“I can truthfully say that this technology intervention has given me the most independence I have enjoyed for over 15 years.”

“With the EMG probe placed on my left pectoral muscle, I have full functionality from the twitch of my shoulder.”

Power Wheelchair User

Power user Darren Gabbert

Amyotrophic lateral sclerosis (ALS) patient & power wheelchair user Darren Gabbert says:

The EMG switch was the key for me to make single-switch scanning an effective option for controlling my power wheelchair.  Due to having an advanced form of spinal muscular atrophy, I have used and modified numerous driving mechanisms to accommodate the progression of the disease.  It wasn’t until July 2004 that I had no alternative but to consider single-switch scanning navigation, or what rehabilitation professionals call the “option of last resort.”  While by itself it may be worthy of this title, using the Tinkertron EMG Switch* with an EMG probe as the “single-switch” introduced significant benefits that has changed the “option of last resort” to an “option of great report!”

I have been using a Permobil power wheelchair, PG Technologies’ Omni+ single-switch scanning interface, and Tinkertron’s EMG switch for since 2005.  With the EMG probe placed on my left pectoral muscle, I have full functionality from the twitch of my shoulder.  After a slight learning curve with regard to avoiding inadvertent triggers from muscle movement, using the switch quickly became second nature.  The response rate of the EMG switch allows me to press, hold, and release at the necessary split-second intervals to effectively navigate the wheelchair.  No fatigue.  Very impressive!  And being freed from the necessity of having my arm or head precisely positioned to operate a more traditional driving mechanism, I can independently use the full range of seating functions without losing my ability to return to a driving position.

With the EMG probe, a vast scope of possibilities exists for finding an efficient, minimal-fatiguing way for anyone to engage the system.  Furthermore, once an effective placement site has been determined for the EMG probe, all seating and positioning considerations can focus on stability and comfort.  This is in stark contrast to solutions where comfort must take a back seat to finding and maintaining a range of movement necessary to operate the control mechanism.

While single-switch scanning is clearly not as fluid and “natural” as proportional control, I think I would have given up the proportional control earlier than I did had I known the overall benefits to be gained.  With the EMG driven single-switch scanning system, I have experienced increased independence and functionality while having lost physical ability. 

  • Am I able to confidently navigate indoors and outdoors without anyone else present?  YES!
  • Am I able to change position using the full range of backrest, tilt in space, footrests and seat elevator functions? YES!
  • Am I able to travel long distances without fatigue?  YES!

When I measure according to these terms, I can truthfully say that this technology intervention has given me the most independence I have enjoyed for over 15 years.

It is all too common for people with progressive neuromuscular diseases to have a net loss of independence and functionality while trying to maintain and modify proportional technology that they have became accustomed to.  For those who are hobbling along trying to make proportional driving mechanisms work beyond your ability to use them, take a second look at the “option of last resort.”  With the right Omni+ parameter settings, single-switch scanning can be very effective using different profiles for different environments and functions (e.g. indoor proximity navigation, outdoor distance navigation, tedious precision navigation).  Combine this with the benefits of using the EMG switch, and the scales of overall independence begin to tip.

The first use of my chair outside of my home environment came on September 25 at my daughter’s wedding.  With the Permobil seat elevator raised, I enjoyed conversation at eye level and easily mingled within a crowded room without being a risk to myself or others.  I have also independently (at my wife’s consternation) drove all over our acreage.  Having my wife leave the front door cracked, I have mastered opening, entering, and closing (yes, closing) the front door.  Pretty fluid-like behavior from a single-switch system.   I certainly don’t think anyone has gotten this much mileage out of their left pectoral.

An important key issue making this really work is the ability the EMG switch gave me to use another (slightly more functioning) muscle to engage a “cutoff” switch.  The cutoff switch is definitely necessary to make single-switch navigation safe and practical.