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This study was carried out to establish which type of cholesteatoma is controllable by conservative treatment from the viewpoint of mastoid ventilation. We examined the area of the air cell system and airspace (aeration) in the mastoid cavity by computed tomography and eustachian tube (ET) function by inflation-deflation test in 20 ears (20 patients) with severe attic retraction for over 12 months (retraction pocket group), 16 ears (16 patients) with cholesteatoma which could be controlled only by conservative treatment for over 12 months (nonsurgical group) and 43 ears (43 patients) which required surgery within a year in spite of similar conservative treatment (surgical group). The size of the mastoid air cell system in the retraction pocket group, nonsurgical group and surgical group was 2.9 +/- 1.3, 1.9 +/- 0.7 and 1.5 +/- 0.9 cm(2) on average, respectively, with no significant difference between both cholesteatoma groups (nonsurgical and surgical group). While aeration was observed in the mastoid in 17 of 20 ears (85.%) in the retraction pocket group and in 12 of 16 ears (75.0%) in the nonsurgical group, aeration was present only in 9 of 43 ears (26.5%) in the surgical group, being significantly less in the surgical group than in the nonsurgical group and the retraction pocket group. In all ears in the retraction pocket and nonsurgical groups, and 19 of 30 ears in the surgical group, ET function was poor, there being no significant difference among the three groups. The present clinical observations suggest that progressiveness of cholesteatoma could be related to the ventilatory conditions in the mastoid rather than ET function, and that conservative treatment may be effective when ears with cholesteatoma have aeration in the mastoid.

Background: it is believed that the number of neurons of the human cortex increases rapidly in the first postnatal year, and then decreases gradually towards adult level as their functions are revised up to 11 years of age ('synaptic revision'). It is also confirmed that regional cerebral blood flow (rCBF) at rest represents the density of the neurons and decreases in accordance with the synaptic revision in process. If synaptic revision does not occur, rCBF remains at high level. Thus, we can evaluate whether functional differentiation has occurred in the human cortex by measuring rCBF at resting state., Objective: to examine functional differentiation of the auditory association area (A2) in prelingually deaf subjects., Methods: six postlingually and six prelingually deaf subjects who had undergone cochlear implant (CI) were involved in the current study. All prelingually deaf subjects underwent CI over 8 years old. The rCBF in A2 was examined during resting and listening to speech sounds using positron emission tomography (PET) and H2(15)O intravenous injection. Twelve normal subjects' rCBFs were also measured as control. Furthermore, three prelingually deaf subjects underwent follow up PET studies in which cortical activities in A2 for listening and lipreading were examined., Results: in the examination of rCBF at rest, rCBFs of prelingually deaf subjects in A2 showed significantly higher than those of either the postlingually deaf subjects or normal subjects. During listening, rCBFs in A2 increased in postlingually deaf subjects and normal subjects, while there was no significant rCBF increase in the prelingually deaf. High rCBF level in A2 at rest observed in prelingually deaf subjects implied a lack of synaptic revision, and it was suggested that the functional differentiation for auditory processing was little in the A2 of prelingually deaf subjects. In the follow up study for three prelingually deaf subjects, activation of A2 was observed during lipreading but not during listening in two cases, who had developed the skill of lipreading while speech recognition was not improved by CI. In contrast, the other case had not used any visual clues in daily communication prior to CI, and the hearing acuity was well improved by CI. This case demonstrated an activity in A2 during listening, while lipreading induced no activation., Conclusion: it is suggested that functional differentiation of A2 should differ according to which of visual and auditory clue is chiefly used during critical periods for speech acquisition. The findings are thought to be important for us to schedule the education and treatment for prelingually deaf children.

To try to solve the pathogenesis of severe attic retraction viewed from mastoid condition, we examined the residual soft tissue density (RSTD) in the mastoid by computed tomography (CT) in 85 patients (107 ears) with otitis media with effusion (OME) 3 months after tympanostomy tube insertion or later. The incidence of RSTD in the mastoid was significantly higher in OME of adults (52.6%) than in children (24.1%). Ears with severe attic retraction had RSTD significantly more frequently (80%) than those with no or mild attic retraction, and many of the mastoids with severe attic retraction were occupied totally by RSTD. The area of the mastoid (mastoid pneumatization) was significantly smaller, and CT density of the mastoid (sclerotic tendency) was significantly higher in ears with RSTD than in those without. RSTD after tympanostomy tube insertion in the mastoid indicating organic change of effusion was considered one of the important factors relating to the pathogenesis of severe attic retraction.

Cortical activation during vocalization was studied in an attempt to elucidate verbal self-monitoring mechanisms in cochlear implant users. Six post-lingually deafened subjects using cochlear implants were included in this study. Significant activation was observed in the bilateral temporal cortices during reading sentences aloud, which was not found in normal subjects in our previous study. The activation patterns in the temporal cortex were similar for reading aloud and for listening to the examiner's speech, and the activation foci in the middle temporal gyri for the two tasks were almost identical. Cochlear implant users may monitor their own speech during speech production, and their verbal self-monitoring mechanisms are thought to depend on similar mechanisms that are used to monitor externally generated speech.

Objective: The postoperative speech perception abilities of severely hearing-impaired patients with multi-channel cochlear implant were compared with preoperative speech perception performance with conventional hearing aids., Methods: Cochlear implantation was performed in six severely to profoundly hearing-impaired patients. They had unaided pure-tone thresholds of 70-100-dB HL and aided thresholds of 35-90-dB HL in the better ear, but were not able to perceive speech sounds well with hearing aids., Results: Postoperatively, all the patients had significantly improved speech perception performance, exceeded the average skills of profoundly deaf cochlear implant users, and were able to communicate without writing., Conclusion: These results imply that cochlear implant may be indicated for severely to profoundly deaf subjects, if they receive little or no benefit from conventional hearing aids.

Objective: Although cochlear implants (CIs) have provided the opportunity for bilaterally deaf individuals to recover their hearing abilities, the speech perception performances of the CI users varies considerably. To elucidate the cortical mechanisms of processing speech signals coded by CIs, we evaluated the correlation between the brain activity during speech activation and speech perception in CI users by PET., Methods: Fourteen postlingually deaf CI users were examined. CI used in the patients was a 22-channel system and its speech-coding strategy was the Nucleus spectral peak (SPEAK) strategy. To evaluate the speech perception performances, we examined vowel perception, consonant perception and speech tracking performances in the Japanese language. Regional cerebral blood flow (rCBF) was measured during no sound stimulation and speech sound stimulation. PET data of the silent condition was subtracted from that of speech stimulation to determine changes in rCBF. In the search for changes in rCBF in the areas for auditory processing, three regions of interest (ROI) were selected; primary auditory area, auditory association area and Broca's area. The correlation between the rCBF changes in the ROIs and the speech perception performances was analyzed using Pearson's correlation coefficient., Results: The patient's speech perception performances ranged widely. Although there were no significant correlations between the speech perception and the rCBF increases in the primary auditory area and Broca's area, there were positive correlations in the auditory association area. In the left auditory association area, the correlation coefficient of the vowel perception performance was 0.546 (P <0.05) and that of the speech-tracking test was 0.657 (P < 0.05). Regarding the consonant perception performance, the correlation coefficient was 0.743 (P < 0.01). There was a positive correlation only between the consonant perception performance and the rCBF increase (R = 0.576, P < 0.05) in the right auditory association area. These correlations are stronger in the left hemisphere than in the right hemisphere., Conclusions: It is suggested that the improvement of the auditory processing of speech in CI users with SPEAK strategy is accompanied by the recruitment of more neurons in the auditory association areas. The adult auditory cortices may still have plasticity or

Objective: To test whether the posterior external auditory canal (EAC) wall reconstructed only by soft tissues retracts after surgery in the noninflamed ear., Study Design: The condition of the posterior EAC wall was observed for more than 1 year after surgery in 20 noninflamed ears in which only the posterior EAC wall skin was preserved or in which the wall was reconstructed only by soft tissue during surgery., Patients: Eighteen patients (20 ears) underwent ear surgery for conditions other than otitis media, including ossiculoplasty in 12 ears, cochlear implant in 3, resection of congenital cholesteatoma in 4, and resection of glomus tympanicum tumor in 1., Results: Retraction of the soft posterior EAC wall was observed in only 1 of the 20 ears. In this ear, the posterior EAC wall showed only a slight retraction without any serious problems. Computed tomography revealed that mastoid aeration recovered in all 20 ears., Conclusions: In noninflamed ears, surgeons can remove the bony posterior EAC wall if necessary, and may not need to reinforce or reconstruct the wall with hard tissue. This enables surgeons to spare time and energy and obtain the same advantages as in the intact-canal-wall technique or canal wall reconstruction by a hard material.

Fifty-six patients after tympanomastoid surgery were examined to determine recovery of mastoid aeration and various pre- and intraoperative factors such as eustachian tube (ET) function, how the mastoid mucosa had been treated during surgery and whether or not a large silastic sheet had been placed in the middle ear or a ventilation tube used. Mastoid aeration recovery was confirmed by computed tomography in 27 of the 57 cases (47%) within 12 months of surgery. Among the factors examined, preservation of the epitympanic mucosa was found to be most important in mastoid aeration recovery. Use of a large silastic sheet to cover the area from the bony ET and tympanic cavity to epitympanum, aditus ad antrum or antrum was found to be of some help in recovery mastoid aeration after complete resection of the mucosa and mastoid air cells. Preoperative ET function, anterior tympanotomy and use of a ventilation tube did not influence recovery.

In Meniere's disease, spontaneous nystagmus beating toward the affected ear (ipsilateral nystagmus) is frequently observed especially during vertiginous periods. VOR against horizontal rotation was recorded in 19 patients with Meniere's disease exhibiting ispilateral beating nystagmus, and the dynamic aspect of vestibular function during vertiginous periods was examined by determining VOR gain and directional preponderance (DP). The patients sat on a rotation chair and were passively rotated at about 0.3-0.6 Hz. The maximal head velocity ranged from 80 to 120 deg/s and the duration of rotation from 20 to 30 s. In most patients exhibiting ipsilateral nystagmus, VOR gain toward the affected side was higher than that toward the intact side, indicating that the peripheral vestibular system on the affected side could still respond to head movements and that its dynamic function was increased. This asymmetry disappeared along with disappearance of ipsilateral nystagmus. During the period with contralateral nystagmus, VOR gain toward the affected side became lower than that toward the intact side. These findings indicate that alterations in the dynamic property of the peripheral vestibular system may correlate with the directional change of spontaneous nystagmus. However, the degree of VOR DP (VOR DP%) did not correlate with the slow phase velocity of spontaneous nystagmus, indicating that observation of spontaneous nystagmus alone cannot determine with precision the degree of imbalance in the dynamic aspect of vestibular function.

Compound action potentials (CAPs) evoked by the short Japanese syllables /a/ and /ka/ were recorded by extratympanic electrocochleography in 17 subjects with normal hearing (17 ears) and 34 patients with sensorineural hearing losses (35 ears) to investigate the temporal aspects of speech coding for perception. In normal ears, three characteristics were found common to the temporal patterns of all CAPs: (1) a prominent CAP at the beginning of both stimuli; (2) periodic CAPs with the same interval as the pitch period through the vowel part of both stimuli; (3) absence of a prominent CAP at the onset of voice. These characteristics may help to produce consonant recognition. Among the subjects with sensorineural hearing loss, some ears showed the following two characteristics different from those with normal hearing: (1) a significantly lower CAP at the onset of both stimuli than in those with normal hearing; (2) decay of CAPs during the voiced part. These findings may result in abnormal loudness perception in sensorineural hearing loss as produced by loudness recruitment and pathological adaptation. Such different temporal patterns of CAPs may have an adverse influence on the speech discrimination of patients with sensorineural hearing impairments.

A new vestibulo-ocular reflex (VOR) recording system was developed, which consists of an infrared eye camera, a small velocity sensor and a frequency modulator. Using this system, the head velocity signal was frequency modulated and simultaneously recorded as a sound signal on the audio track of a Hi8 video recorder with eye images. This device enabled recording of the VOR response in routine vestibular clinical practice. The reliability and effectiveness of this system were estimated by recording and analysing the VOR response against manually controlled rotation in normal subjects (n = 22) and in patients with unilateral severe vestibular hypofunction (n = 11). VOR gain on clockwise rotation viewed from the top was defined as R gain, and counterclockwise rotation as L gain. Directional preponderance (DP%) was also calculated. VOR gain towards the diseased side was significantly lower than that towards the intact side, and also significantly lower than that of normal subjects. DP% of unilateral vestibular hypofunction cases was significantly larger than that of normal subjects. These findings indicate that this VOR recording system reliably detects severe unilateral vestibular hypofunction.

Diagnostic and prognostic values of eardrum mobility were determined by pneumatic otoscopy in 37 patients (56 ears) having otitis media with effusion (OME). Eardrum mobility was impaired or lost in less than half of the ears (46.4%), while a tympanogram detected 77.8% of OME. In 27 of the 37 patients (42 of the 56 ears), aeration of the middle ear space was examined by CT and demonstrated that the presence or absence of aeration was significantly correlated with the presence or absence of eardrum mobility. In another 38 children (62 ears with OME), effect of antibiotics was correlated with eardrum mobility before treatment, and the improvement rate was found to be significantly higher in ears with positive mobility of eardrum (34.3%) than in ears without eardrum mobility (10.0%). These results indicate that eardrum mobility is a good prognostic indicator of OME rather than its diagnostic indicator alone.

The effects of a speech-coding strategy of cochlear implant (CI) on cortical activity were evaluated using positron emission tomography. The CIs used in the present study were those of a 22-channel system using the Multipeak speech-coding strategy (MPEAK) and the spectral peak strategy (SPEAK). On comparing the 2 groups, it was found that the speech-tracking performance was significantly higher in the SPEAK group than in the MPEAK group. Regional cerebral blood flow (rCBF) was measured during the silent resting, noise stimulus and speech stimulus periods. The increase in rCBF was localized mainly in the primary auditory area during the noise stimulus period. The increase in rCBF in the auditory association area during the speech stimulus period was stronger in the SPEAK group than in the MPEAK group. This finding suggests that the SPEAK strategy activates more speech processing neuronal networks in the auditory association area than the MPEAK strategy.

To investigate the effect of unilateral deafness on central auditory mechanisms, we examined patients with unilateral deafness of various durations. Auditory evoked magnetic fields (AEF) were recorded using a whole-head neuromagnetometer. In patients who had unilateral deafness for more than 3 weeks, the average N100m latency in the ipsilateral hemisphere did not differ from that in the contralateral hemisphere. In addition, in some patients with congenital or early onset deafness, the equivalent current dipole (ECD) moment was larger in the ipsilateral hemisphere than in the contralateral hemisphere. These findings suggest that unilateral deafness may cause reorganization of the central auditory pathway. They also suggest that central auditory pathway in adults has some plasticity, though not as much as in childhood.

This paper discusses the cortical processing of speech recognition and the vocalization function from the results of previous PET studies, and speculates that the neuronal network encompassing the right ear, the left auditory area, and the cerebellum is engaged in accurate cognition of acquired speech, and the network of the left ear, right auditory area, and the supplementary motor area (SMA) is contributed to analyzing unknown language. A system of categorized word sounds may exist in the cerebellum, for the comparison and inspection of sound stimuli, which facilitates accurate and prompt cognition. On the other hand, for unknown speech sound, the SMA may propagate categorization of the sound input by analyzing the pattern of vocalization action.

To investigate the influence of gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases, the authors examined the mastoid pneumatization among patients with sniffing habit using computed tomography, and also examined the change of negative middle ear pressure induced by sniffing using tympanogram. In 20 ears with cholesteatoma or adhesive otitis media, the areas of mastoid cavity measured at the level of the lateral semicircular canal were significantly smaller than those in 26 ears with otitis media with effusion (OME) or attic retraction and in eight normal ears with sniffing habit (P < .01 and P < .0001, respectively). In 26 ears with OME or attic retraction, the areas of mastoid cavity were significantly smaller than those in eight normal ears with sniffing habit (P < .0001). By contrast, in the four ears with sniff-induced middle ear disease, the recovery of negative middle ear pressure in 5 minutes without swallowing was less than 10 mm H2O, whereas in all seven ears with normal eardrum, negative middle ear pressure recovered by more than 20 mm H2O in 5 minutes. These findings suggested that impairment of gas exchange function through the middle ear mucosa, as well as eustachian tube dysfunction, might be closely related to the development of sniff-induced middle ear diseases.

Objective: To determine the relationship between preservation of the mastoid mucosa during ear surgery and retraction of the attic or posterior wall of the external auditory canal (EAC) and mastoid aeration after surgery., Methods and Design: Retraction of the posterior EAC wall and mastoid aeration were evaluated after surgery in 48 individuals (50 ears) with cholesteatoma, adhesive otitis media, or chronic suppurative otitis media, in whom the posterior bony EAC walls were removed with or without preservation of mucosa and reconstructed with soft tissues alone (EAC skin and temporal fascia) during surgery., Results: Postoperative computed tomography showed that in ears with notable retraction of the posterior EAC wall appearing like an open mastoid cavity, there was no air in the mastoid, whereas in ears with no or only slight retraction there was computed tomographic evidence of mastoid aeration. Second, notable retraction of the posterior EAC wall occurred in a significantly smaller percentage of ears in which at least the epitympanic mucosa had been able to be preserved during surgery than in those that had undergone removal of all mucosa (mastoidectomy)., Conclusions: These results indicate that 1) preservation of epitympanic mucosa during surgery is an important factor for prevention of retraction of the posterior EAC wall and for reaeration of the mastoid after surgery, and 2) the intact canal wall technique seems to be indicated whenever at least the epitympanic mucosa can be preserved, and when no mucosa can be preserved the canal wall down procedure seems to be indicated.

Using nitrous oxide, we examined the gas exchange function through the middle ear mucosa in ears with otitis media with effusion (OME) in children, and found the function to be impaired in 50% of them. The size of the mastoid was significantly smaller in ears with negative gas exchange function than those with positive function, and the presence or absence of the function was even more significantly correlated with the presence or absence of aeration in the middle ear. Furthermore, the presence or absence of aeration in ears with OME was found to be significantly correlated with their prognosis (response of OME to antibiotics treatment) and also with the presence or absence of eardrum mobility examined by a pneumatic otoscope. Finally, after myringotomy and removal of effusion, the gas exchange function recovered in most of the ears with impaired function. These results indicate that the eardrum mobility test may serve as an appropriate indicator for the surgical treatment for OME.

Gas exchange function through the mastoid mucosa was investigated in ears after surgery using nitrous oxide. Increase in the mastoid pressure was assessed by a micropressure sensor placed in the mastoid cavity during the second-stage revision operation performed under general anesthesia using 67% nitrous oxide, 33% oxygen, and sevoflurane on 14 ears with chronic adhesive otitis media or cholesteatoma as well as on seven ears without inflammation as controls. All seven control ears showed pressure increase in the mastoid in various degrees. In the 14 postoperative ears, nine of the 10 ears on which the mastoid mucosa had previously been able to be preserved in various degrees showed pressure increase in the mastoid, but none of the remaining four ears, which had previously had mastoidectomy, showed any pressure increase. The presence or absence of the mastoid pressure increase of those ears was also found to be correlated well with the presence or absence of mastoid aeration on computed tomography examined just before the second-stage operation. These results appear to indicate that, in ears after surgery, recovery of both the gas exchange function and aeration in the mastoid is expected only when the mastoid mucosa can be preserved even partially.

To investigate the relationship between motor and sensory speech center, cortical activity was examined using PET while normal subjects perceived their own voice which sounded different to the articulated one. The results showed significant activation in the superior temporal gyri with absence of activity in the supplementary motor area (SMA). In a previous study we found significant activation in SMA with no activity in the superior temporal gyrus when normal subjects simply vocalized. Thus, two different cortical pathways for vocalization were delineated: programmed pathway in SMA, and pathway with auditory verbal feedback. The former is thought to be the mature system in the adult, and the latter may be related to speech acquisition.

To elucidate the temporal coding system for speech recognition, we synthesized stimulation sounds which do not contain formant information but do contain temporal information by transforming original sound wave to click sequences. Using this stimulation sound, we performed a recognition test and used PET to examine the cortical activities in normal subjects listening to this sound. The results of the recognition test showed a good perception of the sounds made from sequential speech. The PET study demonstrated significant activation of the superior temporal gyri while listening to the stimulation speech sounds. Our results imply that these stimulation sounds were processed semantically in the auditory cortices. The temporal processing system is thought to make an important contribution to speech recognition.

Changes of regional cerebral blood flow (rCBF) in the auditory cortices induced by sound stimulation were examined in nine postlingually and five prelingually deaf cochlear implant (CI) users by 15O-labeled water Positron Emission Tomography, and the results were compared with those of eight normal volunteers. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the auditory association area in normal and postlingually deaf subjects. In prelingually deaf subjects, however, speech activation of the auditory association area was much less than that found in either of the other two groups. Neuronal networks for speech sound processing in the auditory association area in postlingually deaf individuals are thought be similar to those in normal subjects, while those in prelingually deaf patients who received CI after the speech acquisition period may not develop completely.

To clarify the influence of inflammation on tubal compliance in children with otitis media with effusion (OME), we investigated the change of compliance of the ET by upper respiratory tract infection (URTI) in 18 children (23 ears) with OME using the forced response test. The tubal compliance index (TCI), the ratio of passive tubal resistances at two different airflow rates, significantly increased during URTI represented by acute rhinitis or paranasal sinusitis in comparison with non-URTI periods (paired t-test: t = 4.14, p < 0.001). In nine ears, the TCI could be followed for some months after that, during which the children had had URTI several times. A clear reproducible correlation was found between the presence or absence of URTI and the TCI values; the TCI values increased again during URTI and decreased after the URTI periods. These results seemed to support our hypothesis that compliance of the ET may depend not only on the property of the cartilaginous framework of the ET but also upon the mucosal condition.

A simple, fast and sensitive flow-injection method is proposed for the determination of nanomolar amounts of ascorbic acid in tea, urine and blood. The procedure is based on the accelerating effect of a nanomolar level of ascorbic acid on the reaction of cooper(II) with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin, H(2)tmpyp(4+). Ascorbic acid reduces Cu(II) to Cu(I) which catalyzes the incorporation of Cu(II) into H(2)tmpyp(4+) to form Cu(II)(tmpyp)(4+). In this method two solutions, one containing ascorbic acid and H(2)tmpyp(4+) and the other containing copper(II) and acetate buffer (pH 5.0), were injected into two flowing streams of water through two sample injectors of 120 mu1 sample volume. The mixture was allowed to react in a 2 m reaction coil and the colored solution of Cu(II)(tmpyp)(4+) was monitored at 550 nm (epsilon = 2.01 x 10(4)M(-1)cm(-1)). The present method was applied to the determination of ascorbic acid in tea, urea and blood. Reducing agents such as sugars and vitamins B(1), B(2), B(6) and B(12) did not give serious errors at a concentration of 10(-6) M for the determination of 1.0 x 10(-8)M ascrobic acid. The relative standard deviation of the present method was 2.8% for the determination of 1.0 x 10(-8)M ascorbic acid. The reaction mechanism was clarified from the kinetic results of the formation of Cu(II)(tmpyp)(4+) in the presence of various concentrations of ascorbic acid, copper(II) and hydrogen ion.

Effect of adenoidectomy on sinusitis was investigated in 78 children (aged 5 to 7) with adenoid vegetation, sinusitis and otitis media with effusion. After a 6 month period, improvement of the sinusitis was observed in 25 of the 45 children (56%) in the adenoidectomized group, and only in 8 of the 33 children (24%) in the non-adenoidectomized group. This was statistically significant in the adenoidectomized group (mean 2 = 7.65, p < .01). Through nasopharyngeal endoscopy in the adenoidectomized children in the 6 months following surgery, we noted decreased evidence of infection and/or inflammation. These findings may indicate that adenoidectomy is effective for sinusitis in children.

An auditory-evoked magnetic field was recorded before and during tinnitus remission induced by an intravenous lidocaine injection. One and 4 kHz probe tones were presented monaurally in four tinnitus patients, and the responses were recorded using a 122-channel magnetometer. Three normal volunteers were also examined as controls. In tinnitus patients, the N100 m peak became sharper, while there was no marked change except for slight reduction in amplitude in normal subjects. Tinnitus remission by lidocaine may be related to attenuation of a masking-like effect of tinnitus on the sound-evoked responses.

To investigate how auditory input from each ear contributes to spoken language processing, cortical activation by monaural speech sound stimulation was examined in 12 normal subjects using 15O-labeled water positron emission tomography. Regional cerebral blood flow (rCBF) was measured under four different sound stimulation conditions: (1) silence, (2) white noise, (3) sequential Japanese sentences ("speech"), and (4) Japanese sentences played backward ("reversed speech"), and the results were evaluated by statistical parametric mapping (SPM). Noise induced significant rCBF increase in the contralateral Heschl's gyrus. Speech and reversed speech stimuli caused significant rCBF increase in the contralateral Heschl's gyrus and the bilateral superior temporal gyri, with contralateral activation broader than that in the ipsilateral hemisphere. Monaurally input speech sound signals that reach the contralateral Heschl's gyrus may be processed chiefly and phonologically in the surrounding superior temporal gyrus in the same hemisphere. Comparison of speech activation with reversed speech activation failed to demonstrate a significant difference, which made it difficult to identify the area for lexical and semantic processing.

Thirty-eight patients suffering from tinnitus resistant to several medical therapies for more than 6 months were treated by low power laser irradiation. A 40 mW laser with a wavelength of 830 nm was irradiated via their external auditory meatus toward the cochlea for 9 min once a week, 10 times or more. Patients were asked to score their symptoms on a 5 point scale before and after the treatment for a subjective evaluation of the effect. The results were estimated by the change of the loudness and duration of tinnitus, and the degree of annoyance due to tinnitus. Although only 26% of the patients had improved duration, loudness and degree of annoyance were relieved in up to 58 and 55%, respectively, without major complication. Laser therapy seemed to be worth trying on patients with intractable tinnitus.

To estimate the usefulness of magnetic resonance imaging (MRI) in diagnosing vertebro-basilar insufficiency (VBI), 41 VBI patients with vertigo or dizziness and 26 subjects without vertigo or dizziness (as control) were examined by MRI. Sixty-eight percent of the VBI group and 12% of the control group showed a large difference between the right and the left vertebral artery diameter, the incidence being significantly higher in the VBI group. Thirty-nine percent of the VBI group and 12% of the control group had lacunar infarction in the brain stem, of which the incidence was significantly higher in the VBI group, MRI can be recommended to diagnose VBI providing information on both blood vessel disorder and ischemic changes in the brain.

Parasagittal surface coil magnetic resonance imaging (MRI) of the internal auditory canal and the inner ear was performed in patients with otoneurological diseases. T2-weighted fast spin-echo sequences, plain and enhanced T1-weighted sequences were used to examine the inner ear and the individual nerves in the internal auditory canal. Normal parasagittal images of the inner ear and the internal auditory canal and 4 patients with otoneurological disorders are presented. Precise location of the acoustic tumor was visualized and postoperative status of the internal auditory canal and the inner ear was assessed by the present method. The cochlear nerve was not identified in a patient with long-standing unilateral deafness. A follow-up study with MRI was performed in a patient with Meniere's disease who underwent endolymphatic-mastoid shunt surgery, showing gradual postoperative shrinkage of the shunted endolymphatic sac. The present method provides a new approach to the assessment of otoneurological disorders.

Over the last 4 decades remarkable progress has been made in the treatment of cleft palate: the rate of attaining normal or nearly normal speech after surgery has risen from about 65% 40 years ago to nearly 90% or more nowadays. One of the main factors is intratracheal intubation anesthesia that has made the surgery much safer and easier. Improved surgical technique and speech therapy also played a great role. This paper deals with two problems: (1) Slight velopharyngeal incompetence: The combined use of fiberscopy and fluorovideoscopy can provide useful information as to: (a) the exact place of the faulty articulation, (b) the detailed pattern of inconsistent velopharyngeal function, (c) changes in articulation induced by speech therapy, and (d) the relation between velopharyngeal function and faulty articulation. All the above information greatly facilitates speech therapy for cleft palate speech. It should be done with utmost care though due to possible adverse effects of radiation. (2) Analysis of faulty articulation. It was revealed that faulty articulations such as laryngeal fricative and affricates, pharyngeal stop, and glottal stop in cleft palate speech, secondary to velopharyngeal incompetence, were produced by articulation in the larynx at various sites such as the epiglottis, arytenoids, aryepiglottic folds and vocal folds. These faulty articulation points were located lower than supposed on the basis of auditory perception.

A simple and low-cost eye monitoring system with infrared illumination was developed. This system consists of a small board mounted with an infrared sensitive CCD camera and its control unit and a swimming goggle; it is light-weight and visualizes eye movements by connecting the output lines of the board to the video input on a monitor. We have found the present system useful in the routine vestibular clinic practice.

Gas exchange function through the middle ear mucosa was assessed using nitrous oxide (N2O) in patients with otitis media with effusion (OME), as well as in normal ears during elective surgery for unrelated disorders. In all normal ears except one (n = 43), an increase in pressure was observed after N2O inhalation. In 42 of 84 ears with OME, a pressure increase was observed, but not in the remaining 42 ears (50%), indicating that the gas exchange function in these latter ears was impaired. In 21 of the 42 ears showing no middle ear pressure increase following N2O inhalation, the middle ear pressure was again monitored after myringotomy and aspiration of the effusion A pressure increase was found in 16 ears, indicating that the impairment in gas exchange function in ears with OME may be reversible in most cases. Computed tomography of the mastoid was examined preoperatively in 66 ears, with the presence or absence of a middle ear pressure change well correlated in 57 ears with the presence or absence of mastoid aeration.

To elucidate cortical processing during vocalization, we used positron emission tomography to measure regional cerebral blood flow during vocalization in six Japanese subjects. During reading Japanese sentences used daily or short syllables aloud, the visual cortices, the left Heschl's gyrus, Broca's area, the primary motor area of the articulatory organs, the supplementary motor area and the cerebellum were significantly activated, compared with resting conditions. The superior temporal gyri were rarely activated. Significant activation of the cerebellum was observed by comparing cortical activity during reading sentences used daily with that during reading meaningless short syllables. These results suggest that vocalization of familiar materials is taken over by the cerebellum, rather than cortical speech areas, and without engagement of the superior temporal gyri.

To clarify the influence of the mucosal condition of the eustachian tube (ET) upon its collapsibility, three experimental studies were performed by using the forced response test. First, by washout of the mucous blanket of ET, the tubal compliance index (TCI), the ratio of passive tubal resistances at two different airflow rates, significantly increased in all the 6 ETs of 5 cats, and all returned to the baseline within 50 min. Second, the TCIs significantly decreased in all the 7 ETs of 5 cats after application of Triton X (surfactant) into the ET washed out by saline. Third, the increased TCIs of a tubal model by application of saline significantly decreased after application of Triton X. These results seem to support our hypothesis that compliance of the ET, which means its collapsibility, may depend upon the mucosal condition as well as on the property of the cartilaginous framework of ET.

In order to clarify the cause of the constriction of the eustachian tube during swallowing that is often seen in patients with otitis media with effusion, video endoscopy of the pharyngeal orifice of the eustachian tube was performed and superimposed with videograms of the tubal airflow and resistance, which were simultaneously examined by the forced response test. In children with otitis media with effusion (17 ears), when the eustachian tube constricted on the videogram on swallowing, the tubal orifice was found to be squeezed between an elevated soft palate and a hypertrophied adenoid (7/17), squeezed between an elevated soft palate and edema of the posterior lip (7/17), or blocked by nasal discharge (5/17). In adults with otitis media with effusion (7 ears), edema of the posterior lip (5/7) was the main cause of the constriction of the tubal orifice during swallowing. Inflammation in the nasopharynx and the pharyngeal portion of the eustachian tube was considered to be closely related to the tubal constriction, which represents a considerable part of the cause of tubal ventilatory dysfunction in otitis media with effusion.

We used 15O-labelled water in a PET study to test the efficiency of cochlear implants (CIs) in transmitting auditory information to the brain in 10 profoundly deaf subjects. Five were postlingually deaf, and five were prelingually deaf. All the subjects were right-handed. White noise and verbal stimuli, delivered through the CIs, were used for cortical activation. Similar tasks were performed by six right-handed hearing subjects as a control group. In the postlingually deaf subjects, verbal stimulation activated the transverse temporal gyri (primary auditory cortices) mainly on the side contralateral to the CI. The left posterior superior temporal gyrus (Wernicke's area), and the left inferior frontal gyrus (Broca's area) were also activated irrespective of stimulated side. The location of these activated foci was the same as that of the control group. White noise stimulation led to an increase of regional cerebral blood flow (rCBF) only in the primary auditory cortices of the postlingually deaf subjects, only on the side contralateral to the CI, and the intensity of activation was less than that obtained with verbal stimulation. In the prelingually deaf subjects, Wernicke's area and Broca's area were significantly activated by verbal stimulation, whereas there was no activation in the primary auditory cortices. White noise did not activate the primary auditory cortex in the prelingually subjects. These findings suggest that cortical representation of language is not dependent on early auditory experience, while processing in the primary auditory cortices is experience-dependent. The postlingually deaf subjects had a greater increase of rCBF in the Broca's and Wernicke's areas and better sentence comprehension than the prelingually deaf subjects, which suggest a parallel relation between rCBF increase and the ability to recognize spoken language. H2(15)O-PET with auditory stimulation is an effective means of objectively quantifying the response of auditory and association cortices after CIs in deaf subjects.