ATP Series

To Intervene or Accommodate

When a Seating Client Appears “Fixed,” How Should the Rehab Team Respond?

• By Missy Ball
• May 01, 2013

Posture and position are two distinctly different terms, even though they’re often used interchangeably by seating& mobility specialists.

Position describes the location of an object in space. It is non-responsive and passive.

But posture is dynamic and multifaceted in regard to what can influence it.

When someone talks about positioning a client, immediately what comes to my mind is statically addressing the client: evaluating range-of-motion limitations, skeletal deformities, pressure distribution and comfort needs.

Posture, on the other hand, is fluid, ever able to receive input and possibly change in some manner. Postural stability is the ability to manage one’s center of mass over one’s base of support. Postural orientation is the ability to orient the body to perform a specific task. Both of these are dynamic skill sets. Throughout the day, individuals manage changes in weight distribution to keep stable as well as to perform everyday tasks: putting on shoes, lifting a fork of food to the mouth.

What Impacts Posture?

There are many influences on posture, including skeletal alignment, muscle strength/endurance, neuromotor status (muscle tone, force generation and scaling of force, interplay between different muscle groups around a specific joint), four sensory systems, sensory-motor strategies learned through experience, and cognitive influences. These can enhance or diminish one’s postural fluidity.

For instance, unrelenting spasticity can over time reduce joint range of motion, as well as impact muscular balance at the specific joint. Contractures can develop, which limit potential. Skeletal deformities that can develop for several reasons can also hamper postural control.

In clients diagnosed with the various types of cerebral palsy, multiple variables — including tonal abnormalities, muscle weakness or imbalance or sensory issues — can off set normal skeletal alignment during motor development.

Take a simple example, such as propping up on our elbows.

When doing this, the general population biomechanically places elbows forward or directly under the shoulder girdle, which provides a biomechanical advantage for the middle trapezius and rhomboids to activate and produce spinal extension.

But in clients with quadriplegic cerebral palsy, the spastic muscle groups of pectorals, rectus abdominus and tight scapular-humeral muscles change the skeletal alignment. The elbows are pulled back of the shoulders, so with effort these muscles flex the trunk forward, which reduces spinal extension needed for further gross motor progress. Also, internal rotation occurs in these clients’ arms, which over time produces heavy load to the prehensile side of the hands, which interferes with fine motor activities.

Hence for a specific task, these clients learn to couple the wrong muscle groups (synergy) together, which ends up limiting their full postural potential. A therapist working with children will attempt to intervene and facilitate more effective sensory-motor strategies before they are habituated to allow greater improvement in gross and fine motor functional skills and preservation of the musculoskeletal system. Seating & mobility equipment as well as therapy can be useful here.

Case Study: Intervening with a 4-Year-Old

An intelligent 4-year-old male diagnosed with spastic diplegia cerebral palsy had been followed by a neurodevelopmental-certified occupational therapist for several months when his family requested physical therapy.

The OT had been working with the child on beading to improve his active forearm supination. His mode of mobility in the home was commando crawling, which he performed rapidly and regularly throughout the home.

He had just received a scooter with a central tiller, and the family’s goal was independent ambulation. I observed this child using a rollator walker with moderate assistance at least, much lower-extremity scissoring and limited reciprocity.

A piece of artwork that he created showed how he perceived himself: When asked to draw his body image, he drew a single line for his torso and legs, two lines for his arms and a circle for his head. Why? He rarely felt dissociation of his legs, so he therefore drew only one line to represent both his torso and his legs. Body image is learned, and movement is a major way in which we learn it.

The muscle synergy he used to stabilize his pelvis was composed of hip flexors, adductors, internal rotators and hamstrings. This produced limited segregation of his legs during walking, much scissoring, and limited postural stability. Due to his weak grip strength, when squeezing the tiller on the scooter, he pulled in the muscular strategy of pectorals and rectus abdominals, which further impaired his fine motor capability and spinal extension. This is the strategy he used to commando crawl and had therefore habituated. He also crushed the scooter’s pommel with his knees.

So what could be done? And what did I, as his physical therapist, want to keep in mind?

He was only 4 years old, with many years ahead of him. I did not want to feed into strategies that would limit him functionally.

Also, there was an attendant switch on the scooter, so I suggested his mother drive him to school one block away, and that he use the scooter only intermittently on his own. (In the long term, the better choice would have been a power chair with joystick mounted off to side and with an intermittent anterior-sloped seat.)

But for this child, a manual wheelchair was introduced with a seat that could be flat or anteriorly tipped periodically throughout the day. The footplate was moved back to disadvantage the hamstrings from being used.

The sloped seat challenged this child’s postural stability, which elicited active buttock muscles with lateral hip muscles. No abduction pommel was used or needed, versus in the scooter, where he crushed the pommel with his knees.

When placed in this chair for the first time, the child immediately sat upright with his legs separated. He said, “This is it!” and took off . He pushed the chair all over the house, which also encouraged thoracic extension.

We also swapped the rollator walker he’d been using for a walker model that facilitated external rotation of the humerus when his arms were loaded. That in turn encouraged spinal extension. His ambulation did improve gradually as he learned more effective muscle strategies.

Choosing Accommodation Instead of Intervention

It does not always work the way it did for this little boy. In his case, he needed more time to practice more effective sensory motor strategies. And he successfully incorporated those more efficient strategies.

But sometimes, other factors will make intervention more difficult and less likely. We know that what’s practiced often is what will be used and habituated. In layman’s terms, when we keep performing the same actions, good or “bad,” over and over, they become habits. Also, skeletal limitations, skeletal deformity, muscle imbalance and muscle tone will worsen over time and limit the effective changes that clients are capable of making.

From another perspective, after clients have spent many years using these strategies to move, who are we to force change on them unless they wish it? Some of their movement strategies may be more necessary and effective than we realize. Hence, accommodating these individuals would be the way to go.

Pressure relief, comfort, reducing skeletal deterioration and maintaining their functional status at present are our goals for these types of clients.

Listening to What Clients Have to Say

If they are cognitively intact, we should ask our clients what their goals are, as well as ask questions regarding their living environment, assistance available to them, transportation, etc. Eliciting a client’s input will usually increase their interest and motivation to carry through with an activity.

And in some cases, our clients’ goals will surprise us and possibly make us consider other possibilities or strategies.

A first-hand example of this:

• A 5-year-old client had spastic athetoid cerebral palsy. His original seating team had supplied a custom-molded seating system to provide full postural control for the client to improve his distal control for accessing a joystick on a power wheelchair.
• He used the chair for several years with remolds provided as needed.
• When he returned to the team for a new wheelchair five years later, he stated he did not want a molded system. The team was surprised. He explained that the system provided too much control. When his mother took him out of the system after school, he felt like a fish out of water for a couple of hours as he tried to figure out how to manage his body.
• The seating system was doing all the work and actually de-functionalized him.

So listen to your clients. Their requests maybe quite reasonable and very enlightening to the professionals working with them.

This article originally appeared in the May 2013 issue of Mobility Management.