Seating: Positioning the Head
By Michelle L. Lange
One of the most challenging areas of positioning can be the neck and head. How many times have you seen clients sitting with their heads touching their chests, looking at their knees? Or balancing their heads over hyperextended necks while trying to breath and swallow? Head support is usually the last element addressed in a seating system because control depends heavily on the position of the pelvis and trunk. However, poor support of the neck can lead to overstretched neck extensors, poor visual field and attention, poor socialization, poor swallowing and feeding, and impaired respiration. The goals of supporting the head include: aligning the neck to provide a slight chin tuck with no hyperextension, distributing pressure (especially if the client is tilted a great deal of the time with the head in constant contact with the headrest), and providing adequate pressure distribution between the trunk and the head.
Posterior Head Support
Posterior headrests and neck rests are designed to assist with head control, not to keep the head upright. Decreased head control can be caused by overstretched neck extensors, flexor tone, hypotonia, low or no vision, compensation for a tilted position in space and muscle weakness. Posterior headrests are also used to minimize or prevent neck hyperextension. Hyperextension is often a compensation for forward trunk flexion or part of a total extensor pattern.
Posterior headrests always include a pad that is designed to contact the back of the skull. This pad may be flat or contoured. Some headrests add an occipital ledge or contours that provide some upper cervical support and help hold the head in correct alignment. Neck rests lack a pad above the occipital ledge and are rarely used without additional head support because they can elicit extensor tone and provide inadequate pressure distribution during tilt or recline. A neck rest should not be used to correct hyperextension because the head merely rolls over the top of the pad.
Headrests and neck pads can be made from a variety of materials. Using softer materials in the headrest (e.g., when the client is tilted back frequently). Custom carved or moulded foam headrests can be very effective posteriorly and laterally for clients who require more support or to limit head movement (i.e., to inhibit reflex activity). I look for covers that allow the hair to move with the head. Vinyl covers often lead to bald spots on the back of the head. Common posterior headrests include those manufactures by Otto Bock, Whitmyer, and Adaptive Engineering Lab (AEL).
Simply changing the client's position in space can eliminate enough gravity to allow more head control. Even a fraction of an inch can make the difference between the head resting on the headrest and the head falling forward. For example, Paul who is fifteen years old, used a flat headrest in which he tended to hyperextend his neck. We switched to an AEL Headrest with an occipital support to better align his head. This slight change in his neck position resulted in improved functional vision and swallowing.
Anterior Head Support
Anterior headrests and neck rests are designed to keep the head upright when the client has very little or no head control. Anterior solutions include support under the chin (e.g., collar) and around the forehead (e.g., straps or halos) and are used in combination with a posterior support. When providing anterior head support, anterior trunk support is crucial. If the client’s trunk moves forward, the head is restrained, which can lead to neck injury.
Many collars are available, and they vary in degree of support provided; materials used; and the ability to be used in the seating system, out of it, or both. Collars can pose a choking risk if used inappropriately (e.g., a very soft collar, if used with a client who has a lot of neck flexion, can fold and create pressure against the throat). Often, the collar choice is determined by aesthetics. Common collars include Danmar’s Hensinger, Snug Seat’s Heads Up, and Symmetric’s Headmaster Collar.
Forehead support is provided by a strap, halo, or even a baseball cap attached to the back of the chair. Straps must be monitored because a poorly adjusted strap could slip down around the client’s neck. Some clients get out of straps or halos by hyperextending their necks. This is often intentional! Having one’s head restrained is not fun and many of our clients do not understand the advantages. If the client repeatedly "escapes" a forehead support, try a collar. This is often better tolerated. Some forehead supports (i.e., the Mantis) also limit head rotation. Although not usually necessary, occasionally rotation is purposefully limited to inhibit reflexes, such as an asymmetrical tonic neck reflex (ATNR). Common forehead supports include Whitmeyer’s forehead strap, Symmetric’s Mantis halo, and Mulholland’s halo.
Mark is six years old and used a forehead strap but he was constantly getting out of it by hyperextending his neck. He tried a Hensinger collar, but this was too bulky and hot for him. Finally, he tried a Headmaster Collar, which supports his head well. Most importantly, he tolerates it!
Lateral Head Supports
Lateral head supports are designed to prevent or limit neck rotation or lateral flexion. Rotation and flexion can be caused by visual compensation, poor head control, compensation for lateral trunk flexion, increased tone, torticollis, or ATNR. Some headrests have optional lateral components (e.g., Whitmeyer, AEL). If the surface area of a lateral pad is not large or adequately padded, pressure can be an issue because many clients push into this lateral pad rather than simply rest on it. A custom carved or moulded foam headrest may be indicated- this type of headrest requires three points of control to correct lateral challenges (e.g., if the head is flexed laterally to the right side, support is required bilaterally along the lower skull or jaw line and at the upper right side of the head).
Kelly is ten years old and has a metabolic disorder. She has an extreme ATNR that is elicited by head movement and would leave her with her eyes locked to the side. We fashioned a custom-moulded head support that allowed no head rotation and thus prevented the ATNR. Kelly was then able to use her eyes functionally.
Conclusion
Determining the best positioning intervention for head control can be quite challenging and requires simulation. If you are interested in this fascinating area, contact some of the companies below and ask to borrow some of their products to try for yourself. Let’s not leave our clients “hanging”!
For More Information
The Head Control Dilemma
By S.J. Taylor, June 1999. Technology Special Interest Section Quarterly, 9, 3-4
Manufacturers:
Adaptive Engineering Lab, Inc 800-327-6080
Danmar: 313-761-1990
Otto Bock 800-984-8901
Mulholland 800-543-4769
Snug Seat 800-336-7684
Symmetric Designs 800-537-1724
United States Manufacturing Co. 818-796-0477
Whitmeyer Biomechanix, Inc. 904-656-9448
Michelle L. Lange, OTR, ABDA, ATP, has been working with assistive technology for more than ten years and is the clinical director of The Assistive Technology Clinics at The Children’s Hospital of Denver in Colorado. Her reviews are based on her personal experience and do not reflect an endorsement by AOTA. To respond to this column by mail, write to Michelle L. Lange, OTR, ABDA, ATP, c/o OT Practice, PO Box 31220, Bethesda, MD 20824-1220; by fax 301-652-7711, attn.: OT Practice; by email:
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