Auditory brainstem response and otoacoustic emission assessment of hearing-impaired children of mothers who contracted rubella during pregnancy

Conclusions Based on the auditory brainstem response (ABR) results obtained in this study, the incidence of deafness in children whose mothers had rubella during pregnancy is high (29.5%), and deafness is profound in most cases (80%). Vaccinating women of childbearing age against rubella is essential to reduce the number of cases of childhood sensorineural hearing loss caused by gestational rubella.

Objective It has been shown in the literature that, in Brazil, gestational rubella is responsible for ≈21% of cases of deafness in children. The purpose of this study was to assess the incidence of deafness in children whose mothers had rubella during pregnancy.

Material and methods Between February and July 2001, we conducted a prospective study assessing hearing status in 17 children (mean age 6 months). The mothers had serologically (ELISA) confirmed gestational rubella. We recorded ABRs and analysed distortion product otoacoustic emissions (DPOAEs).

Results In 5 children (29.5%), ABRs revealed sensorineural hearing loss, which was moderate to severe in 1 (20%) and profound in 4 (80%). The hearing loss was bilateral in 3 children (60%) and asymmetrical in 4 (80%). Regarding DPOAEs, 7 children (41%) presented no response, and this occurred bilaterally in 4 (57%). All children with abnormal ABRs also presented abnormal DPOAEs. Two children with normal ABRs presented abnormal DPOAEs.     

Differentiating the cause of acute sensorineural hearing loss between Ménière's disease and sudden deafness

CONCLUSIONS: Most patients with Ménière's disease (MD) reveal abnormal vestibular-evoked myogenic potentials (VEMPs) and the recruitment phenomenon, whereas most sudden deafness patients display normal VEMPs without the recruitment phenomenon. We therefore recommend using both the recruitment phenomenon and VEMP testing as a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. OBJECTIVE: To recommend a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. MATERIAL AND METHODS: Between January 2002 and December 2003, 14 consecutive patients with "probable" MD who also had acute sensorineural hearing loss were enrolled in the study, together with another 14 age- and sex-matched patients with idiopathic sudden deafness. Each patient underwent a battery of audiovestibular function tests, including pure-tone audiometry, a stapedial reflex test, distortion-product otoacoustic emissions (DPOAEs), electronystagmography and a VEMP test. All patients were followed for at least 12 months after presentation. RESULTS: Significant differences were found between MD and sudden deafness in terms of the recruitment phenomenon (86% and 21% of cases, respectively) and abnormal VEMP responses (71% and 21% of cases, respectively). However, the diseases did not differ significantly in terms of abnormal DPOAEs or caloric test results.     

Hearing assessment in pre-school children with speech delay

OBJECTIVE: The purpose of this study was to detect any underlying hearing loss among the healthy pre-school children with speech delay. METHODS: 76 children, aged from 1 to 5 years, underwent a thorough audiological examination consisting of tympanometry, free field testing, otoacoustic emission recordings and auditory brainstem responses (ABRs). If hearing was normal, then they were evaluated by a child neurologist-psychiatrist. RESULTS: According to our findings, the children were classified into 3 groups; those with normal hearing levels (group I, 52 children, 68.4%), sensorineural hearing loss (group II, 22 children, 28.9%) and conductive hearing loss (group III, 2 children, 2.6%). In group I, speech delay was attributed to pervasive developmental disorder (PDD), which represents high-functioning autistic children (37 cases). Other causes were specific language impairment (SLI)-expressive (3 cases), bilingualism (2 cases), and unknown etiology (10 cases). More than half (59%) of the children diagnosed with PDD evidenced significant language impairment limited to more than two words. Children with SLI-expressive and bilingualism used a maximum of two words. In group II, 13 children suffered from profound hearing loss in both ears, 3 from severe, 3 had profound hearing loss in one ear and severe in the other, 2 from moderate, and 1 had moderate in one ear and severe in the other. No child had mild sensorineural hearing loss. The children with profound hearing loss in at least one ear had total language impairment using no word at all (10 cases), or a maximum of two words (6 cases). When hearing loss was moderate to severe, then the speech vocabulary was confined to several words (more than two words-6 cases). Only two children suffering from conductive hearing loss both presented with complete lack of speech. CONCLUSION: A great number of healthy pre-school children with speech delay were found to have normal hearing. In this case, the otolaryngologist should be aware of the possible underlying clinical entities, especially of psychiatric nature. The children with profound sensorineural hearing loss exhibited more severe speech delay than those with moderate to severe. Regardless of etiology, the early identification and intervention contribute to positive outcome in this critical period of childhood for language development.     

Diagnostic Potential of Distortion Product Otoacoustic Emissions in Severe or Profound Sensorineural Hearing Loss

To evaluate the potential of distortion product otoacoustic emissions (DPOAEs) in differential diagnosis of hearing loss, these were routinely measured in 232 ears of severe or profound sensorineural hearing loss. Normally recordable DPOAEs were found in 16 ears (8 patients) and the results were confirmed through retests after intervals; positive responses of transiently evoked otoacoustic emissions (TEOAEs) were additionally tested. The findings suggest that nerve deafness and hair cell deafness may be partly distinguishable.     

Nonsyndromic isolated unilateral cochlear nerve aplasia without narrow internal auditorymeatus: a previously overlooked cause of unilateral profound deafness in childhood

OBJECTIVES: Juvenile or adolescent unilateral profound sensorineural deafness (worldwide prevalence, 0.1% to 0.2%) has been attributed to postnatal viral infection, sudden deafness, prenatal and perinatal problems including maternal rubella and viral infections, congenital innerear anomalies, and other factors. Herein, 2 cases are reported and another potentially important cause of unilateral profound hearing loss is proposed. METHODS: Two nonsyndromic cases of a presently "very rare" cause of pediatric unilateral deafness are presented as a retrospective case study. RESULTS: The 2 patients showed isolated aplasia of the cochlear nerve; other branches of the eighth cranial nerve, the seventh nerve, and the inner ear were spared,and there was no anomaly of the internal auditory meatus. Both functional and imaging studies confirmed the isolated lesion (absence) of the cochlear nerve. CONCLUSIONS: Because of the absence of bony abnormalities, such cases may have been overlooked. The authors would like to advocate this isolated anomaly of thecochlear nerve as an important cause of juvenile or adolescent unilateral profound deafness.     

Causes of deafness in British Bangladeshi children: a prevalence twice that of the UK population cannot be accounted for by consanguinity alone

Objective: To study the causes and prevalence of sensorineural deafness in Bangladeshi children resident in East London. Methods: This was a cross sectional survey of children of Bangladeshi origin living in East London with bilateral sensorineural hearing loss of 40 db HL or more. In this study, 134 patients were included. The study looked primarily at the causes of sensorineural hearing loss in this population. Results: The prevalence of deafness in Bangladeshi children in East London is approximately 3.86 per 1000 [95% confidence intervals (CI) 3.20, 4.65] which is significantly greater than the average UK prevalence of 1.65 per 1000. The prevalence of deafness in these Bangladeshi children belonging to non‐consanguineous families only, the prevalence falls to 2.73 per 1000 (95% CI 2.19, 3.41). In 60% cases the cause of deafness was genetic. The single most common cause of sensorineural hearing loss in this population was mutations in the GJB2 gene (Connexin 26) in 20 of these patients (17%). Parents were consanguineous in 33% of the families. Conclusion: This study concludes that prevalence of sensorineural deafness in Bangladeshi children is at least 2.3 times the national average. This study also concludes that genetic causes are the common cause of deafness in this ethnic group, with nearly 30% of children with non‐syndromic deafness having mutations in GJB2. Although parental consanguinity was very high in this population it did not account for the whole increase in prevalence.     

Connexin 26 mutations in nonsyndromic autosomal recessive hearing loss: speech and hearing rehabilitation

OBJECTIVE: Hearing loss is the most common form of sensory impairment, with approximately one infant/1000 born with profound congenital deafness. A pre-lingual bilateral sensorineural hearing impairment poses a substantial problem as it negatively impacts on the subject's ability to conduct a normal social life. The aim of the study was to observe, in a group of children affected by pre-lingual non-syndromic autosomal recessive hearing impairment: (1) the role of the possible mutation of connexin 26 in the pathogenesis of the hearing loss; (2) the audiological and clinical aspects of the hearing impairment; (3) therapy to be adopted for the different patients. METHODS: The study was carried out on 39 patients, 16 males and 23 females, aged between six and 17 years (mean 12 years), affected by non syndromic congenital deafness, presumably hereditary, referred to the out-patients audiology clinic for children of the Department of Otolaryngology of the Federico II University of Naples. RESULTS: Our study conducted on 39 children with pre-lingual bilateral sensorineural autosomal recessive deafness showed as follows: (I) from a molecular perspective: an incidence of 41% in the cases studied of mutations in the encoding of the connexin 26 gene; a prevalence in our case study of the 35delG mutation (69%). (II) The characteristics of the hearing impairments in the children studied were homogeneous, regardless of the presence or absence of a connexin 26 mutation: the hearing impairment was pre-lingual bilateral sensorineural, the impairment often involved mainly the high frequencies, but, especially in the severe forms an involvement of all the frequencies was not rare; the hearing impairments were symmetrical and non progressive in time. (III) The results of the application of prosthesis and thereafter rehabilitative language therapy are generally satisfactory but correlated of course to the severity of the hearing loss. CONCLUSION: In conclusion, we hope that further developments in the research on genetic hearing impairments will promptly result in advances in clinical practice.     

Cochlear neuronal populations in developmental defects of the inner ear. Implications for cochlear implantation

A histological study was made to determine the cochlear neuronal populations of 20 human ears having hearing loss caused by developmental defects. The neuronal populations ranged from 7677 in an ear with Mondini dysplasia to 30 753 in an ear with DiGeorge's syndrome, the norm for young human subjects being 35 000 neurons. The length of the cochlear (spiral) ganglion varied from 7.3 mm to 14.8 mm, the norm for human subjects being 12 mm. The sensorineural hearing losses in all cases were attributable to malformation or degeneration of the sensorineural structures. The hearing loss was moderate in one case of Alport's syndrome, severe in one case of Usher's syndrome and in one case of severe Mondini dysplasia; it was profound in one case of maternal rubella, one of congenital deafness of unknown cause, another case of severe Mondini dysplasia and one of Down's syndrome (Trisomy 21). One case of mild Mondini dysplasia and one of DiGeorge's syndrome were known to have normal hearing. In 4 other cases hearing status was absent.     

Audiological chronological findings in children with congenital anomalies of the central nervous system

Objective

To determine the frequency of hearing impairment in children with congenital anomalies of the central nervous system (CNS) by using detailed audiological evaluation methods.

Methods

The patients were 78 children with congenital anomalies of the CNS with a mean age of 29.5 months. They had been observed for a mean period of 38.5 months. Hearing levels were evaluated behavioral observation audiometry (BOA), visual reinforcement audiometry (VRA) and distortion product otoacoustic emissions (DPOAEs) were performed. Auditory brainstem responses (ABRs) and computed tomography (CT) scans of the temporal bone were performed in the cases in which the minimum response levels (MRLs) were above 30 dBHL. All cases were assessed in terms of developmental age.

Results

A total of 14.1% (11/78) of the children with congenital anomalies of the CNS were initially diagnosed with bilateral sensorineural hearing loss (SNHL). However, the hearing levels of nine of them improved by the time of the last diagnosis. Therefore, the patients with bilateral SNHL were only 2.6% (2/78) of the total patients with congenital anomalies of the CNS at last diagnoses. As shown by our results, many children with bilateral SNHL at initial diagnosis showed improved ABR thresholds and behavioral hearing thresholds with age. In this series, the use of hearing aids was arranged for six patients. However, four patients stopped using hearing aids when their hearing threshold levels improved. In two cases, there were no changes in hearing levels and the children continued using hearing aids.

Conclusion

Our results suggest that hearing level recovery can occur in some children with CNS anomalies. Confirmation of hearing loss in children with congenital anomalies of the CNS takes a long time. There are improvements in hearing loss during the observation period. Therefore periodic assessment of hearing is important.     

Validity of the Western blot immunoassay for heat shock protein-70 in associated and isolated immunorelated inner ear disease

OBJECTIVE: To assess the validity of the Western blot immunoassay for heat shock protein-70 (hsp-70) for diagnosis of autoimmune inner ear disease. STUDY DESIGN: Retrospective study of 53 patients affected by sudden deafness (n = 19), idiopathic progressive sensorineural hearing loss (n = 24), and Meniere's disease (n = 10) who were treated from 1995 to 1999. The clinical course and response to corticosteroid were evaluated. METHODS: A purified hsp-70 antigen from bovine kidney cell line was used for the Western blot immunoassay. RESULTS: Only five patients (9.4%) showed anti--hsp-70 antibodies: Two presented a sudden sensorineural hearing loss (sudden deafness group), two showed an idiopathic progressive sensorineural hearing loss (idiopathic progressive sensorineural hearing loss group), and one was affected by fluctuating hearing loss (Meniere's disease group). A systemic autoimmune condition was observed in 29.1% of patients with idiopathic progressive sensorineural hearing loss. CONCLUSIONS: The low sensitivity of Western blot immunoassay for patients affected by idiopathic progressive sensorineural hearing loss and Meniere's disease may result from either the long time elapsed from the hearing loss and vertigo to the initial examination or from the increased percentage of cases of systemic autoimmune disease present in patients with idiopathic progressive sensorineural hearing loss. More studies to detect the immune-mediated inner ear disease in Western blot immunoassay-negative patients are required.     

Incidence of coexisting sensorineural hearing loss and secretory otitis media

There are currently no standard guidelines for assessing hearing in children who are evaluated for tympanostomy tubes. We describe the results of audiologic testing on 587 children, age 2 months to 17 years admitted to Pediatric Otolaryngology Department Bia?ystok for treatment of secretory otitis media. Ten children (1.7%) were found to have previously unrecognized sensorineural hearing loss. In four cases total unilateral deafness, in six others moderate to severe sensorineural bilateral hearing loss was diagnosed. Three other children referred to our clinic as sensorineural hearing loss were found to have secretory otitis media as the only or coexisting cause of deafness. Results of our study show the importance of age--appropriate hearing assessment as part of diagnostic procedure for secretory otitis media.     

Etiological diagnosis of bilateral, sensorineural hearing impairment in a pediatric Greek population

Early diagnosis, evaluation and treatment of childhood deafness are essential for a child's normal growth. Etiological diagnosis of hearing loss makes prevention, family scheduling and more effective therapy feasible goals. Etiological assessment of sensorineural deafness still remains difficult although recently with the progress of genetics it has become more efficient. In this retrospective study, the etiology of bilateral, sensorineural hearing loss with indication for hearing aids has been studied in 153 hearing impaired children. Etiological diagnosis was based on family and patient record, physical, audiological and laboratory examinations. Among the 94 children who completed the diagnostic protocol etiological groups revealed the following distribution: non-hereditary acquired hearing impairment was present in 36 children (38%) and hereditary was present in 44 (47%) children. The etiology remained unknown in 14 (15%) children. Non-syndromic autosomal dominant type accounted for 13 (29% of hereditary hearing loss) children, non-syndromic autosomal recessive type for 21 (48%) children and syndromic deafness for 10 (23%) children. Modern diagnostic methods, such as genetic testing, help diminish the number of cases with hearing impairment of unknown etiology, for the benefit of children who receive early and appropriate medical, audiologic, genetic and educational counseling based on the etiology of their hearing loss.     

Chronological changes of auditory brainstem responses in Cockayne''s syndrome

Cockayne's syndrome (CS) is a rare autosomal recessive premature-aging disorder which is clinically characterized by physical and mental retardation, retinal pigmentation, sensorineural deafness and other neurological abnormalities. Auditory brainstem responses (ABRs) and behavioral audiometry were studied in 4 cases of confirmed CS chronologically. In one case, ABRs were normal at first but became abnormal. Initially, ABRs revealed only wave I with prolonged latency and thereafter no response. In another case, ABRs revealed the absence of all waves beyond wave III and then revealed the disappearance of all waves. In 2 other cases, ABRs were absent from the first testing. Behavioral levels were elevated in all 4 cases. In 2 cases, behavioral levels did not change in spite of partial disappearance of ABR waves, but they had elevated severely since all waves including wave I disappeared. Our findings suggest that the disease spreads from the upper brainstem to the cochlear nerve and that the site of the lesion causing hearing loss in CS is in the brainstem lesion as well as the peripheral one.     

Hearing loss in vestibular schwannomas: analysis of cochlear function by means of distortion-product otoacoustic emissions

Objective

We investigated cochlear function in a group of patients affected by vestibular schwannoma (VS), by means of recording distortion-product otoacoustic emissions (DPOAEs).

Methods

Between January 1996 and January 2007, we observed 183 patients affected by unilateral VS. DPOAEs, compared to the corresponding hearing thresholds, were subjectively classified into three categories: “compatible” with hearing function, “cochlear” and “retro-cochlear”. We also related the responses to some clinical variables (tumor size, intracanalicular tumor and radiologic appearance of the internal auditory canal). Statistical analysis was performed.

Results

In 137 cases (74.9%), DPOAEs were as expected based on audiometry responses, while in 11 patients (6%) a “cochlear” DP-gram was recorded and in 35 patients (19.1%) DPOAEs evidenced a “retro-cochlear” pattern. In eight cases we detected acoustic responses despite a profound hearing loss. No statistically significant data merged from the comparison between “cochlear” and “retro-cochlear” responses and the clinical variables.

Conclusion

Our results confirm that sensorineural hearing loss due to VS can be of sensory and/or neural origin. DPOAEs still remain just a complementary auditory test; nevertheless, in case of severe or profound unilateral hearing loss, recorded acoustic responses may be suspicious for the presence of a vestibular schwannoma.     

Hearing defects in children born of mothers suffering from rubella in the first trimester of pregnancy

The investigations concerned women that had suffered from symptomatic rubella in the first trimester of pregnancy. The presence of immunoglobulin G and immunoglobulin M antibodies in mothers and their children was detected, and the hearing organ was examined. In early childhood (up to 3 years of age), hearing loss was confirmed in 50% of the children born of mothers with rubella.     

耳聋基因芯片技术在耳聋病因诊断中的应用

目的使用耳聋基因芯片技术对耳科门诊耳聋患者进行病因诊断。方法收集26例明确为感音神经性听力下降的聋病患者,使用基因芯片检测试剂盒进行检测。结果 26例患者中先天性耳聋者10例,检出率为40.00%;成年感音神经性耳聋者13例,检出率为23.08%;突发性耳聋者3例,检出率为66.67%。结论遗传性耳聋基因检测试剂盒对于明确聋病患者致聋原因有一定的帮助,具有临床推广价值。     

梅毒性感音神经性聋的临床分析

目的:探讨梅毒性感音神经性聋的临床表现、诊断和治疗.方法:回顾性分析3例梅毒性感音神经性聋患者的临床症状、体征、血清学及治疗.结果:3例梅毒性感音神经性聋患者中,2例RPR和TPPA均阳性;1例RPR阴性,TPPA阳性;2例在外院已确诊为梅毒并行驱梅治疗;2例为突发性聋起病,伴有耳鸣,1例为耳鸣起病伴高频听力下降.均已排除了其他原因所致的:千聋耳鸣,治疗后听力无改善.结论:梅毒性感音神经性聋可以突发性聋或耳鸣发病,易漏诊.对病因不明的听方下降,伴有耳鸣、眼球震颤的患者,应行必要的实验室检查以明确诊断.     

Hearing in congenital hypothyroidism

The hearing profile of children with congenital hypothyroidism was studied in 45 patients with thyroid gland agenesis, hypogenesis or dyshormogenesis, during adequate substitution therapy. Preliminary, secretory otitis media was found in 6 patients under the age of 6 years; in these children, hearing assessment was performed after cure of the middle ear effusion. Hearing threshold was measured either by conventional pure-tone audiometry or conditioned orientation reflex audiometry according to the patient's age (above and below 4 years). In 36 patients (80%) the auditory thresholds were normal; in the remaining 9 patients (20%) a sensorineural hearing loss of different degree was detected; in 5 cases (11%) the deafness was important and required auditory rehabilitation, with the use of a hearing aid in 4 of them. No relation could be found between hearing acuity and bone age at diagnosis of hypothyroidism or aetiology of thyroid dysfunction. It is concluded that in about one tenth of the children with congenital hypothyroidism a substantial deafness persists. The sensorineural nature of the hearing loss is in agreement with reported histological findings in congenital hypothyroid animals, where an immature development of the organ of Corti including hair cells and tectorial membrane has been observed.     

Audiological and electrocochleography findings in hearing-impaired children with connexin 26 mutations and otoacoustic emissions

We recorded cochlear potentials by transtympanic electrocochleography (ECochG) in three hearing-impaired children with GJB2 mutation who showed otoacoustic emissions. Pure tone thresholds, distortion product otoacoustic emissions (DPOAEs) and, auditory brainstem responses (ABRs) were also obtained. Subjects 1 (35delG/35delG) and 3 (M34T/wt) had profound hearing loss and showed the picture of auditory neuropathy (AN) as DPOAEs were detected with absent ABRs in both ears. The hearing impairment found in subject 2 (35delG/35delG) was profound in the right ear and moderate in the left ear. Both DPOAEs and ABRs with normal latencies and morphology were recorded only from the left ear. On the ECochG recording the cochlear microphonic was obtained from all children. No compound action potential (CAP) was detected in subject 1. A neural response was recorded only from the left ear in subject 2 with a threshold corresponding to the audiometric threshold while no CAP was detected on the right side. The ECochG obtained from subject 3 showed a low-amplitude broad negative deflection which was identifiable down to low stimulus levels. This response decreased in amplitude and duration when utilizing a high-rate stimulation paradigm. The amount of amplitude reduction was close to that calculated for normal ears, thus revealing the presence of an adapting neural component. These findings indicate that patients with GJB2 mutations and preserved outer hair cells function could present with the picture of AN. The hearing impairment is underlain by a selective inner hair cell loss or a lesion involving the synapses and/or the auditory nerve terminals. We suggest that neonatal hyperbilirubinemia may play a role in protecting outer hair cells against the damage induced by GJB2 mutations.     

Hearing in Congenital Hypothyroidism

The hearing profile of children with congenital hypothyroidism was studied in 45 patients with thyroid gland agenesis, hypogenesis or dyshormogenesis, during adequate substitution therapy. Preliminary, secretory otitis media was found in 6 patients under the age of 6 years; in these children, hearing assessment was performed after cure of the middle ear effusion. Hearing threshold was measured either by conventional pure-tone audiometry or conditioned orientation reflex audiometry according to the patient's age (above and below 4 years). In 36 patients (80%) the auditory thresholds were normal; in the remaining 9 patients (20%) a sensorineural hearing loss of different degree was detected; in 5 cases (11%) the deafness was important and required auditory rehabilitation, with the use of a hearing aid in 4 of them. No relation could be found between hearing acuity and bone age at diagnosis of hypothyroidism or aetiology of thyroid dysfunction. It is concluded that in about one tenth of the children with congenital hypothyroidism a substantial deafness persists. The sensorineural nature of the hearing loss is in agreement with reported histological findings in congenital hypothyroid animals, where an immature development of the organ of Corti including hair cells and tectorial membrane has been observed.