Power Wheelchair Joystick Use in Spastic Cerebral Palsy
Condition: Cerebral Palsy; Spasticity
MeSH terms: Muscle Spasticity; Paralysis; Cerebral Palsy
Study type: Observational

Summary: 
      There are over 750,000 individuals in the U.S. with Cerebral Palsy (CP). Up to 46% of adults
      with CP report limited mobility in their communities. However, upper limb spasticity and
      problems with movement can make the independent use of a wheelchair difficult. Forty percent
      of individuals who desire mobility via electric wheelchairs are precluded from using them
      because of problems with upper limb function. No studies to date have produced devices that
      definitively improve mobility for these individuals. We will recruit 22 subjects with Spastic
      CP and 22 age and gender matched control subjects without apparent disability from
      advertisements, mailings, and outpatient clinics. Both a conventional joystick (MSJ) and a
      novel joystick that is customized for each subject will each be used six different computer
      screen tasks that simulate driving a wheelchair on a path. We will compare subjects and
      joysticks based on driving performance. Understanding problems with driving will help us to
      design joysticks and other assistive devices, not only for CP but for Traumatic Brain Injury,
      Spinal Cord Injury, Parkinson's Disease, stroke, or a variety of other disabilities.
    

Detailed description: 
      There are over 750,000 individuals in the U.S. with Cerebral Palsy (CP). Up to 46% of adults
      with CP report limited mobility in their communities. However, upper limb spasticity and
      motor control impairment can make the independent use of a wheelchair difficult. Forty
      percent of individuals who desire mobility via electric wheelchairs are precluded from using
      them because of problems with upper limb function including motor, sensory, or cognitive
      impairments that can make the use of a conventional joystick difficult. No studies to date
      have produced devices that definitively improve mobility for these individuals. We will
      recruit 22 subjects with Spastic CP and 22 age and gender matched control subjects without
      apparent disability from advertisements, mailings, and outpatient clinics. Both a
      conventional motion sensing joystick (MSJ) and a novel isometric joystick that is customized
      for each subject will each be used to maneuver a sprite on a computer screen in six different
      tasks. Each task involves a path with 90-degree turns. Two tasks have paths that are
      completely visible to the subject, while four have paths that appear either immediately or at
      1, 2, or 3 seconds ahead of the sprite. Because subjects with CP and control subjects are
      likely to drive at different speeds, subjects will drive under conditions of freely chosen
      speed and with speed controlled at 1.2 m/s. Joystick input signals that represent the
      sprite's velocity and position will be recorded. Changes in direction and speed, average
      deviation from path center, number of boundary violations, start and stop reaction times,
      response times to turns, and duration of subject movement will be calculated. We will use a
      Repeated Measures design, treating speed as a covariate under the condition when it is freely
      chosen. We hypothesize that, regardless of joystick or speed condition, subjects with Spastic
      CP will have more direction and speed changes, greater average deviation from path center,
      more boundary violations, prolonged reaction times and response times to turns, and prolonged
      subject movement time compared to controls. We hypothesize that, regardless of joystick or
      speed condition, decreasing warning time before turns will be correlated with more direction
      and speed changes, greater average deviation from path center, more boundary violations, and
      prolonged subject movement time and that the magnitude of these changes will be greater for
      those with Spastic CP. We hypothesize that, regardless of speed condition, subjects with
      Spastic CP, when using a MSJ compared to the isometric joystick, will have more direction and
      speed changes, greater average path deviation, more boundary violations, and prolonged
      subject movement. Understanding driving task deficits and warning time for movement decisions
      will help to identify customization parameters for joysticks and other assistive devices, not
      only for CP but for Traumatic Brain Injury, Spinal Cord Injury, Parkinson's Disease, stroke,
      or a variety of other disabilities.
    

Intervention name(s): isometric joystick
Intervention type(s): Device
Intervention description(s): isometric joystick
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        subjects with CP and controls
      
Keywords: Cerebral Palsy; Spasticity; Joystick; Wheelchair; rehabilitation