Standard Pure Tone Audiometry Research Articles

Progressive auditory neuropathy in patients with Leber’s hereditary optic neuropathy

Objective: To investigate auditory neural involvement in patients with Leber’s hereditary optic neuropathy (LHON). Methods: Auditory assessment was undertaken in two patients with LHON. One was a 45 year old...

Tympanometric findings in patients with enlarged vestibular aqueducts.

The purpose of this study was to study systematically some relationships between the resonance frequency of the middle-ear transmission system and the volume of the endolymphatic duct and sac in patients with an enlarged vestibular aqueduct (EVA). Prospective study. Thirteen patients (24 ears) with EVA, 17 subjects (29 ears) with normal hearing, and 17 patients (21 ears) with sensorineural hearing loss without EVA served as experimental subjects. Standard pure-tone audiometry, standard clinical tympanometry (using a 226-Hz probe tone), and multifrequency tympanometry were performed on each ear. Magnetic resonance imaging was used to determine the area of the cochlear modiolus and the volume of the endolymphatic duct and sac. The audiometric configurations for most patients sloped downward from the low to the high frequencies. A significant air-bone gap was computed at each of these test frequencies. Multifrequency tympanometry yielded resonance frequencies for the patients with EVA that was significantly lower than those measured for the control subjects. In general, for patients with EVA, the resonance frequency of the middle ear system decreased as the volume of the endolymphatic duct and sac increased. This inverse relation was significant (correlation coefficient = -0.483, P =.0157). However, there was no correlation between resonance frequency and the degree of cochlea modiolar deficiency. Clinically, our findings suggest that EVA probably should be included in the differential diagnosis for a patient who presents with a moderate to severe mixed hearing loss, a normal tympanogram at 226 Hz, and a resonance frequency that is abnormally low.

Auditory Dysfunction in Stroke

The auditory and vestibular systems share the same end organ and cranial nerve, yet vestibular signs and symptoms are common with stroke, whereas hearing disturbances are much less frequent. Several reasons would appear to account for this striking dissimilarity. One is that the auditory pathway is less ubiquitous than the vestibular pathways. The likelihood that a stroke involves the auditory pathway is, therefore, less on this basis alone. A second difference, to our knowledge not previously reported, is that the auditory pathway is often spared by the most common strokes. This is because major parts of the auditory pathway, such as the cochlear nucleus, inferior colliculus and medial geniculate body, have multiple sources of blood supply. A third well-recognized factor is the redundancy of the central auditory system and its strong bilateral representation above the level of the cochlear nuclei. Consequently, rostral to the cochlear nuclei gross deficits in hearing, such as those measured by standard pure-tone audiometry and speech discrimination, only occur if lesions are bilateral. Furthermore, widespread bilateral lesions of the auditory system typically render the patient unable to respond or are incompatible with life. In contrast, language disorders are more frequent because language is usually unilaterally represented in the cortex. Certainly, cerebral stroke often includes the auditory system, resulting in various types of auditory disorders, but most hemispherical lesions produce subtle hearing dysfunctions that can only be detected with sophisticated psychoacoustic and electrophysiological testing. The purpose of this review is to provide an overview of the auditory system and its blood supply and to review how auditory processing can be affected by stroke. Psychoacoustic and electrophysiological test procedures for identifying lesions in the central auditory system are described. The literature of hearing disorders due to stroke is reviewed and illustrative cases are presented.

Reliability of 80-Hz Amplitude- Modulation-Following Response Detected by Phase Coherence

The reliability and frequency specificity of the 80-Hz amplitude-modulation-following response (80-Hz AMFR) during sleep detected by phase coherence as a measure of the hearing threshold was evaluated in 169 affected ears of 125 children with hearing impairment. The 80-Hz AMFR at a carrier frequency of 1000 Hz was monitored in all 169 ears and the auditory brainstem response (ABR) elicited by 1000-Hz tone pips was evaluated in 93 ears. Both responses were examined during sleep, and the thresholds were compared with the behavioral hearing threshold, which was determined by standard pure-tone audiometry or play audiometry. In 24 ears of 22 children with various patterns of audiogram, the 80-Hz AMFR was examined at different carrier frequencies, and the threshold pattern was compared with the pure-tone audiogram to investigate the frequency specificity of 80-Hz AMFR. The mean and standard deviation of the difference between the 80-Hz AMFR at a carrier frequency of 1000 Hz and pure-tone thresholds of 1000 Hz was 3.8 and 12.9 dB, and that between the ABR and pure-tone thresholds was 6.8 and 14.1 dB, respectively. The threshold patterns of 80-Hz AMFR clearly followed the corresponding audiogram patterns in all types of hearing impairment. The measurement of 80-Hz AMFR thus appears to be accurate in hearing assessment and to have good frequency specificity in children during sleep.

Noise induced temporary otoacoustic emission shifts.

Otoacoustic emissions are considered to reflect the outer hair cell activity of the cochlea, which in turn is recognised as the site most affected by noise exposure. The purpose of this study was to assess temporary cochlear alterations following brief noise exposure. Twenty young male subjects were exposed to 10 minutes of white noise at 90 dB SL. Standard pure tone audiometry, along with click and distortion product otoacoustic emissions (CEOAEs and DPOAEs), were measured before and after the noise exposure. Auditory pure tone threshold shifts of the order of 15 dB were accompanied by temporary CEOAE shifts of the order of 3 dB. DPOAE thresholds were elevated by approximately 5 dB. A positive, significant, and relatively strong correlation was obtained between the CEOAE shifts and the pure tone temporary threshold shifts (TTSs). However, in a number of cases emission shifts were unaccompanied by notable TTSs. Emissions appear to be more sensitive to cochlear changes following noise exposure and therefore more appropriate for screening and monitoring ears at risk of noise induced hearing loss (NIHL). The objectivity of the measurements and the short test time required further enhance their usefulness as a cochlear measure.

Evaluation of the hearing loss associated with cis-platinum treatment by high-frequency audiometry

The effect of cis-platinum treatment on the hearing of 23 ovarian cancer patients was evaluated using standard and high-frequency audiometry. Twenty-two percent of the patients developed a hearing loss of at least 15 db, 13% in the range 125–8000 Hz and 9% only in the high-frequency area above 8 kHz. However, due to the high-frequency hearing loss (presbyacusis) in older patients high-frequency audiometry was often unobtainable. Hearing screening using standard pure-tone audiometry is recommended for cis-platinum patients as a routine procedure.

学校健診で非器質性難聴を疑われる学童について

The purpose of this paper is to discuss the results of hearing tests on 14 children suspected of nonorganic hearing loss and to advocate some diagnostic procedures to avoid incorrect nonorganic hearing loss.The effective test methods were: (1) play audiometry in 6 cases; (2) re-test of standard pure tone audiometry in 4 cases and (3) random presentation of test sounds in the pure tone audiometry in 1. In 11 out of the 14 cases, nonorganic hearing loss was finally denied by utilizing these tests. It was considered that these 11 children merely could not understand the instructions given them during the previous test. Therefore, prior to ABR test, other hearing tests such as play audiometry, etc., should be given to those children suspected of nonorganic hearing loss to confirm their actual hearing acuity.We stress that the diagnosis of nonorganic hearing loss should be made only after the hearing tests mentioned above were carefully used.

The role of type I allergy in otitis media with effusion

In order to clarify the role of type I allergy in etiology of otitis media with effusion (OME), three groups of children, and control subjects selected at random, from kindergarden and elementary school, were evaluated for their incidence of nasal allergy (NA) or OME. Group A consisted of 244 patients (median age, 6) with OME; Group B, of 512 patients (median age, 9) with NA; and Group C, of 104 control subjects (median age, 6). All subjects were submitted to routine nasal allergy tests (eosinophilia in nasal secretion smears, peripheral blood eosinophilia, skin test, nasal provocation test, serum IgE) and otological tests (impedance audiometry, standard pure tone audiometry). Several patients among the three groups were evaluated for eustachian tube function before, and after, the nasal provocation with histamine, by inflation deflation test, and nine step method.Results showed 109 patients (49%) of Group A suffered from NA; 109 patients (21%) in Group B from OME; whereas in Group C (the Control group), 18 patients (17%) had NA; and 6 patients (6%) had OME. The percentage of patients in Group A suffering from NA (109 patients (49%)) was significantly higher than that in Group C (18 patients (17%)). The percentage of patients in Group B suffering from OME (109 patients (21%)) was significantly higher than that in Group C (6 patients (6%)).It was also found that the incidence of tubal dysfunction was higher in patients with OME associated with NA than in normal subjects.The findings of the present study suggest that NA affects tubal function, (even if the effect is temporary) and NA may be a risk factor in OME proneness in children.

Auditory agnosia due to incision of splenium corporis callosi.

The symptoms in a case of auditory agnosia are described. The patient, a 13-year-old boy, underwent surgical operation for pinealoma, in which the splenium of corpus callosum was incised. After the operation he suffered from auditory agnosia. There were pure word-deafness and musical agnosia. The inner language was intact and the ability to read and write was unimpaired. Standard pure tone audiometry revealed a slight bilateral hearing loss at the low frequencies. With the speech audiogram, the verbal perception was poor in both ears, especially the left. On the other hand, the musical test showed the melody perception was poorer in the right ear. Within 2 months of the episode, the patient recovered from auditory agnosia to normal limits.

STUDIES ON PURE TONE AUDIOMETRY FOR YOUNGER CHILDREN

The present study was undertaken to evaluate the practical application of different audiometric methods for younges children and to determine the reliability of the threshold values obtained by these methods.Subjective test methods of the hearing, i. e. ordinary pure tone audiometry and play audiometry were carried out on 291 children without hearing impairment. It was found that standard pure tone audiometry could be successfully performed on school children down to the age of 6 or 7 years, and play audiometry was preferable for pre-school children down to this age limit.The attainment of successful results is said to be dependent upon the degree of the mental developement and the age level of the subjects. However, in those who showed to have normal hearing, there was no statistically significant correlation between threshold and intelligence as expressed by the quotient system. So far as the age level concerned, threshold values showed a general tendency to fall as the age of the subjects became older.Final threshold determination should be based on at least two audiograms after stabilization and it seems probable that deviation from true hearing acuity may be 10 db for school children and 15db for pre-school children.