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Biomedical subjects

Wei-yan Yang

Publications and source records attributed to Wei-yan Yang.

At least 19 recordsLinked to original sources
PubMed2006

Relationship between the external aperture and hearing loss in large vestibular aqueduct syndrome.

BACKGROUND: Large vestibular aqueduct syndrome (LVAS) is a major cause of hearing loss in childhood. This study aimed at measuring external aperture of enlargement of the vestibular aqueduct (EVA) and analyzing relationship between the size of external aperture and hearing loss. METHODS: Diagnostic criteria of LVAS were based on hearing loss and CT images. CT images of temporal bone of 100 LVAS patients were collected and 60 control subjects were reviewed retrospectively in the past 10 years. A battery of audiometric and vestibular function tests were performed. The width of the vestibular aqueduct (VA) was measured on axial CT images of the temporal bone. RESULTS: One hundred patients (65 men, 35 women) were diagnosed as having the isolated EVA. Hearing loss mostly occurred in early childhood. The diagnosis age of LVAS was 7.7 years on average. The causes of hearing loss could not be confirmed by initial consult. Typically, audiometric curve is the high-frequency down-sloping configuration. 92% of the cases had severe or profound sonsorineural hearing loss (SNHL). The mean size of the external aperture was (7.5 +/- 1.2) mm in present LVAS. Statistical analysis showed that the degree of hearing loss is unrelated to the width of VA. CONCLUSIONS: LVAS is a distinct clinical entity characterized by fluctuating, progressive SNHL. The degree of hearing loss is unrelated to the size of external aperture of VA. The protective management and hearing aid have become the main therapies. The cochlear implantation might be performed if the hearing loss affected learning at school.

Adolescent↗
PubMed2006

[Preliminary study of intraoperative auditory monitoring techniques in acoustic neuroma surgery].

OBJECTIVE: To investigate the value of intraoperative auditory monitoring techniques in acoustic neuroma surgery. METHODS: Ten cases with acoustic neuroma were resected with retrosigmoid approach. Continuous hearing monitoring of auditory brainstem responses (ABR) and transtympanic electrocochleography (ECochG) was performed during operation. RESULTS: Before surgery, 3 patients had class A hearing, 4 had class B hearing, and 3 had class C hearing. With ABR monitoring, 5 patients had waves I , III and V, 5 had only waves I preoperation. After anesthesia,only 2 cases had waves I, III and V, 6 had wave I (Compound action potential, CAP N1 is equivalent to wave I of ABR) and 2 had no waves. The hearing was preserved in 2 cases, which had class A hearing post operation with tumor size <2 cm. With continuous hearing monitoring, the waves of I , III and V could be evoked in one case. In another case, the waves of I, III could be evoked after the tumor resection with the disappearance of wave V. The hearing was not preserved in 8 cases. The 6 out of 8 cases showed up CAP (waves I ) waveform. The CAP amplitudes decreased significantly in 4 cases and even dropped to zero while dissecting the tumor at the lateral end of the internal auditory canal (IAC) or clamping the internal auditory artery (IAA) during operation. After surgery, the CAP amplitudes were recovered to 50%-60% of normal level or normal. In one case, although the cochlear nerve was cut down, the CAP could still be recorded after the tumor resection. However, the CAP amplitudes was dropped to zero while pressurized and pulled cochlea nerve of brainstem lateral and the wave disappeared post-operation in another cases. The waves had not been recorded in two cases after anesthesia. One of them showed low amplitude of CAP wave when the tumor partially removed. The others had no wave all the time. CONCLUSIONS: In combination with ABR monitoring, ECochG proved to be a useful supplementary tool for hearing preservation in acoustic neurinoma surgery. Drilling of the IAC and tumor removal at the lateral end of the IAC were the most critical steps for achieving hearing preservation. The surgeon's experience are the most significant factors influencing the hearing outcome after removal of acoustic neuroma.

Adolescent↗
PubMed2006

[Audio-vestibular function in patients with benign paroxysmal positional vertigo].

OBJECTIVE: To investigate the audio-vestibular function and the possible mechanism of benign paroxysmal positional vertigo (BPPV) and to raise the therapeutic strategy. METHODS: Patients with BPPV were tested with pure tone audiometry, high frequency ABR audiometry, bithermal caloric test and vestibular evoked myogenic potential test (VEMP). The positive rate of these otologic function test were analyzed. RESULTS: Primary BPPV comprised 82 percent (70/86) of patients with BPPV. Among all of the patients, the results of pure tone audiometry were abnormal in 52 percent (45/86) of the cases. High frequency auditory brainstem response (ABR) was abnormal in 60 percent (30/50) of cases. Vestibular evoked myogenic potential (VEMP) was abnormal in 34 percent (11/32) of cases who had this examination. And bithermal caloric test were abnormal in 28 percent (20/72) of cases. In the abnormal cases, 67 percent (12/18) of cases were ipsilateral with BPPV. The majority of the BPPV with abnormal results of bithermal caloric test (89%, 16/18) belong to posterior semicircular canal BPPV. CONCLUSIONS: The incidence of primary BPPV was higher than that of secondary BPPV. The abnormality in superior labyrinth was much more correlated with the occurrence of BPPV. The inner ear ischemia might be a factor in the morbidity of BPPV, especially for the primary BPPV.

Adolescent↗
PubMed2006

[Neurootological manifestation of migrainous vertigo].

OBJECTIVE: To analyzed the characteristics of migrainous vertigo (MV), a kind of paroxysmal vertigo, in order to demonstrate the extent of damage and dysfunction in MV and to judge whether MV is peripheral or central vertigo. METHODS: Twenty-two cases of acute (5 cases) or subacute (17 cases) MV were examined with oto-neurological tests, spontaneous nystagmus, positional nystagmus and auditory tests. RESULTS: There were 6 males and 16 females. Among those patients, 15 had migraine, 17 motion sickness, 15 family history of migraine or motion sickness, 1 visual aura, 7 motion intolerance (vertigo from head movement and body movement), 4 photophobia, 6 phonophobia and 5 vertigo from insomnia and emotion. There were likely to have vertigo in menstrual period in 2 cases. The duration of vertigo lasted from minutes to days. For pure-tone audiometric, 9 were normal which from mild to moderate hearing loss. Three cases had abnormal high frequency ABR bilaterally and 10 abnormal unilaterally. Subjective visual vertical were normal in all of the cases. Vestibular evoked myogenic potentials were abnormal in 14 cases (13 had low amplitude and 1 had longer latency of P13 wave). Bithermal caloric test was abnormal in 3 cases and 11 had abnormal ocular movement (9 with low gain of optokinetic nystagmus, 1 with overshoot in saccade and 1 with vertical nystagmus after head shaking), in which 10 had abnormal high frequency ABR and 1 was normal. CONCLUSIONS: MV could be peripheral or central vertigo and MV should be included in the differentiation of peripheral and central vertigo.

Adolescent↗
PubMed2006

[Clinical significance of vibration-induced nystagmus in patients with unilateral peripheral vestibular disorders].

OBJECTIVE: To clarify the clinical significance of vibration-induced nystagmus (VIN) and to calculate the sensitivity and the specificity of the vibration test. METHODS: One hundred and twelve patients with unilateral peripheral vestibular disorders and 30 normal subjects were enrolled into this study. However, patients with spontaneous nystagmus were excluded. Vibratory stimuli (approximately 92Hz) were presented to the mastoids and the forehead. Patients and normal subjects also underwent head shaking testing and caloric testing. RESULTS: Of the 112 patients, 91 (81%) showed VIN which were mainly horizontal. VIN was more frequently evoked on the mastoids than on the forehead. In the majority of patients (76 cases), the direction of VIN was toward the healthy side, whereas patients with Meniere's disease (15 cases), showed nystagmus toward the affected side. None of 30 normal subjects showed VIN. Whereas, HSN was found in 70 (63%) patients and 9 (30%) in normal subjects. Of 112 patients, 10 showed a canal paresis (CP) value of caloric test less than 25% ,while 32 with a CP value between 25% and 40%, 48 with a CP value between 40% and 70%, and 22 with a CP value more than 70%. It is notable that with increasing canal paresis value on caloric testing, VIN was more likely to be evoked. CONCLUSIONS: VIN testing is a simple, non-invasive and well-tolerated clinical test that indicates unilateral peripheral vestibular dysfunction. VIN testing had greater sensitivity and the specificity than HSN testing in the diagnosis of unilateral peripheral vestibular disorders.

Adolescent↗
PubMed2005

[Clinical features of a Chinese pedigree with Waardenburg syndrome type 2].

OBJECTIVE: To investigate detailed clinical features of a Chinese pedigree with Waardenburg syndrome type 2. METHODS: Members of this pedigree were interviewed to identify personal or family medical histories of hearing loss, the use of aminoglycosides, and other clinical abnormalities by filling questionnaire. The audiological and other clinical evaluations of the proband and other members of this family were conducted, including pure-tone audiometry, immittance and auditory brain-stem response and ophthalmological, dermatologic, hair, temporal bone CT examinations. RESULTS: This family is categorized as Waardenburg syndrome type 2 according to its clinical features. It's an autosomal dominant disorder with incomplete penetrance. The clinical features varied greatly among family members and characterized by sensorineural hearing loss, heterochromia irides, freckle on the face and premature gray hair. Hearing loss can be unilateral or bilateral, congenital or late onset in this family. CONCLUSION: This Chinese family has some unique clinical features comparing with the international diagnostic criteria for Waardenburg syndrome. This study may provide some evidences to amend the diagnostic criteria for Waardenburg syndrome in Chinese population.

Asian People↗
PubMed2005

[Long-term effect of stapes surgery on tympanosclerosis].

OBJECTIVE: To study the long-term effect of stapes surgery on tympanosclerosis and its influence factors. METHODS: The effect of stapes surgery on tympanosclerosis was retrospectively summed up in 119 patients (149 ears) in General Hospital of people's Liberation Army from April 1984 to March 2002. The Stata 7.0 software was used as a statistical tool. RESULTS: The average of hearing threshold (hearing level) of air conduction was (50.7 +/- 12.1) dB before operation, and the hearing loss was mostly on low frequency. Following-up the half-year post-operation, the average of hearing threshold of air conduction was (25.6 +/- 15.2) dB. The total successful rate of post-operation half year, 1 year, 2 and 5 years were 50.3%, 45.8%, 41.3% and 34.5%, respectively. Comparing the different operation methods, stapedotomy (piston technique) owned the best effect on hearing recovery (62.5%), then was stapedectomy (43.1%), but the last one was stapediolysis (30.8%). There was significant difference effect among three different operation methods (P < 0.05). The average of hearing threshold of air conduction was steadily within the first five-years following-up (Ridit analysis, P > 0.05), but obviously increased more than 5 years after operation (Ridit analysis, P < 0.05). The influence factors to successful rate were the following-up time post-operation, pathological changes of stapes, operative methods, and complications during operation, respectively. CONCLUSION: Stapes surgery is the effective method to treat tympanosclerosis, but the long-term effect is not good enough as expectation. It is important to select proper operation methods for better hearing results.

Adolescent↗
PubMed2005

[Cross-check of caloric test and head shaking nystagmus].

OBJECTIVE: To investigate the manifestation of head shaking nystagmus (HSN) and the relationship between HSN and vestibular bithermal test while cross-checking the HSN and vestibular bithermal test. METHODS: One hundred and twenty-four patients were examined by HSN and vestibular bithermal test. The latency and duration of HSN were observed and the dynamic changes of HSN were also investigated. The results of bithermal test were clarified by the values of canal paresis (CP). RESULTS: There were 3 types of HSN, including 41 monophasic HSN, 11 biphasic HSN and 7 perverted HSN. The latency of monophasic HSN was (2.75 +/- 1.41) ms and the duration of it was (32.16 +/- 20.30) ms; as for the biphasic HSN, the first phase had no latency and the duration was (12.33 +/- 4.42) ms which was shorter than that of the second phase (57.00 +/- 17.19) ms (P < 0.01) and the latency of second phase was (57.00 +/- 17.19) ms. The value of canal paresis in the patients without HSN was lower than that in the patients with HSN. CONCLUSIONS: The existence of HSN was dependent on the loss of the function horizontal canal and also on the stage of vestibular compensation. The variation of duration of HSN among individuals was great. In the acute stage of unilateral vestibular function loss, there appeared to be prominent HSN, and the direction of HSN is the same as that of spontaneous nystagmus. With the development of vestibular compensation, biphasic nystagmus would appear instead of monophasic HSN and the direction of first phase represent the direction of un-lesioned side. After compensation, HSN would not be elicited. However,when HSN existed, it suggested that the value of CP should exceed 25%. Perverted nystagmus pointed to central abnormality.

Adolescent↗
PubMed2005

[Diagnostic methods and clinic application for mtDNA A1555G and GJB2 and SLC26A4 genes in deaf patients].

OBJECTIVE: To establish the method of clinic genetic testing for common deaf genes such as mtDNA nt1555, GJB2 gene and SLC26A4 (Pendrin's syndrome gene, PDS) gene. METHODS: Three hundred and sixty seven sporadic patients with hearing loss from out-patient department of General Hospital of Chinese People's Liberation Army, 60 patients with history of maternal inherited hearing loss from 27 family, 20 congenital deaf patients from special educational school for deaf and dumb, 3 deaf patients with enlarged vestibular aqueduct (EVA) confirmed by CT scan, 50 control individuals with normal bone conductive hearing were analyzed. The genetic testing kit for mtDNA A1555G mutation was used to detect mtDNA A1555G mutation. The whole gene sequencing were accomplished in 20 congenital deaf patients. In 3 patients with EVA, fragments covering all exons of PDS gene were analyzed by denatured high productive liquid chromatogram and special exons were sequenced when DHPLC showed abnormal wave patterns of amplicons covering these exons. RESULTS: Fifty nine patients from 26 family and 5 sporadic patients were found to carry mtDNA A1555G mutation. Among 20 congenital deaf patients, 2 cases were found to have homozygous GJB2 235 del C mutation, 1 case had compound 235del C and 299-300 del AT mutation. Other 2 cases carried heterozygous 109 A-G mutation. Among 3 patients with EVA, 1 case was found to have heterozygous PDS G316X mutation and other 2 cases had homozygous 919-2 A-G mutation. CONCLUSIONS Genetic testing for deafness is feasible procedure with remarkable clinic significance.

Adolescent↗
PubMed2004

Stereo morphology of temporal bone and ear.

BACKGROUND: The temporal bone has the most complicated anatomic feature among the whole human body, which always challenges otolaryngologists. This study was to study three-dimensional (3D) morphology of the temporal bone and the ear by means of a computer image processing technique, for the purpose of providing a 3D image to help in pathological, diagnostic and surgical procedures. METHODS: Forty sets of temporal bone celloidin serial sections with reference points were prepared and the contours of selected structures and reference points were entered into a graphics programme. The technique of computer-aided 3D reconstruction was applied to obtain 3D images and parameters of the temporal bones and the ears. Stereo views of the ossicles (n = 5), the facial nerves (n = 11), the posterior tympanic sinuses (n = 11), the posterior ampullary nerves (n = 4), the endolymphatic ducts and sacs (n = 5), and the bony and membranous labyrinth (n = 1) were reconstructed. RESULTS: Three-dimensional images, including the cochlea, the ossicles, the nerves, the tendons and the endolymphatic fluid system in the temporal bone, were obtained. Stereo picture pairs and 3D parameters of spatial dimensions, angle and volume for these reconstructed structures were calculated. The arrangement of the ossicles, spatial relationship of the bony and membranous labyrinth, the whole course of the facial nerves, the endolymphatic sac and posterior tympanic cavity were clearly observable. Stereo picture pairs made the spatial relationships among the above-mentioned structures much clearer. The operation of the posterior ampullary nerve transection was designed and simulated on the graphic computer based on 3D anatomic investigations. CONCLUSION: The technique of computer-aided 3D reconstruction provides a new tool to observe the morphology of the temporal bone and thus may allow design and study of new surgical approaches.

Ear↗
PubMed2004

[Refractory recovery function of electrical auditory on the survival auditory nerve in cochlear implant recipients].

OBJECTIVE: To evaluate the cochlear implant recipient's electrical auditory temporal properties in order to estimate the maximum stimulating rate which can be reached when they adopted some speech coding strategies based on time mechanism, such as continuous interleaved sampling (CIS). METHODS: Thirty-eight Nucleus CI24 cochlear implant recipients were divided into 4 groups by etiology and history. Their survival auditory nerve fibers' refractory recovery time function was measured via neural response telemetry (NRT). Electrical pulses with the amplitude of recipient's loudest acceptable presentation were stimulated in mono-polar mode, with the width of 25 microseconds and the frequency of 80 Hz. Least-squares regression procedures were used to fit individual recovery functions with the equation A = C + K e(-t/tau), in which tau is the time constant of recovery from refractory state. Statistic analysis showed the relationship between the time constants of individuals and etiology as well as electrode position in the cochlea. RESULTS: Congenital deaf patient's recovery time constants were shorter than that of postnatal deaf groups of ototoxicity (P = 0.0056) and large vestibular aqueduct syndrome (P = 0.0349). There was no significant difference between the recovery time constants of congenital deaf patients and those of group with long history of deafness. The ANOVA of the recovery time constants of 5th, 10th, 15th electrode showed no significant statistical difference (P > 0.05). CONCLUSION: The recovery time constants are related with etiology. In mono-polar mode, the time constants of congenital deafness or subjects with short duration of deafness are shorter than those of postnatal deafness or subjects with long duration of deafness. Time constants do not vary systematically with electrode location along the implanted array. The reciprocal of individual electrode seems to be used in determining the maximum of stimulating rate of CIS strategy and as criteria of choosing the usable channels from 22 electrode bands.

Acoustic Stimulation↗
PubMed2004

[Cochlear implant in patients with congenital malformation of inner ear].

OBJECTIVE: To study surgical difficulty and key of the cochlear implant in patients with congenital malformation of inner ear. METHODS: The cochlear implantations were performed in our department from Jan. 2001 to Apr. 2003 for 18 patients with the malformation of inner ear. RESULTS: In this series, there were 11 cases of large vestibular aqueduct syndrome (LVAS), 3 cases of Waardenberg syndrome, 3 cases of Mondini malformation, and 1 case of Usher syndrome. All 18 patients accepted the Nucleus 24-channel cochlear implantations, including Nucleus straight electrode in 13 cases but Contour implantation in 5 cases of LVAS. During operations, leakage of perilymph but not cerebrospinal fluid (CSF) from the open of scala tympani occurred in 11 cases of LVAS, however, the electrode was inserted successfully. The abnormalities of round window occurred in one of 3 cases of Waardenberg syndrome and 3 cases of Mondini malformation, respectively. CONCLUSION: The cochlear implant could be conducted successfully for the LVAS, and the postoperative effect was same as the ones for the deafness persons with normal development of inner ear. However, for the patients with Mondini syndrome and common cavity, it is important to accurately assess the extent of abnormalities in the inner ear and accompanied malformation before operation, and to evaluate the full extent of difficulties of the operation in order to minimize the risk of CSF leakage and meningitis.

Adolescent↗
PubMed2004

[Evaluation of the clinical studies of prevention and treatment of sudden deafness in China].

OBJECTIVE: To summarize and evaluate the current situation on sudden deafness in China by retrospective review of the articles appeared in Chinese journals in the past 3 years. METHODS: The terms of sudden deafness and therapy were used to search all of the articles on the therapy of sudden deafness through the Chinese bio-medicine literature data base and Chinese journal net from 2000 - 2002. All of the articles were analyzed according to the standards of evidence-based medicine. RESULTS: One hundred and seventy-six articles were collected. 126 were on the curative effect of medicine, of which 26 (20.6%) based on the diagnosis and therapy standards settled by the otolaryngology branch of Chinese medical association in 1996, 89 (70.6%) were controlled clinical trials and 36 (28.5%) were randomized controlled trials. Most of the articles mentioned the 5 items diagnosis based and not detailed weather hypertension, diabetes and hyperlipemia were excluded. CONCLUSIONS: There are many articles on the therapy of sudden deafness. However, the inconsistent understanding of the prognosis and evaluation and unstuck trial design limited the therapy, research and the standards of literature on sudden deafness to progress further.

Evaluation Studies as Topic↗