Han Dong-yi

Development of a script of phonemically balanced monosyllable lists of Mandarin–Chinese

Abstract Objectives To develop a set of monosyllable audiometry test material that can be used in speech recognition testing in Mandarin Chinese. Materials and Methods In an effort to improve reliability and efficiency in clinical practice, a set of 30 test lists of 25 monosyllable test items each was designed with consideration of the following: length of the list, phonemical balance (PB), word utility frequency, coverage of common words, and equivalency among lists. The 30 lists contained 750 monosyllabic words and were constructed on the basis of Chinese phoneme distribution probability summarized in the Manual of Acoustic. The occurrence incidence of the 22 consonants, 36 vowels, and 4 tones of the Chinese Mandarin characters in the 30 test lists were calculated. To achieve PB, 489 monosyllables were selected from the 2500 most commonly used Chinese characters and the 4000 most commonly used Chinese phrases to compile the 30 monosyllable test lists using a computer algorithm with manual adjustment. Results Thirty phonemical balanced word lists of common Mandarin Chinese monosyllabic words were compiled. Each list consisted of 25 monosyllables. A total of 489 phonemes (consonants, vowels and tones) were included in the set. Conclusions This set of lists can potentially be used as the basic lists for future development of Mandarin PB monosyllable speech test materials.

Screening of GJB2 mutations in Chinese population

Abstract The GJB2 gene (connexin 26) has been shown to be responsible for DFNB1 and DFNA3. We screened the GJB2 gene in 488 patients with prelingual deafness(Group 1), 124 with postlingual deafness(Group 2), and 117 normal hearing subjects (Group 3). We found that, in Group 1, 65 patients (13.32%) were homozygotes or compound heterozygotes and 51 patients (10.45%) carried a single pathogenic mutation. The 235delC mutation was the most frequent mutation, accounting for 73.22% of the known pathogenic alleles in Group 1. No homozygotes or compound heterozygotes were detected in Group 2 or Group 3. Some postlingual deaf patients (2.42%) and normal hearing subjects(4.27%) were 235delC carriers. Our preliminary data indicate that 235delC, the most frequent mutation identified in this study, is a major cause for prelingual deafness.

GJB2 mutation spectrum in deaf population in a typical southeastern area of China

Mutations in GJB2 gene are the most frequently found mutations in patients with nonsyndromic hearing impairment. However, the spectrum and prevalence of mutations in this gene vary among different ethnic groups. In China, 30,000 infants are born with congenital hearing impairment annually. In order to provide appropriate genetic testing and counseling to the families, we investigated the molecular etiology of nonsyndromic deafness in 103 unrelated school children attending Nantong School for the Deaf and Mute in Jiangsu Province, China. The coding exon of the GJB2 gene was PCR amplified and sequenced. Sixty two GJB2 mutant alleles were identified in 35.9% (37/103) of the patients. Twenty five patients carried two pathogenic mutations and 12 patients carried one mutant allele. The 235delC was the most common mutation accounting for 69.4% (43/62) of GJB2 mutant alleles. The GJB2 mutant alleles accounted for 30.1% (62/206) of all chromosomes responsible for nonsyndromic hearing impairment. Testing of the 3 most prevalent deleterious frame shift mutations in this cohort detected 100% of all GJB2 mutant alleles. These results demonstrate that an effective genetic testing of GJB2 gene for patients and families with nonsyndromic hearing impairment is possible.

ADVANCES IN SURGICAL TREATMENT OF ACOUSTIC NEUROMA

Acoustic Neuroma (AN) arises from the eighth cranial nerve. It primarily involves the vestibular branch of the nerve and is therefore also called vestibular schwannoma(VS). To the date, diagnosis and surgical treatment of AN have advanced significantly. Along with advances in audiology and imaging technologies, cases of diagnosed AN have been increasing, making it a common

Utility of Vibrant Soundbridge in Patients with Congenital Middle and Outer Ear Deformities

Abstract Objective To report use of the Vibrant Soundbridge (VSB) in patients with congenital deformation of the middle and outer ears and investigate its utility in this patient population. Method Four patients with congenital deformation of middle and outer ears underwent VSB implantation. All were male (aged 3-18 years, average 13.5 years) and operated on the left side. Malformation was bilateral in 3 patients and unilateral in 1 patient. Surgical techniques were modified to accommodate each patients unique conditions and needs. The implant site was approached via the facial recess in 3 patients and through a retro-facial nerve route in 1 patient. The VSB implant was connected to either the stapes (2 cases) or the round window (2 cases). Pure tone and speech audiometry results and daily communication capabilities before and after VSB activation were compared. Results The operations were successful in all patients, with no complications. The patient communication level improved significantly after VSB activation. Average air conduction pure tone threshold or conditioned reflex audiometry threshold improved by 35 dB in the 0.25-4 kHz range, from 69 dB HL before VSB activation to 34 dB HL after. The sentence recognition rate in quiet at 65 dB SPL went up to 86% from 0% without VSB for patients with bilateral deformation and remained at 100% for the patient with unilateral deformity. However, for the latter patient, the rate improved to 20% from 0% without VSB in noise (-8 dB SNR). Conclusion VSB is an excellent solution for improving hearing in patients with congenital deformation of middle and outer ears. Operation can be completed and good results can be achieved even in patients with unique conditions and needs.

Endoscope-Assisted Cerebellopontine Angle Surgery

Abstract Objective To report experiences with use of otoendoscopy in cerebellopontine angle (CPA) surgeries. Methods Twenty five cases of CPA surgeries performed between November 2002 and December 2008 in which microscope enabled otoendoscopy was used were reviewed.The 25 cases included 19 cases of acoustic neuroma, 3 cases of CPA facial nerve tumors, 1 case of trigeminal neurinoma, a case of glossopharyngeal neuralgia and 1 case of hemifacial spasm. Endoscopy was used in all cases together with monitoring of brainstem auditory responses and facial electromyography. Postoperative hearing and facial nerve function were evaluated and compared to pre-operative levels. Results Endoscopy provided improved visualization of local anatomy, revealed hidden lesions and reduced unnecessary anatomical distortions. Total resection was achieved in 18 of the 19 acoustic neuroma cases, Facial nerve anatomical integrity was preserved in all 19 cases. One week postoperative House-Brackmann grading was I in 3 cases, II in 10 cases and III in 6 cases. Facial nerve function continued to improve in some cases at 3 months. Total tumor resection was achieved in all 3 patients with facial neurinoma. The facial nerve was sacrificed in 2 of the 3 cases with primary faciohypoglossal nerve anastomosis. Facial nerve function was Grade II and Grade III one year after surgery, respectively. In the case with anatomically preserved facial nerve, postoperative facial nerve function was initially Grade III and improved to II at 3 months. The tumor was completely resected in the trigeminal neurinoma patient with a Grade III postoperative facial nerve function which improved Grade II three months later. Seventeen of the 19 patients with acoustic neuroma retained hearing postoperatively, of these 12 maintained preoperative levels of hearing. Preoperative hearing capacity was preserved in 2 of the 3 patients with facial nerve tumors, but lost in patients with other tumor types. Glossopharyngeal neurotomy (n=1) and microvascular decompression (n=1) resulted in satisfactory symptom relief and no recurrence at 5- and 3-year follow up, respectively Conclusions Otoendos aope-aided technique greatly helps surgical management of CPA and internal auditory canal lesions and other disorders. This minimally invasive technique overcomes many shortcomings inherent to the traditional retrosigmoid approach.

Congenital cholesteatoma of the middle ear – a report of 10 cases

Abstract Objectives To study clinical, imaging features and treatment outcomes of congenital cholesteatoma of middle ear (CCME). Methods This is a retrospective review of 10 CCME cases selected from 952 cholesteatoma cases treated between January 1995 and December 2005 at the Department of Otolaryngology-Head and Neck Surgery, Chinese PLA General Hospital. The main outcome measures were the site of origin, clinical features, surgical findings, imaging characteristics and hearing results. Results The mean age of the 10 patients was 16 years(ranged from 10 to 24 years), with 6 being older than 18 years. There were 7 males and 3 females. The average delay to diagnosis was longer than 2 years. The mean preoperative PTA was 55 dB HL, with a mean ABG of 45 dB. Typical cholesteatomas were seen behind the tympanic membrane in the superoposterior quadrant on otoscopy only in 2 patients. High resolution CT was completed in all patients. Most of the patients(8/10) were diagnosed with otosclerosis or ossicular abnormality before operation. All patients underwent a one-stage tympanoplasty following transmeatal explorative tympanotomy and complete cholesteatoma removal, except one, who underwent a CWU mastoidectomy due to extensive cholesteatoma involvement. The choleasteatoma lesion was confined to the superoposterior mesotympanum in all patients. The mean postoperative PTA was 20 dB HL. All patients were followed-up for at least 1.5 years postoperatively. Revision procedures were performed in 2 patients for hearing deterioration. No residual or recurrence of cholesteatoma was found. Conclusion CCME is a rare disease that often gets delayed diagnosis. Residual lesions and the prognosis mainly depend on the extent of the lesion.

Prevalence of the GJB2 Mutations in Deafness Patients of Different Ethnic Origins in Xinjiang

Abstract Objective To investigate GJB2 mutation prevalences in the Uigur and Han ethnic groups in Xinjiang, China, and determine the relationship between ethnicity and GJB2 gene mutations. Methods Information regarding ethnicity of patients’ families was obtained through medical records review and/or patient interview. Blood samples were collected from 61 Uigurs and 66 Hans for direct sequencing of the coding region and intron/exon boundaries of the GBJ2 gene. Results Carrier frequency of GJB2 mutations was similar between the Uigur and Han subjects. The GJB2 35delG mutation was seen only in Uigur patients with hearing loss, whereas the 235delC mutation was identified in both Uigur and Han patients. The allelic Frequency of 35delG mutation was 7.4% (9/122) in Uigur deaf students, but none in Han deaf students (0/128) and Uigur controls (0/196). The allelic frequency of GJB2 235delC mutation in Uigur and Han deaf students was 5.7% and 9.8%, and that of 299-300delAT mutation was 0.8% and 5.5%, respectively. V27I and E114G were the most frequent types of polymorphism. Conclusion We found an Asian-specific GJB2 diversity among Uigurs, and comparable GJB2 contribution to deafness in Uigur and Han patients. The high carrier frequency of 35delG in Uigurs (11.5%) is probably defined by gene drift/founder effect in a particular group. Even though GJB2 mutations have been widely reported in the literature, this discussion represents the first report of GJB2 mutations in Chinese multi-ethnic populations.

Mitochondrial DNA A1555G mutation screening using a testing kit method and its significance in preventing aminoglycoside-related hearing loss

Abstract To report a new screening method for mitochondrial DNA 1555A→G mutation and the results of genotype analysis in 19 maternal inherited deafness pedigrees. Method Five hundred and forty-six non-syndromic neuro-sensory hearing loss patients were tested for 1555A→G mutation using a new compact testing kit, which allows clear distinction between wild type and 1555 A→G mutated mtDNAs. Results Nineteen subjects among the 546 patients (3.48%) were found to carry mtDNAA1555G mutation. The results were confirmed by sequencing in an ABI 3100 Avant sequencer. Conclusions Maternal inherited deafness families are a frequently seen in outpatient group. The detection of mtDNA 1555 A→G mutation with a low cost, ready to use detection kit is needed and suitable in China for large scale screening and preventive testing before usage of aminoglycoside antibiotics.

Hearing Preservation in Acoustic Neuroma Surgery

Abstract Objective To report the authors’ experiences in hearing preservation during acoustic neuroma (AN) resection procedures. Methods Two cases of AN removal via retrosigmoid approach were reviewed. Hearing preservation was attempted in the aid of endoscopic technique along with continuous monitoring of the compound action potential (CAP) and auditory brainstem response(ABR) during the surgery. Results The tumor in Case 1 was 1.5 cm in diameter. The average pure-tone hearing threshold was 30 dB HL and ABR was normal. Waves I, III and V of ABR were present following tumor removal. At 7th month follow-up, audiometric thresholds and ABR inter-peak intervals had recovered to pre-operative levels, with normal facial nerve function. The patient in Case 2 had bilateral AN. The tumors measured 4.0 cm(left) and 5.0 cm (right) on MRI scans. The AN on the right side was removed first, followed by removal of the left AN four months later. Intraoperative CAP monitoring was employed during removal of the left AN. While efforts to preserve the cochlear nerve were not successful, CAPs were still present after tumor removal. Conclusions Intraoperatively recorded CAPs are not reliable in predicting postoperative hearing outcomes. In contrast, ABRs are an indicator of function of the peripheral auditory pathway. Presence of waves I, III and V following tumor removal may represent preservation of useful hearing.