No abstract

Vibration frequencies of ulnae in 19 children aged between 10 and 15 years old were correlated with their bone mineral densities (BMDs) determined using dual energy x-ray absorptiometry. A correlation analysis method to identify the best frequency range for the vibration analysis was developed. The correlation of subjects' bone vibration frequencies in the identified frequency range with their BMDs were 0.71 (for first order polynomial) and 0.81 (for second order polynomial). This is an initial study, based on a small group of subjects. We are currently continuing the work on a larger number of subjects to confirm the findings.

The purpose of this study was to use frequency spectrum analysis to determine the effects of skin and muscle on the bone's low frequency vibration signals recorded from vibration sensors placed on the skin. A setup was developed that allowed low frequency vibration signals to be recorded. Tests were performed on a sample of 8 turkey legs in vitro, using four vibration sensors placed on the skin, muscle (i.e. leg with the skin removed) and bone (i.e. leg with skin and muscle removed). It was found that bone's vibration signals could be recorded from sensors placed on the skin, but there were changes in their magnitudes and vibration frequencies. There was also a direct relationship between the main frequency of bone's vibration and its mass/volume ratio. This is a preliminary study. The ultimate aim of this study (to be achieved in further work) is to predict fracture risk and target therapy appropriately.

No abstract

Osteoporosis is a systemic disease, characterised by low bone mineral density (BM D) with a consequent increase in bone fragility. The most commonly used method to examine BM D is dual energy X-ray absorptiometry (DXA). However DXA cannot be used reliably in children less than 5 years old because of the limitations in the availability of required normative data. Vibration analysis is a well-established technique for analysing physical properties of materials and so it has the potential for assessing BM D. The overall purpose of this study was development and evaluation of low frequency vibration analysis as a tool to assess BM D in children. A novel portable computer-controlled system that suitably vibrated the bone, acquired, stored, displayed and analysed the resulting bone vibration responses was developed and its performance was investigated by comparing it with DXA-derived BM D values in children. 41 children aged between 7 and 15 years suspected of having abnormal BM D were enrolled. The ulna was chosen for all tests due to the ease with which it could be vibrated and responses measured. Frequency spectra of bone vibration responses were obtained using both impulse and continuous methods and these plus the participants' clinical data were processed by a multilayer perceptron (M LP) artificial neural network. The correlation coefficient values between M LP outputs and DXA-derived BM D values were 0.79 and 0.86 for impulse and continuous vibration methods respectively. It was demonstrated that vibration analysis has potential for assessing fracture risk.