Physical Therapy and Deep Brain Stimulation in Parkinson Disease
Physical Therapy and Deep Brain Stimulation in Parkinson Disease
While deep brain stimulation of the subthalamic nucleus (STN-DBS) is commonly used to reduce
 tremor, muscle stiffness, and bradykinesia in people with Parkinson disease (PD), preliminary
 studies suggest balance may worsen and falls may increase after STN-DBS. Walking speed, known
 to be reduced in PD, typically improves after surgery; however, other important gait
 qualities may not improve. Given the potential for worsening balance and gait and increasing
 falls after surgery, it is imperative that researchers explore interventions that complement
 the positive effects of STN-DBS and delay worsening of balance and gait.

 Physical therapy (PT) is reported to be effective in improving balance and walking in people
 with PD. However, there have been no studies to investigate how individuals with STN-DBS
 respond to PT. As such, it is unclear if exercise in the post-DBS population is safe,
 feasible, and effective. The purpose of this study is to examine the safety, feasibility, and
 efficacy of PT in people with PD with STN-DBS.

 The investigators hypothesize that PT will be safe and feasible for people with PD with
 STN-DBS. Further, the investigators hypothesize that those assigned to PT group will
 demonstrate improvements in balance and gait while those assigned to the control group will
 demonstrate no change or a decline in balance and gait.
Deficits in balance and gait may lead to falls, fall-related complications, and physical
 inactivity in people with PD. These negative effects are thought to lead to a 'malignant'
 form of PD in which there is reduced quality of life and increased risk for mortality. While
 people who have had STN-DBS often experience reductions in tremor, rigidity, and
 bradykinesia, surgical management of PD may not be effective in ameliorating impairments in
 balance and gait. In fact, investigators have reported that DBS may worsen balance, which may
 accelerate an individual's decline toward 'malignant' PD. To this end, recent studies
 indicate physical activity levels did not increase after STN-DBS. This finding should not go
 unnoticed as physical activity may have a disease modifying effect, slowing the progression
 of motor disability. As of 2011, approximately 70,000 people with PD have undergone DBS, with
 the annual number of DBS procedures for PD totaling between 8,000-10,000. In addition,
 investigators are now studying the effects of STN-DBS in people with early PD. The procedure
 appears to be safe and effective in this population, which will increase the number of
 surgical candidates. With the number of people with PD expected to double to more than 8
 million by 2030, the number of those receiving DBS is expected to substantially increase.

 Given the expected rise in STN-DBS procedures and potential for worsening of postural
 instability and gait deficits, there is a clear need for interventions that prevent these
 negative complications of STN-DBS.

 Physical therapy, delivered using various treatment approaches (e.g. treadmill training,
 balance training), is effective in reducing postural instability and improving spatiotemporal
 gait characteristics among individuals with PD who do not have DBS. To our knowledge, there
 are no studies to date that assessed the impact of PT for those with PD who have DBS. In
 fact, the current standard of care following STN-DBS does not include PT. Current care
 post-DBS includes pharmacologic management and monitoring of DBS settings, which are
 optimized based on Unified Parkinson's Disease Rating Scale motor subsection (UPDRS III)
 scores. Despite the introduction of substantial changes to neural activity in areas of the
 brain governing movement with DBS, formal movement training or assessment of functional
 mobility and safety are not provided after surgery. As such, patients may not experience
 significant improvements in postural stability and gait following surgery, and may be at
 increased risk for falls, fall-related complications, and development of a sedentary
 lifestyle. Physical therapy is a personalized intervention that can be used to address
 specific movement impairments that remain even when patients are on optimal regimens of
 medication and DBS. There is an urgent need to determine if PT is effective in improving
 postural stability and gait performance over time following STN-DBS. If the intervention is
 safe and feasible, future studies could evaluate the efficacy of PT for gait and balance
 deficits in this population before and/or immediately post-surgery, increasing the potential
 impact of this research.

 In this pilot randomized controlled trial, participants will be randomly assigned to either
 the physical therapy group or control group. Those in the physical therapy group will attend
 1-hour sessions of PT twice weekly with a treatment plan designed to improve balance and
 gait. Those in the control group will not be prescribed an exercise intervention.

 Each participant will undergo the same battery of balance and gait tests. Although STN-DBS
 settings are typically stable at 12 months post-surgery, participants will be allowed to
 follow up with their neurologists as needed for programming and medication adjustments. All
 changes in programming settings and medication dosages will be noted. A rater, blinded to
 group assignment, will collect all outcomes at each time point. Participants will be tested
 in the following conditions: 1) OFF stimulation and OFF medication and 2) ON stimulation and
 ON medication. Testing participants OFF stimulation/OFF medication will allow us to determine
 if the addition of PT after STN-DBS affects balance and gait independent of other treatments.
 OFF medication is defined as greater than or equal to 12 hours since the last intake of
 anti-PD medication. For OFF stimulation/OFF medication testing, participants will arrive to
 the laboratory OFF medication but with stimulators on. The stimulators will be turned OFF
 upon arrival at the laboratory and testing will commence 45 minutes after the stimulators are
 turned OFF. Stimulators will be turned back on upon completion of this testing session. The
 investigators anticipate the total time for this laboratory visit to be 2 hours. Testing ON
 stimulation/ON medication will provide insight into how participants perform on an everyday
 basis. ON medication is defined as 1-1.5 hours after medication intake. For ON stimulation/ON
 medication assessments, participants will arrive to the laboratory 1-1.5 hours after taking
 their normal anti-PD medication dose with stimulators on and stimulators will remain on
 throughout the session. Assessments will occur at baseline and at 8 (i.e. post-test) and 12
 weeks (i.e. follow up). Assessments will take place on two separate days and the order of
 testing condition (OFF medication/OFF stimulation vs. ON medication/ON stimulation) will be
 randomized. The Movement Disorders Society-Unified Parkinson Disease Rating Scale III
 (MDS-UPDRS III) will be administered in each condition.
Inclusion Criteria:

 -  Diagnosis of idiopathic Parkinson disease

 -  Hoehn & Yahr stages II-IV

 -  At least 1 year post-STN-DBS

 -  Able to provide informed consent

 Exclusion Criteria:

 -  Diagnosis of atypical parkinsonism

 -  Hoehn & Yahr stages I or V

 -  Evidence of dementia (MMSE < 24/30)

 -  Inability to walk 10 meters with or without assistive device