Tuning algorithms for control interfaces for users with upper-limb impairments

Alcinto S. Guirand, Brad E. Dicianno, Harshal Mahajan, Rory A. Cooper

Research output: Contribution to journalArticlepeer-review


Objective: Approximately 40% of Americans with disabilities cannot operate wheeled mobility devices and computers adequately because of diminished upper-limb motor control, sensory limitations, and cognitive impairments. We developed tuning software that can customize control interfaces for individuals with upper-limb impairments. This study compared the differences in each parameter among different diagnostic groups. Design: The age of the subjects ranged from 18 to 80 yrs. The participants were classified into the following groups: athetoid cerebral palsy, spastic cerebral palsy, multiple sclerosis, upper-limb spasticity, and control. We used a validated tuning software protocol to customize an isometric joystick before a virtual tracing or driving task. Tuning parameters were then compared across groups. Results: Seventy-five subjects were included. Gain, the parameter responsible for force-to-output ratios, in each directional axis (leftward gain: P = 0.018; rightward gain: P = 0.003; reverse gain: P = 0.007; forward gain: P = 0.014) was significantly different across the diagnostic groups. Post hoc analyses showed that the control group required smaller leftward gain than spastic cerebral palsy, multiple sclerosis and upper-limb spasticity groups and smaller gain in all other directions compared with spastic cerebral palsy. Conclusions: Gain may be a useful parameter in tuning by clinicians, and efforts aimed at gain customization may aid the development of commercially available tuning software packages.

Original languageEnglish (US)
Pages (from-to)992-998
Number of pages7
JournalAmerican Journal of Physical Medicine and Rehabilitation
Issue number12
StatePublished - Dec 2011
Externally publishedYes


  • Assistive Technology
  • Isometric Joystick
  • Movement Disorders
  • Rehabilitation
  • Wheelchairs

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation


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