High levels of sound pressure: acoustic reflex thresholds and auditory complaints of workers with noise exposure

IntroductionThe clinical evaluation of subjects with occupational noise exposure has been difficult due to the discrepancy between auditory complaints and auditory test results. This study aimed to evaluate the contralateral acoustic reflex thresholds of workers exposed to high levels of noise, and to compare these results to the subjects’ auditory complaints.MethodsThis clinical retrospective study evaluated 364 workers between 1998 and 2005; their contralateral acoustic reflexes were compared to auditory complaints, age, and noise exposure time by chi-squared, Fisher's, and Spearman's tests.ResultsThe workers’ age ranged from 18 to 50 years (mean = 39.6), and noise exposure time from one to 38 years (mean = 17.3). We found that 15.1% (55) of the workers had bilateral hearing loss, 38.5% (140) had bilateral tinnitus, 52.8% (192) had abnormal sensitivity to loud sounds, and 47.2% (172) had speech recognition impairment. The variables hearing loss, speech recognition impairment, tinnitus, age group, and noise exposure time did not show relationship with acoustic reflex thresholds; however, all complaints demonstrated a statistically significant relationship with Metz recruitment at 3000 and 4000 Hz bilaterally.ConclusionThere was no significance relationship between auditory complaints and acoustic reflexes.     

Heat shock response in noise-induced hearing loss: effects of alanyl-glutamine dipeptide supplementation on heat shock proteins status

IntroductionThe 72 kDa heat shock protein, HSP72, located intracellularly provides cochlear cytoprotective and anti-inflammatory roles in the inner ear during stressful noise challenges. The expression of intracellular HSP72 (iHSP72) can be potentiated by alanyl-glutamine dipeptide supplementation. Conversely, these proteins act as pro-inflammatory signals in the extracellular milieu (eHSP72).ObjectiveWe explore whether noise-induced hearing loss promotes both intracellular and extracellular HSP72 heat shock response alterations, and if alanyl-glutamine dipeptide supplementation could modify heat shock response and prevent hearing loss.MethodsFemale 90 day-old Wistar rats (n = 32) were randomly divided into four groups: control, noise-induced hearing loss, treated with alanyl-glutamine dipeptide and noise-induced hearing loss plus alanyl-glutamine dipeptide. Auditory brainstem responses were evaluated before noise exposure (124 dB SPL for 2 h) and 14 days after. Cochlea, nuclear cochlear complex and plasma samples were collected for the measurement of intracellular HSP72 and extracellular HSP72 by a high-sensitivity ELISA kit.ResultsWe found an increase in both iHSP72 and eHSP72 levels in the noise-induced hearing loss group, which was alleviated by alanyl-glutamine dipeptide treatment. Furthermore, H-index of HSP72 (plasma/cochlea eHSP72/iHSP72 ratio) was increased in the noise-induced hearing loss group, but prevented by alanyl-glutamine dipeptide treatment, although alanyl-glutamine dipeptide had no effect on auditory threshold.ConclusionsOur data indicates that cochlear damage induced by noise exposure is accompanied by local and systemic heat shock response markers. Also, alanyl-glutamine reduced stress markers even though it had no effect on noise-induced hearing loss. Finally, plasma levels of 72 kDa heat shock proteins can be used as a biomarker of auditory stress after noise exposure.     

Lack of protection against gentamicin ototoxicity by auditory conditioning with noise

IntroductionAuditory conditioning consists of the pre-exposure to low levels of a potential harmful agent to protect against a subsequent harmful exposure.ObjectiveTo confirm if conditioning with an agent different from that used to cause the trauma can also be effective.MethodsThis was an experimental study with 17 guinea pigs, divided into three groups: an ototoxic control group (Cont) that received intramuscular administration of gentamicin 160 mg/kg/day for ten consecutive days, but no sound exposure; a sound control group (Sound) that was exposed to 85 dB broadband noise centered at 4 kHz, 30 min each day for ten consecutive days, but received no ototoxic medications; and an experimental group (Expt) that received sound exposure identical to the Sound group and after each noise presentation, received gentamicin similarly to Cont group. The animals were evaluated by distortion product otoacoustic emissions (DPOAEs), brainstem auditory evoked potentials (BAEPs), and scanning electron microscopy.ResultsThe animals that were conditioned with noise did not show any protective effect compared with the ones that received only the ototoxic gentamicin administration. This lack of protection was observed functionally and morphologically.ConclusionConditioning with 85 dB broadband noises, 30 min a day for ten consecutive days does not protect against an ototoxic gentamicin administration of 160 mg/kg/day for ten consecutive days in the guinea pig.     

Association between interleukin-6 polymorphism in the −174 G/C region and hearing loss in the elderly with a history of occupational noise exposure

IntroductionThe biological processes involved in noise-induced hearing loss (NIHL) are still unclear. The involvement of inflammation in this condition has been suggested.ObjectiveTo investigate the association between interleukin – 6 (IL-6) polymorphism and susceptibility to NIHL.MethodsThis was a cross-sectional study with a sample of 191 independent elderly individuals aged >60 years of age. Information on exposure to occupational noise was obtained by interviews. Audiological evaluation was performed using pure tone audiometry and genotyped through PCR by restriction fragment length polymorphism – PCR-RFLP. Data were analyzed using the chi-square test and the odds ratio (OR), with the significance level set at 5%.ResultsAmong elderly with hearing loss (78.0%), 18.8% had a history of exposure to occupational noise. There was a statistically significant association between the genotype frequencies of the IL-6 −174 and NIHL. The elderly with the CC genotype were less likely to have hearing loss due to occupational noise exposure when compared to those carrying the GG genotype (OR = 0.0124; 95% CI 0.0023–0.0671; p < 0.001).ConclusionThis study suggests there is an association of polymorphisms in the IL-6 gene at position – G174C with susceptibility to noise-induced hearing loss.     

Hearing in Noise Test Brazil: standardization for young adults with normal hearing

IntroductionIndividuals with the same ability of speech recognition in quiet can have extremely different results in noisy environments.ObjectiveTo standardize speech perception in adults with normal hearing in the free field using the Brazilian Hearing in Noise Test.MethodsContemporary, cross-sectional cohort study. 79 adults with normal hearing and without cognitive impairment participated in the study. Lists of Hearing in Noise Test sentences were randomly in quiet, noise front, noise right, and noise left.ResultsThere were no significant differences between right and left ears at all frequencies tested (paired t − 1 test). Nor were significant differences observed when comparing gender and interaction between these conditions. A difference was observed among the free field positions tested, except in the situations of noise right and noise left.ConclusionResults of speech perception in adults with normal hearing in the free field during different listening situations in noise indicated poorer performance during the condition with noise and speech in front, i.e., 0°/0°. The values found in the standardization of the Hearing in Noise Test free field can be used as a reference in the development of protocols for tests of speech perception in noise, and for monitoring individuals with hearing impairment.     

Representation of amplified speech at cortical level in good and poor hearing aid performers

IntroductionHearing aid users reject their own hearing aid because of annoyance with background noise. The reason for dissatisfaction is located anywhere from the hearing aid microphone to the integrity of neurons along the auditory pathway. In this preview, the output of hearing aid was recorded at the level of ear canal and at auditory cortex in good and poor hearing aid users, who were classified using acceptable noise level.ObjectiveTo study the representation of amplified speech in good and poor hearing aid performers.MethodsA total of 60 participants (age ranged 15–65 years) with moderate bilateral sensorineural hearing impairment grouped into good (n = 35) and poor (n = 25) hearing aid performers. Gap detection test and aided SNR 50 were administered. In addition, ear canal acoustic measures and cortical auditory evoked potentials were recorded in unaided and aided conditions at 65 dB SPL.ResultsHearing aid minimally alters temporal contrast of speech reflected in envelope difference index. Although having similar temporal impairment, acoustic characteristics of amplified speech sounds and SNR 50 scores from both groups, the aided cortical auditory evoked potentials surprisingly showed significant earlier latencies and higher amplitudes in good performers than poor performers. In addition, good and poor performers classified based on annoyance level was predicted by latencies of 2N1 and 2P2 components of acoustic change complex. Further, a follow-up revealed hearing aid use has relation with acceptance towards noise.ConclusionParticipants who are willing to accept noise from those who are not willing to accept noise have subtle physiological changes evident at the auditory cortex, which supports the hearing aid usage.     

Polymorphism in GRHL2 gene may contribute to noise-induced hearing loss susceptibility: a meta-analysis

InstructionNoise-induced hearing loss is a leading occupational disease caused by gene-environment interaction. The Grainy Like 2, GRHL2, is a candidate gene. In this regard, many studies have evaluated the association between GRHL2 and noise-induced hearing loss, although the results are ambiguous and conflicting.ObjectiveThe purpose of this study was to identify a precise estimation of the association between rs3735715 polymorphism in GRHL2 gene and susceptibility of noise-induced hearing loss.MethodsA comprehensive search was performed to collect data up to July 8, 2018. Finally, 4 eligible articles were included in this meta-analysis comprising 2410 subjects. The pooled odds ratios with 95% confidence intervals were used to evaluate the strength of the association.ResultsSignificant association was found in the overall population in the dominant model (GA/AA vs. GG, odds ratio = 0.707, 95% confidence interval = 0.594–0.841) and allele model (G allele vs. A allele, odds ratio = 1.189, 95% confidence interval = 1.062–1.333). When stratified by source of the subjects, we also found association between rs3735715 and noise-induced hearing loss risk in the dominant model (GA/AA vs. GG, odds ratio = 0.634, 95% confidence interval = 0.514–0.783) and allele model (G allele vs. A allele, odds ratio = 1.206, 95% confidence interval = 1.054–1.379).ConclusionRs3735715 polymorphism in GRHL2 gene may influence the susceptibility of noise-induced hearing loss. Additional large, well-designed and functional studies are needed to confirm this association in different populations.     

Osteoporosis and hearing loss: findings from the Korea National Health and Nutrition Examination Survey 2009–2011

IntroductionAge-related hearing impairment is the most common sensory dysfunction in older adults. In osteoporosis, the mass of the ossicles will be decreased, affecting the bone density of the cochlea, and interfering with the sound transmission to the cochlea. Age related hearing loss might be closely related to osteoporosis.ObjectiveTo determine the relationship between age-related hearing impairment and osteoporosis by investigating the relationship between hearing loss and cortical bone density evaluated from femur neck bone mineral density.MethodsWe used data from the Korea National Health and Nutrition Examination Survey to examine the associations between osteoporosis and age-related hearing impairment from 2009 to 2011. Total number of participants was 4861 including 2273 men and 2588 women aged 50 years or older. Osteoporosis was defined as a bone mineral density 2.5 standard deviations below according to the World Health Organization diagnostic classification. Age-related hearing impairment was defined as the pure-tone averages of test frequencies 0.5, 1, 2, and 4 kHz at a threshold of 40 dB or higher on the more impaired hearing side.ResultsTotal femur T-score (p < 0.001), lumbar-spine T-score (p < 0.001) and, femur neck T-score (p < 0.001) were significantly lower in the osteoporosis group compared to the normal group. Thresholds of pure-tone averages were significantly different in normal compared to osteopenia, and osteoporosis groups. In addition, there were significantly higher pure-tone averages thresholds in the osteoporosis group compared to other groups (p < 0.001). After adjusting for all covariates, the odds ratio for hearing loss was significantly increased by 1.7 fold with reduced femur neck bone mineral density (p < 0.01). However, lumbar spine bone mineral density was not statistically associated with hearing loss (p = 0.22).ConclusionOur results suggest that osteoporosis is significantly associated with a risk of hearing loss. In addition, femur neck bone mineral density was significantly correlated with hearing loss, but lumbar spine bone mineral density was not.     

The characteristic of otoacoustic emissions in full-term neonates according to ABO blood groups

IntroductionPrevious research has suggested that individuals with different blood groups show varied incidences of noise-induced hearing loss. The reduced otoacoustic emissions amplitudes indicate the higher possibilities of outer hair cell damage for noise exposure.ObjectiveThe objective is to analyze the characteristics of otoacoustic emissions, including the occurrence of spontaneous otoacoustic emission and the amplitudes of distortion product otoacoustic emission at certain frequencies in full term neonates with different ABO blood groups.MethodsA total of 80 selected full-term female neonates who passed the initial newborn hearing screen were enrolled into the study, with equal number of participants in four ABO blood groups (Blood Group A, Blood Group B, Blood Group AB, Blood Group O). Measurements of spontaneous otoacoustic emission and distortion product otoacoustic emission were performed in both ears for all participants.Results(1) The blood group O participants showed significantly fewer spontaneous otoacoustic emission occurrences than the other three blood groups (A = 70%, B = 80%, AB = 67%, O = 25%, p <  0.05). (2) The blood group O participants showed lower DPOAE amplitudes at 1257 Hz (M = 4.55 dB, SD = 8.36), 1587 Hz (M = 11.60 dB, SD = 6.57), 3174 Hz (M = 7.25 dB, SD = 5.99), 5042 Hz (M = 13.60, SD = 6.70) than participants with the other three blood groups in left ears (p < 0.05). In right ears, the blood group O participants showed reduced amplitudes at 1257 Hz (M = 6.55 dB, SD = 8.36), 1587 Hz (M = 13.60 dB, SD = 6.57), 3174 Hz (M = 7.65 dB, SD = 6.43), 5042 Hz (M = 13.65 dB, SD = 6.50) than participants from non-O blood groups (p < 0.05).ConclusionFemale individuals with blood group O have lower otoacoustic emissions values than individuals with the other three blood groups. We need to further investigate the possible relationships between ABO blood group and cochlear function, including the potential influences of noise damage on cochlear outer hair cells.     

High frequency hearing thresholds and product distortion otoacoustic emissions in cystic fibrosis patients

IntroductionThe treatment of patients with cystic fibrosis involves the use of ototoxic drugs, mainly aminoglycoside antibiotics. Due to the use of these drugs, fibrocystic patients are at risk of developing hearing loss.ObjectiveTo evaluate the hearing of patients with cystic fibrosis by High Frequency Audiometry and Distortion Product Otoacoustic Emissions.MethodsCross-sectional study. The study group consisted of 39 patients (7–20 years of age) with cystic fibrosis and a control group of 36 individuals in the same age group without otologic complaints, with normal audiometric thresholds and type A tympanometric curves. High Frequency Audiometry and Distortion Product Otoacoustic Emissions tests were conducted.ResultsThe study group had significantly higher thresholds at 250, 1000, 8000, 9000, 10,000, 12,500, and 16,000 Hz (p = 0.004) as well as higher prevalence of otoacoustic emission alterations at 1000 and 6000 Hz (p = 0.001), with significantly lower amplitudes at 1000, 1400, and 6000 Hz. There was a significant association between alterations in hearing thresholds in High Frequency Audiometry with the number of courses of aminoglycosides administered (p = 0.005). Eighty-three percent of patients who completed more than ten courses of aminoglycosides had hearing loss in High Frequency Audiometry.ConclusionA significant number of patients with cystic fibrosis who received repeated courses of aminoglycosides showed alterations in High Frequency Audiometry and Distortion Product Otoacoustic Emissions. The implementation of ten or more aminoglycoside cycles was associated with alterations in High Frequency Audiometry.     

Deeper insertion of electrode array result in better rehabilitation outcomes – Do we have evidence?

ObjectiveTo study the outcome analysis in cochlear implantees in relation to depth of insertion.Methods30 patients of non-syndromic congenital profound hearing loss in the age range of 2–12 years received cochlear implantation by a posterior tympanotomy round window approach. Depth of insertion was calculated using post-operative X-rays (modified Stenver's view) and categorized into four groups, viz. fair insertion (Group A <180°), good insertion (Group B 180–<270°), very good insertion(Group C 270–360°), excellent insertion (Group D >360°). The outcome analysis of each implantee was carried out in a follow up interval of every 3 months using Meaningful Auditory Integration Scale (MAIS), Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS), Category of Auditory Performance (CAP), and Speech Intelligibility Rating (SIR).ResultsOverall 30, 29, 25, and 22 patients have completed 3, 6, 9, and 12 months follow up respectively. The MAIS scores in Group C were significantly better than Group B at 6, 9, and 12 months (P < 0.05). The mean CAP score of Group C was more than rest of the groups with significant difference between Group C and Group D at 12 months (P < 0.05). The mean SIR scores were maximum in Group C with significant difference between Group C and Group B at 9 and 12 months (P < 0.05).ConclusionThe study demonstrates that insertion from 270° to 360° gives optimum hearing outcomes as compared to deeper insertion, although larger sample and long term follow-up is warranted for definite conclusions.     

Análisis de la potencia de salida y del rendimiento auditivo de los dispositivos auditivos osteointegrados

Background and objectiveOsseointegrated auditory devices are hearing gadgets that use the bone conduction of sound to produce hearing improvement. The mechanisms and factors that contribute to this sound transmission have been widely studied, however, there are other aspects that remain unknown, for instance, the influence of the processor power output. The aim of this study was to know if there is any relationship between the power output created by the devices and the hearing improvement that they achieve.Materials and methodsForty-four patients were implanted with a percutaneous Baha® 5 model. Hearing thresholds in pure tone audiometry, free-field audiometry, and speech recognition (in quiet and in noise) were measured pre and postoperatively in each patient .The direct bone conduction thresholds and the power output values from the processors were also obtained.ResultsThe pure tone average threshold in free field was 39.29 dB (SD 9.15), so that the mean gain was 29.18 dB (SD 10.13) with the device. This involved an air-bone gap closure in 63.64% of patients. The pure tone average threshold in direct bone conduction was 27.6 dB (SD 10.91), which was 8.4 dB better than the pure tone average threshold via bone conduction. The mean gain in speech recognition was 39.15% (SD 23.98) at 40 dB and 36.66% (SD 26.76) at 60 dB. The mean gain in the signal-to-noise ratio was ?5.9 dB (SD 4.32). On the other hand, the mean power output values were 27.95 dB μN (SD 6.51) in G40 and 26.22 dB μN (SD 6.49) in G60. When analysing the relationship between bone conduction thresholds and G40 and G60 values, a correlation from the frequency of 1,000 Hz was observed. However, no statistically significant association between power output, functional gain or speech recognition gain was found.ConclusionsThe osseointegrated auditory devices generate hearing improvement in tonal thresholds and speech recognition, even in noise. Most patients closed the air-bone gap with the device. There is a direct relationship between the bone conduction threshold and the power output values from the processor, but only in mid and high frequencies. However, the relationship between power output and gain in speech recognition is weaker. Further investigation of contributing factors is necessary.     

Effect of contralateral stimulation on acoustic reflectance measurements

IntroductionAcoustic reflectance is an important tool in the assessment of middle ear afflictions, and the method is considered advantageous in relation to tympanometry. There has been a growing interest in the study of contralateral acoustic stimulation and its effect on the activation of the efferent auditory pathway. Studies have shown that the introduction of simultaneous stimulation in the contralateral ear generates alterations in auditory response patterns.ObjectiveTo investigate the influence of contralateral stimulation on acoustic reflectance measurements.MethodsCase study of 30 subjects with normal hearing, of both genders, aged 18–30 years. The test and retest acoustic reflectance was conducted in the frequency range 200–6000 Hz. The procedure was repeated with the simultaneous presence of contralateral white noise at 30 dBNS.ResultsThe analysis of the conditions of test, retest, and test with contralateral noise showed statistical difference at the frequency of 2 kHz (p = 0.011 and p = 0.002 in test and retest, respectively) in the right ear.ConclusionThe activation of the auditory efferent pathways through contralateral acoustic stimulation produces alterations in response patterns of acoustic reflectance, increasing sound reflection and modifying middle ear acoustical energy transfer.     

Reproducibility (test–retest) of vestibular evoked myogenic potential

IntroductionThere is still no consensus in the literature as to the best acoustic stimulus for capturing vestibular evoked myogenic potential (VEMP). Low-frequency tone bursts are generally more effective than high-frequency, but recent studies still use clicks. Reproducibility is an important analytical parameter to observe the reliability of responses.ObjectiveTo determine the reproducibility of p13 and n23 latency and amplitude of the VEMP for stimuli with different tone-burst frequencies, and to define the best test frequency.MethodsCross-sectional cohort study. VEMP was captured in 156 ears, on the sternocleidomastoid muscle, using 100 tone-burst stimuli at frequencies of 250, 500, 1000, and 2000 Hz, and sound intensity of 95 dB nHL. Responses were replicated, that is, recorded three times on each side.ResultsNo significant difference was observed for p13 and n23 latencies of the VEMP, captured at three moments with tone-burst stimuli at 250, 500, and 1000 Hz. Only the frequency of 2000 Hz showed a difference between captures of this potential (p < 0.001). p13 and n23 amplitude analysis was also similar in the test–retest for all frequencies analyzed.Conclusionp13 and n23 latencies and amplitudes of VEMP for tone-burst stimuli at frequencies of 250, 500, and 1000 Hz are reproducible.     

Accuracy of peripheral arterial tonometry in the diagnosis of obstructive sleep apnea

IntroductionThe use of handheld devices that assess peripheral arterial tonometry has emerged as an auxiliary method for assessment and diagnosis of obstructive sleep apnea syndrome.ObjectiveTo evaluate the accuracy of peripheral arterial tonometry in the diagnosis of obstructive sleep apnea.MethodsContemporary cohort cross-sectional study. Thirty patients with suspected obstructive sleep apnea underwent peripheral arterial tonometry and assisted nocturnal polysomnography concomitantly.ResultsThe mean apnea/hypopnea index by peripheral arterial tonometry was significantly higher than that by polysomnography (p < 0.001), but the values of both sleep studies were significantly correlated (r = 0.762). There was a high correlation between variables: minimum oxygen saturation (r = 0.842, p < 0.001), oxygen saturation < 90% (r = 0.799, p < 0.001), and mean heart rate (r = 0.951, p < 0.001). Sensitivity and specificity were 60% and 96.2% (AUC: 0.727; p = 0.113), respectively, when at a threshold value of 5 events/h. In severe cases (≥30 events/h), the result was a sensitivity of 77.8% and a specificity of 86.4% (AUC: 0.846, p = 0.003).ConclusionPeripheral arterial tonometry is a useful portable device for the diagnosis of obstructive sleep apnea; its accuracy is higher in moderate and severe cases.     

A multicentre clinical evaluation of paediatric cochlear implant users upgrading to the Nucleus® 6 system

ObjectivesThe aim of this study was to investigate whether experienced paediatric cochlear implant users could show benefits to speech perception outcomes from the introduction of noise reduction and automated scene classification technologies as implemented in the Nucleus^® 6 sound processor. Previous research with adult cochlear implant users had shown significant improvements in speech intelligibility for listening in noisy conditions and good user acceptance for upgrading to the Nucleus 6 processor. In adults, these improvements for listening in noise were primarily attributed to the use of a range of new input processing technologies including noise reduction, as well as introduction of automatic scene classification technology.MethodsExperienced paediatric cochlear implant users (n = 25) were recruited from four clinics located in three countries. Research participants were evaluated on three occasions, an initial session using their Nucleus 5 sound processor; a second session in which participants used the Nucleus 6 processor programmed with the same technologies as were used in their Nucleus 5 sound processor; and a final session in which participants used the Nucleus 6 processor programmed with the default technologies including automatic scene classification (SCAN) which automatically selects the microphone directionality, noise reduction (SNR-NR), and wind noise reduction (WNR) technologies. Prior to both the second and third evaluations, research participants had approximately two weeks take-home experience with the new system. Speech perception performances on monosyllabic word tests presented in quiet and in noise, and a sentence test presented in noise, were compared across the three processor conditions. Acceptance of the Nucleus 6 default settings was assessed in a final session.ResultsNo group mean difference in performance was found for monosyllabic words in quiet. A significant improvement in speech perception was found for both monosyllabic words and sentences in noise with the default Nucleus 6 program condition as compared with the Nucleus 5 condition. No acceptance issues were noted for any of the children.ConclusionsExperienced paediatric cochlear implant users showed a significant improvement in speech perception in listening in noise when upgraded to the Nucleus 6 sound processor primarily due to the introduction of a noise reduction technology, and all children accepted the default program. These findings suggest that school-aged children may benefit from upgrading to the Nucleus 6 sound processor using the default program.     

Speech audiometry in noise: SNR Loss per age-group in normal hearing subjects

ObjectivesThe present study aimed to determine normal SNR values per age group for the 50% speech reception threshold in noise (SNR Loss) on the VRB (Vocale Rapide dans le Bruit: rapid speech in noise) test.Material and MethodsTwo hundred patients underwent pure-tone threshold and VRB speech-in-noise audiometry. Six ages groups were distinguished: 20–30, 30–40, 40–50, 50–60, 60–70 and > 70 years. All subjects had normal hearing for age according to ISO 7029. SNR Loss was measured according to age group.ResultsMean SNR Loss ranged from ?0.37 dB in the youngest age group (20–30 years) to +6.84 dB in the oldest (> 70 years). Range and interquartile range increased with age: 3.66 and 1.49 dB respectively for 20–30 year-olds; 6 and 3.5 dB for > 70 year-olds. Linear regression between SNR Loss and age showed a coefficient R² of 0.83.ConclusionThe present study reports SNR Loss values per age group in normal-hearing subjects (ISO 7029), confirming that SNR Loss increases with age. Scatter also increased with age, suggesting that other age-related factors combine with inner-ear aging to impair hearing in noise.     

Contralateral occlusion test: The effect of external ear canal occlusion on predicting conductive hearing loss

Introduction and objectivesThe contralateral occlusion test (COT) has the potential to allow the quantitative evaluation of unilateral conductive hearing loss. The purpose of this study was to determine the accuracy of the test in predicting the degree of hearing loss.Materials and methodsFifty-three subjects with unilateral conductive hearing loss were recruited from an otolaryngology department of a tertiary hospital. The COT was performed using 128, 256, 512, 1024 and 2048 Hz tuning forks with the non-affected ear canal totally occluded to determine lateralization. Pure-tone audiometry was performed to establish the presence and degree of the air-bone gap (ABG) and the pure-tone average (PTA). The tuning fork responses were correlated with the ABG and the PTA to determine their accuracy.ResultsThe COT showed a better association between hearing loss and the lateralization response using the 512 Hz tuning fork (p = 0.001). The sensitivity of the 512 Hz fork in detecting a PTA of at least 35.6 dB was 94.6% and the specificity was 75.0% for a positive predictive value of 89.7% and a negative predictive value of 85.7%, assuming a pretest prevalence of 69.8%.ConclusionsThe overall accuracy of the COT in predicting the degree of unilateral conductive hearing loss was significant. The COT had significant power in one direction: if lateralization to the affected ear occurred, it was almost certain evidence of a moderate or severe conductive hearing loss.     

Tone and sentence perception in young Mandarin-speaking children with cochlear implants

ObjectivesThe purpose of this study was to examine the outcomes of cochlear implantation in young children in terms of (1) perception of lexical tones in quiet, (2) perception of sentences in quiet and in noise, (3) the effects of five demographic variables (i.e., preoperative hearing level, age at implantation, duration of cochlear implants use, maternal educational level, and whether a child underwent a hearing aid trial before implantation) on lexical tone perception and sentence perception, and (4) the relationship between lexical tone perception and sentence perception.Methods96 participants, aged from 2.41 years to 7.09 years, were recruited in mainland China. The children exhibited normal cognitive abilities and received unilateral implants at an average age of 2.72 years, with ages ranging from 0.69 to 5 years of age.ResultsThe mean score for tone identification was 77% (SD = 13%; chance level = 50%). Tone 2/tone 3 was the most difficult tone contrast to identify. Children with a longer duration of CI use and whose mothers had more years of education tended to perform better in sentence perception in quiet and in noise. Having undergone a hearing aid trial before implantation and more residual hearing were additional factors contributing to better sentence perception in noise. The only demographical variable that related to tone perception in quiet was duration of CI. In addition, while there was a modest correlation between tone perception and sentence perception in quiet (r_s = 0.47, p < 0.001), the correlation between tone perception in quiet and sentence perception in noise was much weaker (r_s = −0.28, p < 0.05).ConclusionsThe findings suggested that most young children who had been implanted before 5 years of age and had 1–3 years of implant use did not catch up with their aged peers with normal hearing in tone perception and sentence perception. The weak to moderate correlation between tone perception in quiet and sentence perception might imply that the improvement of tone perception in quiet may not necessarily contribute to sentence perception, especially in noise condition.     

Chemical and cytological analysis of cerebral spinal fluid after intrathecal injection of hypodense fluorescein

IntroductionIntrathecal fluorescein has been effective for topographic diagnosis of rhinoliquorrhea. Nonetheless, there are no reports on the study of cerebral spinal fluid (CSF) after use of intrathecal fluorescein.ObjectiveA prospective study attempting to evaluate CSF through chemical and cytological analysis, after injection of fluorescein.MethodsProspective analysis of 24 samples of CSF after intrathecal injection of fluorescein for topographic diagnosis of CSF fistulae, collected at the time of puncture and after 24 and 48 h, divided by cellularity: Group 1, up to five cells, and Group 2, with more than five cells.ResultsThe yellow-greenish color of CSF remained after 48 h in 36%, evidencing permanence of fluorescein. No changes in protein and glucose levels were observed between 0–24 h and 0–48 h. In group 2, an increase in cell count was observed between 24 h and 48 h (p = 0.019). In both groups, there was an increase of neutrophils between 0 and 48 h (p = 0.048) and a decrease between 24 and 48 h (p = 0.05).ConclusionIntrathecal fluorescein provoked discreet meningeal reactions, such as an increase of cells between 24 and 48 h and an increase of neutrophils at 24 h, with a subsequent decrease at 48 h with no correlation with symptomatology.