ABSTRACT
OBJECTIVE@#To explore the function of outer hair cells and its influencing factors in the workers of occupational exposure to low frequency electric and magnetic fields.@*METHOD@#502 high-strength LF EMFs-exposed workers were taken as the study subjects. The field intensity indicator and noise analyzer were employed for the examination of the electromagnetic energy intensity and noise value at the working sites. Self-administered questionnaires were adopted. Universal hearing screening by distortion product otoacoustic emission (DPOAE) and pure tone audiometry (PTA) were done. 100 workers who had abnormal POAE were taken as the observation group and 100 workers who had normal DPOAE were taken as the control group. The workers need be confirmed with ABR testing when the pure tone threshold of two consecutive frequencies were above 20 dB HL or DPOAE detection in any frequency did not pass. Multiple factor analysis with logistic regression was performed for the risk factors.@*RESULT@#The average electric power density in job locations was 21-38 KV/m, which was higher than national standard (< 5 kv/m). Average noise-level in job locations was 52-65 dBHL, which was within the standard (< 85 dB(A). Questionnaire presented that low frequency electric and magnetic fields might increase the incidence of headache, insomnia and tinnitus in the observed group. The incidence of abnormal DPOAE was higher in the subjects of the observed group (P < 0.01). At 676, 933, 3616, 5 130, 7253 Hz, the DPOAE amplitudes of the observed group workers were significantly lower than the control group. Multivariate analysis showed that the risk factors of abnormal DPOAE included exposure of EMF, length of service, daily exposure time, conservatory measures might be protective factors.@*CONCLUSION@#The changes of DPOAE indicated that the exposure to low frequency electric and magnetic fields had a subtle, discreet and localized impairing effects on outer hair cells. Exposure of low frequency electric and magnetic fields, length of service, daily exposure time might be risk factors, conservatory measures might be protective factors.
Subject(s)
Humans , Male , Auditory Threshold , Case-Control Studies , Electromagnetic Fields , Hair Cells, Vestibular , Pathology , Magnetic Fields , Noise , Occupational Exposure , Surveys and QuestionnairesABSTRACT
OBJECTIVE@#Our purpose was to investigate occupational high-strength very low frequency electric and magnetic fields (VLF EMFs) and assess changes of function of the inner ear.@*METHOD@#The people exposed to high-strength VLF EMFs were divided into three groups: long- term exposure group ( > 5 years), short-term exposure group (< 5 years) and the control group. The field intensity indicator and noise analyzer were employed for the examination of the electromagnetic energy intensity and noise value at the working sites. Self-administered questionnaire was adopted. Universal hearing screening by pure tone audiometry (PTA) and distortion product otoacoustic emission (DPOAE) were done. The subjects who failed the screening tests were confirmed with auditory brainstem response (ABR) test.@*RESULT@#The frequency of the electromagnetic field was 20 kHz, the average electric power density in job locations was 21-38 kV/m, which was higher than national standard (< 5 kV/m). Average noise-level in job locations was 52-65 dBHL, which was within the standard. Questionnaire presented that VLF EMFs might increase the incidence of headache, insomnia and tinnitus in long-term exposure. The incidence of abnormal DPOAE was higher in the subjects of the long-term exposure group than the short-term exposure group and the control group (P < 0.01). At 676, 933, 3616, 5130, 7253 Hz, the DPOAE amplitudes of the long term exposure group workers were significantly lower than the short-term exposure group and the control group. There was no obvious difference of the incidence of abnormal DPOAE between the short-term exposure group and the control group. The result of ABR with those subjects with abnormal DPOAE were no significant abnormalities.@*CONCLUSION@#The average electric power density in job locations was significant worse than health standards. The changes of DPOAE indicated that the exposure to high-strength VLF EMFs had a subtle, discreet and localized impairing effect on outer hair cells. Effective intervention measures should be taken.
Subject(s)
Adult , Humans , Male , Audiometry, Pure-Tone , Auditory Threshold , Electromagnetic Fields , Hair Cells, Auditory , Radiation Effects , Occupational Exposure , Otoacoustic Emissions, Spontaneous , Surveys and QuestionnairesABSTRACT
Objective To explore the role of multi-media teaching in the ENT physician training. Methods 32 further-study professionals were randomly divided into 2 groups. The control group received traditional teaching methods(n = 16), and the experimental group received the multi-media teaching method (n = 16). After the training, all trainees would take the theory test and skill assessment Results The basic theory and clinical skill scores of the experimental group are better than the control group at the end of the training. Conclusion Multi-media teaching method is very suitable for ENT refresher training.
ABSTRACT
Objective To investigate the effect of PBL teaching method in the otomicrosurgery anatomy training.Methods 40 students were randomly divided into 2 groups:the control group received traditional teaching methods(n=20),and the experimental group received the PBL teaching method(n = 20).After the training,all trainees would accept the theory test,while all anatomical specimens of the two groups would receive clinical skills ratings.Results The scores of the basic theory and clinical skills of the experimental group are better than the control group at the end of the training.Conclusion PBL teaching method is very suitable for otomicrosurgery anatomy training and can enable students to achieve better results.