The purpose of the present study was to examine speech intelligibility of a profound impaired person in the general public. The hearing task of the speech intelligibility consisted of 50 monosyllables (57-S) in Japanese. Speech samples were recorded by the digital audio tape recorder (SONY TCD-10). 50 monosyllables of a profound impaired person were judged by 316 normal listeners. The following findings were observed.The mean speech intelligibility obtained for this hearing task presented by 50 monosyllables were 24.3%, corresponding closely with results of previous studies. Fricative sounds /ha/, /ho/ and /hu/ showed high percentages of speech intelligibility. Monosyllables of /su, ku, yo, tsu, ro ne/ showed a large number of phonetic confusion. It was suggested that training toward improvement of the hearing impaired person should enable listeners in the general public to examine speech intelligibility.
We measured the pure tone audiogram and distortion product otoacoustic emissions of a patient with hearing loss after administration of streptomycin. A 33-year-old male received streptomycin for lung Tbc as an inpatient. Two months after administration of streptomycin, the patient complained of bilateral tinnitis and progressive high tone sensorineural hearing loss. We found that the DP level had declined, and the appearance of tinnitis and changes in the pure tone audiogram preceded the decline of DP level. We report a case of streptomycin-induced hearing loss and monitoring by otoacoustic emissions for early detection of drug-induced hearing loss.
The hearing loss and otoacoustic emissions were evaluated among those who practiced kendo. Audiograms, spontaneous otoacoustic emissions (SOAE) and distortion-product otoacoustic emissions (DPOAE) were measured in 130 ears of 65 subjects. The subjects were classified according to age, years of experience, mean hours of practice and age at the beginning of practice to compare and evaluate each result. Abnormalities in audiogram were noted in 15%, with sensorineural-hearing loss with 2kHz-dip and high frequency area. The rate of appearance of auditory disturbance tented to be higher as years of experience and hours of practice increased. The rate of appearance of SOAE tended to be lower in groups with higher age and longer years of experience. In the group with normal auditory function, DP level tended to be lower in groups with longer mean hours of practice than in those with shorter hours at all levels of frequency. In the audiogram, DP levels were compared at each level of stimulation frequency between the 2kHz-dip group and the group with normal auditory function. In the 2kHz-dip group, a significant decrease of the DP level was noted mainly at the frequency of 2.5kHz and in near by frequency ranges.
In order to compare the relationship between evoked and distortion product otoacoustic emissions, otoacoustic emissions of 63 ears of 32 adults and 41 ears of 23 neonates and infants were measured. Several parameters including spontaneous otoacoustic emissions were studied for comparisons. To compare evoked and distortion product otoacoustic emissions, mid-frequency of around 1.5-2kHz was found to be mostly related and this tendency was more apparent in those who spontaneous otoacoustic emissions was positive. By plotting the X-axis of DP gram with F1 or 2F1-F2 instead of the normal F2, the S/N ratio and DP level was seen to be closely related in every frequency level of evoked otoacoustic emissions.
Some patients with acute sensorineural hearing loss are anti-mumps IgM antibody positive on serological examination, although they do not have clinical symptoms of mumps. They account for 1-7% of patients with acute sensorineural hearing loss. It has been reported that anti-mumps IgM antibody becomes negative about 3 months, 6 months at longest, after mumps infection. A patient had acute progressive hearing loss (The mean hearing threshold of 63.8dB) probably of inner ear origin. Hearing loss was refractory to medical therapy, and it was considered to be caused by latent mumps infection. The anti-mumps IgM autibody titer was 2.30 (positive) on the onset of disease, remained at a high level and 1.60 (positive) 15 months after therapy. An antigen absorption test and globulin fractionation with a sucrose density gradient centrifugation method showed that anti-mumps igM antibody in the patient's serum was mumps-specific. IgG avidity was found to be 7%. A relationship between the onset of acute sensorineural hearing loss and persistent positivity of anti-mumps IgM antibody was suspected. Anti-mumps IgM antibody positive patients with acute sensorineural hearing loss may have persistent mumps infection as cause of hering loss.
Severe unilateral sensorineural hearing loss (SNHL) of unknown etiology, with preserved hearing in the other ear, has previously been reported as juvenile unilateral deafness or unilateral total deafness. However, although cases of mild to moderate unilateral SNHL are rarely described, and most of them are asymptomatic and rarely give rise to functional difficulties, the deficit may be discovered if vertigo or progressive deafness (in either the impaired or the other ear) develop. We examined the records of 211 children (113 males, 98 females) with unilateral SNHL who attended the Ear Nose and Throat Department of Iwate Medical University hospital over a 33-year period between April 1970 to March 2002. These patients, who had no remarkable past medical history, were found to have a mild to moderate hearing loss in the impaired ear, but no hearing deficit on the other side. Among them 55 cases (26.1%) experienced vertigo and/or progressive deafness. The group might have included the several cases with endolymphatic hydrops.