Pure-tone Auditory Thresholds Research Articles

Auditory steady-state responses to multiple simultaneous stimuli in children with functional or sensorineural hearing loss

The goal of our study was to identify the role of auditory steady-state responses for hearing assessment in patients with functional hearing loss. The study design was to compare auditory steady-state response thresholds and standard pure-tone audiometry thresholds between patients with functional or sensorineural hearing loss. Subjects comprised 16 patients (24 ears) with functional hearing loss and 17 patients (24 ears) with sensorineural hearing loss. Differences and correlations between auditory steady-state response thresholds and standard pure-tone audiometry thresholds at 500, 1,000, 2,000 and 4,000 Hz were evaluated. In children with functional hearing loss, pure-tone audiometry thresholds and auditory steady-state response thresholds were significantly different at all frequencies and were not significantly correlated. In patients with sensorineural hearing loss, pure-tone audiometry thresholds and auditory steady-state response thresholds did not differ significantly at any frequencies and were significantly correlated. Auditory steady-state responses may have principal role in the assessment of auditory brainstem acuity, particularly at low frequencies in patients with functional hearing loss.

Neurotomie vestibulaire vs. labyrinthectomie chimique dans la maladie de Menière invalidante

To evaluate the efficiency on the vertigos and the impact on the audition of the vestibular neurotomy (VN) and the chemical labyrinthectomy (CL) in patients with severe Menière's disease, in order to determine the precise place for each technique in treatment algorithm. Retrospective study of 71 VN (performed between 1986 and 2003) and 35 CL (performed between 1997 and 2003). These two treatments both aim at obtaining a vestibular deafferentation in order to free definitely the patient of vertigo manifestations. Vestibular results have been assessed by caloric tests performed before and 6 months after treatment. Subjective success was evaluated by searching for recurrent attacks of vertigo and by the AAO-HNS (American Academy of Otolaryngology-Head and Neck Society) scale of subjective evaluation of vertigos (follow-up of 6.4 years after VN and 2.4 years after CL). Pure tone audiometry before treatment and then 6 months later was performed. Complications of two types of treatment were recorded and evaluated. In 90% of the cases after VN and 86% of the cases after CL, caloric tests indicated a strong vestibular hyporeflexy (hypovalence > 90%). Attacks of vertigo reoccurred in 5.6% of the cases when the hyporeflexy was strong and 85.7% of the cases when it was weak. The quality of the vestibular results on vertigo depends on the degree of hypovalence after treatment. An improvement of the AAO-HNS scale have been obtained in 93% of the cases in the NV group and in 81% of the cases in the LC group. Attacks of vertigo were recurrent in 7% of the patients operated on by VN and 11.4% of the patients treated by CL. Mean pure tone auditory thresholds changed from 50.24 dB HL to 55.64 dB HL (p=0.003) in the VN group and from 69.11 dB HL to 74.51 dB HL (p=0.41) in the CL group. Comparison of the variations of the mean pure tone auditory thresholds before treatment and 6 months after the end of the treatment doesn't show any significant difference between the 2 groups (p > 0.05). Impairment of the audition superior to 20 dB HL was observed in 8.5% of the patients of each group. The auditive results are similar in the 2 groups. These two methods of treatment can not be strictly compared due to several bias in this study. Indeed more patients were treated by VN with a longer follow-up and only the patients with a class C or D audition according to the criteria of the AAO-HNS could be treated by CL. The VN provides a better control of the vertigos than the CL which is an efficient method of treatment in invalidating Meniere's disease. In all the cases, the quality of the results on vertigos depends on the degree of hypovalence after treatment. The auditive results are similar. Since the results of the two treatments are similar, the simplicity of CL encourages us to broaden the indications and to modify the place of the VN in the therapeutic algorithm of Menière's disease.

The mechanism of hearing loss in Paget's disease of bone.

Objectives/HypothesisThe mechanism of hearing loss (HL) in Paget's disease of bone was investigated. The present study was a systematic, prospective, controlled set of clinical investigations to test the hypothesis that there is a general underlying mechanism of HL in Paget's disease of bone and to gain additional insights into the auditory and otologic dynamics of this disease. Specific questions were 1) whether the mechanism is cochlear or retrocochlear and 2) whether the bone mineral density of the cochlear capsule is related to hearing levels.Study DesignSeveral double-blinded, cross-sectional, prospective, correlational studies were conducted in a population of elderly human subjects with skull involvement with Paget's disease versus a control population of elderly subjects free of Paget's disease. Demographic and clinical data were recorded. Longitudinal observations were made in subjects under treatment.MethodsSubjects were recruited from a Paget's disease clinic. Pure-tone auditory thresholds, word recognition, and auditory brainstem responses (ABRs) were recorded. The dimensions of the internal auditory canals were measured using computed tomographic (CT) images and digital image analysis. The precision, accuracy, and temporal stability of methods to measure the bone mineral density of the cochlear capsule and an adjacent area of nonotic capsule bone were validated and applied. Correlations were sought between hearing levels and cochlear capsule bone mineral density.ResultsABRs were recorded in 64 ears with radiographically confirmed Paget's disease involving the skull. Responses were absent in eight ears, all of which had elevated high pure-tone thresholds. ABRs were interpreted as normal in 56 ears; none were abnormal. The mid-length diameter and minimum diameter of the internal auditory canal of 68 temporal bones from subjects with Paget's disease were found to have no statistically significant relationship to hearing thresholds. The Pearson product-moment correlation coefficients (age- and sex-adjusted) in the group with Paget's disease involving the temporal bone were −0.63 for left ears and −0.73 for right ears for high-frequency air conduction pure-tone thresholds (mean of 1, 2, and 4 kHz) versus cochlear capsule density. Correlation coefficients (age- and sex-adjusted) between cochlear capsule density and air-bone gap (mean at 0.5 and 1 kHz) for the affected group were −0.67 for left ears and −0.63 for right ears. All correlations between hearing thresholds and cochlear capsule density in pagetic subjects were significant at P < .001. The regressions were consistent throughout the ranges of hearing level. There were no significant correlations between cochlear capsule mean density and hearing level in the volunteer subjects.ConclusionsThe evidence supports the existence of a general, underlying, cochlear mechanism of pagetic HL that is closely related to loss of bone mineral density in the cochlear capsule. This mechanism accounts well for both the high-frequency sensorineural HL and the air-bone gap. Early identification, radiographic diagnosis of temporal bone involvement, and vigorous treatment with third-generation bisphosponates are important to limit the development and progression of pagetic HL.

Delayed loss of residual hearing in Clarion cochlear implant users.

Hearing threshold has been measured in a group of patients following cochlear implantation with a Clarion device for the last eight years. The patients had received either a pre-curved carrier or the Hi-Focus I plus Electrode Positioner System (EPS). The assessment was carried out within the first post-operative week as well as at a later stage, between six and 87 months, post-operatively. Residual hearing thresholds were still measurable early after surgery in 24.5 per cent of the patients, without differences between the two different Clarion models. However, the number of subjects with measurable hearing dropped to 16.3 per cent as observed when hearing was measured at a later stage, with an equal distribution between the two groups of patients. From this study it has been possible to observe that only a limited number of patients maintain residual hearing after Clarion cochlear implantation, and that this tends to decrease further over time. Nevertheless, the performance of these patients for speech tests did not appear to be affected by deterioration of the pure-tone auditory threshold.

Hearing screening.

Hearing screening.

Auditory function in young patients with type 1 diabetes mellitus

Comprehension of the effect of diabetes mellitus on auditory function has been hindered by the fact that previous studies have evaluated hearing function in heterogeneous groups of patients with diabetes mellitus, thus giving conflicting results. We have performed audiometric studies in 46 consecutive patients, 13 with newly diagnosed type 1 diabetes mellitus (group 1) and 33 with type 1 diabetes mellitus of more than 3 years of duration (group 2), of 14 to 40 years of age. The results were compared to an age-matched control group. Pure-tone auditory thresholds were significantly higher in all frequencies 250–8000 Hz in both groups when compared to the control subjects. Ten patients, all of which belonged to group 2, had auditory thresholds above 30 dB in at least one frequency, showing a conversational hearing loss that ranged between 11 and 44%. However, none of them referred subjective hypoacusia. Univariate analysis revealed significant associations between auditory thresholds and age, duration of disease as well as retinopathy, but not with neuropathy, HbA 1c or hypoglycaemic episodes. Only age and duration of disease independently correlated with an auditory threshold using multiple regression. We conclude that type 1 diabetes mellitus can cause mild sensorineural hearing impairment which correlates with age and duration of disease.

Hearing disability and communication handicap for compensation purposes based on self-assessment and audiometric testing.

It is reasoned that for compensation or epidemiological studies an evaluation of hearing disability and the concomitant handicap must include the ability to perceive visual cues. A scaling procedure for hearing- and audiovisual communication handicap is presented. The procedure deviates in two ways from previous handicap assessments: (1) It is based on individual self-assessment of semantic speech perception but can be implemented by means of professional audiological test procedures. (2) The system does not make use of pure-tone auditory thresholds as a predominant audiological principle, but is based on speech perception. The interrelationship between auditory and audiovisual handicap is evaluated. A total score including audio- and audiovisual perception handicap is proposed and a suggestion for disability percentages is presented.

A comparison of pure tone auditory thresholds in human infants and adults

Pure tone auditory thresholds for frequencies from .250 to 8.0 kHz were obtained from 277-to-11-month-old human infants and nine adults using a go-no-go operant head-turning technique combined with an adaptive staircase (tracking) discrimination procedure. New methods were devised for maintaining infants under stimulus control during threshold testing through the use of randomly interleaved "probe" and "catch" trials. Reliable threshold data were obtained from every infant studied, and identical threshold criteria were applied to infants and adults alike. Although infant thresholds were 17-27 dB higher than those of adults, infant inter-subject variability was no greater than that of adults. Adult audiograms were nearly flat between frequencies of .500 and 8.0 kHz with sensitivity ranging between 7 and 14 dB SPL. Infant audiograms were flat between frequencies of .500 and 4.0 kHz, with sensitivity ranging between 30 and 36 dB SPL. The most sensitive frequency for infants was 8.0 kHz (25 dB SPL).

On objective criteria for hearing impairment and hearing disability.

The relationship between subjective symptoms of hearing disorder and objective criteria of hearing impairment and hearing disability was examined in a group of 77 male subjects (median age 57 years, range 49-68) suffering from noise-induced permanent hearing loss. Among all subjects, 52% (40/77) reported having a general impression of subjective hearing disability. The average of pure-tone auditory thresholds at 0.5 + 1 + 2 + 3 + 4 kHz greater than or equal to 20 dB HL used as an objective criterion for hearing impairment and hearing disability appeared to be the more sensitive and reliable of the various criteria used. Based on the definition of hearing handicap, it is suggested that more sophisticated testing than pure-tone auditory thresholds should be taken into account when approving or disapproving hearing disability as a hearing handicap.

Clinical Application of Auditory Evoked Brain Stem Responses elicited by Bone-Conducted Stimuli

Auditory evoked brain stem responses elicited by air and bone-conducted sinusoidal one wave stimuli (0.5, 1, 2 and 4kHz) were studied in patients affecteed by conductive, neurosensory or mixed type hearing disorders. We set 0dBNSL as the mean sensation level of six normal hearing adults. As the maximum bone-conducted stimuli producible be our equipment is 45dBNSL, no responses may by elicited by bone-conducted stimuli when the patient's sensation level is more than 35dBNSL.The A-B gaps obtained by ABR were compared with the ones by pure-tone audiometry.The A-B gaps obtained by these two methods were approximately equal, but in some cases showed some differences varying from-20dB to+20dB.The bone-conducted ABR thresholds were compared with the puretone auditory thresholds for bone conduction. The ABR thresholds elicitied by low frequency stimuli were influenced by hearing level in high frequencies. But the thresholds by both methods were similar in all frequencies (0.5, 1, 2 and 4kHz). As regards frequency specificity, we also found the usefulness of the bone-conducted ABR thresholds in clinical cases.

Brain Stem Response and Cochlear Action Potential in Cases of Post-traumatic Disorders of Head and Neck Injury accompanied with Auditory Disturbance

Relation of pure tone auditory threshold to BSR and AP threshold was studied in 72 cases of head and neck injury with auditory disturbance.A difinite corelation was found between pure tone hearing threshold and BSR threshold in most of patients of head and neck injury.Amplitude of BSR delivered from the side of the patient's head received craniotomy decreased in 4 cases of 7 cases.There were significant differences on the amplitude of BSR waves and the appearance of the Ist to V th waves between the right and left ear.Topographic recording of BSR was attempted in the cases of central nervous disorder. BSR was topographically delivered from 10-16 points on the scalp according to the international 10-20 electrodes system. On the topographic recording of the BSR, there was a clear difference on the ampulitude of IV-V waves of BSR between cases of central nervous disorder and normal hearing adults. Measurement of BSR and AP on the posttraumatic syndrome will provide a worthwhile information for the diagnosis of hearing disturbance and central nervous disorder.

Serial auditory thresholds in relation to noise and other factors

Six‐monthly serial data from 224 children aged 4–18 years include puretone auditory thresholds, noise exposure, otological histories, and data relating to body size and maturity. Otological abnormalities in these “normal” children may be associated with higher auditory thresholds. Also auditory thresholds are related negatively to stature and levels of sexual and skeletal maturity. The girls have slightly lower thresholds than the boys; this sex difference is larger in the older children and the median total noise exposure scores are considerably higher for boys than girls in the older groups indicating noise exposure may adversely affect hearing ability. Furthermore, in the older groups, especially boys, the six‐monthly increments are larger, in the direction of hearing loss. The noise exposure data indicate specific important sources of noise. [Work supported by U.S. Environmental Protection Agency and the Aerospace Medical Research Laboratory.]

Pure-tone auditory behavioral thresholds in three species of lemurs.

Absolute thresholds were determined for pure tones of frequencies 100 Hz–40 kHz by the method of constant stimuli using a two-bar operant technique. Lemurs of three subspecies were trained to press a white bar to turn on a tone lasting 5 sec. During the tone, a single press on a second (black) bar resulted in food reward. Failure to respond simply terminated the trial. Response in the absence of tone was scored as a false positive response and resulted in a 12-sec shock of from 0.6 to 1.3 mA. Thresholds, based on a response probability of 0.5, indicate a lesser sensitivity in the low and middle frequencies than found in the anthropoid primates, but an apparent extension of sensitivity into the higher frequencies beyond the upper-frequency cutoff points found for the anthropoids.

Sensorineural hearing loss and upward spread of masking.

Pure-tone auditory thresholds were obtained in quiet and in three levels of masking noise for one normal-hearing group and five groups of subjects with different degrees of sensorineural loss. The masker was a low-pass noise, cut off at 250 Hz. It was presented at overall levels of 77, 97, and 107 dB SPL. Pure-tone thresholds were obtained at test frequencies within and above the masking band. A measure of noise rejection slope was used to describe spread of masking. Degree of loss, configuration of loss, and level of masking noise appear to have marked influences on upward spread of masking patterns in sensorineural subjects.