Cochlear Implantation Via a Scala Vestibuli in Postmeningitic Ossified Cochlea / 대한이비인후과학회지

Obstruction of the fluid spaces of the cochlea was previously thought to contraindicate cochlear implantation due to difficulties of electrodes insertion and questions about potential benefits. However, the concept of implantation of ossified cochlea and its subsequent acceptance have progressed rapidly. A 62-year-old man complained of both hearing loss after meningitis and temporal bone CT scan showed partial obliteration of cochlea bilaterally. We fully inserted 22 active electrodes via scala vestibuli without difficulty. The purpose of this study is to determine the safety and efficacy of scala vestibuli electrode insertion in partially ossified cochlea.

Mismatch Negativity according to the Changes of Auditory Stimuli / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Infrequent sounds (deviant stimuli) occurring in a sequence of repetitive sounds (standard stimuli) elicit an event-related potential response called the mismatch negativity (MMN) even in the absence of attention to these sounds. The purposes of these studies are to record the MMNs elicited by the changes of auditory stimuli in stimulation rate, duration and probability in healthy adults and to record the MMNs in healthy children. SUBJECTS AND METHOD: Three studies were performed. The subjects were 15 adults in study 1, 20 adults in study 2, and 22 children in study 3. The standard stimulus was 50 msec, 750 Hz, 80 dB SPL tone burst. In study 1, the deviant stimulus was 750 Hz, 80 dB SPL tone burst, in which duration of the deviant stimulus was varied (25, 75, 100, 125, 150 msec) and stimulation rate was varied (0.9/sec, 2/sec). In study 2, the deviant stimulus was 125 msec, 750 Hz, 80 dB SPL tone burst and the probabilities of the deviant stimulus were varied (40, 35, 30, 25, 20, 15, 10, 5%). In study 3, the deviant stimulus was 125 msec, 750 Hz, 80 dB SPL tone burst and the probability of the deviant stimulus was 20%. RESULTS: We obtained stable MMNs in adults and children. The amplitude of MMN was largest when duration of the deviant stimulus, stimulation rate and probability of the deviant stimulus were 125 msec, 0.9/sec and 5% respectively. CONCLUSION: The MMNs can be obtained from healthy adults and cooperative children. The MMN could be used as an objective measure for central auditory processing and individual discrimination ability.

Comparison of Auditory Brainstem Response and Auditory Steady-State Response Thresholds in Infants and Young Children / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The aim of this study was to assess the accuracy of threshold estimates determined by the auditory steady-state response (ASSR) in a group of sedated infants and young children with a range of hearing losses. MATERIALS AND METHOD: Two studies were performed because the behavioral audiometric information was not available from infants and young children. In the first study, a retrospective analysis was performed for 36 children (mean age: 3 years 4 months) who had completed auditory brainstem response (ABR) and pure tone audiometry to verify that ABR threshold is a good predictor for pure tone threshold in our laboratory. The ABR thresholds to 500 Hz, 1000 Hz tone-pip and click were compared with behavioral thresholds. In the second study, a prospective analysis of 23 children (mean age: 12 months), the ABR thresholds to 500 Hz, 1000 Hz tone-pip and click were compared with ASSR thresholds to amplitude and frequency modulated tones. RESULTS: The first study in which strong correlations were found between ABR and pure tone thresholds (r> or =0.92) demonstrated that ABR thresholds could be used to predict the pure tone thresholds. The second study which showed that ASSR thresholds were highly correlated with ABR thresholds (r> or =0.93) indicated that ASSR thresholds provided reliable audiometric information in infants and young children. CONCLUSION: These studies showed that ASSR could be used to estimate hearing thresholds with reliable accuracy in infants and young children.

Auditory Neuropathy: A Report of Three Cases / 대한이비인후과학회지

Auditory neuropathy is a hearing disorder characterized by an absent or severely abnormal auditory brainstem response, with preservation of the cochlear microphonics and otoacoustic emissions. This suggests that outer hair cell (OHC) function is normal but that auditory function proximal to the OHCs is impaired. These patients demonstrate mild to severe hearing loss for pure tones and impaired word discrimination out of proportion to pure tone loss. Hearing aid alone is of little or no benefit in patients with auditory neuropathy. Visual support via cued speech or signed language can be a fail-safe method for insuring language development. Recently, there are some reports that cochlear implantation is highly successful in patients with auditory neuropathy. We report three cases (two children and one woman) with auditory neuropathy. Each patient was tested with cochlear microphonics, otoacoustic emissions, auditory brainstem response and middle latency response, etc. All three patients had normal cochlear microphonics or otoacoustic emissions with absent auditory brainstem response. Two of them had evidence of a peripheral neuropathy. We should be aware of auditory neuropathy and implications for its management, which differs from treatment of sensorineural hearing loss. Auditory neuropathy also raises a concern about the risk of false-negative findings when newborn hearing screening is restricted to otoacoustic emissions.

A Clinical Study on Back Pain after Lumbar Puncture on Aseptic Meningitis

PURPOSE: This study is to assess the occurence rate, severity, and duration of the back pain after lumbar puncture. METHODS: The occurence rate, severity and duration of the back pain that developed after lumbar puncture were recorded prospectively in patients with aseptic meningitis who had been admitted to the department of Pediatrics, St. Benedict Hospital in Pusan, from May 1993 to July 1993. The cases with traumatic taps, repeated taps, undelying diseases and age group below 2 year were excluded. The overall number of cases included in this study was 136. RESULTS: 1) In the 136 patients, back pain was developed in 53 cases (39.0%) after lumbar puncture and mean age of 53 cases was 5.4+/-2.8 years and male to female ratio was 1.4:1. 23 cases (16.9%) were mild, 17 cases (12.5%) were moderate and 13 cases (9.6%) were severe. 2) On each age group, the incidence of back pain was as followed : These were 21 patients (38.9%) out of 54 cases in group 1 (2-4 yrs), 22 patients (37.3%) out of 59 cases in group 2 (5-8 yrs) and 10 patients (43.5%) out of 23 cases in group 3 (9-12yrs). After lumbar puncture, there were no significant correlations between occurence rate of back pain and age groups. 3) The mean intervals between onset of back pain and lumbar puncture were 0.5 day in 8 patients, 0.5-1.0 day in 25 patients (47.2%), 1.0-1.5 days in 12 patients (22.6%), and 1.5-2.0 days in 4 patients. 4) The mean duration of the back pain was 2.4+/-1.3 days, and 1.4+/-0.8 days in mild pain group, 2.9+/-1.2 days in moderate pain group and 3.3+/-1.2 days in severe pain group. The mean duration of the back pain was significantly longer in moderate and severe pain groups than mild pain group (p<0.01). CONCLUSIONS: In the patient with aseptic meningitis, occurence rate of the back pain after lumbar puncture was 39.0%. All back pain were subsided within six days after onset of pain.