Audiologic features of hearing loss due to the 1,555 mutation of mitochondrial DNA.

We proved a 1,555 mutation of mitochondrial DNA in one member of each of three families with familial streptomycin hearing loss, and report the pedigrees and audiologic features. DNA was extracted by the standard method. The 1,555 A to G mutation was identified in all three patients and confirmed by direct sequencing of the polymerase chain reaction products by a cycle sequencing method. On audiograms, the hearing loss was sensorineural, bilateral, and symmetric, showing a high-tone loss or a profound loss particularly in the high-tone range, and the "symmetry law" of Langenbeck was applicable. The superimposed audiograms of members of one family did not cross themselves, proving the applicability of the "never-cross principle of audiograms."

Clinical study of audiograms in the initial stage and fixed stage of sudden deafness.

Audiograms in the initial stage and the fixed stage of sudden deafness were analyzed in 79 cases using the following 5 criteria; i) the onset is sudden and time of onset definite, ii) hearing loss at 1 kH is more than 35 dB, iii) the course of hearing recovery is clear, iv) unaffected ear has normal hearing, and v) the first examination and treatment is within 15 days after onset. Consequently, at least in cases receiving treatment within 6-15 days after onset, it was considered that the prognosis of hearing recovery could be established rather than the pattern of hearing loss than by the period of treatment after onset.

Study on self-recording audiogram of sudden deafness.

Self-recording audiograms of sudden deafness in 54 patients were studied for the relationship between type of Jerger's classification, hearing loss at the initial examination, and prognosis of hearing loss. Type I of Jerger's classification was shown in patients with slight to profound hearing loss, whereas Type II + IV was shown more frequently in cases with profound hearing loss. Many patients of Types I and II were among those who recovered completely or markedly, while patients of Type II + IV were found more frequently among those who recovered or had unchanged hearing.

[Clinical views of cases with discontinuity of the ossicular chain].

It is well known that reconstruction for discontinuity of the ossicular chain, without inflammatory disease, has a good prognosis. Eleven cases of congenital ossicular chain malformation without ossicular fixation and 6 cases of ossicular chain injury due to the head trauma or an earpick , were treated surgically. The method of reconstruction and the prognoses, according to short-term and long-term follow up, were studied in these 17 cases. The following results were obtained: 1) In almost all cases, the pure tone audiograms were flat or slightly rising types, and the mean air conductive hearing loss was about 60 dB. Only 2 cases showed the falling type with conductive hearing loss. Connective tissue was observed at the incudo-stapedial joint intraoperatively in these two cases. 2) Mean hearing improvement was in 31.8 dB in the low frequency region (125, 250, 500 Hz), 22.7 dB in the middle frequency region (500, 1000, 2000 Hz), and 12.9 dB in the high frequency region (2000, 4000, 8000 Hz), within 3 weeks after operation, in all 17 cases. 3) No clear changes in hearing level were seen postoperatively, for the four periods evaluated; 1-3 weeks, 1-3 months, 4-6 months and over 7 months in all cases. 4) The cases in whom the reconstruction was performed between the incus and stapes, especially the foot plate of the stapes, showed poor hearing recovery. 5) There was no relation between hearing recovery and the prostheses used in reconstructions. However, it was thought that pieces of the patient's own cartilage or bone should be used whenever possible.

[Progressing cases from low tone sudden deafness to Menière's disease--cochlear impairment in the so-called pre-Menière's disease period].

Among 80 patients with low tone sudden deafness (LTSD) who visited our department over the past 15 years, there were 6 cases (7.5%) who subsequently progressed to Menière's disease. The clinical and audiological processes of the 6 patients were studied in detail and the following results were obtained. (1) In these 6 patients, the time between onset of LTSD and the diagnosis of Menière's disease ranged from 4 months at the shortest to 6 years and 8 months at the longest, 2 years and 9 months on average. (2) Two pattern types were seen in the change from LTSD to Menière's disease: changing within a short period of time after recurrence of an LTSD-like attack, and changing after more than one year without recurrent attack. (3) The monoattack-nonrecovered type of LTSD and the recurrent type of LTSD within three months after the onset (short-term prognosis) frequently progressed to Menière's disease. (4) There were no close relationships between subjective symptoms and audiological features in the pre-Menière's disease period (from the onset of LTSD to the recurrence of vertigo with cochlear symptoms). (5) The 6 patients showed various audiogram shapes at the time of progression to Meniere's disease; 3 cases with the slightly rising type, 1 with the high frequency-impaired type, and 2 with the moderate, gradual and flat type. (6) Of the 6 patients, 3 had good hearing during long term observation. At least 2 patients seemed to have the mild type of Menière's disease.(ABSTRACT TRUNCATED AT 250 WORDS)

[Study of tinnitus masking by self-recording audiometer].

The tinnitus masking test, in which the minimum masking levels of tinnitus by various pure tones and band noises are measured and used to produce tinnitus masking curves, is one of the methods for evaluating the character of tinnitus. At present, the tinnitus masking test is usually performed using a pure tone audiometer. In this study, tinnitus masking curves were produced using a self-recording audiometer (Bekesy audiometer) in 22 cases of tinnitus, and the basic nature of the tinnitus masking curves from the self-recording audiometer was investigated and compared with those from a pure tone audiometer. The results showed no changes in the masking level, and the amplitudes of the tinnitus masking curves from the self-recording audiometer were observed to be at the tinnitus pitches. The amplitude of the tinnitus masking curve showed a negative correlation with tinnitus loudness as measured by the loudness balance test for tinnitus, that is, the amplitude tended to decrease as the tinnitus became louder. This suggests that the loudness of the masking tone influences the tinnitus masking phenomenon.

[Review of the evaluation criteria for low tone sudden deafness].

Low tone sudden deafness (LTSD) has the three following features; obscure origin, acute or sudden onset and sensorineural hearing loss limited to low frequencies without vertigo. Twenty LTSD patients with total hearing levels at low frequencies (125 Hz, 250 Hz, 500 Hz) from 70 dB to 95 dB (Group A) and 19 LTSD patients (typical LTSD) with levels above 100 dB (Group B) were studied. All patients visited our department within one week after onset. All presented over the past 3 years and were followed up for two years or more after initial examination. The clinical parameters such as incidence, subjective symptoms, the configuration of the audiogram and the prognoses of patients in the two groups were investigated comparatively. The following results were obtained. (1) Patients in their twenties were more frequently affected in group A, but patients aged 20 to 50 were equally affected in group B. (2) Females were more frequently affected in both groups, remarkably so in group B. (3) Hearing disorders frequently occurred after an upper respiratory tract infection and stress in both groups. (4) Fullness of the ear, tinnitus and hearing disturbance were common chief complaint and subjective symptoms in both groups. (5) The configuration of the audiogram seemed to be variable within each group and between the two groups. (6) The ratios of recurrent type to monoattack type were almost the same and the patients had good prognoses in both groups. From the results mentioned above, both groups were considered to belong to the same category of LTSD.(ABSTRACT TRUNCATED AT 250 WORDS)

[A study on auditory disturbances after microvascular decompression for hemifacial spasm].

After establishing an operation of microvascular decompression by Jannetta in 1975, an improvement rate of hemifacial spasm have increased. However, postoperative hearing deficits, equilibrium disturbances and facial paresis have been described in some publications. Fifty-seven of 119 patients with hemifacial spasm operated from 1982 to 1989, were examined by audiometry before and after operation. In patients with tinnitus at the time of facial spasm and closing eyelids, tinnitus improved almost in many cases. Of 57 patients, 8 (5 with sensorineural hearing loss, 3 with conductive hearing loss) had postoperative hearing impairments in operated ears, and 7 (7 with sensorineural hearing loss) had in the other ears, too. Of 7 patients having sensorineural hearing loss observed for several months, 4 having slight sensorineural hearing loss recovered at the same hearing level before operation. In 2 patients having profound sensorineural hearing loss, however, hearing improvement did not observed in each case.

[Study on tinnitus masking--an evaluation of ipsilateral and contralateral masking for tinnitus].

In this study, the tinnitus masking curves measured by the ipsilateral and contralateral masking test were evaluated for the unilateral tinnitus cases of following 4 groups; 40 cases without hearing loss, 22 cases with symmetrical sensorineural hearing loss, 12 cases with unilateral deafness, and 70 cases with unilateral sensorineural hearing loss. Then the characteristics of tinnitus masking curves and central masking phenomenon for tinnitus masking were investigated. Consequently, tinnitus was masked by a masking tone given from nontinnitus ear when it reached at some definite loudness level, in spite of the presence of hearing loss or the degree of hearing loss in tinnitus ear. Then it was suggested to be a influence of central masking phenomenon in the contralateral tinnitus masking.

[Statistical study of 41 cases with denture foreign bodies in the air and food passages and significance of the duplicated denture model].

A statistical study of 41 cases with denture foreign bodies in the air and upper food passages which were treated in our department during the past 21 years was done. (1) Males were more frequently affected. The ratio of male to female was about 2 to 1. (2) Of 41 dentures, 2, 2 and 37 were lodged in the air passages, hypopharynx and esophagus respectively. (3) There were 5 complete mandibular dentures in 41 cases. (4) The causes of the denture foreign bodies were originated to the problem of denture itself in 29 cases, that of the patient himself in 2 cases and both in 10 cases. (5) Of 39 problematic dentures, 16 showed the breakage such as plate fracture and clasp deformity, but the other 23 showed no breakage. In this latter group, poor holding of the denture was ascribed to miss-making or miss-planning. (6) Of 12 patients with problems in their physical function, 5 had suffered from cerebrovascular disease and 3 from geriatric dementia. (7) The denture foreign body in aged patients with physical hypofunction tends to increase in recent years. (8) Of 39 dentures tried to remove by esophagoscopy, 18 were done with difficulty and they were detachable partial dentures with one artificial tooth and 2-arm-clasps lodged at the first and/or second isthmus of the esophagus. Though we have a denture removed successfully at the third trial, we have no case needed external esophagotomy. (9) Duplicated denture models were made in 20 cases prior to the procedure, and we certify that these models play an important role for the safer removal of denture foreign bodies.

[Suppression of evoked otoacoustic emissions by contralateral noise exposure in humans].

The effects of contralateral noise exposure on evoked otoacoustic emission (e-OAE) were investigated in 10 normal hearing subjects and 3 cases with unilateral deafness. The e-OAE was recorded by ILO88 and weighting noise was given to the contralateral ear (impaired side in unilateral deafness cases). The air conducted noise exposure showed suppressive effect on e-OAE along with the increase of noise stimulus intensity in normal hearing subjects, but did not in unilateral deafness cases. The degree of suppression in e-OAE was most remarkable in highest peak power between 1 kHz and 2 kHz in FFT picture and the mean value of maximal suppression in 10 normal hearing subjects was 2.2 dB. The bone conducted noise exposure showed no effects on e-OAE in either normal hearing subjects or unilateral deafness cases. It was suggested that the contralateral noise exposure could suppress the function of cochlear micromechanics probably via crossed olivocochlear bundle.

[A study of the relationship between hearing-aid usage and residual hearing].

Fifty-eight children (from 4 to 19 years of age) with bilateral, symmetrical, sensorineural hearing loss, who had used a hearing aid in only one ear for 1 to 19 years were investigated to study the influence of hearing-aid upon the residual hearing between the used and no used ears. The results were as follows, 1) The average hearing level for the used ear at seven frequencies was 49. 5 dB of pre-hearing-aid usage and was 53. 8 dB of post-hearing-aid usage. The discrepancy of audiograms between the aided and unaided ear was not remarkable. 2) The hearings for both the aided and the unaided ears in Audiograms was progressive for a long time. But no significance relation was observed between changes in used-ear hearing of the aided and unaided ears. 3) When the hearing levels of the children were scrutinised on an individual basis, it was found that 9 cases (15.5%) in both ears, 2 cases (3.4%) in only used ear and 1 case (1.7%) in only no used ear out of 58 cases showed deterioration of hearing. 4) These data did not lead us to the conclusion that hearing-aid usage was detrimental on the residual hearing of children with sensorineural hearing loss.

[Audiological study for ears with aural stenosis and atresia].

The audiological study for ears with aural stenosis and atresia was performed. The hearing level of ears with three types of ear plugs (with the hole of phi 1mm, with the hole of phi 3mm and without the hole) was tested experimentally by 10 normal hearing subjects in pure tone audiometry, and the audiograms of congenital and acquired aural stenosis and atresia were investigated statistically. And then following results were obtained. 1) The air conduction levels were higher, as the diameter of ear plug's hole got shorter in normal hearing subjects. And the shape of their audiograms was gradual sloping type. 2) The air conduction levels of ears with congenital aural stenosis and atresia were almost from 60 to 70 dB, and the levels were almost same throughout 7 frequencies. But the audiograms of ears with acquired aural stenosis and atresia showed conductive and gradual sloping type. 3) From the results mentioned above, the reason why the hearing loss of ears with aural stenosis and atresia showed conductive hearing loss limited to low and middle frequencies was considered to depend on the abnormality of the middle ear. 4) An average value of hearing threshold level in bone conduction among normal hearing subjects with three types of ear plugs was almost -7.8dB. There was no relation between the size of ear plug's hole and the shift of bone conduction level.

Sudden deafness: an investigation of hearing loss.

The expression 'profound hearing loss' used in the diagnostic criteria for sudden deafness should be changed to 'moderate to profound hearing loss'. In clinical diagnosis, a 30-dB hearing loss at 1 kHz can be used as a tentative criterion for sudden deafness.

Clinical study of sudden deafness with special reference to onset.

In a comparative study, patients with sudden deafness were classified into four groups according to type of onset. The results showed that those who noticed deafness occurring when awakening had a better prognosis than others, particularly those who found themselves already suffering from deafness on awakening. These findings suggest that among patients who have deafness on awaking, the disorder may not be sudden deafness in sensu strictu.

Increased left ventricular function as an adaptive response in vibration disease.

Vibration disease results from the long-term use of vibrating tools. Vibration, noise, and cold are stressors that impair the human body, inducing vibration disease. From echocardiographic methods, the left ventricular ejection fraction in vibration disease was 79 +/- 4%, a significantly higher value than that in control subjects (75 +/- 6%) (p less than 0.01). The increase in ejection fraction appeared to be due mainly to an increase in left ventricular end-diastolic dimension. The value of the ejection fraction was proportional to the activity of the autonomic nerves. The stroke volume index in patients with vibration disease was also significantly larger than that in the control subjects (p less than 0.001). Electrocardiograms revealed a significantly lower heart rate at rest and an increase in the ratio of T waves to R waves in precordial lead V6. These data suggest that the cardiovascular system in patients with vibration disease provides an adaptive response to the stressors.