Interface pressure distribution of elderly Japanese people in the sitting position

Aim. To investigate the characteristics of elderly Japanese people sitting in a wheelchair using pressure mapping and an objective method to classify sitting patterns. Method. This descriptive observational study was conducted in a senior care facility and a geriatric hospital, with 107 elderly subjects (37 group A (house-bound), 34 group B (chair-bound) and 36 group C (bed-bound)) and 36 able-bodied. Maximum pressure, total support area, distance from backrest to coccyx and sitting pattern were collected by using a pressure mapping system. Results. Maximum pressure was significantly lower for able-bodied than groups B and C (p < 0.001 and p = 0.024, respectively). Total support area was significantly larger for able-bodied than each elderly group (group A p = 0.014, group B p = 0.021, and group C p < 0.001). Distance from backrest to coccyx was significantly longer for group C than able-bodied (p < 0.001). The occurrence of proper sitting pattern significantly decreased as the degree of independence reduced (p < 0.001). Conclusion. Elderly people with disabilities have high interface pressure on a small support area, malposition, which is confirmed by longitudinal and lateral supporting balance indices, and imbalance in a wheelchair. The following concepts for developing cushions should be considered: low interface pressure with large support area, individual adjustment of sitting position and stability of body trunk.