Assuntos
Acústica , Luxação do Quadril/diagnóstico , Articulação do Quadril , Humanos , Recém-Nascido , Triagem NeonatalRESUMO
An acoustical technique has been developed for the measurement of structural symmetry of the hip joints. A mild vibratory force was applied to the sacrum and sound signals were picked up at both hips by a pair of microphones installed in two stethoscopes. These stethoscope-microphone assembles were calibrated to achieve a difference in relative sensitivity of less than 0.2 dB. The relative transmission of sound signals was analysed and compared between both hips by a dual-channel signal analyser. Twenty-seven healthy adults, 20 healthy pre-school children and 19 normal neonates were tested. Results from these three groups showed high coherence of the sound signals and that the discrepancy between both hips was smallest in the frequency range of 200-315 Hz. For normal neonates, the sound signals maintained a high coherence (gamma2>0.97) and small discrepancy (D<1.25 dB) between both hips. This study has shown that the acoustical technique provides a practical structural testing for bony symmetry of the hips and the results offer a baseline for further investigation into developmental dysplasia of the hip (DDH) in neonates. Clinical screening for DDH is still problematic in developing countries.
Assuntos
Estimulação Acústica/instrumentação , Luxação Congênita de Quadril/diagnóstico , Articulação do Quadril/anatomia & histologia , Articulação do Quadril/patologia , Processamento de Sinais Assistido por Computador/instrumentação , Som , Acústica , Adulto , Fatores Etários , Criança , Pré-Escolar , Feminino , Luxação Congênita de Quadril/patologia , Humanos , Recém-Nascido , Masculino , Fenômenos Físicos , FísicaRESUMO
An acoustical technique has been developed for early screening of developmental dysplasia of the hip (DDH) in neonates by comparing the sound transmitted across the hips while a vibratory force was applied to the sacrum. The baseline for 90 normal neonates has been established and tests in the frequency bands of 200, 250, and 315 Hz were found to be most effective, achieving high coherence and smallest discrepancy. Sixteen patients with unilateral DDH were examined and the results suggested that coherence below 0.8 in at least one of these frequency bands was strongly indicative of structural asymmetry between both hips, and there was a significant difference between normal neonates and patients with unilateral DDH. By setting the cut-off discrepancy at 2.0 dB, the best sensitivity (100%) would be achieved, and this could be proposed as the threshold for wide-scale screening of DDH.
