ABSTRACT
This study aimed to develop a non-invasive diagnostic technique for the measurement of acoustic transmission in hip joints to reflect the dynamic response of the observed structure. This instrument consists of three sub-systems. An stimulation system applied a vibratory force at the sacrum of the test subject. A transduction system included a pair of identical microphones was installed in the tubes of two stethoscopes, which were placed at the greater trochanters on both sides for picking up the acoustic signals transmitting across the hip joints. The data acquisition and analysis system was a portable frequency analyser with a program of dual channel digital filter for measuring the power of acoustic signals in 1/3-octoscn frequency bands. Twenty-seven normal adults, 20 normal pre-school children and 40 normal neonates were recruited for the testing. Coherence function (CF) of the signal and the discrepancy (D) of bilateral hips were measured during the testing. The results from the three groups showed that there was a high coherence of the signals (CF > 0.9) and a small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, the frequency range (160-315 Hz) was wider in which the acoustic signals maintained a high coherence (CF > 0.94) and a smaller discrepancy (D < 2 dB) were observed between bilateral hips. This study has shown that the development of the acoustical diagnostic technique could provide a practical method with objective parameters. The results obtained in this study can offer a base for further investigation of hip disorders, particularly those related to structural abnormalities of hip joints.
Subject(s)
Adult , Child, Preschool , Female , Humans , Infant, Newborn , Male , Acoustic Stimulation , Hip Joint , Signal Processing, Computer-Assisted , SoundABSTRACT
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-systems. 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 transmitted across the hip joints. The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for measuring the power of acoustical signal in 1/3-octave frequency bands. 27 normal adults, 20 normal pre-school children and 40 normal neonates were randomly 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 small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, there was a wider frequency range of 160-315 Hz in which the acoustical signals maintained a high coherence (CF > 0.93) and a smaller discrepancy (D < 2 dB) was observed. This study showed that the development of the acoustical technique provided a practical method with objective parameters. The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnormalities of the hip.
Subject(s)
Adult , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Acoustic Stimulation , Age Factors , Hip Joint , Sacrum , Signal Processing, Computer-Assisted , SoundABSTRACT
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-systems. 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 transmitted across the hip joints. The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for measuring the power of acoustical signal in 1/3-octave frequency bands. 27 normal adults, 20 normal pre-school children and 40 normal neonates were randomly 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 small discrepancy (D 0.93) and a smaller discrepancy (D < 2 dB) was observed. This study showed that the development of the acoustical technique provided a practical method with objective parameters. The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnormalities of the hip.