Childhood fever and hearing loss associated with CAPOS syndrome.

CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss) syndrome is a rare genetic disorder caused by the heterozygous mutation, c.2452G > A, in the ATP1A3 gene. CAPOS syndrome involves a characteristic episode in which neuropathy develops after a fever in childhood, and here, we describe the case of a patient with CAPOS syndrome. The patient had repeated episodes of a fever around 74 months of age. Although he could speak at 23 months of age, he presented with hearing difficulty after the fever. Pure-tone audiometry revealed moderate-to-severe bilateral sensorineural hearing loss, and auditory brainstem response (ABR) showed poor response in the both ears. Auditory stead-state response (ASSR) produced relatively consistent results compared to pure-tone audiometry. A mutation in the ATP1A3 gene was detected through genetic testing. In CAPOS syndrome, a genetic mutation leads to desynchronization during neural firing. We believe that this desynchronization in neural firing is responsible for the lack of response in the ABR and the presence of a response in the ASSR. In this patient, we attribute the response detection in ASSR to its greater tolerance for errors in the timing of neural firing compared to ABR.

Systemic cisplatin increases the number of patients showing positive off-frequency masking audiometry.

OBJECTIVE: The study aimed to evaluate the effect of systemic cisplatin administration on off-frequency masking audiometry. METHODS: Among 26 patients receiving systemic cisplatin, 48 ears were included in the analysis. All patients underwent pure-tone audiometry with ipsilateral narrow-band masking noise (off-frequency masking audiometry). In the off-frequency masking audiometry, 70 dBHL band-pass noise (center frequency 1000 Hz, 1/3 octave bandwidth) was administered to the tested ear. The acquired thresholds were compared to those of standard pure-tone audiometry, and threshold elevations greater than 10 dB were regarded as significant. The number of patients showing abnormal threshold elevation was compared between before and after the cisplatin administration. RESULTS: Before cisplatin administration, 91.7, 93.8, 97.9, and 93.8% of ears showed normal off-frequency masking audiometry outcomes at 125, 250, 6000, and 8000 Hz, respectively. After cisplatin administration, a higher number of patients showed abnormal off-frequency masking audiometry outcomes. This change was more prominent with increasing doses of cisplatin. After the cisplatin administration of 100∼200 mg/m2, the prevalence of patients with normal off-frequency masking audiometry outcomes was 77.3, 70.5, 90.9, and 88.6% at 125, 250, 6000, and 8000 Hz, respectively. At 250 Hz, the change was statistically significant (p = 0.01, chi-squared test).

A Case of Actinomycosis in the Rosenmüller's Fossa.

Actinomycosis is an infrequent infectious disease caused by Actinomyces species. Actinomycoses in the nasopharynx are extremely rare, especially in the Rosenmüller's fossa. This report presents a case of actinomycosis in the Rosenmüller's fossa. A 75-year-old woman presented with a 6-month history of bloody sputum. A grayish-white caseous tissue was found in the right Rosenmüller's fossa after retracting the torus tubarius. Magnetic resonance imaging showed a well-defined lesion with low-signal intensity on T1- and T2-weighted images; small low-signal areas were interspersed inside. The lesion was removed under an endoscope. Histopathological examination revealed eosinophilic, club-shaped structures surrounding a hematoxylophilic center, leading to the diagnosis of actinomycosis. The symptoms improved after 3 months of amoxicillin administration but recurred quickly. After 6 months of amoxicillin administration, the bloody sputum disappeared, and local and imaging findings were normal.

Effect of hearing aids on body balance function in non-reverberant condition: A posturographic study.

OBJECTIVE: The purpose of this study was to evaluate the effect of hearing aids on body balance function in a strictly controlled auditory environment. METHODS: We recorded the findings of 10 experienced hearing aid users and 10 normal-hearing participants. All the participants were assessed using posturography under eight conditions in an acoustically shielded non-reverberant room: (1) eyes open with sound stimuli, with and without foam rubber, (2) eyes closed with sound stimuli, with and without foam rubber, (3) eyes open without sound stimuli, with and without foam rubber, and (4) eyes closed without sound stimuli, with and without foam rubber. RESULTS: The auditory cue improved the total path area and sway velocity in both the hearing aid users and normal-hearing participants. The analysis of variance showed that the interaction among eye condition, sound condition, and between-group factor was significant in the maximum displacement of the center-of-pressure in the mediolateral axis (F [1, 18] = 6.19, p = 0.02). The maximum displacement of the center-of-pressure in the mediolateral axis improved with the auditory cues in the normal-hearing participants in the eyes closed condition (5.4 cm and 4.7 cm, p < 0.01). In the hearing aid users, this difference was not significant (5.9 cm and 5.7 cm, p = 0.45). The maximum displacement of the center-of-pressure in the anteroposterior axis improved in both the hearing aid users and the normal-hearing participants.

Multicenter Study of Congenital Middle Ear Anomalies. Report on 246 Ears.

OBJECTIVES/HYPOTHESIS: Congenital middle ear anomalies represent a relatively rare condition. This study aimed to describe the characteristics and the surgical outcomes for patients with middle ear anomalies. METHODS: A multicenter study was conducted of consecutive patients with congenital middle ear anomalies who underwent primary surgical treatment between January 2008 and December 2017. Demographics, surgical procedures, and audiometric data were registered into the institutional database. Hearing changes and postoperative air-bone gap (ABG) were evaluated 1 year after surgery. RESULTS: A total of 246 patients (246 ears) (median age: 14 years, range: 4-75 years old) were included in this study. Anomalies were subdivided using the Teunissen and Cremers classification: 53 ears (22%) were categorized as class I, comprising only stapes ankylosis; 35 ears (14%) as class II, having ossicular chain anomalies with stapes ankylosis; 139 ears (57%) as class III, having ossicular chain anomalies with a mobile stapes-footplate; and 19 ears (8%) as class IV, with aplasia of the oval window. Evaluation of hearing outcomes for 198 ears with more than 1 year of follow-up revealed that good postoperative ABG (≤20 dB) was achieved in 82% of class I, 68% of class II, 74% of class III, and 23% of class IV anomalies. The postoperative ABG in class IV was significantly worse than in class I (P < .001) or class III (P < .01). CONCLUSIONS: This study demonstrated that class III anomalies comprised the majority of middle ear anomalies and surgical outcomes for class IV anomalies are unfavorable. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2323-E2328, 2021.

Central processing of speech sounds and non-speech sounds with similar spectral distribution: An auditory evoked potential study.

OBJECTIVE: The purpose of this study was to measure the auditory evoked potentials for speech and non-speech sounds with similar spectral distributions. METHODS: We developed two types of sounds, comprising naturally spoken vowels (natural speech sounds) and complex synthesized sounds (synthesized sounds). Natural speech sounds consisted of 5 Japanese vowels. Synthesized sounds consisted of a fundamental frequency and its second to fifteenth harmonics equivalent to those of natural speech sounds. The synthesized sound was filtered to have a similar spectral distribution to that of each natural speech sound. These sounds were low-pass filtered at 2000 Hz. The auditory evoked potential elicited by the natural speech sound /o/ and synthesized counterpart for /o/ were measured in 10 right-handed healthy adults with normal hearing. RESULTS: The natural speech sounds were significantly highly recognized as speech compared to the synthesized sounds (74.4% v.s. 13.8%, p < 0.01). The natural speech and synthesized sounds for the vowel /o/ contrasted strongly for speech perception (96.9% vs. 9.4%, p <0.01). However, the vowel /i/ and its counterpart were barely recognized as speech (4.7 v.s. 3.1%, p = 1.00). The N1 peak amplitudes and latencies evoked by the natural speech sound /o/ were not different from those evoked by the synthesized sound (p = 0.58 and p = 0.28, respectively). The P2 amplitudes evoked by the natural speech sound /o/ were not different from those evoked by the synthesized sound (p = 0.51). The P2 latencies evoked by the natural speech sound /o/ were significantly shorter than those evoked by the synthesized sound (p < 0.01). This modulation was not observed in a control study using the vowel /i/ and its counterpart (p = 0.29). CONCLUSION: The early P2 observed may reflect central auditory processing of the 'speechness' of complex sounds.

Detectability of minute temporal bone structures with ultra-high resolution CT.

OBJECTIVE: Computed tomography (CT) is the imaging tool of choice in the diagnosis of temporal bone lesions. With the recent progress in imaging technology, CT with higher spatial resolution (Ultra-high resolution CT) has become available in the clinical setting. The purpose of this study is to evaluate the visibility of small temporal bone structures using ultra-high resolution CT. MATERIAL AND METHODS: The visibility of 27 minute temporal bone structures on ultra-high resolution CT images was evaluated. Non-helical axial scans were performed in 18 normal hearing ears without previous otologic diseases. Visibility was scored by an experienced radiologist and otologist. RESULTS: Minute temporal bone structures including the ossicular chain, the crus of the stapes, the greater superficial petrosal nerve, and the anterior malleolar ligament were clearly visualized on ultra-high resolution CT. The stapedius muscle tendon and the chorda tympani exiting the posterior canaliculus and coursing medial to the malleus could be visualized. CONCLUSION: Ultra-high resolution CT provides good visualization of small temporal bone structures in normal subjects.

Intraoperative Evaluation of Cochlear Implant Electrodes Using Mobile Cone-Beam Computed Tomography.

OBJECTIVE: To evaluate the electrode status during cochlear implantation (CI) using mobile cone-beam CT (mCBCT). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral hospital. PATIENTS: Fifty-seven patients (7 bilateral surgeries, 64 ears) who underwent CI and who received intraoperative mCBCT imaging. INTERVENTION: CI and CBCT during surgery. MAIN OUTCOME MEASURE: Electrode location and angular insertion depth determined by intraoperative mCBCT images. RESULTS: There were six cases with cochlear malformation where intraoperative mCBCT was useful to confirm electrode location. Of 58 ears with a normal cochlear morphology, perimodiolar, straight, and mid-scalar electrodes were used in 30 (cochleostomy; 14 advance off-stylet technique cases), 27 (26 round window [RW] insertion, 1 extended round window [ERW] insertion), and 1 (RW insertion) ears, respectively. Complete scala-tympani (ST) insertion was achieved in 35 ears (14 cochleostomy, 21 RW or ERW insertion). The complete ST-insertion rate was significantly higher with RW or ERW insertion than that for cochleostomy insertion (p = 0.03), although cochleostomy insertion using the advanced off-stylet technique had a similar rate to RW or ERW insertion. The angular insertion depth values (average ±â€Šstandard deviation) for perimodiolar electrodes (354.4 ±â€Š29.44 degrees) were significantly smaller than those for Flex24 (464.8 ±â€Š43.09 degrees) and Flex28 (518.2 ±â€Š61.91 degrees) electrodes (p < 0.05). CONCLUSIONS: Evaluation of CI electrodes using intraoperative mCBCT was comparable to that with fan-beam CT or c-arm-based CBCT. Considering the low radiation dose of mCBCT and its availability in any operation room, mCBCT is the better modality for evaluating cochlear implant electrode arrays.

Body balance function of cochlear implant patients with and without sound conditions.

OBJECTIVE: The relation between well-controlled auditory stimulation through cochlear implant (CI) and the body balance has been sparsely investigated. The purpose of this study was to evaluate the body balance function of CI patients with- and without-sound in anechoic sound-shielded room. METHODS: We recorded 8 experienced CI recipients and 8 young normal-hearing volunteers. All subjects were assessed using posturography under 4 conditions: (1) eyes open with-sound, (2) eyes closed with-sound, (3) eyes open without-sound, and (4) eyes closed without-sound. RESULTS: The total path length and the total area were significantly larger in the eyes closed condition than in the eyes open condition. In normal hearing subjects, the average displacement of center of pressure (COP) in the mediolateral direction under with-sound condition was not different from that under without-sound condition. In CI recipients, the COP significantly displaced to the CI side after the deprivation of visual cues in without-sound condition. This shift was eliminated in with-sound condition (significant interaction among sound condition, eye condition, and between-group factor). CONCLUSION: In CI subjects, sound stimulation improves the abnormal displacement of COP in the mediolateral direction. SIGNIFICANCE: A posturographic study under an anechoic condition proved that sound stimulation improves body balance function in CI subjects.

Cochlear implant function in a patient with Jervell and Lange-Nielsen syndrome after defibrillation by countershock.

Jervell and Lange-Nielsen syndrome (JLNS), a rare autosomal recessive congenital QT prolongation syndrome, is characterized by cardiac arrhythmias, syncopal episodes, and profound deafness. A cochlear implant (CI) for patients with JLNS is expected to result in hearing improvement. Sometimes, defibrillation is required if a patient experiences lethal arrhythmia. In this paper, we report a pediatric patient with JLNS who received defibrillation after CI surgery in his right ear at the age of 2 years. With intensive care, the post-operative course was uneventful, and the patient acquired satisfactory speech and hearing abilities. Five years after the surgery, he underwent defibrillation because of the incidence of syncopal attack. Thereafter, arrhythmic syncope recurred three times, which necessitated defibrillation therapy. To prevent recurrence of cardiac arrhythmia, he underwent ICD (implantable cardioverter-defibrillator) implantation at the age of 11 years. At present, CI works well and provides good hearing, while syncopal attack is prevented by ICD. From the experience of this case, electronic circuit of CI is thought to tolerate emergency countershock if the speech processor is removed.

Papercraft temporal bone in the first step of anatomy education.

OBJECTIVE: (1) To compare temporal bone anatomy comprehension taught to speech therapy students with or without a papercraft model. (2) To explore the effect of papercraft simulation on the understanding of surgical approaches in first-year residents. METHODS: (1) One-hundred and ten speech therapy students were divided into three classes. The first class was taught with a lecture only. The students in the second class were given a lecture and a papercraft modeling task without instruction. The third class modeled a papercraft with instruction after the lecture. The students were tested on their understanding of temporal bone anatomy. (2) A questionnaire on the understanding of surgical approaches was completed by 10 residents before and after the papercraft modeling. The papercraft models were cut with scissors to simulate surgical approaches. RESULTS: (1) The average scores were 4.4/8 for the first class, 4.3/8 for the second class, and 6.3/8 for the third class. The third class had significantly better results than the other classes (p<0.01, Kruskal-Wallis test). (2) The average scores before and after the papercraft modeling and cutting were 2.6/7 and 4.9/7, respectively. The numerical rating scale score significantly improved (p<0.01, Wilcoxon signed-rank test). CONCLUSION: The instruction of the anatomy using a papercraft temporal bone model is effective in the first step of learning temporal bone anatomy and surgical approaches.

Histopathological evaluation and long-term results of soft tissue preservation technique in cholesteatoma surgery.

The goal of cholesteatoma surgery is total removal of the cholesteatoma matrix and prevention of recurrence. Preservation of soft tissue in the attic is reported to improve post-operative middle ear aeration, and thus prevents recurrence. However, the histology and nature of the preserved tissue have rarely been reported. The aim of this study is to clarify the histology of the preserved soft tissue in cholesteatoma surgery, and to show its relationship to the clinical course. Surgical specimens were obtained from ten patients with pars flaccida-type cholesteatoma. In these patients, cholesteatoma occupied the attic and the mastoid cavity. The cholesteatoma was removed so as not to expose the bone in the attic. After the removal of the lesions, soft tissue was harvested from the floor of the attic, using cupped forceps. The specimens were fixed with 10 % formalin, and stained with hematoxylin-eosin. The patients were followed-up for 8 years after the surgery. No patients showed post-operative inner ear disturbance or facial nerve palsy. In one patient, residual lesion was found during the revision surgery. The area of residual lesion was not explored during the first operation. Two other patients showed recurrent cholesteatoma in the pars tensa; one of these patients had accompanying otorrhea. The other seven patients showed no residual or recurrent cholesteatoma 8 years after the surgery. The histological examination showed that the harvested tissue was mainly composed of collagen fiber and fibroblasts. Ciliary epithelial cells were found in one patient. In three patients, cysts of mucosal remnants (glandular cysts), were embedded in the connective tissue. Two of these three patients experienced recurrent cholesteatoma, while the other seven patients were without recurrence at follow-up. Preservation of soft tissue behind the cholesteatoma matrix is a safe technique if the surgical field is fully visible. In most cases, the preserved tissue was fibrous connective tissue and lacked the characteristics of mucosa. The glandular cysts in the preserved soft tissue seem to be related to the recurrence of cholesteatoma.

Temporal bone chondroblastoma totally invisible on MRI.

We report a case of temporal bone chondroblastoma that was totally invisible on MRI. The patient was a 64-year-old man who presented with several months history of vertigo. The CT scan with bone window setting showed destruction of the temporomandibular joint, the floor of the middle cranial fossa, and the superior semicircular canal. Calcific foci were seen within the tumor. On MR imaging, the tumor, situating mainly medial to the temporomandibular joint, showed no signal on both T1- and T2-weighted images. The tumor was not enhanced with gadolinium. In summary, the tumor was totally signal negative or "invisible" on pre- and postcontrast T1- and T2-weighted images. The tumor was resected through transpetrosal - transzygomatic approach.

Prognostic impact of salvage treatment on hearing recovery in patients with sudden sensorineural hearing loss refractory to systemic corticosteroids: A retrospective observational study.

OBJECTIVE: To determine the prognostic factors for hearing recovery in patients with sudden sensorineural hearing loss (SSHL) refractory to systemic corticosteroids following salvage treatment. METHODS: This is a retrospective observational study at nine tertiary referral hospitals. A total of 120 patients with sudden deafness refractory to systemic corticosteroids were enrolled. The patients were randomly assigned to receive topical application of recombinant human IGF-1 or intratympanic injection of dexamethasone as salvage treatment. Multiple regression analysis was performed to identify determinants of hearing recovery using pure tone audiometry results at 8 weeks after treatment. Clinical predictors that were evaluated included age, sex, pretreatment hearing level, presence of vertiginous symptoms, days to study entry from symptom onset and salvage treatment assignment (IGF-1 vs. dexamethasone). RESULTS: The linear regression model identified age (P=0.001), pretreatment hearing level (P<0.001), days to study entry from symptom onset (P=0.011) and treatment assignment (P=0.033) at 8 weeks after treatment as significant variables influencing the recovery of pure tone audiometry average thresholds. Younger age (<60 years), early initiation of salvage treatment and treatment with topical IGF-1 therapy had significant effects on hearing recovery. CONCLUSION: The results indicate that early initiation and choice of treatment modalities for salvage treatment may be important for the prognosis of patients with refractory SSHL. The positive effect of topical IGF-1 therapy on hearing recovery indicates its utility as salvage treatment.

The sensitivity and accuracy of a cone beam CT in detecting the chorda tympani.

The facial recess approach through posterior tympanotomy is the standard approach in cochlear implantation surgery. The size of the facial recess is highly variable, depending on the course of the chorda tympani. Despite their clinical importance, little is known about the sensitivity and accuracy of imaging studies in the detection of the chorda tympani. A total of 13 human temporal bones were included in this study. All of the temporal bones were submitted to a cone beam CT (Accuitomo, Morita, Japan). The multi-planar reconstruction images were rotated around the mastoid portion of the facial nerve to locate the branches of the facial nerve. A branch was diagnosed as the chorda tympani when it entered the tympanic cavity near the notch of Rivinus. The distance between the bifurcation and the tip of the short crus of the incus was measured. In all temporal bones, the canal of the chorda tympani or the posterior canaliculus was detected. In the CT-based evaluation, the average distance from the bifurcation to the incus short crus was 12.6 mm (8.3-15.8 mm). The actual distance after dissection was 12.4 mm (8.2-16.4 mm). The largest difference between the distances evaluated with the two procedures was 1.1 mm. Cone beam CT is very useful in detecting the course of the chorda tympani within the temporal bone. The measured distance is accurate.

The Outcome of Cochlear Implantation for Mitochondrial Disease Patients With Syndromic Hearing Loss.

OBJECTIVES: To evaluate the outcome and to confirm the validity of cochlear implantation for syndromic deafness in patients with mitochondrial disease. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: We reviewed medical charts of 367 cochlear implantation cases at Kyoto University Hospital between 1987 and 2012. We identified five patients with syndromic mitochondrial disease who underwent cochlear implantation surgery. The mean age of the patients (four women and one man) when they underwent surgeries was 44.4 years (range, 30-64 yr; median, 41 yr). INTERVENTIONS: Therapeutic and rehabilitative. MAIN OUTCOME MEASURE: In four of five patients, speech perception performance was measured using Japanese vowels, consonant-vowel syllables, and short sentences. RESULTS: Only 1.4% (5 of 367) of cochlear implantation cases at Kyoto University Hospital underwent cochlear implantation surgery because of syndromic mitochondrial diseases. Four of those patients showed significantly improved speech perception outcomes, and the beneficial effects of the intervention continued long after surgery. One patient could not perform speech perception test presumably because of poor cognitive function. CONCLUSION: Mitochondrial disease patients who underwent cochlear implantation surgery sustained gains in hearing performance even long after surgery. A single patient showed poor postoperative speech perception associated with cognitive problems. Cochlear implantation for mitochondrial disease patients seems to be a viable treatment option in the absence of significant cognitive impairment.

A randomized controlled clinical trial of topical insulin-like growth factor-1 therapy for sudden deafness refractory to systemic corticosteroid treatment.

BACKGROUND: To date, no therapeutic option has been established for sudden deafness refractory to systemic corticosteroids. This study aimed to examine the efficacy and safety of topical insulin-like growth factor-1 (IGF-1) therapy in comparison to intratympanic corticosteroid therapy. METHODS: We randomly assigned patients with sudden deafness refractory to systemic corticosteroids to receive either gelatin hydrogels impregnated with IGF-1 in the middle ear (62 patients) or four intratympanic injections with dexamethasone (Dex; 58 patients). The primary outcome was the proportion of patients showing hearing improvement (10 decibels or greater in pure-tone average hearing thresholds) 8 weeks after treatment. The secondary outcomes included the change in pure-tone average hearing thresholds over time and the incidence of adverse events. RESULTS: In the IGF-1 group, 66.7% (95% confidence interval [CI], 52.9-78.6%) of the patients showed hearing improvement compared to 53.6% (95% CI, 39.7-67.0%) of the patients in the Dex group (P = 0.109). The difference in changes in pure-tone average hearing thresholds over time between the two treatments was statistically significant (P = 0.003). No serious adverse events were observed in either treatment group. Tympanic membrane perforation did not persist in any patient in the IGF-1 group, but did persist in 15.5% (95% CI, 7.3-27.4%) of the patients in the Dex group (P = 0.001). CONCLUSIONS: The positive effect of topical IGF-1 application on hearing levels and its favorable safety profile suggest utility for topical IGF-1 therapy in patients with sudden deafness. TRIAL REGISTRATION: UMIN Clinical Trials Registry Number UMIN000004366, October 30th, 2010.

Peripheral facial palsy caused by neoplastic meningitis.

OBJECTIVES/HYPOTHESIS: To describe the clinical presentation of peripheral facial palsy caused by neoplastic meningitis. STUDY DESIGN: Retrospective case series. METHODS: Retrospective review, including accompanying symptoms and magnetic resonance imaging (MRI) findings. RESULTS: Between January and December 2011, six patients were diagnosed with peripheral facial palsy caused by neoplastic meningitis. The patient age at presentation ranged from 56 to 77 years. The tumor origins were as follows: malignant lymphoma (n = 3), lung cancer (n = 2), and kidney cancer (n = 1). In three patients, sudden sensorineural hearing loss accompanied the facial palsy. Three patients were judged to be tumor-free at the onset of the facial palsy. In two patients, the malignancy was not diagnosed at the onset of facial palsy and hearing loss. Only one patient was diagnosed as having a tumor at the onset of the facial palsy. On the MRI, a mass lesion was detected in the internal auditory canals (IAC) of four patients; one had a solitary IAC tumor. In this patient, the diagnosis required a histopathological study using a translabyrinthine approach. In the other two patients, the facial nerve was enhanced with gadolinium, but it was difficult to differentiate the observed condition from Bell's palsy. In these patients, repeated cytological studies led to the correct diagnoses. CONCLUSIONS: The clinical symptoms and MRI findings of peripheral facial palsy caused by neoplastic meningitis sometimes mimic those of benign facial palsy.

Preattentive processing of horizontal motion, radial motion, and intensity changes of sounds.

Localization of sound sources is critical for an appropriate behavioral response. This is not only true for localization in the horizontal plane but also for localization in depth. Depth ranging of sound sources implicates various distance cues, among others sound intensity. In this study, we measured human electroencephalography and compared mismatch negativity (MMN) amplitudes and latencies for horizontal motion, radial motion, and pure intensity changes in the free field. We observed similar MMN latencies for horizontal and radial motion, whereas MMN responses to pure intensity changes were comparably delayed. MMN amplitudes and latencies were not different for approaching and receding sounds. Our data suggest similar fast processing for horizontal and radial motion, whereas pure intensity changes are possibly processed with less priority.

Detection of the petrosquamosal sinus in chronic otitis media using high-resolution CT.

OBJECTIVE: To evaluate the prevalence of the persistent petrosquamosal venous sinus in patients with chronic otitis media using a high-resolution CT scan. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Eighty-four patients older than 6 years of age underwent surgery (in a total of 92 ears) for chronic otitis media at Kyoto University Hospital, Department of Otolaryngology-Head and Neck Surgery. We used high-resolution CT scans to evaluate the prevalence and size of persistent petrosquamosal sinuses, as well as their relative position to the middle fossa. RESULTS: A petrosquamosal sinus was detected in 42 (45.7%), a higher frequency than in ears without chronic otitis media (10.3%). The diameter of the sinuses was <1.0 mm in 20 ears, 1.0 mm to 2.0 mm in 17 ears, and >2.0 mm in 5 ears. The petrosquamosal sinus was positioned inferior to the lowest part of the middle fossa in 10 ears. CONCLUSION: The petrosquamosal sinus was detected frequently in high-resolution CT scans in patients with chronic otitis media. In approximately half of the patients, the sinus was larger than 1 mm in diameter and may be encountered during mastoidectomy.