LAUSR

BACKGROUND Sensory feedback between a device and its user helps to improve the effectiveness of control and training processes. These improvements involve corrective actions and the accumulation of experience to accelerate patient training in device control. OBJECTIVES Vibrations from rehabilitation devices are used as sensory feedback signals for improving rehabilitation outcomes. STUDY DESIGN Variations in the bone-anchored prosthesis frequency responses and vibration transmissibility under compressive loading were studied. METHODS Five laboratory samples consisting of the above-knee prosthesis, custom-made implant, and cadaver bone were first axially compressed using universal testing machine; preloaded construction vibrations were generated with a shaker to imitate external forces acting on these samples. The oscillations at the sample surface control points were tested with a laser vibrometer. For different values of axial loading, the frequency responses of the samples and indexes of vibration attenuation were obtained to examine the correlations between vibration transmissibility in the samples and axial loads. RESULTS Increase in axial loading caused an increase in the resonance frequency and a simultaneous decrease in vibratory displacement within the sample. At low frequencies (40-80 Hz), increasing the axial load degraded transmissibility; at medium and high frequencies, transmissibility changes were unstable on increasing the axial load. CONCLUSIONS The osseoperception phenomenon is because of perceived prosthesis vibration analysis by the user. Vibration transmissibility of a prosthesis sample depends on the axial compression and frequency of excitation. Decreasing the vibration amplitude while increasing axial load is the primary reason for reduced perception of vibration.