Medical Disabilities: Mobility Impairment

What is Mobility Impairment?

There are many different conditions that can affect a person's mobility, including but not limited to:

• Reduced range and speed of muscle movement
• Reduced ability to grasp objects
• Reduced fine control of muscle movement
• Paralysis
• Involuntary muscle movement (tremors)

These conditions can be brought on by a variety of diseases or circumstances, including by not limited to:

• Muscular dystrophy
• Cerebral palsy
• ALS
• Parkinson's disease
• Stroke
• Carpal tunnel syndrome
• Sprained muscle
• Broken bone

While many of the diseases listed above are not curable, a sprained muscle and broken bones usually heal in time.  Even so, the impairment of these temporary conditions can still be very impactful for the duration of the condition.

Finally, while not a medical impairment, it is important to recognize that not all devices for accessing the web will work the same way.  For example, more than half of the population access the web through cell phones and tablets, which are touch-only devices.  So, if you design a web application and only think about desktop and notebook computers with mice and trackpads, you could be creating impediments for those on touch devices who are effectively impaired due to not having a movable cursor on those devices.

How Does Someone with Mobility Impairment Experience the Web?

Generally, with a greater level of impairment, there is a greater likelihood of a person using an alternative input device.  These can include navigating by keyboard alone, using a joystick, or one of many specialty devices.  Many specialty devices function a little like a joystick, but allow something other than the hand to be used for control (e.g. head movements, eye movements, mouth movements, etc.)

Even though alternative input devices can allow for a range if interactions, mobility impaired users are still limited in the range of complex interactions they can perform.  They may also find it difficult to position a cursor on a small target, since the precision of their control may be limited, especially for people with involuntary movement impairments.

Web Accessibility for Mobility Impairment

There are several best practices for making website content as accessible as possible for people with mobility impairment:

• Make links and buttons large, so they can easily be selected (but don't make them too large or overly wordy)
  • Avoid single words as links, especially short meaningless words like "here" or even "click here".  An ideal link will be in the neighborhood of two to five words that clearly describe the destination of the link.
  • Never suppress the marking of links.  They should always display with some form of an underline and in an alternate color from the body text color.
• Do not hide any information or functionality behind "hover" or "roll-over" areas.  This blocks access to such information or functions for those who are unable to use cursor-based input device like a mouse or trackpad.  Also keep in mind that "hover" and "roll-over" areas also block access to non-impaired users who are on touch-screen devices like cell phones and tablets.
  • A hover / drop-down menu or similar feature is acceptable as long as one can also tab into the feature via a keyboard and access all of the options.
  • For larger blocks of information, a positive open / close mechanism, like an accessibly implemented accordion set or tab panel system, is also acceptable.
  • The key is that opening an initially hidden area must be possible through something other than just the position of an input device cursor.