A non- invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints.The instrumentation consisted of three sub- system s. An excitation system employed ...A non- invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints.The instrumentation consisted of three sub- system s. An excitation system employed a vibratory force at the sacrum of the test subjects.A transduction system included a pair of identical microphones installed in the tubes of two stethoscopes,which were placed at the greater trochanters on both sides for picking up the acoustical signals transm it- ted across the hip joints.The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for m easuring the power of acoustical signal in 1/ 3- oc- tave frequency bands.2 7normal adults,2 0 normal pre- school children and 4 0 norm al neonates were random ly selected for testing.Coherence function (CF) and discrepancy(D) was measured during the testing.Results from the three groups showed that there was a high coherence of the signals (CF>0 .9) and a sm all discrepancy(D<3d B) between bilateral hips in the frequency range of2 0 0— 315 Hz.For normal neonates,there was a wider frequency range of16 0 - 315 Hz in which the acoustical signals m aintained a high coherence (CF>0 .93) and a smaller discrepancy (D <2 d B) was observed.This study showed that the development of the acoustical technique pro- vided a practical m ethod with objective parameters.The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnorm ali- ties of the hip.展开更多
文摘A non- invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints.The instrumentation consisted of three sub- system s. An excitation system employed a vibratory force at the sacrum of the test subjects.A transduction system included a pair of identical microphones installed in the tubes of two stethoscopes,which were placed at the greater trochanters on both sides for picking up the acoustical signals transm it- ted across the hip joints.The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for m easuring the power of acoustical signal in 1/ 3- oc- tave frequency bands.2 7normal adults,2 0 normal pre- school children and 4 0 norm al neonates were random ly selected for testing.Coherence function (CF) and discrepancy(D) was measured during the testing.Results from the three groups showed that there was a high coherence of the signals (CF>0 .9) and a sm all discrepancy(D<3d B) between bilateral hips in the frequency range of2 0 0— 315 Hz.For normal neonates,there was a wider frequency range of16 0 - 315 Hz in which the acoustical signals m aintained a high coherence (CF>0 .93) and a smaller discrepancy (D <2 d B) was observed.This study showed that the development of the acoustical technique pro- vided a practical m ethod with objective parameters.The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnorm ali- ties of the hip.
