Involuntary-movement disorder. That’s a very simplistic description of dystonia, a condition that is anything but simple to understand, treat and work with from a seating & mobility perspective.

Seating & mobility clinicians and complex rehab technology providers see many clients with dystonia — and yet, those clients’ dystonia can present in a number of ways and can be impacted by a number of other factors…not all of which are currently understood.

Even for healthcare professionals who specialize in working with movement disorders, dystonia can be a highly challenging and even baffl ing condition that constantly tests their ability to observe and respond effectively.

Defining Dystonia

It seems nothing about dystonia is very simple, including its definition.

Jessica Feeley — the editor and special projects coordinator for the Dystonia Medical Research Foundation — explains dystonia via a metaphor.

“I once heard our scientific director — Mahlon DeLong at Emory (University) — use the analogy that you could say dystonia is almost similar to fever,” Feeley says. “There are lots of different conditions or disorders that can involve fever. Sometimes it’s a primary symptom of what’s going on, and sometimes it’s one of many symptoms.

“The pathologies are completely different, but I thought (the fever analogy) was interesting, to help frame the different forms that dystonia can take, the different disorders that it can piggyback — because it can be pretty confusing.”

Let’s start at the beginning.

Though dystonia affects various voluntary muscle groups, it is neurologically, not orthopedically, based.

Feeley says, “The signaling in the nervous system that normally instructs movement and what muscles contract when others relax in order to coordinate voluntary movement — the signaling is just chaotic. It’s considered a circuitry disorder. The electrical system of the brain is what’s not working properly.”

Dystonia comes in many, many forms, but one of the major ways to categorize it is whether the condition initially presented in childhood or adulthood.

When the condition appears early in life — from childhood through the mid 20s — it’s typically referred to as an early-onset form. In those cases, Feeley says dystonia is more likely to be a generalized form, “which means it’s going to affect the limbs, the torso, the neck — and it’s going to affect several big muscle groups at once.”

Dystonia that starts appearing in adults typically “will stay relatively isolated to a particular body part,” Feeley says. “Sometimes the neck or the shoulders, sometimes just the eyes, sometimes the hand, sometimes the vocal cords. Sometimes you get little clusters of dystonia, so someone who has symptoms in their neck will also experience it in their jaw and in their eyes.”

Dystonia that appears in adults and is relatively isolated is referred to as a focal form of the condition.

“These are usually referred to as primary dystonias, where there doesn’t seem to be anything else neurological going on,” Feeley says. “Many are presumed to have some sort of genetic component. You can contrast that primary category with secondary dystonia, in which case you see dystonia as the result of a stroke or a head injury or exposure to certain medications or toxins.”

Secondary forms of dystonia — in which dystonia presumably can be definitively traced to a traumatic injury or event — can, obviously, happen at any age.

Despite its neurological roots, the effects of dystonia can require interventions on multiple fronts.

For instance, while dystonia doesn’t directly affect muscles required for breathing, respiration can certainly be impacted.

Feeley explains, “In some cases — because of the way the musculature can be involved, whether it’s laryngeal muscles or sometimes if the torso is twisted or not aligned properly — difficulty breathing can definitely be a side effect of dystonia. It’s more a side effect than a characteristic symptom, more sort of how the mechanics of dystonia get in the way of some of these processes.”

She notes that a diagnosis of dystonia involves “a lot of moving parts.” Therefore, the Dystonia Medical Research Foundation understands the need for an interdisciplinary reaction.

“Sometimes there are orthopedic needs,” she says as an example. “Because dystonia affects people in such different ways, there isn’t necessarily a catch-all specialty. We advise people that in terms of diagnosis and treating the actual dystonia, a movement-disorder specialist is really the best trained to identify that. But someone who has the dystonia primarily in their eyelids may see an ophthalmologist. So there are different branches, and people are going to have different needs.”

Far-Reaching, But Not Degenerative

One important note on a dystonia prognosis: While there is no cure, there are a number of therapies and treatments; Feeley references “a whole host of oral medications that are helpful in some cases. There’s typically a lot of trial and error in terms of finding the drug or the cocktail of drugs that’s going to work. Botulinum toxin injections really revolutionized dystonia treatments in the ’90s, and they’re used primarily to treat those focal, isolated dystonias.”

Brain surgery has also had some success, and today’s use of deep-brain stimulation — implanting electrodes that use pacemaker batteries into the brain — works by stimulating areas of the brain thought to be associated with dystonia, rather than actually destroying brain tissue.

One of the most hopeful aspects of dystonia, Feeley says, is that the condition causes no degeneration of brain tissue. While dystonia can be a symptom of degenerative diseases, such as Parkinson’s and Huntington’s, the dystonia itself is not considered degenerative.

“In theory,” Feeley says, “if you can reteach the brain to (use) different loops and different circuits, (dystonia) is reversible. In the vast, vast majority of cases, it’s not life threatening, and it’s not going to shorten your lifespan.”

Nor is dystonia likely to become widespread if it’s the focal, adult-onset form.

“The younger you are when you develop symptoms, the more likely it is to spread,” Feeley says. “So typically, around age 9, a kid will start limping or have problems with handwriting. And within a number of years, that dystonia will spread typically to the limbs, the torso, all these major muscle groups.”

The focal dystonias, Feeley says, typically do not spread, though there is a period of time after initial onset during which more muscle groups could become affected.

As an adult-onset example, she says, “You’ll wake up and you’ll feel like you slept on your neck wrong. And then over a period of weeks, you look in a mirror, and you realize your head has tilted to the right. There’s sort of a window of about three years in which the symptoms may get worse, and sometimes you do have symptoms spreading to adjacent parts of the body, but still staying relatively focused. If it starts in the neck, possibly (the dystonia will spread to) the jaw and the face, the eyes. It’s also not that uncommon for people to have symptoms in the neck and a hand.

“But for example, if you’re an adult and it starts in your neck or your face, chances are it’s not going to go into your legs.”

The Seating & Mobility Challenges

While not all patients with dystonia need mobility technology, those who do can present unique sets of symptoms for seating & mobility specialists.

Jay Doherty, OTR, ATP, is Quantum Rehab’s clinical education manager, but has an extensive history of working with children with cerebral palsy and dystonia.

Because children with dystonia are likely to be affected in multiple muscle groups, Doherty says, “That makes seating even tougher — seating as well as access to mobility because there are multiple locations in the body that are being affected.”

While dystonia is neurologically based, Doherty explains how orthopedic changes can also occur: “You’ve got muscles that normally we can control the contracture over, but in those individuals (with dystonia), these muscles involuntarily contract on them. So you can have actual orthopedic changes happen over time because those muscles are contracting and moving the body in ways that the person otherwise might not normally move.”

As an example, Doherty says, “If you think of somebody whose arm is affected, and they go into extension and their fist clenches, and they’re constantly going into that position — there’s going to be a change in that arm over time in some cases. Not all, but in some cases. There are folks where their trunks are impacted, so you may have some asymmetry in the trunk that appears over time because of the postures they take on because of the dystonia.”

Those asymmetries can present positioning and seating challenges, but Doherty points out that a client’s ability to adapt may cause additional challenges.

“These folks learn to use their bodies, much like folks with other diagnoses,” he says. “They learn to use their bodies in certain ways. So if we position them in such a way that we restrict their movement, we now restrict their function also in some cases.

“You have to weigh the pros and cons of the seating system and how can we best provide function for that individual as well as good positioning.”

Understanding the Basis of Tone

Theresa Plummer, Ph.D., MSOT, OTR, ATP, is a faculty member of the school of occupational therapy at Belmont University in Nashville, Tenn. Plummer says that when she teaches on this topic, she begins with an introduction on tone.

“I actually start explaining to people what tone is, because what I find with both therapists and suppliers is their understanding is tone is an active movement, when in fact tone is only assessed passively,” Plummer says. “You may have heard people say, ‘I can break the tone.’ Well, you can’t break tone, because tone is a passive state. And so learning what tone is and what contributes to tone helps us in terms of the seating and positioning. Because if somebody is hypotonic, meaning they have really low tone, it means their joints are unstable. So if you’re asking for a lot of movement around an unstable joint, the person’s never going to have refined function.”

For clients with hypertonicity, Plummer says, “You need to allow for movement of the joint around the joint capsule itself, and that’s what helps to infl uence the tone so that the tone can be managed.”

Understanding the neurological basis of tone and dystonia, Plummer says, is crucial to successful seating & mobility outcomes.

“In the seating and positioning world for the most part, tone is greatly infl uenced by proprioception, which is the receptive ability around the joint, and by sensory systems, so if you don’t allow for good weight bearing through the joint, it’s difficult to manage tone. And for seating in particular there are mechanoreceptors, which are very, very specific proprioceptors — receptors in the hip capsule. So if a person in a sitting position has their shoulders behind their hips, those proprioceptors really can’t be fired.”

Plummer says that seating & mobility interventions frequently come from an orthopedic perspective. “The pelvis has to be level,” she says as an example. But with neurologically based conditions, “really the point is you have to have a neurological understanding of them rather than orthopedic. That’s why you can infl uence it, because it’s neurological as opposed to orthopedic. So restricting movement is not what you want to do with somebody with dystonia.”

A Neurological Approach

Plummer’s approach to dystonia, she says, is “I really look at their sensory systems in terms of my evaluation to see what provides them with best posture and typically weight-bearing posture. So that rather than the knee being extended, the knee should be a little bit fl exed so they can have weightbearing through their feet. It’s the weight-bearing that helps facilitate proprioception in the joints. It’s the information that the proprioceptors send to the brain that tell the brain, ‘Oh, you’d better relax a little bit down there.’

“If you have a child with dystonia and you put on ankle huggers, the sensory input — the feeling of the ankle huggers — makes the ankles even more uncontrolled or the movements more involuntary because (the child’s) sensory system doesn’t know what to do with that information. So I typically would use a shoe holder that tells the body where it’s supposed to be rather than restricts the movement. So you guide the movement, because it is movement driven. Guide the movement rather than restrict the movement. You need to influence what’s going on in the brain.”

Plummer also says that it can be possible to use those classic dystonic movements in a functional way.

“When you see it from a posture perspective, you see a child writhing around, and you think, ‘Oh, I need to restrain them, I need to tie them down, I need to stop that movement,’” she says. “When in fact, oftentimes if you do that, you restrict their function. They may have involuntary movement, but they can still use that movement to manage their posture, to manage their activities, to navigate a power chair.

“It’s not always the same with every client. Some kids with dystonia also have hypertonicity, so their muscles are more rigid, and you may have another child with dystonia that has no increased tone. Particularly with voluntary movements, the minute they try to move, the body goes into all these distorted patterns and positions. So that doesn’t mean you don’t allow them to move, it means you channel that movement into functional movement.”

Because trying to execute a voluntary movement can trigger involuntary movement in people with dystonia, Plummer says she is mindful of asking a child to try to move too much while learning to drive a power chair.

“In that case, if I’m trying to teach a child to use a power device, I’m not going to start with a joystick that requires too much movement,” she says. “I might start with a switch where they can just slide their hand forward with their hand on the switch and make the chair move. Then once they have some movement, it’s the movement around space that helps their visual and vestibular systems to start taking in all this information.”

For very young children, dystonia presents an additional challenge — one that can have a life-long impact on their development.

Plummer has intensively studied how posture impacts the vision and therefore the development of very young children.

“There’s a pretty significant relationship between posture and vision,” Plummer says. “And with dystonia, because the child doesn’t have a stable posture, a static posture — and because children develop their vision after their posture — oftentimes kids with dystonia don’t have normal ocular motor control.”

Plummer says her specialty practice is the relationship between vision and posture, which is a significant consideration for children with dystonia.

“Kids with dystonia who don’t have a stable base of support don’t have proximal control, meaning control of their trunk,” she explains. “They can’t gain control of their head and neck. And if they can’t gain control of their head and neck, they cannot gain control of their oculomotor muscles. We gain control proximal to distal —the trunk being proximal, the eyes being distal — and so in kids who are constantly moving around, their eyes do not develop what’s called visual fixation, meaning the ability to look at something for a period of 10 seconds.”

That lack of visual fixation, Plummer says, means “it’s really difficult for these kids to learn anything. So they appear to have more cognitive involvement than they might, just because it’s difficult for them to learn from their environment.”

As an analogy, Plummer suggests imagining how difficult it would be to read a document that’s printed in small type while riding a roller coaster at the same time. Because the roller coaster is jostling you so much, you’d continually lose your place while reading. So how much of the document could you read and learn?

That’s what it’s like for young children with dystonia, Plummer says: “They’re constantly in motion, so for them to be able to see anything is really difficult.

“Structurally, there’s nothing wrong with their eyes; functionally, there is. They can see, it’s not like they don’t have acuity. But their oculomotor system doesn’t work together, because you have to have a stable base of support.”

While adding a head positioning system to a child’s power chair might seem an easy solution, Plummer says finding the right balance between support and movement can be tricky.

“You want to allow a little bit of movement, and you cannot restrict their ability to turn their head from left to right,” she says. “You cannot restrain the head in any way, but you still need to provide some base of support so their visual systems can develop as well.

“Our visual system actually feeds our vestibular system; the vestibular system tells us where our heads should be in space. Any child who doesn’t have stable trunk posture is not developing normal vision. That’s why we struggle so much with head control with the pediatric population. A normally developing child at two months of age can start to extend their head and neck, and as they do that, their eyes can visually fixate. If you don’t have posture, if you don’t have postural control, your eyes never get to that point. So almost all kids with impaired posture have impaired vision.”

Achieving Balance

Just as finding a proper balance between head support and freedom of movement is important, Doherty says the need to find a similar balance applies to the rest of the seating & mobility system.

That can involve significant observation periods to learn, for example, how a client with dystonia typically moves.

While clients who move frequently may not be at a particularly high risk for classic skin breakdown caused by pressure, Doherty says shearing could be an issue. He recommends learning the client’s skin integrity history, “as well as watching how the person sits, how they move. You have to look at how they’re moving, the surfaces they’re on, what they are in contact with — and you still want to inspect their skin thoroughly and look for areas that may have some redness or may be susceptible to developing a sore over time.”

Because dystonia also has a sensory component, observation periods should also include learning what sorts of sensations exacerbate the involuntary movements or cause discomfort.

“They do have sensory impairment,” Plummer says of kids with dystonia. “They might really dislike the touch of neoprene, for instance. One child may be more sensitive to that, where another child may be sensitive to the touch of vinyl-like products. Some like deep pressure; other kids don’t like deep pressure at all. Understanding what calms the person or centers the person in terms of posture is also helpful.”

Stress and fatigue have been known to worsen episodes of dystonia; says Jessica Feeley, “We hear from people that when they’re in a stressful situation, usually the most inconvenient public situations, their symptoms will get worse. Stress management is also a huge part of the daily maintenance — learning relaxation.”

Despite the broad numbers of people affected by dystonia, Feeley calls the disorder “very individual — even individuals who have the ‘same type’ of dystonia may have symptoms that don’t resemble each other very much at all.” That’s a truth that seating & mobility professionals who work with these client know all too well.

“It’s a huge, broad disorder,” Doherty says. “It’s going to be very different from person to person.”