Why Computer Speed Matters for Motor Disabilities

For people with motor disabilities — including Parkinson's disease, cerebral palsy, multiple sclerosis, essential tremor, and spinal cord injuries — standard computer interfaces can move too quickly to interact with comfortably.

Menus close before they can be selected. Double-click windows are too short. Drag-and-drop operations require precision that tremors make difficult. Scroll speeds are too fast to control accurately.

Slowing down the CPU reduces the speed at which the entire system responds, giving users more time to interact with every element. This is particularly useful for applications that do not have their own speed or accessibility settings.

CPUKiller Accessibility Tool

CPUKiller's Accessibility tool provides a browser-based CPU throttle specifically designed for accessibility use. It includes four presets:

  • Very Slow (10%): Maximum slowdown for severe motor impairment
  • Slow (25%): Significant slowdown with extra time for all interactions
  • Moderate (40%): Comfortable for most users who need additional response time
  • Light (60%): Slight slowdown for users who need a little more time

CPUKiller has been recommended for this purpose by the Center for Disability Rights, the North Western Melbourne Primary Health Network, and the Victorian Government's accessibility pages.

Windows Built-In Accessibility Settings

Windows includes several built-in settings that can help users with motor disabilities, independent of CPU speed:

Mouse settings (Ease of Access > Mouse):

  • Reduce pointer speed to give more time for precise movements
  • Enable Mouse Keys to control the pointer with the numeric keypad
  • Increase the double-click speed threshold

Keyboard settings (Ease of Access > Keyboard):

  • Enable Sticky Keys so modifier keys (Shift, Ctrl, Alt) can be pressed one at a time
  • Enable Filter Keys to ignore brief or repeated keystrokes caused by tremors
  • Enable Slow Keys to require keys to be held down for a moment before registering

macOS Accessibility Settings

macOS includes similar accessibility features under System Settings > Accessibility:

  • Pointer Control: Adjust tracking speed, enable Mouse Keys, and configure scrolling behaviour
  • Keyboard: Enable Slow Keys and Sticky Keys
  • Switch Control: Full keyboard or switch-based navigation of the entire interface

Combining Tools for Best Results

The most effective approach combines multiple tools:

  1. Use CPUKiller's browser-based throttle to slow the overall system response
  2. Enable Windows/macOS Slow Keys to give more time for keyboard input
  3. Reduce mouse pointer speed for more precise control
  4. Enable Mouse Keys if a standard mouse is difficult to use
  5. Consider a trackball or joystick mouse, which many users with tremors find easier to control than a standard mouse

Resources and Support

Several organisations provide free advice and support for people with motor disabilities who need help with computer accessibility:

  • AbilityNet (UK): Free advice service and home visits for disabled people needing help with technology
  • Center for Disability Rights (US): Advocacy and resources for people with disabilities
  • Australian Network on Disability: Resources and support for Australians with disabilities in the workplace