Open CRT & ALS: From Snowflakes to Ice Cubes
- By Steve Mitchell
- Oct 01, 2016
Open Complex Rehab
involves sharing practice-based evidence to
improve the effectiveness of
complex rehab technology (CRT)
for specific populations using an
open, user-centered, collaborative
In this final installment on amyotrophic
lateral sclerosis (ALS), I
will show how this approach can
lead to better CRT outcomes for users who require the
most complex power chair configurations.
Let me start by sharing practice-based evidence from
my own clinical setting, since we at the Cleveland VA
Medical Center started our multidisciplinary ALS clinic in
- The vast majority of veterans with ALS have been
successful using conventional joysticks. Almost every
veteran who initially drove with a joystick has continued
to use a joystick for as long as he/she had the power chair.
- During this period, only seven proximity head arrays
were prescribed. All but one were prescribed for
veterans with Flail Arm syndrome. Only one veteran
who was initially using a standard joystick needed to
use a head array later on.
- Only two recipients of proximity head arrays used them
proficiently without significant customization.
- No ALS power chairs have been equipped with proportional
joysticks configured for chin or foot control.
- The success rate for low-effort and mini joysticks has
- No ALS power chairs have been equipped with true
sip-’n’-puff driving systems.
At first glance, one might conclude that my “success
rate” with alternative controls is lower than most other
settings. If my definition for success was strictly mobility,
that would be true. Many people seem to use that
criteria, which I think is unfortunate. I have heard many
“success stories” where someone who could no longer
use a joystick uses an alternative control to drive across
the clinic. If it turned out they never tilted their seating
system beyond 30° because they can’t overcome
gravity, is this really success?
Redefining Successful Mobility
We can and should do better. At a minimum, a
successful ALS outcome should be defined in terms of
the user’s ability to safely drive and effectively use the
seating system. With ALS, both are equally important.
This type of outcome can be difficult to achieve if we
are counting on the function in a single body part to
control everything on the chair.
Hybrid Alternative Driving Systems (HADS) combine
characteristics of more than one system to enable key
functions to be assigned to other points of control. HADS
can be effective when an end user lacks sufficient head
control, oral motor function, active movement, or cognitive
function to use any single type of system.
Because ALS is such a pervasive disease that affects
motor neurons throughout the body, the concept
behind HADS makes total sense. So why are we only now
reading about them in the October 2016 issue of Mobility
It’s not the technology that’s holding us back, it’s how
we have traditionally approached the configuration of
a complex rehab power chair. Using the conventional
approach, creating a hybrid system for one user would
be a labor-intensive process that would involve mounting
four or five switches in accessible locations, determining
the function of each switch, and routing its cable to the
location associated with that function. In essence, each
HADS becomes a one-of-a-kind system that would be
difficult to modify because everything is wired in place.
On the other hand, if the basic configuration provides
a flexible infrastructure that supports switch access,
it becomes possible to implement HADS in a more
practical way. Instead of configuring the chair like a
“snowflake” where no two are alike, an ALS power chair
becomes an “ice cube” that can adapt to changing
AltDrive Armrest Conversion Module
Approximately 20 percent of the ALS power chairs I
prescribe are potential candidates for hybrid systems.
Some will have marginal joystick drivers who may not use
a joystick for long, while other drivers will have Flail Arm
syndrome. The AltDrive Armrest Conversion Module is a
self-contained unit that replaces the original joystick and the entire armrest
an Omni display
and a compact
It was created
so I could
was feasible for
and allows a
HADS to be used
on the chair as
a second driving
Left: The self-contained AltDrive Armrest Conversion
Right: In the AltDrive Armrest Conversion Module, the
original joystick is replaced by an Omni display and
What can seven
to the versatility
of an ALS power
chair? Much more than you might think. I developed
the “Connector Hub” to eliminate the need to hard wire
switch cables to specific locations in order to be able
to perform specific functions. To assign a function to
a switch, simply plug it in to a color-coded extension
cable located on one of the seat rails or accessory rail.
Each of these cables has been routed to a central “hub”
on the backrest. Two more cables are routed from the
hub to the display and are plugged into the power and
mode jacks. The
result is a “plug & play” network
that works like a
Assigning a function
to a switch is
simply a matter
of identifying the
plug at the hub
and choosing the
in a two-function
mounted to the
Si-X module in
with an AltSwitch
seating interface and a switch driving interface, it
becomes possible for any switch to function as a power
switch, mode switch, operate a seating function, or be
used as part of a hybrid alternative driving system.
With the AltDrive Ready Connector Hub, any
switch can function as a power switch, mode switch,
operate a seating function, or be used as part of a
hybrid alternative driving system.
The AltDrive Ready Connector Hub eliminates the need to hard wire switch
cables to specific locations in order to be able to perform specific functions.
Raising One Bar By Lowering Another
is an area where
we may find that
if we “lower the
bar” required to
can raise the bar
with respect to
the outcomes we
Left: Sip-’n’-puff knee steering system.
Middle: Sip-’n’-puff head steering system.
Right: Toggle-drive knee steering system.
I provided all
three of the HADS
pictured here —
steering systems — to actual
it be surprising
to know that
each uses a
It’s true. All
as four-axis step-latched systems. Four-axis step-latched
driving requires five switch inputs (a separate mode
switch is required).
It is an ideal
many users with
ALS because it
requires only brief
inputs to drive,
and the reverse
be used to slow
down. The incremental
is also easier to
the user can
see the results
of each input.
need for a mode
switch, but require the user to stop instead of slowing
down and toggle between forward/reverse.
Two of the three configurations in the picture use a
two-function pneumatic switch. Unlike a dedicated
sip-’n’-puff driving system, the two-function variety does
not require precise regulation of intraoral pressure.
In practice, it has been underutilized due to a
misperception that good oral motor or respiratory function
are required. Provided that sustained inputs aren’t
required, most users with ALS can use this type of switch!
Because it provides two inputs from a single location that
is not affected significantly when the seating system is
used, we should be considering it more than we should
be ruling it out.
Used in combination
“position & place” switch
mounts from last
month’s issue, the
bar to implementing
has never been
Modular headrest “position & place” switch mounts.
Ideas & Changing the
Once a manufacturer
what you are
trying to do, they
the concept even
Take a look at Quantum Rehab’s “ALS concept
chair,” based on the ideas and systems we’ve been
Such is the
case with the
Rehab shown here on their Q6 Edge 2.0 “ALS concept
That’s also a prototype “position & place” fiber optic
sip-’n’-puff head array based on a Stealth Products
Maybe Open CRT does give us hope for changing the
Editor’s Note: Steve Mitchell works at the Cleveland VA Medical Center. His opinions
do not represent official policy or positions of the Department of Veterans
Affairs. The first four parts of this “Open CRT” series are available to read on
mobilitymgmt.com. Use the search function with key words Steve Mitchell.
This article originally appeared in the October 2016 issue of Mobility Management.