Dermoid cyst of the infratemporal fossa: a case report of surgical resection by infratemporal fossa type B approach.

OBJECTIVE: This is a case report of a dermoid cyst located in the infratemporal fossa and its surgical removal using infratemporal fossa type B approach. CASE REPORT: A 15-year-old male was referred from a local clinic after an incidental finding of a mass lesion in the skull base area on computed tomography (CT). Pre-operative magnetic resonance imaging showed a large cystic mass lesion, expanding to the foramen ovale with fat component in the right infratemporal fossa region. The lesion was completely excised using an infratemporal fossa type B approach. CONCLUSION: An extremely rare case of dermoid cysts of the infratemporal fossa was managed with infratemporal fossa type B approach without severe complication.

Predictable Factors of People with Asymmetrical Hearing Loss Wearing a Hearing Aid in the Worse Ear Only.

In patients with bilateral asymmetrical hearing loss (AHL), where only one hearing aid is available, it is difficult to decide which ear to amplify. The aim of this study was to evaluate the outcomes of hearing aid use for AHL patients fitted with a hearing aid in their worse ear only. One-hundred-two adults with asymmetrical-mixed or sensorineural hearing loss were retrospectively included. AHL was classified into three subgroups: unilateral hearing loss (UHL) and AHL type 1 (AHL1) and type 2 (AHL2). The main outcome measures were (1) the time spent wearing a hearing aid, (2) the hearing in a noise test (HINT), (3) the sound localization test and (4) the Korean version of the International Outcome Inventory for Hearing Aids (IOI-HA). The 1 kHz-hearing threshold of the better ear was significantly better in the successful users than in the intermittent users for UHL. Younger age was associated with significantly better outcomes than older for AHL1 and AHL2. Among the etiologies of AHL, sudden hearing loss was associated with significantly better outcomes of hearing aid use for AHL, UHL and AHL1 patients. In this study, the success rate and usage rates were 43.1% and 67.6% in AHL patients wearing a hearing aid in the worse ear. This study identified the hearing threshold of 1 kHz from the better ear, age and etiology of sudden hearing loss as audiometric and non-audiometric factors that affected the outcomes of hearing aid use.

Discrepancies in Hearing Thresholds between Pure-Tone Audiometry and Auditory Steady-State Response in Non-Malingerers.

OBJECTIVES: To evaluate discrepancies between pure-tone audiometry (PTA) and auditory steady state response (ASSR) tests in non-malingerers and investigate brain lesions that may explain the discrepancies, especially in cases where the PTA threshold was worse than the estimated ASSR threshold. DESIGN: PTA, speech audiometry, auditory brainstem response, ASSR, and neuroimaging tests were carried out on individuals selected from 995 cases of hearing impairment. Among these, medical records of 25 subjects (19 males, 6 females; mean age = 46.5 ± 16.0 years) with significant discrepancy between PTA and estimated ASSR thresholds were analyzed retrospectively. To define acceptable levels of discrepancy in PTA and ASSR hearing thresholds, 56 patients (27 males, 29 females; mean age = 53.0 ± 13.6 years) were selected for the control group. Magnetic resonance images, magnetic resonance angiograms, and positron emission tomograms were reviewed to identify any neurologic abnormalities. RESULTS: Pathologic brain lesions were found in 20 cases (80%) in the study group, all of which showed a significant discrepancy in hearing threshold between PTA and ASSR. Temporal lobe lesions were found in 14 cases (70%), frontal lobe lesions in 12 (60%), and thalamic lesions without the frontal or temporal lobe in 2 cases (10%). On repeated PTA and ASSR tests a few months later, the discrepancy between ASSR and behavioral hearing thresholds was reduced or resolved in 6 cases (85.7%). Temporal lobe lesions were found in all 3 cases in which the estimated ASSR threshold worsened with unchanged PTA threshold, and frontal lobe lesions were found in all 3 cases in which the PTA threshold improved but the estimated ASSR threshold was unchanged. No neurological lesions were found in 5 cases (20%) of patients with a discrepancy between ASSR and behavioral hearing thresholds. CONCLUSIONS: Clinicians should not rely exclusively on ASSR, especially in cases of central nervous system including temporal, frontal lobe, or thalamus lesions. If no lesions are found in a neuroimaging study of a patient with a discrepancy between PTA thresholds and estimated ASSR thresholds, further functional studies of the brain may be needed. If clinicians encounter patients with a discrepancy between PTA thresholds and estimated ASSR thresholds, an evaluation of brain lesions and repeat audiologic tests are recommended in lieu of relying solely on ASSR.

Prediction of uptake and retention of conventional hearing aids in Korean pediatric patients with unilateral hearing loss.

OBJECTIVE: The purpose of this study was to describe and predict hearing aid uptake and retention in Korean pediatric patients with unilateral hearing loss (UHL) in a secondary referral hospital. METHODS: This was a retrospective study using clinical data collected at the time of UHL diagnosis. The study included data collected from 2009 to 2016. Serial audiograms were extracted from clinical charts, and follow-up status and rehabilitation decisions were analyzed. RESULTS: Of 102 children and adolescents (9.5 ±â€¯5.1 years, 64 male), 52.9% followed a check-up schedule, and 31 (30.4%) obtained a hearing aid. Hearing threshold and speech discrimination scores were predictive parameters of hearing aid uptake. Among those who used a hearing aid, 17 (56.7%) subjects used it successfully based on significant predictive parameters of channel number. CONCLUSION: Hearing aid retention in pediatric patients seems less predictable than in adults with UHL. No good predictable parameter for hearing aid retention was identified except channel number for pediatric UHL cases. Regular monitoring of hearing and selection of a multi-channel hearing aid are crucial to minimize the potential negative effects of UHL.

Prediction of the use of conventional hearing aids in Korean adults with unilateral hearing impairment.

OBJECTIVE: To determine the use of a hearing aid at six months post-fitting and to evaluate the predictors of its ongoing use in Korean adults with unilateral hearing impairment (HI). DESIGN: Retrospective study at a secondary referral hospital over a 15-year period. STUDY SAMPLE: This study analysed 119 adults with unilateral HI who had been recommended for hearing amplification (55 men and 64 women, mean age, 58.0 ± 11.7 years). Six months after the fitting, all of the participants were surveyed regarding subsequent decisions and actions about obtaining hearing aids. RESULTS: General uptake rate for a hearing aid was 68.1% (58.0% of participants surveyed were successful users, and 10.1% were intermittent users). The most significant parameter associated with hearing-aid use was social and/or work activities (R(2) = 0.457), and the significant predictors for successful hearing-aid use were social and/or work activities and method of signal processing (discriminatory power = 56.3%). CONCLUSIONS: Six months post-fitting, 68.1% of Korean adults with unilateral HI who had agreed to try a hearing aid continued to use it regularly. The predictors for hearing-aid use six months post-fitting included social and/or work activities and digital signal processing.

Efficacy of intratympanic steroid therapy for idiopathic sudden sensorineural hearing loss: comparison with systemic steroid therapy and combined therapy.

CONCLUSION: Intratympanic steroid therapy (IT-S) was as effective as systemic steroid therapy (SST) or combined therapy (CT) and could be considered a first-line therapeutic modality for idiopathic sudden sensorineural hearing loss (SSNHL). Due to its known safety and efficacy, IT-S will be particularly suitable for patients with SSNHL who have chronic diseases such as diabetes mellitus, hypertension, or chronic renal failure. OBJECTIVES: Systemic high dose steroid therapy is the main therapeutic modality for SSNHL. Comparable therapeutic efficacies for IT-S and CT with SST and IT-S for SSNHL have been reported recently. We compared the efficacy of IT-S, SST, and CT for treating SSNHL. METHODS: A retrospective, multicenter study investigating the therapeutic efficacy of SST, IT-S, and CT for SSNHL was designed and involved 735 patients with idiopathic SSNHL who were diagnosed and treated at seven tertiary referral medical centers of the Catholic University of Korea between 2007 and 2011. Patients were divided into three groups according to the treatment methods they received: IT-S group, SST group, and CT group (SS plus IT-S). Hearing was evaluated by pure tone audiogram performed before initial treatment and at 4 weeks following the final treatment. More than a 10 dB HL decrease in average air conduction threshold of hearing at 500, 1000, 2000, and 3000 Hz was defined as improved hearing. RESULTS: Among 735 patients with SSNHL, 94 were included in the IT-S group, 444 in the SST, and 197 in the CT group. Age, gender, interval from disease onset to start of treatment, and initial hearing level were not different among the three groups. Patients who had concomitant medical disorders such as diabetes mellitus, hypertension, or chronic renal failure were more frequently treated with IT-S. No difference in the level of hearing gain or ratio of hearing improvement was observed among the three groups (p = 0.147 and p = 0.067, respectively).

Effects of meteorological factors on the onset of Bell's palsy.

OBJECTIVE: The etiology of Bell's palsy (BP) has not yet been clarified, although viral infection or reactivation is probably a major cause. The objective of this study was to evaluate the effects of meteorological factors on the onset and incidence of BP. METHODS: Meteorological data from 2007 to 2011 were obtained from the Web-based 'Monthly Weather Reports of the Meteorological Administration' database. Patients with BP who attended Incheon St Mary's Hospital during the same period, presenting on the precise day that their symptoms appeared, were included in this retrospective chart review. Twelve meteorological factors were compared for days on which BP onset was and was not observed. The weather conditions occurring 1-7 days before BP onset (D-1-D-7) were included to assess any possible delayed effects of meteorological factors on the onset of BP. The seasonal and monthly distributions of BP were evaluated. RESULTS AND CONCLUSION: The mean values for the meteorological parameters did not differ significantly between the days when BP onset did and did not occur. However, the maximum wind speed on day -1 (D-1) was significantly higher for BP onset days than for days with no BP onset. The seasonal and monthly distributions of BP did not differ significantly. It is suggested that stronger wind speed of preceding day may be related to the occurrence of BP.

Comparison of functional and morphologic characteristics of mice models of noise-induced hearing loss.

OBJECTIVES: This study was conducted to compare morphologic and audiologic changes after noise exposure in two different strains of mice (CBA and C57) and to create morphologically proven models of noise-induced hearing loss. METHODS: Mice were exposed to white noise at 110-dB sound-pressure level for 60 minutes at the age of 1 month. Hearing thresholds and outer hair cell functions were evaluated by auditory brainstem response recordings and distortion product otoacoustic emission immediately and 22 days after noise exposure. Cochlear pathology was observed and compared by light and electron microscopic studies. RESULTS: Both mice strains showed hearing threshold shifts with decreased outer hair cell function immediately and 22 days after noise exposure. More severe auditory brainstem response threshold shifts were observed in C57 mice compared with CBA mice at click, 8-, 16-, and 32-kHz tone-burst stimuli. A cochlear morphologic study demonstrated predominant outer hair cell degeneration at all turns of the cochlea; degeneration was most severe at the basal turn in both mice strains. A scanning electron microscopic study revealed more severe ultrastructural damage of outer hair cells at each turn of the cochlea in C57 mice. The lateral wall of the cochlea was more severely degenerated in CBA mice. CONCLUSION: Both mice strains showed consistent, permanent noise-induced hearing loss with different susceptibilities and site vulnerabilities. Further studies to investigate the mechanism of the different degree and cochlear site vulnerability to noise exposure between two mice strains are necessary.

Binaural electric-acoustic interactions recorded from the inferior colliculus of Guinea pigs: the effect of masking observed in the central nucleus of the inferior colliculus.

OBJECTIVES: To investigate the electric-acoustic interactions within the inferior colliculus of guinea pigs and to observe how central masking appears in invasive neural recordings of the inferior colliculus (IC). METHODS: A platinum-iridium wire was inserted to scala tympani through cochleostomy with a depth no greater than 1 mm for intracochlear stimulation of electric pulse train. A 5 mm 100 µm, single-shank, thin-film, penetrating recording probe was inserted perpendicularly to the surface of the IC in the coronal plane at an angle of 30-40° off the parasagittal plane with a depth of 2.0-2.5 mm. The peripheral and central masking effects were compared using electric pulse trains to the left ear and acoustic noise to the left ear (ipsilateral) and to the right ear (contralateral). Binaural acoustic stimuli were presented with different time delays and compared with combined electric and acoustic stimuli. The averaged evoked potentials and total spike numbers were measured using thin-film electrodes inserted into the central nucleus of the IC. RESULTS: Ipsilateral noise had more obvious effects on the electric response than did contralateral noise. Contralateral noise decreased slightly the response amplitude to the electric pulse train stimuli. Immediately after the onset of acoustic noise, the response pattern changed transiently with shorter response intervals. The effects of contralateral noise were evident at the beginning of the continuous noise. The total spike number decreased when the binaural stimuli reached the IC most simultaneously. CONCLUSION: These results suggest that central masking is quite different from peripheral masking and occurs within the binaural auditory system, and this study showed that the effect of masking could be observed in the IC recording. These effects are more evident and consistent with the psychophysical data from spike number analyses than with the previously reported gross potential data.

How Does Speaking Clearly Influence Acoustic Measures? A Speech Clarity Study Using Long-term Average Speech Spectra in Korean Language.

OBJECTIVES: To investigate acoustic differences between conversational and clear speech of Korean and to evaluate the influence of the gender on the speech clarity using the long-term average speech spectrum (LTASS). METHODS: Each subject's voice was recorded using a sound level meter connected to GoldWave program. Average long-term root mean square (RMS) of one-third octave bands speech spectrum was calculated from 100 to 10,000 Hz after normalizing to 70 dB overall level using the MATLAB program. Twenty ordinary Korean were compared with 20 Korean announcers with equal numbers of men and women in each group. RESULTS: Compared with the LTASS of ordinary men, that of ordinary women was lower at low frequencies, but higher at 630, 800, 1,600, 5,000, and 10,000 Hz. Compared with the LTASS of male announcers, that of female announcers was lower at low frequencies. Compared with the LTASS of ordinary men, that of male announcers was significantly lower at 100, 125, 200, and 250 Hz. Compared with the LTASS of ordinary women, that of female announcers was lower at 100, 125, 160, 200, 250, 500, and 10,000 Hz. The LTASS of announcer showed lower levels at 100, 200 Hz and higher at 500, 630, 800, and 1,000 Hz that that of ordinary Koreans. CONCLUSION: This study showed that the drop-off of the LTASS in the low frequency region might make the ratings of women and announcers more clearly than those of men and ordinary persons respectively. This drop-off in the low frequency might result in less upward spread of masking and clearer speech. This study reduced an error resulting from a wide variability of clear speech strategies and intelligibility gains, because this study recruited professional speakers. We hope that our results demonstrate the difference in acoustic characteristics of the speech of ordinary Korean persons.

Cross-language identification of long-term average speech spectra in Korean and English: toward a better understanding of the quantitative difference between two languages.

OBJECTIVE: To identify the quantitative differences between Korean and English in long-term average speech spectra (LTASS). DESIGN: Twenty Korean speakers, who lived in the capital of Korea and spoke standard Korean as their first language, were compared with 20 native English speakers. For the Korean speakers, a passage from a novel and a passage from a leading newspaper article were chosen. For the English speakers, the Rainbow Passage was used. The speech was digitally recorded using GenRad 1982 Precision Sound Level Meter and GoldWave® software and analyzed using MATLAB program. RESULTS: There was no significant difference in the LTASS between the Korean subjects reading a news article or a novel. For male subjects, the LTASS of Korean speakers was significantly lower than that of English speakers above 1.6 kHz except at 4 kHz and its difference was more than 5 dB, especially at higher frequencies. For women, the LTASS of Korean speakers showed significantly lower levels at 0.2, 0.5, 1, 1.25, 2, 2.5, 6.3, 8, and 10 kHz, but the differences were less than 5 dB. Compared with English speakers, the LTASS of Korean speakers showed significantly lower levels in frequencies above 2 kHz except at 4 kHz. The difference was less than 5 dB between 2 and 5 kHz but more than 5 dB above 6 kHz. CONCLUSIONS: To adjust the formula for fitting hearing aids for Koreans, our results based on the LTASS analysis suggest that one needs to raise the gain in high-frequency regions.

Direct measurement of ear canal volume in a pediatric population: can we explain its individual variation in terms of age and body weight?

OBJECTIVE: The aim of this work was to measure the external auditory canal (EAC) volume in children directly and to analyze its variation according to age and body weight. METHODS: This was a prospective study at a university-based, secondary referral hospital. Volumes of the bony and cartilaginous EACs were measured using a 1 ml tuberculin syringe filled with 95% ethyl alcohol before inserting ventilation tube(s). Three hundred thirty-eight ears from 194 children (107 boys and 87 girls) were enrolled in this study (mean age=58.8 ± 25.2 months). They were between the 10th and 90th percentiles for age and gender based on the 2007 growth chart for Korean children. RESULTS: EAC volume tended to increase with age. The volumes of cartilaginous and total EACs were significantly larger in boys than in girls. The volume of the bony EAC was significantly larger in right than in left ears. Under the assumption that EAC volume is a linear function of age as well as body weight, these factors explained less than one-third of overall variation. Preferably, the growth of EAC seemed to be not linear with aging in pediatric population. CONCLUSIONS: Our cubic model seemed to be more fit to the growth of EAC than simple linear model did and age and body weight alone were not clinically useful predictors of ear canal volume needed for the fitting of hearing aids in pediatric population. Because this variation can result in a large variation of real ear to coupler difference (RECD), this study supports that individual measurement of the RECD is crucial for fitting appropriate hearing aids in children.

How close should a student with unilateral hearing loss stay to a teacher in a noisy classroom?

OBJECTIVE: To determine the optimal seating position in a noisy classroom for students with unilateral hearing loss (UHL) without any auditory rehabilitation as compared to normal-hearing adults and student peers. DESIGN: Speech discrimination scores (SDS) for babble noise at distances of 3, 4, 6, 8, and 10 m from a speaker were measured in a simulated classroom measuring 300 m3 (reverberation time = 0.43 s). STUDY SAMPLE: Students with UHL (n = 25, 10-19 years old), normal-hearing students (n = 25), and normal-hearing adults (n = 25). RESULTS: The SDS for the normal-hearing adults at the 3, 4, 6, 8, and 10 m distances were 90.0±6.4%, 84.7±7.9%, 80.6±10.0%, 75.5±12.6%, and 68.8±13.0%, respectively. Those for the normal-hearing students were 90.1±6.2%, 78.1±9.4%, 66.4±10.7%, 61.8±11.2%, and 60.8±10.9%. Those for the UHL group were 81.7±9.0%, 70.2±12.4%, 62.1±17.2%, 52.4±17.1%, and 48.9±17.9%. The UHL group needed a seating position of 4.35 m to achieve an equivalent mean SDS as those for normal-hearing adults seated at 10 m. Likewise, the UHL group needed to be seated at 6.27 m to have an equivalent SDS as the normal-hearing students seated at 10 m. CONCLUSIONS: Students with UHL in noisy classrooms require seating ranging from 4.35 m to no further than 6.27 m away from a teacher to obtain a SDS comparable to normal hearing adults and student peers.

Clinical experience of 71 cases of congenital middle ear cholesteatoma.

CONCLUSIONS: As congenital middle ear cholesteatoma (CMC) is a different disease entity from acquired cholesteatoma, early diagnosis is important for good treatment results. Preoperative computed tomography (CT) imaging is a useful modality for both evaluation of the extent of the disease and selection of appropriate surgical methods. Some modification should be considered based on the findings of the actual operative field for complete removal of CMC. OBJECTIVES: To present the results of surgical treatment of 71 cases of CMC and investigate the applicability of preoperative CT for the treatment of CMC. PATIENTS AND METHODS: A retrospective study over an 11-year period was performed. The presenting symptoms, tympanic membrane findings, surgical findings, methods, and results were investigated retrospectively. RESULTS: CMC was found incidentally in 38 cases (53.5%). A whitish mass medial to the tympanic membrane was observed in 62 cases (87%). Postoperative air-bone gap changes were not statistically significant. There was no predominance of localized lesions of the middle ear. The recurrence rate was 9.9% (seven cases), and higher in open type. Staging by CT and surgical staging matched in 70.4%. Positive predictive value for mastoid involvement of CT staging was 72.7%, with sensitivity and specificity of 68.6% and 87.5%, respectively.

Binaural interactions of electrically and acoustically evoked responses recorded from the inferior colliculus of guinea pigs.

Binaural interactions within the inferior colliculus (IC) elicited by electric and acoustic stimuli were investigated in this study. Using a guinea pig model, binaural acoustic stimuli were presented with different time delays, as were combinations of binaural electric and acoustic stimuli. Averaged evoked potentials were measured using electrodes inserted into the central nucleus of the IC to obtain the binaural interaction component (BIC), computed by subtracting the sum of the two monaural responses from the binaural response. The BICs to acoustic-acoustic stimulation and electric-acoustic stimulation were found to be similar. The BIC amplitude increased with stimulus intensity, but the shapes of the delay functions were similar across the levels tested. The gross-potential data are thus consistent with the thesis that the central auditory system processes binaural electric and acoustic stimuli in a similar manner. These results suggest that the binaural auditory system can process combinations of electric and acoustic stimulation presented across ears and that evoked gross potentials may be used to measure such interaction.