Future Reflections         Winter 2011

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Reweighting and Constraint:
The Development of Movement in Young Blind Children

by Mary Jo Hartle and Jane Clark

Jane ClarkFrom the Editor: In April 2009 the NFB Jernigan Institute hosted "Beginnings and Blueprints," a conference for parents of blind children from birth to age seven. This article is based on a conference presentation by Mary Jo Hartle of the Jernigan Institute and Jane Clark, Professor of Kinesiology at the University of Maryland at Towson.

Mary Jo Hartle: As parents of blind children you're often told that your child isn't going to have typical developmental milestones, that your child will never be able to do this or that. That doesn't always have to be the case. We want to encourage our children to be age-appropriate or stage-appropriate, depending on their capacities. In this session we'll talk about ways to compensate for some of the challenges that blindness may impose on the tasks of child development.

Jane Clark: A lot of college exams are multiple choice, as you probably know. I'm going to give you the answer up front, and later I'll ask for it. Just to tell you now, the answer is C, and it stands for constraints.

Think of the constraints in your life--you have children, you might have two bedrooms when you need four, you only have one tree in your yard, or you have a big lawn to mow. Those are all constraints that influence what you do. Now, if I want to make a movement such as reaching for a glass on the table, everything I do is constrained. My movement is constrained by three things: 1) what I want to do, 2) the environment, and 3) the person I am. So the constraints are you as a person, your social and physical environments, and the task you want to perform.

Gravity is a major constraint within the environment. You've seen on C-Span the astronauts in space--they don't walk, they kind of float. They're in an environment without gravity. All the movements you see in babies during their first year of life--rolling over, sitting up, standing--are about learning to work with gravity.

Sensory Apparatus

Mary Jo Hartle shows young teen how to position her hand on her cane.We all have sensors that tell us where we are in space.  Our biggest sensors are in our heads. There are the sensors inside our ears, our ears themselves, and our eyes. It seems that the body is set to work like a big globe or ball with everything underneath it. I'm listening to Mary Jo on my right. I hear the sound coming from my right side and turn my head. Sensors in my inner ear tell me about my position and the movement as I turn. They tell me if I'm upright or upside down, and they tell me at what velocity I'm moving. Those sensors can be impaired in some people. For example, some people who lose their hearing also lose the sensors in the inner ear, what we call the vestibular system. If you've ever had an ear infection or dizziness from water in your ear, you know those constraints can change the sensory information you receive. Those changes may affect how you move. Closing your eyes or not having vision will also constrain how you move.

Movement within Constraints

The typically developing child has three senses in her head. She'll have sound, the vestibular system, and vision. The child who is blind doesn't have the visual sensor, so she has to figure out how to use the constraints she has. We tend to think of a constraint as something that is not good, something that holds us back. But constraints are not necessarily negative. Actually constraints are just information. If you have four choices and I say that the answer is not A, B, or D, I've constrained the answer to be C.

Now, how do we work with constraints across our life span? Unless there is a physical disability we're all built pretty much the same. We have hands that rotate on our wrists, we have knees that let our legs move back and forth. A problem with our knees or hips places new constraints on the way we walk. We may also change our gait or patterns of movement due to sensory constraints. A person who can't hear may have a slightly different gait from a person with hearing. A person who can't see may have a different gait from a sighted person. Add a cane and the gait changes again, because the center of gravity is now out in front of the body. Holding your arm out in front of you pulls you forward.

The way to address someone's motor system, the way to get someone to move how you want, is to talk about tasks. You can't visually demonstrate movement to a child who can't see. Don't try to move him in the way you want him to move. Moving him may give him a quick sense of what you want him to do, but it isn't very meaningful to his brain. We know now from MRI studies and other brain research that our brain processes are organized around tasks. If I ask you to sign your name, you don't think about the individual strokes that make up the letters. When I reach for the microphone on my right I don't think about the thickness of it and the position of my hand as I grasp it. I think about the task of grabbing the mic. If I change the task I need to do, my constraints change automatically.

MJH: To relate these concepts to blindness, I want to repeat that constraint doesn't have to be a negative thing. The lack of vision may seem like a deficit, but actually it's just a different way of taking in information. When people tell you about all the things your blind child won't be able to do, they're assuming that those things require vision. It's very likely that your child can do whatever it is if they find what we call a nonvisual technique.

Learning by Doing

If your child is learning to crawl, she's not seeing the visual cues that stimulate sighted children to reach and pull forward. There are ways you can adapt for that and help motivate your child to crawl, through modifications in the environment.

JC: Okay, let's think about crawling. From the outside it looks as though crawling is very easy and natural, but actually it takes kids quite a while to learn those movements. Kids are motivated to move by things in the environment, and they figure it out. In a study done on blind babies, they took toys that the children had cuddled and that also made sounds. The babies were familiar with these cuddly toys, and they knew the sounds the toys made when squeezed or shaken. When an adult squeezed the toy, the babies oriented toward the familiar sound and tried to move toward it. Naturally, as a parent, you don't hold the toy too far away. You hold it close enough that the baby has a chance to reach it. As a parent you must find a way to get the task to speak to the child.

Mary Jo HartleMJH: When we teach orientation and mobility, or cane travel, we often talk about structured discovery learning. This topic actually relates to many things in a blind person's life, or in anyone's life. We're always learning through experience. The most constructive way to master a skill is to learn by doing. You can tell your child how to do something, but until he actually has the experience he won't internalize that learning. You might let him feel your hands as you do something, or give a clear verbal explanation to walk him through a task. The most important thing is to give your child lots of opportunities to learn through experience and to get positive reinforcement by accomplishing tasks.

JC: There are three stages to learning a skill. The first and most important one is getting the idea. Pushing the child through a series of movements isn't usually very effective. If he's very young, talking him through it doesn't work well either. I remember teaching two-year-olds to swim and telling them to kick. They didn't have any idea what I was talking about, but when I just let go of them in the water they started kicking by themselves. Then, as they did it, I said, "Kick! Yes, that's good kicking!" and they attached the word to the movement. They got the idea of staying afloat and moving in the water.

The second stage of learning a skill is figuring out what the feedback means, interpreting the sensory information. The third phase is internalization. Think about the experience of learning to drive a car. I remember my father telling me to keep my eyes on the road, not to look at the speedometer, but to stay at forty miles per hour. That assumed that I had an internal sense of what forty feels like. I didn't have that sense when I started driving, but today I do. At first you need feedback, a glance at the speedometer, but after a while you have an internal representation of what you're doing. I think that the same is true of learning to travel with a cane. At first you're depending on a lot of feedback, and eventually you can go on automatic pilot in the same way that a person drives a car.

MJH: What Jane says is relevant for children learning any basic skill. When a child is learning to read Braille, first she has to learn to track with her hands, and later she'll build speed as tracking becomes automatic. When she learns how to pour, pouring becomes automatic and can be applied as she learns more complex tasks around cooking. If children don't experience these basic skills early on, they have so much to learn later. You don't want your child to turn eighteen and try to move out on her own when she doesn't know how to boil water or make the bed!

It's very important for kids to get their hands on things when they're little. As blind people, we get information about things by touching them. I'm looking at this microphone right now as I touch it. Touch is my way of looking at something. We really need to encourage blind kids to be hands on!

Reweighting the Senses

JC: The skin is the largest sense organ we have. It's miles long! There's a lot of touch available in that sensory organ, and it can make up in large measure for the lack of vision.

MJH: As blind people, we learn to use the senses that we have. It's not that we're endowed with super senses of touch and hearing, but we learn to use what we have in ways that a sighted person may not learn. We learn to pay more attention.

JC: To put it another way, the senses are reweighted. Every sense has a weight. Even when you have all your senses, sometimes you need to weight one more than another. There used to be a theory that vision is the dominant sense. Now we think of it quite differently. Vision is very powerful and we use it when we can, but as soon as it becomes unreliable we reweight our sensory information.

Here's an example of reweighting. Can you feel the back of your chair? I bet you weren't thinking about the back of your chair until I asked you that question. If you close your eyes, you can still tell that you're sitting on a chair and not a bench. You can feel the back of the chair against your back. You reweighted the information you were taking in.

Scaling the Mountain

Every developmentalist sees the world as a mountain. You start somewhere and work your way toward the top. This is true for moral development, cognitive development, and motor development. We're all born at the bottom of the mountain. We start pretty much in the same place, beginning with reflexive movements. We have sucking reflexes, withdrawal reflexes, and grasping reflexes. We also have the rooting reflex. If you touch a baby's cheek it turns toward the touch, and then when you touch the lips the sucking reflex kicks in. If you touch a baby's palm the hand closes in a grasp. It's called a flection reflex because it doesn't involve the thumb. The use of the thumb evolves quite a bit later. When the hand closes on an object, the child has opened a dialogue with the environment.

By the time a child is a year old, she can probably feed herself and walk. That's average. Walking can begin anywhere between nine months and eighteen months.

MJH: Professionals in the blindness field sometimes claim that blind children take twice as long to walk as sighted children do. It depends on a lot of factors, such as how much stimulation the child is getting and how much exposure to things. If parents are very involved with their kids and work with them a lot, the kids are much more likely to stay on track.

JC: That's true for all children, blind and sighted. If you think that you shouldn't encourage a child to walk because he might hurt himself, then the child is probably going to be delayed in walking. Vestibular stimulation is very good for encouraging movement. Lifting the child in the air, turning him upside down--those movements help him map the environment in 360 degrees rather than just from a reclining position or even an upright position. I know a family in which both of the parents are gymnasts. All of the children grew up to be gymnasts, too. When the children were young their parents encouraged them to move in all sorts of ways, and they developed incredible balance and spatial awareness. They developed within the constraints of their parents' expectations that they would be comfortable with their bodies and would move easily in their environment.

MJH: For you as parents, reweighting means changing your perception that your blind child can't do certain things. It means finding ways that your child can do things without the use of sight. You yourself have to adjust your way of thinking in order to help your child find ways that will work for her. Your child will rise to your expectations.

Developmental Milestones

Look at the milestones for typically developing children. If you notice that your child is delayed in any area, think of ways to help her move forward. You might offer her certain kinds of play or expose her to an environment that invites a particular kind of activity.

JC: To get back to the mountain--we begin at the bottom in the reflexive period and achieve independent feeding and locomotion in the first year. It's all about survival--we have to get to our food and put it into our mouths. The next period is very critical to becoming a physically active person. This is the period of developing fundamental motor skills. These skills include walking and running, jumping, skipping, hopping, and galloping. Skipping and galloping are playful gaits. Then we learn to move the arms and hands around the trunk, and to coordinate those movements with the movement of the legs. We start with large movements and move to finer, more specific movements. When we acquire skills we gain the ability to adapt movement to new circumstances.

I think blind children can be at risk for a lack of selectivity. If they don't get the chance to experience a lot of activities and learn a wide variety of skills, their range of options becomes quite limited. Using exercise equipment can be very helpful. Blindness is no obstacle for using a treadmill, a rowing machine, or a stationary bicycle. Bowling is a good sport; it's what we call a closed environment in which the target doesn't move. I encourage playing with a ball--rolling it, throwing it, bouncing it.

MJH: There are a lot of adaptive toys available, such as balls with bells inside of them. You can buy a basketball hoop that makes a beeping sound. Also there are often simple ways to adapt things. A friend of mine once adapted a Frisbee so that I could play. He bought a clock radio and took it apart. He clipped the beeper from the alarm onto the Frisbee so I could hear it.

These adaptations not only help our children's motor development; they also have tremendous social implications. Kids learn about being part of a team, having fun with others, and negotiating. It's all extremely valuable experience. By giving our kids the chance to learn motor skills, we open many, many pathways for them later in life.

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