Keeping Your Options Open

Spinal Muscular Atrophy Robs Clients of Their Strength, but Creative Thinking Can Make a Difference

• By Laurie Watanabe
• Nov 01, 2012

In its severest forms, spinal muscular atrophy (SMA) reduces the human lifespan to a few years or even less. The motor neuron disease robs patients of muscle strength, making it difficult for them to breathe, swallow, cough. Children with the worst cases cannot sit up independently, and researchers, such as those at London’s Guy Hospital, have noted that some infants with SMA show reduced movement even in utero.

Yet parents of these children report that they are also expressive, sociable and bright — expansively so. And that can open a surprisingly hopeful window of opportunity for the clinicians and assistive technology providers who work with them.

SMA Defined by Category

SMA is commonly described by type: I, II, III and IV, though researchers also refer to SMA type zero in describing the most severe cases, in which symptoms are present before birth. SMA types serve as shorthand that communicates what physical abilities patients might be expected to have.

Lauren Rosen, PT, MPT, MSMS, ATP/SMS, is the program coordinator for the Motion Analysis Center at St. Joseph’s Children’s Hospital of Tampa (Fla.).

“Children with type I usually have a short life expectancy — less than 2 years,” she says. “They have respiratory and positioning issues throughout their lives and never meet any of their developmental milestones.”

Children with SMA type II, Rosen says, typically begin to show symptoms a little later — from 7 to 18 months of age — and can “learn to sit unassisted, but not to stand or walk independently. Although respiratory complications are a constant threat, children with type II SMA usually live to young adulthood, and many live longer. Once they start using wheelchairs, they have positioning issues and eventually require power wheelchairs with power features.”

When muscle weakness manifests in older children and teens, “who learn to stand and walk, but lose the ability later in life, the disease may be labeled type III SMA, also known as mild SMA or Kugelberg-Welander disease,” Rosen says. “Although some with type III stop walking in adolescence, others walk well into their adult years. These people usually slowly progress so they may use a standard power chair initially, but will eventually need a complex rehab chair with power features.”

Finally, there is type IV SMA, which has its onset “in the late teens adulthood, and people are able to walk during their adult years,” Rosen explains. “A lot of these people will start out with canes, then progress to a scooter or standard power. Some, depending on lifespan and progression, end up in complex rehab with power features.” She adds, “Lifespan is usually normal in types III and IV.” Type I: Immediate Intervention Needed For children with SMA type I, assistive technology intervention is typically needed from the very beginning, and in many different forms.

Karen Patterson, PT, MS, PCS, has worked with children with SMA as part of the University of Wisconsin Doctor of Physical Therapy Program. Patterson also works closely with Families of SMA (fsma.org), an organization devoted to funding research to treat and cure the disease.

While there is some variation of ability even within the diff erent types of SMA, children with type I, Patterson notes, “are never really able to sit by themselves. These are the kids that have the bigger issues (with) respiration, swallowing, tolerance to being upright.”

With this group of children, Patterson explains, even the most basic positions need to be carefully considered: “We’ve got to take into account what is their respiratory status? What is their swallowing status? What position can they tolerate? Some of these kids cannot even tolerate up 30 degrees. It’s harder for them to breathe, and they can’t control their secretions. So they literally are being suctioned every few minutes.”

Rosen says children with type I “usually need medical strollers that have both tilt and recline to aid in breathing.”

Patterson concurs, saying type I patients may need a mobility system “that has the ability to go all the way flat and even to a reverse Trendelenburg. These kids don’t last in any sort of over-the-counter stroller for any length of time.”

For these infants and young children, she adds, having positioning options is critical. “Some of those kids end up with trachs. As they get older and they do end up with a trach, they tolerate upright better, but obviously they need to be able to carry the equipment. So from a positioning standpoint, you’re looking at something that can handle that.”

Deciding whether or not to choose a tracheostomy can be immensely personal and difficult for a family. Patterson notes, “We talk about this on our medical advisory board: not pushing parents to make that choice. This is certainly a diagnosis where parents may not choose to have their child get a tracheostomy and may let nature take its course, so to speak.”

But clinicians and providers who recommend and build the seating & mobility system should still have a plan for accommodating a possible ventilator, as well as other equipment.

“Even early on, and even on those kids that are younger and their tolerance to upright is so-so, they’re still going to have a lot of equipment,” Patterson says. “They’re still going to have a cough-assist machine that they travel with. They’re going to have an IV pole. They’re going to have those extra things that we have to account for. You have to have something that has a lot of options to it.”

Patterson also notes that children with type I need head positioning support that allows for a lot of fine-tuning. “You really need to think about head supports that have a lot of adjustability,” she says. “They have no head support whatsoever, and it affects their swallowing, it affects their breathing, the position of their head. So being able to tweak it just a little bit can make or break whether a kid can tolerate more of an upright position.”

Type II: Adjustability Is Key

Since children with SMA type II can sit unassisted at some point but do not stand or walk, a seating system with adjustability is important.

Rosen notes that while kids with SMA could benefit from molded trunk supports, “in many cases, they don’t like the feel of those systems. So they can end up with significant scoliosis, which makes sitting and breathing more difficult.”

“These are kids that are absolutely at extremely high risk for scoliosis,” Patterson says. “They’re at high risk for hip pathology. The seating system is very important and something that has to continually change with the kid a little bit. Many of these kids end up in TLSOs (thoracolumbosacral orthoses)."

To achieve that changeability, Patterson suggests laterals that can be adjusted. “These kids don’t have enough strength ever to really do a pressure relief,” she says, “so typically, you have to get tilt and recline on the chairs.” She says children with type II can usually control their secretions and don’t need respiratory assistance when they’re upright and in their wheelchairs, though they might still need a cough-assist machine on occasion and oft en use biPAP to help with respiration at night. Recline, Patterson adds, can make some daily activities a little easier for caregivers, while tilt for pressure relief is crucial.

Also, Patterson says, the usual pediatric growth adjustability is important to build in. “I can’t point to any literature that supports it,” she says, “but these kids actually grow fairly quick. Most of the time, they grow long...especially the type Is.”

Children with type II can also benefit from standing, Patterson says, to experience some weight-bearing (kids with type I can also benefit, she adds, though they may prefer standing short of vertical).

Rosen notes, “People with type II frequently go from nothing to a power wheelchair given their age and the likely progression. Frequently, due to their weakness in the shoulders, they need at least power tilt and hopefully power seat elevation. As they get older, adding the other power features is usually necessary as well.”

Patterson adds that parents of kids with type II SMA typically like power seat elevation. “They’re going to be in power (mobility) for so long,” she explains of these children, “so getting at the different levels of their peers, especially when they get to middle school or late elementary when they’re maybe not standing quite as much” is a real benefit.

Types III & IV: Changing Throughout a Lifetime

Children with type III SMA can stand and walk, typically into their teens or even adulthood, when lifetimes of progressing muscle weakness take their toll, “and distances tend to shorten,” Patterson says about walking ability.

Spine issues such as scoliosis tend to be less of a problem in type III patients, Patterson adds, but they do typically use a variety of mobility equipment throughout their lives.

“Depending on their age and type of SMA, some people, especially type III or IV, may initially use an ultralightweight wheelchair,” Rosen says. “Older individuals with type IV may also use scooters for quite some time.”

“Kids that are type IIIs that can still propel need something ultra, ultralightweight,” Patterson points out. “Typically, we see even type IIIs in adulthood go towards a power chair.”

Positioning for Power Chair Operation Success

One of the greatest challenges in working with children with SMA — especially those with types I or II — is figuring out how to support their quest for independent mobility.

Citing the “variability” within the different types of SMA, Patterson says, “There certainly are kids in type I that are strong enough that they tolerate being upright, and they get to the point of being able to drive a chair.” But they need high-tech options to do so, she adds, such as eye-gaze systems, since SMA does not usually impact the eyes. Patterson also says “a little bit of minute pressure of the distal fingers is possible, because they tend to stay stronger distally.”

In that case, the clinician or provider will still have to experiment to determine the most effective position for the child’s hand.

“There’s even a variability of hand position, like maybe with their hand in a neutral position, with thumb up,” Patterson says. “Maybe from there, they can flex their DIP (distal interphalangeal) joint. But if they’re against gravity, they can’t flex it. It’s really that minute. Gravity is their enemy, and if you change the position of their body, you change the pull of gravity on them. You have to take that into account.”

Would bringing drive controls closer to midline be helpful?

“It’s interesting that a lot of kids with type II do move to midline, but a lot of kids with type 1 will stay laterally,” Patterson says of where they prefer drive controls to be mounted. “Probably because there is (no strength) proximally at all with type I. So the wrist has to be extremely supported, but they still can stay (with the joystick) laterally.”

Due to extreme muscle weakness, other types of driving technology, such as fiber-optic switches, may be the best solution for these kids. The good news: Intellectually, they’re up to the task. “These kids are not cognitively affected,” Patterson says. “They’re smart enough to do it.

“There’s a very famous article that I use all the time (see sidebar) of a 20-month-old with SMA learning how to drive proficiently. These kids can learn very early. This is the population you start (on power mobility) really early, because cognitively, they’re going to get it.”

That includes giving kids control over power seating functions, such as tilting to perform weight shifts.

“Absolutely,” Patterson says, emphasizing their cognitive abilities. “And they’ve got complete sensation as well.”

Keeping Your Options Open

While a seating & mobility system’s flexibility and adjustability is always important for complex rehab technology clients, that need is especially acute for kids with SMA. When working with these clients, having a wide range of options is critical.

“I would say it’s one of the biggest issues that I run into,” Patterson says. “I’m in a neuromuscular disease clinic, and we see a fair number of kids from all over the country. It’s the lack of options that is the most frustrating.

“A chair gets selected for a kid, and it may be appropriate. But as the kid changes in a matter of a few years, we can’t do this or that, or we’re going to have to submit all this paperwork to get this change made.”

And in addition to embracing options such as head and arm positioning, ATPs should also keep in mind how typically bright and social kids with SMA tend to be.

“I talk to a lot of families, and parents are always trying to figure out how to tap into that,” Patterson says. “Especially with type I, an eye-gaze system is almost too slow for these kids. They get too frustrated; they’re 10 steps ahead. The iPad has opened up a huge world for these kids, because if they can position their arms correctly, they have enough motion that they can (use) an iPad. I’ve had the UW engineering students take this on as a project: how to mount devices like that on their chairs even if the kid is side-lying or in recline.”

Giving a child with SMA every opportunity to be independent requires work, but Patterson says the effort is well worth it: “These kids are endless in what they can learn.”

This article originally appeared in the November 2012 issue of Mobility Management.