The geriatric health population often faces added challenges due to the effects of aging, which can result in neurological, musculoskeletal, gastrointestinal, cardiopulmonary, urological, immunological, communication and cognitive changes, as well as pain. Additionally, a decrease in skin integrity due to aging tissue can be complicated by decreased mobility, prolonged sitting, ineffective weight shifts, poor nutrition, dehydration, muscle atrophy, incontinence, musculoskeletal deformities, impaired circulation, slower healing and declining cognition.
All these conditions can contribute to seating and mobility issues, especially with an existing disease. In these users, there is a tendency towards postural collapse (posterior pelvic tilt and increased spinal kyphosis), postural asymmetry (leaning to the side) and compromised mobility. To address these issues, we must first identify their causes and then determine the most appropriate solution.
Some of the simplest ways to prevent postural collapse involve proper adjustments of wheelchair components. For example, a simple adjustment of the height of the foot plates provides sufficient support beneath the feet to help maintain upright posture of the pelvis and trunk, promote midline positioning of the legs and decrease pressure on the buttocks. The foot plates should be adjusted such that the thighs are parallel to the seated surface and the feet are fully supported. Similarly, the armrests should be adjusted such that the forearms are well supported and the shoulder joints are neither elevated nor depressed. This can help promote balance, assist with upright posture of the trunk and prevent unstable and/or painful shoulder joints. Additional arm supports, such as trays or arm troughs, may provide further positioning.
A proper back height (not too high, not too low) can also help to prevent sliding into postural collapse. The back should be high enough to provide sufficient support for balance and posture but low enough to allow appropriate movement of the arms for functional activities, including wheelchair propulsion. An improper base of support under the pelvis caused by overstretched sling upholstery is a common cause of poor pelvic position, skin breakdown and discomfort. Even a firm cushion will eventually conform to hammock-shaped upholstery.
A more stable base of support can be achieved with good quality, tight upholstery and a cushion with an appropriately firm base. In some cases, a solid board under the cushion might be necessary.
Similarly, good quality, tight back upholstery or a simple solid back can provide proper support behind the spine. Postural collapse can result when footrest hangers are not angled tightly enough to accommodate the tight hamstrings of many older wheelchair users. These tight hamstrings are stretched beyond their limits of flexibility when the foot is placed on the foot plate, causing the pelvis to be pulled forward. In these cases, a tighter angle in the hanger should be used.
Many older adults are provided with hangers that have the least degree of angle— elevating leg rests (ELRs). In addition, these ELRs are inappropriately used to decrease existing lower extremity edema, when in fact they are only effective in preventing the swelling. If ELRs must be used, the individual should be repositioned in his/her seat after the ELRs have been lowered, in order to correct the pelvic shift caused by the ELRs. Some older individuals propel a wheelchair using one hand and foot or both feet. In these cases, the seat to floor height (STFH) must be low enough to allow the heel(s) to reach the ground. If it is too high, the individual must slide down in the seat, resulting in a posterior pelvic tilt. A lower STFH might be achieved using smaller rear wheels and front casters or a drop seat, however, these options could compromise the ability to reach the hand rims and/or access to the armrests. A better option might be an ultra-hemi frame that provides a very low STFH through the frame design.
Another common cause of postural collapse among the elderly is decreased strength in the core muscles of the pelvis, hips and trunk, which makes it difficult to maintain an upright posture against gravity. There is a tendency to collapse into a slouched posture because this requires much less effort.
There are several ways that we can help compensate for postural weakness. Adding shape to the seat cushion and back support to contour to the natural shape of the body is a good start. A contour in the rear of the seat cushion can help hold the pelvis back in the seat, while a mild posterior contour in the back support will follow the natural curve of the ribs to promote an upright and midline trunk. Both will distribute pressure more evenly and increase comfort. More aggressive contour around the sides of the pelvis and/or trunk can provide additional lateral support.
Even with normal strength, it takes effort to maintain good posture against gravity when sitting with a standard 90-degree angle between the seat and back support. Therefore, there is a tendency to slide into postural collapse. Maintaining upright is even more difficult for older wheelchair users with compromised strength and endurance. A slight recline in the back canes beyond 90 degrees (open seat to back angle) and/or a slight tilt in the wheelchair frame can reduce the effort required to sit upright against gravity, increase comfort and sitting tolerance and prevent postural collapse.
An open seat to back angle might also be effective when permanent tightness in the muscles and joints of the pelvis, trunk or hips causes a posterior pelvic tilt, spinal kyphosis and/or hip extension that cannot be corrected. These fixed deformities create a contour in the pelvis and spine that does not match a standard 90-degree seat to back angle (like putting a round shape into a square hole). A recline in the back posts, however, can accommodate the individual’s shape to allow increased contact with the seating, improved pressure distribution and increased comfort. A fixed tilt in the frame may help prevent further deformity. Two seating solutions that are commonly, but often inappropriately used with the elderly, are lumbar supports and wedge cushions. A lumbar support might be used to discourage collapse into spinal kyphosis.
Many older people have little to no flexibility in the lower spine. Using a lumbar support in these cases will merely push the individual forward on the seat. If the spine is flexible, it is important to choose a pad thickness that matches the extent of the anatomical curve and to position the pad at the correct height.
Beware of back supports with built-in lumbar supports as their height and thickness do not always match the user’s anatomy. A wedge cushion is also often used with the elderly to prevent forward sliding. The upward slope from back to front creates a squeeze in the seat. However, as with the lumbar support, many older individuals do not possess sufficient flexibility in the hip, pelvis or spine to sit at this angle. In these cases a wedge cushion can actually increase poor posture and create a high risk for skin breakdown.
Equipment goals for elderly wheelchair users should be the same as for any other person. This requires a thorough evaluation to identify postural and mobility limitations and to match equipment features to the user’s needs.
A caregiver should identify the simplest, most cost-effective solutions that will most effectively maximize function and comfort. However, many of the most appropriate solutions described above will not be found on the standard, nonadjustable, low-end equipment that is typically prescribed for this population. We should consider all options available and avoid the tendency to pigeon-hole older individuals into inappropriate or insufficient equipment.
