Kent: Using Anterior Trunk Support to Improve Head Position

Kent is a 14 year old young man with the diagnosis of cerebral palsy. He was referred for evaluation of his wheelchair positioning and access to a communication device. Kent was seen at school with his mother, school team, and supplier.

Mat exam:
Kent had adequate range of motion for sitting, though he had significant internal rotation of his right lower extremity and external rotation of the left lower extremity. He demonstrated significant tone and posturing. His postures were influenced by a strong ATNR and included neck hyperextension and generalized extension and rotation. He appeared to have a kyphotic area of his mid-thoracic spine.

Posture in Manual Wheelchair:
Kent was seated in a linear seating system in a tilt in space manual wheelchair. He reportedly only spent one third of his school day in the wheelchair as he was not positioned well in this system. The linear seating system included a biangular back (though the angle was flattened and so acted as a plain linear surface), antithrust seat, pelvic positioning belt, lateral chest pads, shoulder harness, lateral knee supports, medial knee support, and Stealth Products Comfort Plus head support.

In the seating system, Kent displayed a pelvic posterior tilt, pelvic obliquity (left high), pelvic rotation (left forward), trunk kyphosis, and lateral trunk flexion (shortened on right). He also exhibited lower extremity internal rotation on the right and external rotation on the left. It was possible to reposition Kent to achieve a neutral pelvic position within the seating system, though the pelvic belt needed to be closer to a 60 degree attachment angle to better control his tendency toward posterior pelvic tilt.

Kent was positioned in significant neck hyperextension in this seating system. This led to an upward gaze which limited his ability to see the environment around him, including his communication device display. Kent also frequently aspirated and this hyperextension increased this risk significantly.

We repositioned Kent within the seating system, moving the pelvic belt to 60 degrees and adjusting the footrests and shoeholders to accommodate his lower extremity rotation. Although his position was already greatly improved, his neck remained very hyperextended.

Take a look at figure 1 below. Look how far Kent’s shoulder is from the back of the seating system. He was over 6” forward of the back. This was because he tended to ‘pivot’ his head against the head support, pushing his trunk forward. The anterior trunk support was tightened and the head support brought forward to provide counter-pressure to achieve a more neutral neck alignment (see figure 2 – his Mom is brushing the hair out of his eyes, not holding his head up).

Much of wheelchair positioning involves force and counterforce. Only providing force / point of contact behind the head was inadequate to prevent Kent’s neck hyperextension. By providing a counterforce / point of contact at the anterior trunk, his neck could be successfully aligned. Kent’s line of vision was vastly improved and safety in swallow was increased.

So why hadn’t anyone tightened the shoulder straps before? First, Kent’s Mom was convinced that this would cause him pain. We discussed this at length before making the change. Second, his Mom was sure that the head support just needed to be moved forward. As a matter of fact, we took these photos to compare his positioning to convince his Mom that tightening the anterior trunk support would address this issue, not moving the head support forward.

Once Kent’s head position was addressed, finding a successful switch site for accessing the communication device via scanning was fairly straight forward. He was able to successfully use a Microlight switch mounted on a swing-away assembly (off of the Comfort Plus head support) by his left cheek bone (see figure 3). (Kent now uses a Microlight switch by his left cheek bone)

Many times, improving head position means improving overall body position first. I’m so glad Kent is better positioned and can access his communication device!

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