Degree Of Sensorineural Hearing Loss Research Articles

Secreted Factors from Human Vestibular Schwannomas Can Cause Cochlear Damage.

Vestibular schwannomas (VSs) are the most common tumours of the cerebellopontine angle. Ninety-five percent of people with VS present with sensorineural hearing loss (SNHL); the mechanism of this SNHL is currently unknown. To establish the first model to study the role of VS-secreted factors in causing SNHL, murine cochlear explant cultures were treated with human tumour secretions from thirteen different unilateral, sporadic VSs of subjects demonstrating varied degrees of ipsilateral SNHL. The extent of cochlear explant damage due to secretion application roughly correlated with the subjects’ degree of SNHL. Secretions from tumours associated with most substantial SNHL resulted in most significant hair cell loss and neuronal fibre disorganization. Secretions from VSs associated with good hearing or from healthy human nerves led to either no effect or solely fibre disorganization. Our results are the first to demonstrate that secreted factors from VSs can lead to cochlear damage. Further, we identified tumour necrosis factor alpha (TNFα) as an ototoxic molecule and fibroblast growth factor 2 (FGF2) as an otoprotective molecule in VS secretions. Antibody-mediated TNFα neutralization in VS secretions partially prevented hair cell loss due to the secretions. Taken together, we have identified a new mechanism responsible for SNHL due to VSs.

The Relationship Between Cochleovestibular Orientation, Age, and Sensorineural Hearing Loss: Implications for Cochlear Implantation.

To determine if spatial orientation of the cochlea within the temporal bone is related to age or sensorineural hearing loss (SNHL) and describe the implications for cochlear implantation. Five angles of cochlear orientation were determined from computed tomography (CT) imaging of the temporal bones in adults with (n = 55) and without (n = 27) sensorineural hearing loss (SNHL) and children with (n = 45) and without (n = 12) SNHL: facial recess versus basal turn, posterior semicircular canal versus basal turn, round window versus basal turn (axial view), round window versus basal turn (coronal view), and the cochlear axis versus the mastoid facial nerve. All angles showed substantial variation between subjects and between ears. The angles between the round window and basal turn (coronal view) and the posterior semicircular canal and basal turn were significantly correlated with age for all subjects with SNHL (r = 0.22, P = .002 and r = 0.15, P = .03, respectively). Patients with SNHL had significantly more acute angles (46.6° vs 55.8°) between the round window versus basal turn (axial orientation) compared to controls (P < .001). Cochlear orientation within the temporal bone changes with age and the degree of SNHL. These results suggest that the approach to the round window for electrode insertion might differ between children and adults.

A Study of Signal-to-Noise Ratios for Monosyllabic and Sentence Recognition Threshold in Sensorineural Hearing Loss

A major problem for most patients with hearing impairment is understanding speech in background noise. In the current study, we investigated to search of threshold of speech recognition at various signal-to-noise ratios (SNRs) using the monosyllabic words and sentences. Three listener groups consisting of 7 normal-hearing, 20 listeners with mild degree of sensorineural hearing loss, and 20 listeners with moderate degree of hearing loss (HL) were participated in this study. The subjects listen to the target monosyllables or sentences at eight conditions of SNRs (ranging from –12 to 9 dB SNR). The SNR required for 50% word recognition was -2.13 dB, -1.22 dB and 0.55 dB for normal-hearing, mild, and moderate HL listeners. The SNR for sentence recognition was -2.86 dB, -2.31 dB and –1.85 dB for the same listener groups. The 50% recognitions for sentence were obtained at a significantly lower SNR than for monosyllabic word. Regardless of the stimulus type, SNR for speech recognition threshold by sensorineural hearing loss with moderate HL were significantly higher than normal and mild HL. The results can be useful for development of speech-in-noise recognition test and decision on efficient SNR in aural rehabilitation for hearing aid users.

In-situ audiometry: How close is it to conventional audiometry?

Technology in the hearing aid industry is ever changing. One of the many features that may improve accuracy of hearing aid fittings and patients’ satisfaction is the inception of in-situ audiometry, which allows the clinician to measure hearing thresholds with a hearing aid in the patient's ear. Objective: The present study aimed to investigate the validity of in-situ audiometry measured with a behind-the-ear hearing aid coupled to a customized earmould relative to conventional thresholds measured using supra-aural head phones. Study design: A total of 24 ears from 15 participants with varying degrees of sensorineural hearing loss ranging from moderate to severe, were selected for the study. Pure tone hearing thresholds and real-ear-to-dial-differences were measured for both conventional and in-situ thresholds across 250 Hz to 6 kHz. Results: Slight but significant mean differences (p ˂ 0.05, paired t-test) of 3.2 and 3.4dB between conventional and in-situ thresholds at 2000 and 6000 Hz were found before adding REDD corrections with in-situ thresholds yielding better (lower) thresholds. Except at 250 Hz in dB HL, individual threshold variability between conventional and in-situ threshold measurements was within or equal to ± 10dB for > 95% of ears before and after adding REDD corrections. Large inter-participant variation in measured ear canal SPL was noticed at 250, 500, 4000 and 6000 Hz when measured in-situ compared to headphones, which was attributed to differences in earmould vent sizes provided for different degrees of hearing loss at the low frequencies and probe placement in the high frequencies. Conclusion: Overall in-situ audiometry proved to be valid especially in individuals with symmetrical sensorineural hearing loss. Although there are statistically significant differences, they are within clinically accepted standards. Furthermore, thresholds measured in ear canal SPL will be more comparable as any changes in hearing threshold levels in either of the measurements will be reflected by an inverse change in measured ear canal SPL during REDD measurements.

Parent report of the development of auditory skills in infants and toddlers who use hearing aids.

This study investigated the use of the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) as a measure of early auditory skill development in aided infants and toddlers with varying degrees of hearing loss. Specific goals were (1) to rate the change in IT-MAIS score as a function of change in hearing thresholds achieved through amplification; (2) to establish the hierarchy of early auditory skill development for infants who use hearing aids (HAs) relative to what is known in infants with normal hearing; and (3) to analyze background information variables that may account for differences in IT-MAIS performance, as age and duration of HAs use. The study included 106 infants and toddlers (47 girls and 59 boys) aged 7 to 36 months (mean = 19.02, SD = 7.7) with various degrees of sensorineural hearing loss (mean = 86.42 dB, SD = 22.52). Infants used bilateral digital HAs with a mean experience of 8 months. All participants attended the same early intervention program. After at least 2 months of HA use, parents were interviewed with the IT-MAIS questionnaire regarding the auditory behavior of their infants in everyday situations. The results of the present study support the following outcomes: (1) on average, every 10 dB gain in pure-tone average scores (PTA4) threshold improved the IT-MAIS score by 10%; (2) infants who were part of the same unaided hearing categories appeared to have derived different benefits from amplification; (3) when reaching the same aided category, those infants who were originally in a better unaided hearing category achieved higher IT-MAIS scores than those who belonged to a worse unaided hearing category; (4) the hierarchy of auditory development in young aided infants with hearing loss followed that of normal hearing peers; and (5) 62.9% of the variance of IT-MAIS performance was explained by aided hearing level (50.3%), unaided hearing level (6.4%), and duration of HA use (6.2)%. The present study provides important information to assist clinicians and parents in setting realistic expectations regarding the auditory behavior of infants as a function of aided and unaided thresholds. It emphasizes the need for assessing functional hearing in young infants and not relying on hearing thresholds alone. Such data can also contribute to the decision-making process when selecting a sensory device (e.g., HA versus cochlear implant) for infants with hearing loss.

Risk factors for sensorineural hearing loss in pediatric chronic otitis media

ObjectivesTo assess the clinical significance of sensorineural hearing loss (SNHL) in a group of pediatric patients suffering from unilateral chronic otitis media (COM) with or without cholesteatoma, using the contralateral healthy ear as a control, and to define risk factors for the development of SNHL in such patients. MethodsThe subjects of this retrospective study were 124 pediatric patients with unilateral COM admitted for surgery. Mean age at surgery was 13.3±3.2 years (range, 7–18) and mean duration of the disease was 88.4±45.0 months (range, 6–192 months). The preoperative pure-tone average value (PTA) for bone conduction (BC) was calculated in each ear (BC-PTA) as the average of BC thresholds at 500, 1000, 2000, and 4000Hz. Potential risk factors for SNHL that we evaluated were demographics, duration of disease, presence of cholesteatoma, and previous otologic history. ResultsMean BC-PTA values in the diseased ears prior to surgery differed significantly from those in the healthy ears (12.74±8.75dB and 9.36±6.33dB, respectively; P<0.01). The degree of SNHL in the diseased ear at 2000Hz was found to be significantly correlated with the presence of cholesteatoma and with age above 10 years. ConclusionsOne of the complications of COM, with or without cholesteatoma, in addition to the conductive hearing loss, is the development of clinically significant SNHL. It is therefore imperative to actively treat pediatric patients diagnosed with COM, with the aim of preventing the possible development of SNHL.

Exploration of stimulus-frequency otoacoustic emission suppression tuning in hearing-impaired listeners

Objective: Otoacoustic emissions (OAEs) can provide useful measures of tuning of auditory filters. We previously established that stimulus-frequency (SF) OAE suppression tuning curves (STCs) reflect major features of behavioral tuning (psychophysical tuning curves, PTCs) in normally-hearing listeners. Here, we aim to evaluate whether SFOAE STCs reflect changes in PTC tuning in cases of abnormal hearing. Design: PTCs and SFOAE STCs were obtained at 1 kHz and/or 4 kHz probe frequencies. For exploratory purposes, we collected SFOAEs measured across a wide frequency range and contrasted them to commonly measured distortion product (DP) OAEs. Study sample: Thirteen listeners with varying degrees of sensorineural hearing loss. Results: Except for a few listeners with the most hearing loss, the listeners had normal/nearly normal PTCs. However, attempts to record SFOAE STCs in hearing-impaired listeners were challenging and sometimes unsuccessful due to the high level of noise at the SFOAE frequency, which is not a factor for DPOAEs. In cases of successful measurements of SFOAE STCs there was a large variability in agreement between SFOAE STC and PTC tuning. Conclusions: These results indicate that SFOAE STCs cannot substitute for PTCs in cases of abnormal hearing, at least with the paradigm adopted in this study.

Developmental changes of ENaC expression and function in the inner ear of pendrin knock-out mice as a perspective on the development of endolymphatic hydrops.

Pendrin mutations cause enlarged vestibular aqueducts and various degrees of sensorineural hearing loss. The selective abolition of pendrin causes dilation of the membranous labyrinth known as endolymphatic hydrops, loss of the endocochlear potential, and consequently loss of hearing function. Because Na+ transport is one of the most important driving forces for fluid transport, the epithelial Na+ channel (ENaC) is believed to play an important role in fluid volume regulation in the inner ear. Therefore, the dysfunction of Na+ transport through ENaC by the acidification of endolymph in Pendred syndrome is one of the potential causes of endolymphatic hydrops. We investigated the changes of ENaC expression and function during the development of the pendrin knock-out mouse. In the cochlea, the expression of β and γENaC was significantly increased at P56 in Pds−/− mice compared with Pds+/+ mice. In the vestibule, the expression of βENaC was significantly increased at P56, and γENaC expression significantly increased from P6 to P56 in Pds−/− mice. The ENaC-dependent trans-epithelial current was not significantly different between Pds+/+ and Pds−/− mice in Reissner’s membrane or the saccular extramacular roof epithelium at P0, but the current was significantly increased in Pds−/− mice at P56 compared with Pds+/+ mice. These findings indicate that the expression and function of ENaC were enhanced in Pds−/− mice after the development of endolymphatic hydrops as a compensatory mechanism. This result provides insight into the role of Na+ transport in the development and regulation of endolymphatic hydrops due to pendrin mutations.

Prevalence of hearing loss in children following bacterial meningitis in a tertiary referral hospital

BackgroundThis study aimed to examine hearing function in a group of children aged between the ages of six months and twelve years admitted with bacterial meningitis so as to determine the prevalence and degree of sensorineural hearing loss in them. This prospective study was conducted in the audiology unit and paediatric wards of Kenyatta National Hospital, KNH.MethodsThe study involved 83 children (49 males and 34 females) between the ages of six months and twelve years admitted with bacterial meningitis. The median age for the children examined was 14 months (range from 5 to 120 months). They were sequentially recruited and at discharge following treatment, underwent age-appropriate hearing testing to evaluate presence and degree of hearing loss which was analyzed. The study was limited by the absence of otoacoustic emission and auditory brainstem responses testing by excluding the significant numbers of children below six months of age admitted with bacterial meningitis.ResultsThirty six of the 83 children (44.4%) were found to have at least a unilateral mild sensorineural hearing loss during initial audiologic testing. Of the children with hearing loss, 22 (26.5%) had mild or moderate sensorineural hearing loss and 14 (16.9%) had severe or profound sensorineural hearing loss.ConclusionsSensorineural hearing loss was shown to be highly prevalent in children treated for bacterial meningitis. There is therefore a need for objective hearing assessment in infants and young children following bacterial meningitis and further studies involving larger population sizes.

Effect of Hyperinsulinism on Sensorineural Hearing Impairment in Ménière’s Disease

To compare the degree of sensorineural hearing loss in patients with Ménière's disease (MD) with and without hyperinsulinism by different methods of assessment. Historical cohort study. Ménière's Disease Care and Research Clinics of Hospital de Clinicas de Porto Alegre, a tertiary care university hospital in Southern Brazil. Patients with a definite diagnosis of MD based on the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines. Patients were assessed by glucose overload tests (5-h glucose and insulin curves) and under baseline physiological conditions (Homeostasis Model Assessment/Insulin Resistance [HOMA-IR], Quantitative Insulin Sensitivity Check Index [QUICKI], and glucose/insulin ratio). These patients underwent annual pure-tone audiometry and were analyzed using 4-tone average (FTA), that is, arithmetic mean of 500, 1,000, 2,000, and 3,000 Hz, during the third, fourth, and fifth years of disease progression. Hearing loss assessed by FTA and classified in Stages I to IV (AAO-HNS). Forty-nine (76.6%) patients were defined as hyperinsulinemic and 15 (23.4%) as normoinsulinemic. Impairment on FTA was higher in the hyperinsulinemic group (52.04 ± 17.5 versus 39.75 ± 9.20, p = 0.027) when assessed by the 5-hour insulin curve. Hyperinsulinemic subjects were 3.5 times more likely to develop hearing damage greater than 40 dB (i.e., Stages III and IV) than normoinsulinemic subjects (OR = 3.52; 95% CI, 1.05-11.76). A moderate correlation between the insulin curve and the HOMA-IR was found (r = 0.524, p = 0.001). Hyperinsulinism in MD is associated with greater clinical hearing damage.

Link between angiographic extent and severity of coronary artery disease and degree of sensorineural hearing loss

Atherosclerosis is a systemic disease that can affect the whole arterial tree. An important cause of neuronal degeneration is atherosclerosis, which may lead to sensorineural hearing loss. We aimed to investigate the relationship between the angiographic severity and extent of coronary artery disease, which is a surrogate of atherosclerotic burden, and the degree of sensorineural hearing loss. Out of 381 consecutive patients who underwent coronary angiography for symptoms suggesting ischemic heart disease and who had ischemia detected by a noninvasive stress test, 265 patients [mean age, 61.5 ± 13.0 years; median age (25th-75th percentile), 59 years (50.5-67)], including 146 male (55.1 %) subjects met the eligibility criteria and were enrolled. Audiological measurements (hearing levels and discrimination scores) were performed before the coronary angiography. The Gensini score was calculated for each angiogram. There was a statistically significant positive correlation between the degree of hearing loss at all frequencies analyzed (250, 500, 1,000, 2,000, 4,000 Hz) and the Gensini score (p < 0.05 for all frequencies), which remained significant after adjustment according to age and other risk factors. A statistically significant negative correlation was observed between the Gensini score and the speech discrimination score (p < 0.05). The findings of this study suggest that the angiographic severity and extent of coronary artery disease are significantly and independently correlated with the degree of hearing loss. Sensorineural hearing loss was more prominent in patients with higher Gensini scores. We propose that the findings of this study warrant further research and should be verified in large-scale studies.

Congenital Hereditary Endothelial Dystrophy Caused by SLC4A11 Mutations Progresses to Harboyan Syndrome

Homozygous mutations in SLC4A11 cause 2 rare recessive conditions: congenital hereditary endothelial dystrophy (CHED), affecting the cornea alone, and Harboyan syndrome consisting of corneal dystrophy and sensorineural hearing loss. In addition, adult-onset Fuchs endothelial corneal dystrophy (FECD) is associated with dominant mutations in SLC4A11. In this report, we investigate whether patients with CHED go on to develop hearing loss and whether their parents, who are carriers of an SLC4A11 mutation, show signs of having FECD. Patients with CHED were screened for mutations in the SLC4A11 gene and underwent audiometric testing. The patients and their parents underwent a clinical examination and specular microscopy. Molecular analyses confirmed SLC4A11 mutations in 4 affected individuals from 3 families. All the patients were found to have varying degrees of sensorineural hearing loss at a higher frequency range. Guttate lesions were seen in 2 of the 4 parents who were available for examination. Our observations suggest that CHED caused by homozygous SLC4A11 mutations progresses to Harboyan syndrome, but the severity of this may vary considerably. Patients with CHED should therefore be monitored for progressive hearing loss. We could not determine conclusively whether the parents of the patients with CHED were at increased risk of developing late-onset FECD.

Studies on Pathogenesis of Waardenburg Syndrome Type II and Tietz Syndrome Resulting from MITF Gene Mutations

Microphthalmia-associated transcription factor (MITF) controls melanocyte survival and differentiation through directly regulating the expression of the tyrosinase(TYR)and tyrosinase-related proteins 1 and 2(TYRP1 and TYRP2)genes.MITFmutations have been reported to result in an abnormal melanocyte development and lead to Waardenburg syndrome type 2 (WS2), characterized by variable degrees of sensorineural hearing loss and patchy regional distribution of hypopigmentation. Recently,MITFwas also indicated as a causative gene for a more severe syndrome, the Tietz Syndrome (TS), characterized by generalized hypopigmentation and complete hearing loss. However, few functional studies have been performed to compare the diseases-causing mutations. Here, we analyzed thein vitroactivity of two recent identified WS2-associated mutation (p.R217I and p.T192fsX18) and one TS-associated mutation p.N210K. The R217I MITF retained partial activity, normal DNA-binding ability and nuclear distribution, whereas the T192fsX18MITFfailed to activateTYRpromoter due to loss of DNA-binding activity, and aberrant subcellular localization. The aberrant subcellular localization of T192fsX18 MITF may be caused by deletion of a putative nuclear localization signal (NLS) at aa 213-218 (ERRRRF). Indeed, MITF with deletion of the NLS fragment failed to translocate into the nucleus and activated theTYRpromoter. Tagging this NLS to GFP promoted the green fluorescence protein (GFP) translocated into the nucleus. The surprising finding of our study is that a TS-associatedMITFmutation, N210K, showed comparablein vitroactivity as WT. Thus, the possible involvement ofMITFin TS and its underlying mechanisms still need further investigation.

Long-term functional outcome and satisfaction of patients with an active middle ear implant for sensorineural hearing loss compared to a matched population with conventional hearing aids

The objectives of the study were to review the results of an active middle ear implant for sensorineural hearing loss in patients who were unable to wear or did not benefit from conventional hearing aids in comparison to patients with a matched degree of hearing loss successfully fitted with a conventional hearing aid. A retrospective chart review of 10 patients (10 ears) after implantation of an active middle ear implant and 12 patients (13 ears) with conventional hearing aids in one tertiary referral center was performed. Intervention for sensorineural hearing loss was the implantation of an active middle ear implant in one group or fitting of conventional hearing aids in the other group. Outcome measures were pure-tone audiometry (auditory thresholds, functional gain), speech audiometry (Freiburg Monosyllabic Test in quiet and in noise) and a quality-of-life questionnaire (Glasgow Benefit Inventory). Average functional gain was 25.2 ± 8.6 and 14.6 ± 10.8 dB, speech recognition score in noise was 36.6 ± 18.4 and 31.2 ± 19.2 % and in quiet was 66.0 ± 23.2 and 61.5 ± 23.8 %, Glasgow Benefit Inventory total score was 38.3 ± 32.3 and 24.8 ± 22.2 in patients with active middle ear implants and conventional hearing aids, respectively. In two patient groups matched for degree of sensorineural hearing loss, active middle ear implants provided comparable speech recognition and superior functional gain and quality of life compared to conventional hearing aids. 4.

Relationship between behavioral hearing thresholds and estimated auditory steady-state response thresholds in children with a history of neonatal hyperbilirubinemia

Increased serum bilirubin levels during infancy increase the risk of hearing loss in infants. This study aimed to investigate the relationship between pure-tone audiometry hearing thresholds and thresholds estimated using auditory steady-state responses (ASSRs) in children with a history of neonatal hyperbilirubinemia, and to evaluate the usefulness of 90-Hz ASSR in estimating hearing thresholds in children. This study was conducted on 26 children (13 girls and 13 boys) who were aged 2.4-11 years and had a history of neonatal hyperbilirubinemia (bilirubin level >17 mg/dL). ASSR thresholds were compared with behavioral thresholds and were interpreted after considering the amount and type of hearing loss. Of the 26 children, 12 had normal hearing thresholds, and 14 had varying degrees of sensorineural hearing loss. In general, a high correlation (r ≥ 0.81, p < 0.01) was found between the ASSR and behavioral thresholds. The highest correlation was observed at 2,000 Hz (r = 0.88, p < 0.01). No significant difference was observed (p > 0.13) between mean behavioral and ASSR thresholds at 52 studied ears. The results of this study showed that 90-Hz ASSR assessments provide reliable estimates of behavioral hearing thresholds in children who have a history of neonatal hyperbilirubinemia and sensorineural hearing loss or normal hearing.

Study of the Cochlear Function in Patients with Myotonic Dystrophy Type 1

Objectives: Myotonic Dystrophy type 1 is a progressive autosomal dominant multisystem disorder, the second most common form of muscular dystrophy. The disease is associated with various vestibular, oculomotor, and auditory disorders. The aim of the present study was to undertake a detailed vestibular and audiological evaluation, and specifically to analyze the cochlear function using transiently evoked otoacoustic emissions. Methods: 24 patients with genetically diagnosed myotonic dystrophy type 1 were studied during the past 4 years in Eginition hospital of Athens. Twenty-one normal subjects were used as controls. Testing included pure-tone audiometry, tympanometry, auditory brainstem responses (Abr), transiently evoked otoacoustic emissions, and nystagmography. Results: Tympanograms were normal in most patients. 15 (62.5%) patients had a varying degree of sensorineural hearing loss, with no conductive element. In 9 of them (37.5%), ABR abnormalities were found, such as absence of wave I or increased latencies of waves III and V, compatible with sensorineural hearing loss (5 patients), as well as increased I-III and I-V interpeak latencies, compatible with retrocochlear involvment of the auditory pathways (4 patients). Subclinical cochlear damage was found in all patients, as evidenced by absent otoacoustic emissions or lower otoacoustic emission amplitude. Vestibular hypersthesia was found in 9 patients (37.5%), accompanied by spontaneous nystagmus in 4 of them (15.6%). Conclusions: Audiovestibular abnormalities are quite common in patients with myotonic dystrophy type 1. We have found that subclinical cochlear damage is a common finding of the disease, as concluded from the absence or decrease of otoacoustic emissions in these patients.

Upregulation of cognitive control networks in older adults’ speech comprehension

Speech comprehension abilities decline with age and with age-related hearing loss, but it is unclear how this decline expresses in terms of central neural mechanisms. The current study examined neural speech processing in a group of older adults (aged 56–77, n = 16, with varying degrees of sensorineural hearing loss), and compared them to a cohort of young adults (aged 22–31, n = 30, self-reported normal hearing). In a functional MRI experiment, listeners heard and repeated back degraded sentences (4-band vocoded, where the temporal envelope of the acoustic signal is preserved, while the spectral information is substantially degraded). Behaviorally, older adults adapted to degraded speech at the same rate as young listeners, although their overall comprehension of degraded speech was lower. Neurally, both older and young adults relied on the left anterior insula for degraded more than clear speech perception. However, anterior insula engagement in older adults was dependent on hearing acuity. Young adults additionally employed the anterior cingulate cortex (ACC). Interestingly, this age group × degradation interaction was driven by a reduced dynamic range in older adults who displayed elevated levels of ACC activity for both degraded and clear speech, consistent with a persistent upregulation in cognitive control irrespective of task difficulty. For correct speech comprehension, older adults relied on the middle frontal gyrus in addition to a core speech comprehension network recruited by younger adults suggestive of a compensatory mechanism. Taken together, the results indicate that older adults increasingly recruit cognitive control networks, even under optimal listening conditions, at the expense of these systems’ dynamic range.

Cochlear Dead Region and Word Recognition of Mandarin Chinese in Taiwan

In a tonal language, the identity of a word depends largely on the tonal identification of the contour of vocal fundamental frequency energy of which usually centers in a low frequency of less than 600 Hz. However, cochlear dead region (DR) is present mostly in the frequency range of 2000 Hz to 4000 Hz, and the effect of DR on a tonal language is worth investigating. Thirty-two native Mandarin speakers with moderate-to-severe degree of sensorineural hearing loss were included in this study. The pure-tone audiometry, speech recognition threshold (SRT) and word recognition score (WRS) were used to evaluate the degree of hearing loss and word recognition. The threshold equalizing noise (TEN) tests were used to identify the presence of DR. The results showed that most DRs were present in high frequencies. The hearing thresholds of the ears with a DR were not significantly different from those without DR. However, the WRS was significantly worse for the DR ears, especially for those whose DR included three or more audiometric frequencies. A DR caused a significantly worse word recognition for the tonal language speakers of Mandarin in Taiwan, although the DR frequency occurred in the high frequency of 2000 Hz to 4000 Hz.

Assessment of saccular function using cervical vestibular-evoked myogenic potentials in children with sensorineural hearing loss

EnAbstract Objectives The aim of this work was to examine saccular function using cervical vestibular-evoked myogenic potentials (cVEMPs) in children with congenital or acquired sensorineural hearing loss (SNHL). Study design Descriptive cross-sectional study. Participants and methods This study was carried out on 30 children with different degrees of SNHL with normal middle ear function and 25 age-matched and sex-matched typically developing children. All the participants’ age ranged from 5 to 18 years. For each child, the following were administered: history taking, an otologic examination, a basic audiological evaluation in the form of pure tone audiometry and immittancemetry, air-conducted cVEMPs, and computed tomography scan of the temporal bone. The results obtained from the two groups were then compared. In addition, correlation studies between all the results obtained were carried out. Results There was a statistically nonsignificant difference between the patients and the controls in cVEMP P13 and N23 latencies, whereas the cVEMP P13–N23 amplitude and threshold results showed a highly significant difference. cVEMP measurements in relation to sex within the patient group showed that the cVEMP threshold was the only positive outcome that showed a significant difference, and was higher in females. There was a highly significant positive correlation between hearing loss and the cVEMP threshold among the patient groups with different degrees of hearing losses. In addition, there was a significant positive correlation between age and cVEMP P13 and N23 latencies among the patient group. Conclusion SNHL is associated with saccular dysfunction in the pediatric population in the form of decreased cVEMP P13–N23 amplitudes and elevated cVEMP thresholds. Females presented with higher cVEMP threshold values than men, and cVEMP latencies appear to increase with age. An increase in hearing loss is associated with an increase in the cVEMP threshold and cVEMP amplitude appears to decrease with hearing loss irrespective of its degree. We recommend the inclusion of cVEMPs in the battery of evaluation of children with SNHL to detect early subtle changes in saccular function. Future research focusing on the genes causing SNHL and its relation to VEMP findings should be carried out.

Extended mutation spectrum of Usher syndrome in Finland

The Finnish distribution of clinical Usher syndrome (USH) types is 40% USH3, 34% USH1 and 12% USH2. All patients with USH3 carry the founder mutation in clarin 1 (CLRN1), whereas we recently reported three novel myosin VIIA (MYO7A) mutations in two unrelated patients with USH1. This study was carried out to further investigate the USH mutation spectrum in Finnish patients. We analysed samples from nine unrelated USH patients/families without known mutations and two USH3 families with atypically severe phenotype. The Asper Ophthalmics USH mutation chip was used to screen for known mutations and to evaluate the chip in molecular diagnostics of Finnish patients. The chip revealed a heterozygous usherin (USH2A) mutation, p.N346H, in one patient. Sequencing of MYO7A and/or USH2A in three index patients revealed two novel heterozygous mutations, p.R873W in MYO7A and c.14343+2T>C in USH2A. We did not identify definite pathogenic second mutations in the patients, but identified several probably nonpathogenic variations that may modify the disease phenotype. Possible digenism could not be excluded in two families segregating genomic variations in both MYO7A and USH2A, and two families with CLRN1 and USH2A. We conclude that there is considerable genetic heterogeneity of USH1 and USH2 in Finland, making molecular diagnostics and genetic counselling of patients and families challenging.