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Biomedical subjects

T K Koo

Publications and source records attributed to T K Koo.

2 recordsLinked to original sources
PubMed1996

Posture effect on seating interface biomechanics: comparison between two seating cushions.

OBJECTIVE: This study aimed at investigating the effects of sitting posture on ischial pressure and pelvic orientation for two types of cushions. DESIGN: Two types of seating devices, Roho and Polyurethane (PU) Foam cushions, six predefined postures, and two subject groups, Normal and Paraplegic, were tested. Ischial pressure and pelvic orientation were monitored. The sequence in which the cushions were tested were randomized, and the postures were tested according to a preplanned sequence. SETTING: The experiments were carried out in the laboratory of a rehabilitation engineering centre in Hong Kong. PARTICIPANTS: Six paraplegic subjects (referred sample) and 8 normal volunteers were tested. At the time of study, no subjects showed any signs of pressure sore or other health problems. MAIN OUTCOME MEASURES: It was hypothesized that sitting posture could significantly affect pelvic orientation as well as pressure distribution. It was also hypothesized that cushion selection was a critical factor in compensating the adverse effects of postures on pressure distribution. RESULTS: With the paraplegic group, the maximum ischial pressure recorded on Roho for various postures ranged from 88 mmHg for the Trunk-Bent-Forward (PF) posture to 146 mmHg for the Trunk-Bent-Right (PR) posture, whereas on PU foam cushions, the values ranged from 106 mmHg for the PF posture to 221 mmHg for the PR posture. With the paraplegic subjects sitting with their trunks bent laterally, it was found that the mean pressure difference between the left and right ischial tuberosities was more prominent on the PU foam cushion than on the Roho. CONCLUSION: Sitting posture can significantly affect pelvic orientation and ischial pressure. This study was also showed that the Roho cushion was significantly more efficient in compensating the adverse effects of sitting posture on pressure distribution.

Biomechanical Phenomena↗
PubMed1995

Evaluation of an active seating system for pressure relief.

In the first part of this study, the inflation-pressure and interface-pressure profiles of an active cushion system, the Talley active air bellows cushion, were examined continuously for one complete working cycle using the dynamic pressure monitor. The relationship between the inflation pressure and the interface pressure was explored. A well-defined relationship was found in the areas directly over the air bellows. In the second part of this study, the pressure-relieving characteristics of the active cushion were assessed quantitatively and compared to two types of passive cushions--the Roho high-profile air floatation cushion and the polyurethane (PU) foam cushion. Eight non-disabled subjects were positioned on the active cushion at two inflation-pressure levels--30 mmHg and 60 mmHg, or on the Roho or the PU foam cushions. Interface pressures were recorded using the Oxford pressure monitor. For the active cushion it was shown that the higher the inflation pressure was, the better the pressure-relieving characteristics seemed to be. In general, the pressure-relieving characteristics of the active cushion were not as good as those of the passive cushions being tested. The active cushion could alter the pressures over the ischial tuberosities cyclically but the amount of pressure alternation depended on the relative position of the ischial tuberosities and the air bellows.

Adult↗