Open CRT for ALS: A Demonstration
- By Steve Mitchell
- Aug 01, 2016
Whether you are a clinician, manufacturer or supplier, the
future of complex rehab will ultimately depend on our ability to
demonstrate that complex rehab technology (CRT) makes a difference.
Simply put, it’s about getting successful outcomes.
In my June column, I wrote that successful outcomes require
accurate understanding of the person, their problems, products
and effective configurations. While each area of expertise tends
to be associated with the clinician, manufacturer or supplier,
we cannot simply “stay in our lanes” and assume we will get the
outcome we want. Effective solutions require us to stay actively
engaged, validate our assumptions, and critically analyze the
problem from as many perspectives as possible.
Every day, clinicians and suppliers do just that for clients who
need CRT. They accrue “practice-based evidence” every time they
critically assess how well a given product, provided in a specific
configuration, met the needs of its intended user. What most of us
don’t do often enough is share that information with others.
Open Complex Rehab applies “open innovation” and “open
development” to CRT. It is based on the premise that sharing
practice-based evidence is necessary to improve the effectiveness
of CRT for specific populations. I’ll demonstrate how Open CRT can
benefit users with amyotrophic lateral sclerosis (ALS).
How ALS Challenges CRT Provision
ALS is a progressive neurodegenerative disorder affecting motor
neurons in the motor cortex, brainstem and spinal cord. The
diagnosis of ALS implies evidence of degeneration in three of four
neurological regions (bulbar, cervical, thoracic and lumbosacral).
Weakness usually develops in an extremity or in bulbar muscles
that control oral motor function, and spreads to other regions. We
won’t know for certain what the next region will be, but eventually
no region will remain untouched.
Some individuals have “functional variants” of ALS characterized
by very distinct patterns of weakness. Perhaps the most
challenging of these variants for seating/wheeled mobility
professionals is “flail arm syndrome.” These individuals will lose
function in their upper extremities, but retain fairly good function
elsewhere. Approximately 10-15 percent of the veterans I see
have this functional variant. Since they are usually unable to use a
conventional joystick, they require complex configurations capable
of taking advantage of function they have elsewhere.
Regardless of the region of onset or functional variant, there
eventually is extensive loss of motor neurons in all regions. In
time, most individuals will lose the ability to control the muscles
responsible for movement, breathing, swallowing and talking. The
result is extensive paralysis. Those who don’t die due to secondary
complications will become “locked in.”
We do know that progression of weakness in a given individual
will be fairly linear, but the rate of progression among individuals
varies significantly. Those who have rapid onset of symptoms tend
to progress rapidly; those with more insidious onset tend to live
longer. This creates a significant variation in life expectancy. In the
majority of cases, death from respiratory complications will occur
in three to five years, but some individuals die within months, while
others live 10 years or longer.
ALS poses challenges because we do not know the next
symptom or how quickly it will appear. We know we will need at
some point to address changes in function, but we will not know
what changes we need to make. We know some individuals will
use their chairs for years, while others will die before they receive
a power chair that needs to be ordered. They may benefit from an
existing power chair, but reconfiguring a previously used chair so it
effectively meets the needs of a new user can be labor intensive if
it was specifically configured to meet the needs of its previous user
using our conventional “snowflake” approach.
While we don’t know exactly what is in store for a given user, we
can utilize practice-based evidence to identify predictable issues
and incorporate solutions into the configuration of an ALS power
chair so many of these issues may be addressed before they are
even identified as problems.
Solutions that Anticipate Future Needs
Many predictable manifestations of ALS that we can address
through a power chair’s configuration are directly related to the
influence of gravity. As such, we should account for gravity in every
context in which an ALS power chair is likely to be used.
Movements that can appear to be effortless in one plane may
become quite difficult in another. Consequently, we need to know
about the user’s strength and active range of motion when they
are sitting upright and when they are tilted. Eventually, the weight
of the affected body part will exceed the muscle’s capacity to
overcome the force of gravity in a given plane.
ALS power chairs should be configured to be operated by a
user who has 3/5 strength (full range of motion against gravity, but
unable to tolerate resistance). The amount of anti-gravity movement
to operate the chair should be minimized, and we should
provide a base of proximal support where antigravity movements
take place. Since weakened muscles will be very susceptible to
fatigue, the need to sustain efforts should also be minimized.
Here’s a “low, level and inline” joystick configuration (right):
(a) Joystick inline and roughly level to the surface of the arm pad
with a neutral wrist and forearm.
(b) Proximal stability
with even distribution
along length of
(c) Armrest parallel
to seat rail at back
angle needed for
(d) Elbow stop only makes contact when tilted.
(e) Armrest height provides glenohumeral support without
restricting elbow movement.
Gravity also has a detrimental effect on posture during upright
sitting. Progressive postural rounding and a forward migration of
the head are inevitable. The further the head moves away from the
body, the greater the rounding becomes, and the more severe the
implications will be for the user’s quality of life.
Here, we need to be more proactive in our approach. Users with
ALS should be encouraged to frequently tilt their seating systems
in the early stages of the disease to counter the adverse effects
of gravity. Tilting may not prevent postural rounding or a forward
migration of the head, but it may be the most effective tool we
give them to mitigate the rate of progression.
We also need to recognize that as axial weakness causes head
and trunk control to deteriorate, these individuals will lose the
ability to “sit perfectly.” Excessive posterior pelvic tilt becomes the
norm, not the exception, and they will sit slightly differently every
time they use their chair.
When they tilt, their entire body will migrate toward the back of
the seating system, the position of their head relative to the body
will change, and their distance away from the headrest will change
by inches. We need to recognize these changes when we position
joysticks, provide remote switch access or configure systems for
Practice-based evidence can also be used to develop modular
assemblies or more specialized configurations and to allow us
to address many less frequent, but very challenging issues we
can expect to encounter in a subset of users. The ability to easily
implement technology and replicate solutions in the future can
recoup the investment of time and effort needed to develop
Lastly, there are times when practice-based evidence makes it
evident that innovation is necessary to meet unmet needs.
head arrays are
to be three
benefit from characteristics of all three.
ALS affects function in every part of the body, yet today’s alternative
driving system configurations are designed to be operated
using just one body part. Versatile systems that take advantage of
function wherever it exists are needed.
Why haven’t manufacturers developed products to address
these unmet needs? Maybe we haven’t shared practice-based
evidence to identify these needs and propose innovative solutions.
I’ll have specific examples in my next column.
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
This article originally appeared in the August 2016 issue of Mobility Management.