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Objective To explore the microscopic effects of low-intensity pulsed ultrasound(LIPUS)on bone lacunar-canalicular system(LCS).Methods Three consecutive bone cells from the real bone tissue were selected and used to build a LCS model with SolidWorks software,then the LCS model was imported into finite element analysis software COMSOL.LIPUS irradiation was performed on the top of the LCS model to analyze the distribution of the acoustic and thermal fields of the model under different conditions.Results After ultrasonic irradiation of the LCS model,the farther away from the ultrasonic incidence surface,the lower the acoustic field sound pressure was,and the distribution of the sound pressure inside the model had left-right symmetry;the acoustic field sound pressure inside the LCS model increased with the enhancement of the excitation sound pressure;the closer to the ultrasound focusing region,the denser the temperature contours.Conclusion The distribution laws of acoustic and thermal fields within the LCS are revealed from a microscopic point of view,and theoretical references are provided for LIPUS experiments and treatment.[Chinese Medical Equipment Journal,2023,44(11):27-33]
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Objective To investigate the effects of different intensity of wide band noise on acoustic stapedius reflex amplitude in sound field. Methods Acoustical reflex amplitude(at ART+10 dB)were obtained at three fre-quencies (1,2, 4 kHz) from 80 normally hearing subjects with wide band noise at 30,40,50 and 60 dB SL in sound field. Results Acoustical reflex amplitude was significantly decreased in the presence of wide band noise (P 0. 01). The most significant decrease of acoustic reflex amplitude could be observed in the present of 40 dB SL wide band noise. In comparison with the 1 kHz group, significant decrease was found in 2 kHz group and 4 kHz group(P <0. 01),but there was no difference between the 2 kHz group and 4 kHz group(P>0.05). Conclusion Since the decrease of the acoustic stapedius reflex amplitude is mediated by the auditory efferent system in sound field, in clini-cal practice the function of the auditory efferents can be evaluated by testing the change of acoustic stapedius reflex amplitude with the stimulation of the wide band noise in sound field.
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Objective To investigate the different characters between conventional frequency audiometry (125 Hz～8 kKHz) and high frequency audiometry (9～16 kHz)in the normal youth and provide the references for the clinical application of the HFA.Methods 52 male and 48 female normal-hearing subjects were tested with both conventional-frequency (0.25～8 kHz) and high-frequency (10～18 kHz) audiometry.Results Data showed that no difference between male and female in different frequencies. However, the threshold of HFA went up gradually with the frequency increasing. The average threshold of HFA was significantly higher than that of CFA and speech frequency (SFA) and had a positive correlation with both CFA and SFA. Conclusion The results of this study suggest that HFA might be used as an early indicator for CFA and SFA hearing loss resulting from acoustic trauma, ototoxicity and presbycusis.
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Objective To examine adult speech recognition for words presented in different background noise when the adults used 4-band tri-microphone and traditional tri-microphone hearing aid technology,and to examine the ability of sound location when using wireless remote control.Methods A total 40(female 29,male 11) subjects with moderate to severe bilateral sensorineural hearing loss were encountered in this test,and were divided into two groups(group A and group B).With binaural fitting ACURIS P(frequency specific tri-microphone adaptive mode) and Triano 3 P(Tri-microphone adaptive mode),the patients were tested with speech recognition in two sound field through PB test and the accurateness of sound localization were investigated through questionnaire.Results Significant differences were found between the mean L50(the S/N at which 50% of running speech is correctly understood) obtained from group A versus group B in Tri-microphone adaptive directional condition in multiple sound fields(P