The change of mechanical properties by joint immobilization was examined in a rat's knee joint model. The operated joint and the opposite side which served as a control, were kept for a period of up to 7 weeks. Immobilization-induced changes were assessed in view of the soft tissue aspect of the joint and of the osteo-cartilagenous aspect of the dissected femur and tibia.
After recording the contractured flexion angle, the degree of joint contracture was measured biomechanically using viscoelastic parameters. The indentation method revealed changes at the upper and lower end of the femur, and at the subchondral bone of the proximal tibia. Bone mineral density was also examined by dual energy X-ray absorptiometry at the metaphyseal portion of the lower femur.
The results showed an early change of osteo-cartilagenous properties and bone mineral density in periods of 2-3 weeks. Soft tissue analysis with vibration frequency indicated the quantitative course of joint contracture. Disuse or lack of mechanical stress affects cellular remodeling for homeostasis of synovial joints.

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P300 is one of event-related potential which is closely related with cognitive function. P300, occurring when a subject attends a target stimulus intermingled with more frequently presented nontarget stimuli, has been used to diagnose a mental disturbance like dementia. In this study, we designed P300 Biofeedback Therapy (P3BF), using auditory oddball paradigm as cognitive rehabilitation. Patient, who sat 1m in front of an evoked potential machine, had to watch a P300 waveform on a screen of evoked potential machine. If there was a poorly developed P300 waveform, he was explained before and during training that it indicated that his attention was not enough and he should pay more attention to the tones. Five patients (2cases in head injury, 1 case in cerebral hemorrhage, 1 case in temporal lobectomy, 1 ease in bacterial encephalitis) who showed chronic mental disturbance received a four-week period of P3BF at least after 4 months of disease onset in addition to a full-time inpatient rehabilitation program. P3BF lasted 30 minutes 3 times per week. They gave a helpful co-operation to this training.
These five patients showed remarkable improvement of WAIS and WMS, compared with a comparison period of 4 weeks of a full-time inpatient rehabilitation program without P3BF.
These findings indicated that P3BF is a useful cognitive rehabilitation, and furthermore, it can be called one of remediation of attentional deficit from the characteristics of P300.

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