
      involved in a multi-center trial with STN stimulation underwent single session bilateral
      implantation. It is generally accepted that bilateral STN stimulation improves upper and
      lower extremity function. However, bilateral STN stimulation may be associated with
      postoperative morbidity including cognitive deficits and neuropsychiatric changes. In
      contrast, the effects of unilateral STN stimulation on bilateral upper and lower extremity
      motor function are poorly understood. The question of whether to proceed with bilateral or
      unilateral surgery is important, as a significant number of patients for whom surgery is a
      consideration have relative contraindications such as age greater than 70, cognitive decline,
      or other medical conditions that may prevent bilateral implantation. Considering the risks
      for bilateral implantation may be greater than unilateral procedures, it is necessary to
      determine if unilateral stimulation is an effective means of ameliorating PD symptoms. The
      primary aim of this collaborative project is to determine the effects of unilateral STN DBS
      on functional upper (manual dexterity) and lower (postural stability and gait initiation)
      extremity motor performance in Veterans with advanced PD. The results from these studies have
      the potential to impact the use of DBS in the treatment of advanced PD. Positive bilateral
      results with unilateral stimulation of STN may allow patients not currently considered
      eligible for bilateral implantation to be considered for unilateral procedures as a method of
      treating PD symptoms. Our general hypothesis is that unilateral STN DBS acts to override
      disrupted neural activity of the basal ganglia in one hemisphere. The resultant normalized
      basal ganglia output to the SMA then allows for improved planning and control of bilateral
      actions. Bilateral upper and lower extremity motor performance will be quantified in a group
      of advanced PD patients with unilateral STN DBS patients while "on" and "off" stimulation. It
      is hypothesized that unilateral STN DBS will result in bilateral improvements in upper and
      lower extremity motor function.
    

Intervention name(s): Deep Brain Stimulation
Intervention type(s): Device
Time perspective: Prospective
Keywords: deep brain stimulation; gait; manual dexterity; parkinson's disease