1,721,088 research outputs found
Prediction of auditory brainstem wave V latency as a diagnostic tool of sensorineural hearing loss
No full textThe lesion location (cochlear vs. retrocochlear) of sensorineural hearing loss may be differentiated with a diagnostic index (delta V), which is calculated from the wave V latency of the monaurally evoked auditory brainstem response (ABR), and from the pure-tone hearing threshold at 2 and 4 kHz. The delta V values obtained from 80 recruiting ears have proven to correlate linearly to the amount of the hearing loss, hence allowing to define appropriate confidence boundaries for cochlear hearing losses. In contrast, the delta V values obtained from 32 ears of patients with retrocochlear lesions--cerebellopontine angle (CPA) tumors--were all found to exceed the 95% upper confidence limits projected for cochlear lesions, thus giving a 100% rate of true results in the detection of retrocochlear pathology. These results, providing an ABR parametric model for the cochlear hearing loss, suggest a diagnostic strategy for the early detection of CPA tumors based on the exclusion of a cochlear hearing loss
EFFECTS OF DIFFERENT NOISES ON SPEECH-DISCRIMINATION BY THE ELDERLY
No full textElderly people often complain of difficulty in speech discrimination, especially in noise environments. The effects of 4 competing noises on sentence intelligibility were evaluated: speech noise, cocktail party noise, traffic noise and continuous discourse. A comparison was made between young and old normally hearing subjects and young and old hearing-impaired subjects with similar audiograms. The old people with normal hearing had slightly reduced discrimination compared to the young during competing speech noise and cocktail noise. Discrimination in the hearing-impaired elderly was also significantly worse than in the young people with normals hearing, during competing cocktail party noise, traffic noise and continuous discourse. The young hearing-impaired had results between young normal-hearing subjects and old hearing-impaired, except for continuous discourse. Thus the effects of age on speech discrimination in noise are subtle, becoming more pronounced in the presence of hearing loss. Age-related changes in primary speech discrimination were particularly evident during competing continuous discourse
Hearing loss in sports hunters exposed to occupational noise
No full textThe hearing level of 133 railway workers who also hunted for sport was evaluated and compared with that of 82 non-hunting colleagues. Both groups were affected by hearing loss, mostly involving the high-frequency range. Hunters were found to differ from non-hunters by having significantly worse hearing threshold in the ear contralateral to the shoulder supporting the firearm. The interaural threshold difference at 4 kHz was related to the number of rounds fired and exposure duration, thus providing an estimate of the adverse effect of gunfire noise to which the hunters had been exposed
Effect of masking on the auditive potentials of the brainstem and on the action potential of the VIII nerve in man
No full textDoes general anaesthesia affect the child's auditory middle latency response (MLR)?
No full textAuditory MLR and ABR were recorded simultaneously in 9 children under general anaesthesia, after electrocochleography had demonstrated a normal hearing threshold. In contrast to the ABR components which in all cases appeared to be clearly recognizable, and with latencies within the normal range, MLR revealed gross abnormalities represented by instability of the components and abnormal latency of the detectable peaks. Since such variations in the MLR pattern may be thought of as a direct consequence of general anaesthesia, it seems likely that these potentials reflect a neural activity which, in children, is affected by CNS drugs
Auditory evoked potentials of the brain stem and neurosensory hyapacusis: relationship between wave V latency and stapes reflex
No full textPotenziali uditivi evocati del tronco in bambini normoudenti con turbe del linguaggio
No full textThe auditory brainstem responses (ABR) of 57 normally hearing children (age 1-6) suffering from a retarded language development were evaluated. Thirtytwo out of 57 children were suffering from previous diagnosed pathologies (CNS lesions, perinatal, congenital syndrom), 27 had a psychomotor retard. ABR was evaluated in terms of inter-peack I-V latency and V/I amplitude ratio. While the amplitude parameters were normal, 40% of cases showed I-V intervals exceeding the normal boundaries. These findings did not correlate either to pathology nor to psychomotor retard. The I-V intervals showed a bimodal distribution troughout the four age subgroups the children population had been subdivided, with a first peack corresponding to the normal mode, and a second one above the normal limit. This latter approximated the normal range of I-V interval in the age subgroup above 4 years. Assuming the I-V intervals changes as index of the maturation processs in the brainstem auditory pathway, our results seem to indicate that the retarded language development may be frequently associated to a delay in CNS maturation
The behaviour of wave V latency in cochlear hearing loss
No full textThe audiological approach to the early diagnosis of cerebellopontine angle tumours (APC) is based mainly on ABR. In present work, wave V latency has been studied in two groups of patients: 308 cochlear cases and 74 retrocochlear cases (APC surgically confirmed tumours), in order to increase the sensitivity and specificity of the diagnostic indexes I-V, IT5 and Delta V. Wave V latencies have been evaluated in relation to hearing loss at 2-4 kHz and audiometric profile. Both these factors show a highly significant positive correlation with the latency, which consequently increases proportionally to hearing loss and high-frequency audiometric loss. A multiple regression analysis was therefore used to analyse the effects from the two variables, and a correction factor was calculated to compensate the latency values for hearing loss and threshold configuration. The effects of such a correction on the clinical results consist mainly of a reduction in the rate of cochlear false-negative results, which corresponds to improving the ABR specificity
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