Pediatric hearing loss.

After completing this article, readers should be able to: A number of authors suggest that the critical period for development of the auditory system and speech commences in the first 6 months of life and continues through 2 years of age. Specific linguistic experience in the first 6 months of life, before meaningful speech begins, affects infants' perception of speech sounds and their capacity to learn. Moderate-to-severe hearing impairment in the first year of life is believed to compromise speech and language acquisition as well as cognitive and social development. Mild or unilateral hearing deficits also are considered to affect language development and behavior of children. Early intervention (following detection of hearing impairment in those younger than 3 months of age) reduces the age for access to effective medical and habilitative intervention for many infants. Intervention for those younger than 6 months of age also is believed by many to improve speech and language development and cognitive outcomes, diminishing the need for special education and improving quality of life. The evidence for these effects currently is limited in quantity and quality; most studies are retrospective and have significant limitations.The prevalence of moderate through profound hearing impairment‡ in newborns, including both sensorineural (SNHL) and conductive hearing loss (CHL), is in the range of 1 to 3/1,000. Previously published reports are believed to reflect an underestimate of the true prevalence. If infants who have mild SNHL are included, the prevalence would at least double. Furthermore, the prevalence of hearing impairment is increased substantially in newborns who have specific risk indicators (Table 1).Universal newborn hearing screening (UNHS) programs are mandated in at least 32 states in the United States and are being initiated in 20 health districts in the United Kingdom. Prior to these developments, the average age of identification of hearing impairment was about 30 months, with individual cases being diagnosed at a much later age. In addition, children who had mild or moderate hearing losses frequently were not identified until school age. Infants may be referred for testing when a risk indicator for hearing impairment is present (Tables 1 and 2) or if parents, health workers, or other caregivers suspect a hearing deficit. However, it is widely reported that targeted high-risk screening can identify at best about 50% of children who have significant prelingual hearing impairment.A recent systematic review of the evidence supporting UNHS has concluded that modern screening tests for hearing impairment can improve identification of newborns who have permanent hearing impairment, but the efficacy of UNHS to improve long-term language outcomes remains uncertain. That review formed the basis for a recent rating by the United States Preventive Services Task Force of the evidence for effectiveness of UNHS programs as "inconclusive." The review identifies some important gaps and deficiencies in current knowledge about newborn hearing screening, and it is helpful in identifying a research agenda to place screening programs on a more evidentially secure footing. The findings of the review reflect a narrow focus on the scientific quality of evidence relating to specific questions. Such reviews are useful, but they do not encompass a broader picture of poor current identification and a substantial current burden of unidentified and unmanaged hearing disorders in infancy. The review also does not reflect the values that society may place on improvements in early identification, audiologic evaluation, information to parents, access to medical interventions, ability to hear, and other interventions designed to improve communication skills in infancy. These broader considerations are beyond the scope of pure evidence review, but they are within the purview of several multidisciplinary position statements that have been developed nationally and internationally in recent years that generally endorse UNHS.The gold standard for assessing hearing deficit in infants older than 6 months of age comprises behavioral tests that rely on operant conditioning, such as visual reinforcement audiometry (VRA). This involves testing an infant's response to specific tones projected within a soundproof room from different directions. When performed correctly, VRA can yield accurate audiometric thresholds in children as young as 6 months of age who have normal neurologic development. However, in younger infants and in those who have developmental delay or certain physical disabilities, behavioral tests of any type are unreliable and have a low specificity.The auditory brainstem response (ABR) is the only test of auditory function accepted as a proxy gold standard for assessment of hearing sensitivity in newborns and infants. The ABR is an electrical waveform (an evoked potential) generated by neuronal activity in the auditory nerve and brainstem pathways following a transient sound such as a click. Its registration (via skin electrodes, electroencephalographic amplifiers, and computer averaging) does not require a behavioral response. The intensity and rate of stimulation primarily determine the response size, latency, and morphology. The presence of a detectable ABR is considered a proxy for perception of sound. The lowest stimulus level that evokes a detectable ABR is an estimator of the true perceptual threshold for various sounds. There is a high correlation between hearing impairment in infants and alteration in the ABR pattern. Overall, ABR testing provides a reasonable evaluation of thresholds over a broad range of hearing impairments and permits differentiation between CHL and SNHL. Many studies have demonstrated that the click ABR in early infancy is a good predictor of pure tone auditory thresholds in the 2,000 to 4,000 Hz range, although a more technically correct interpretation is that the ABR reflects the best pure tone threshold in the range of 500 to 4,000 Hz. Skill and experience are required for valid and efficient ABR testing and interpretation of results.Current screening technologies include: automated auditory brainstem response (AABR), transient evoked otoacoustic emissions (TEOAE), and distortion product otoacoustic emissions (DPOAE). The screening device objectively and automatically detects the response to sound (either an evoked potential or an otoacoustic emission), and the outcome is designated as a "pass" or "fail" ("refer") by the automated analyser. In the screening mode, the three screening methods indicate presence or absence of a response at a specific stimulus level; they neither quantitatively estimate the severity of the hearing impairment nor distinguish conductive from sensorineural hearing impairment.The AABR is a modification of conventional ABR testing, usually involving a single stimulus level and automated response detection. Typically, a series of click stimuli at a level of approximately 30 to 40 dB nHL (normal hearing level is the threshold of audibility of the clicks in normal young adult listeners) is delivered. The electrical signals from at least three or four electrodes on the head are amplified and computer-processed in an attempt to extract the minute ABR from the ongoing electromyogenic and electroencephalic activity that is unrelated to the stimulus. The key technique is averaging of the waveforms recorded after several thousand stimuli, delivered very rapidly. The resultant waveform is tested statistically to determine whether it is a genuine evoked response or merely random electrical noise.Using statistical response detection eliminates the need for waveform interpretation by a highly trained professional. This is important both to reduce screening manpower costs and to increase the accuracy and consistency of response detection. A variety of automated ABR screening instruments is commercially available.TEOAE are elicited by click stimuli delivered by a probe transducer in the external ear canal. The emission or "echo" from the inner ear is a very faint sound with a complex waveform that is recorded by a sensitive, miniature microphone in an external ear probe assembly. Some method of signal enhancement, such as signal averaging, is necessary to distinguish the otoacoustic emissions (OAE) from ambient sound.TEOAE presence implies integrity of sound transmission through the outer and middle ear structures and functional integrity of the outer hair cells, which are the primary sensory transducers with the organ of Corti in the cochlea and are believed to be the site of emissions generation. Low ambient noise level, a clear external auditory meatus and middle ear, probe stability, appropriate choice of stimulus intensity, later postnatal testing, and cochlear maturation all improve the specificity of TEOAE screening. Because the original patent on the TEOAE method only expired recently, the variety of commercially available TEOAE screening devices is limited, although this is changing rapidly.DPOAE are an alternative form of cochlear emission, also having their origin in the outer hair cells of the cochlea. The stimulus is two simultaneous sustained pure tones (primary frequencies of f1 and f2) typically in the 50 to 70 dB intensity range and with a frequency ratio of about 1.22. Under these conditions, a nonlinear stimulus interaction occurs within the cochlea, and a tonal distortion product at a frequency of 2f1-f2 is generated and radiates back to the external ear. Just as for the TEOAE, the DPOAE are detectable in the external meatus. The frequency-specific nature of the DPOAE may provide more precise information than with the TEOAE, but poor recording conditions may result in inaccurate measurements.Any factor that interferes with the registration of a clear ABR or OAE will cause false-positive screening outcomes. The specificity of the AABR, TEOAE, and DPOAE improves when screening takes place at a later postnatal age and with cleaning of the external auditory meatus. This difference is believed to be due to cochlear maturation, clearance of middle ear fluid after the first 48 hours of life, or improved tympanic membrane mobility. Excessive environmental noise also decreases the specificity of TEOAE and DPOAE.There is good evidence that the TEOAE, DPOAE, and AABR are accurate tests for detection of significant hearing impairment in neonates and infants. A two-stage screening protocol tends to yield lower false-positive rates (with specificity >94%) without substantial reduction in sensitivity. Each technology is affected by environmental conditions and the age at which the screen takes place, with the OAE methods affected more than the AABR. There is more variability in the specificity with the TEOAE and DPOAE than with the AABR. That difference is reduced when a two-stage screening procedure is used and the AABR is used for the second stage of the screen. Any of the three screening technologies may be used in a two-stage procedure to detect hearing impairment in newborns. The tests are noninvasive, brief, and inexpensive.Current screening protocols typically employ either a one-, two-, or three-stage screen, with up to two screens prior to discharge from the birth admission, follow-up screening in the community, or both. A higher rate of false-positive findings immediately postnatally (attributed to resolving middle-ear conditions) may be addressed by multistage screening with an outpatient rescreen. Children failing the screening protocol should undergo prompt confirmatory and diagnostic hearing assessment with manual ABR or VRA (preferably including ear-specific and frequency-specific techniques), tympanometry, acoustic reflexes, and other audiologic tests. A possible screening protocol is outlined in the FigureF1.The current American Academy of Pediatrics guidelines suggest universal identification of hearing impairment by 3 months and commencement of intervention by 6 months of age. Because high referral rates result in increased stress on audiologic services and may cause psychological stress on families of those testing positive, a maximum false-positive rate of 3% is widely endorsed and considered feasible for hearing screening programs. A population coverage benchmark of 95% has been proposed, and a target of 100% sensitivity has been suggested. Realistic values will be determined by the sensitivity and specificity of practicable screening protocols and the outcome cost-benefit structure.The accuracy of screening tests may not be identical in high-risk and low-risk groups. Potential sources of variation include different amounts of progressive or early-onset (ie, noncongenital) pathology in the two groups, confounding of behavioral hearing test outcomes by cognitive deficits, and differences in the distribution of hearing impairment for the two groups. Furthermore, it is easier to achieve behaviorally satisfactory test conditions (ideally, a sleeping baby) in low-risk babies, who generally are less distressed.Important practical issues for UNHS programs include follow-up of both children who fail in-hospital screening and those who are not accessed or successfully screened before discharge. Low rates of screening are of concern and are believed to be due to shorter hospital stays and poor compliance for follow-up of first-stage screening failures. For each additional year of experience with screening, most current programs report increasing participation and follow-up of children who fail the screening. However, ongoing surveillance of infants who pass the neonatal screening but are at risk for progressive or early-onset hearing impairment generally is poor. The yield of UNHS programs is limited by hearing impairment possibly being acquired by both pediatric intensive care unit graduates and well babies (targeted or nontargeted screening). A pass in the UNHS program may give parents a false sense of security that their infant has normal hearing and may lessen parental or professional vigilance for detection of acquired hearing loss. Acquired hearing impairment due to both congenital (eg, cytomegalovirus) or acquired infections (eg, meningitis), acquired conductive hearing impairment (due to recurrent otitis media), or auditory neuropathy will not be detected by UNHS programs.There are concerns that a false-positive screen will result in unnecessary parental anxiety, with a negative effect on the parent-child relationship. Questionnaires of parents whose children underwent UNHS did not confirm this concern. The screen was considered to be quick and painless for the infant. UNHS was considered to be a measure of security except in infants who had unilateral or mild deficits that required no intervention. In addition, high false-positive rates may increase the burden on diagnostic services. High-quality screening programs that have a maximum false-positive rate of 4% (after a two-stage screen) should minimize this effect.Overall, UNHS programs have demonstrated earlier identification of hearing impairment, earlier diagnosis, and earlier intervention, whether by hearing aids or other interventions. It is critical that UNHS activities be followed by timely, appropriate, and well-integrated subsequent steps in the overall process that lead to delivery of effective, efficient, culturally sensitive, and family-centered hearing health care. The overall system is commonly referred to as an Early Hearing Detection and Intervention (EHDI) program.In addition, there now is some indirect evidence that early intervention improves speech, language, cognitive ability, and personal-social skills through amplification with hearing aids or cochlear implants or other communication development programs. Evidence is based largely on retrospective data from cohorts that may not be entirely representative of a universal hearing screening program.Infants who are at risk for postnatal hearing loss that may present after neonatal screening should be rescreened periodically. Intervals of about every 3 to 6 months for at least 3 years have been suggested, but such a schedule is likely to prove impractical. For some risk factors, such as perinatal cytomegalovirus infection, there is evidence of continued postnatal expression over even longer periods. Specific postnatal events such as bacterial meningitis or head injury should be followed systematically by hearing screening. The screening technology most practical for widespread use by nonaudiologist personnel is probably automated OAE, either DPOAE or TEOAE, but because of the increased prevalence of hearing impairment in the at-risk group, the use of a more accurate test such as AABR may be indicated. Infants who fail any such screening, whether periodic or driven by a risk event, should receive full audiologic and otologic examination.It is likely that 5% to 10% of newborns manifest one of the risk indicators for progressive or late-onset hearing loss defined by the Joint Committee on Infant Hearing (Tables 1 and 2), so the total amount of screening activity needing to be directed at progressive and late-onset hearing impairment is substantial. The proportion of children who have hearing impairments at 5 years of age that actually are congenital is not yet well understood, and reported ranges vary widely. This is predictable because epidemiologic patterns of postnatal risk and perinatal management practices affect the distribution of impairment.The key practical aspects of screening young infants relate to the behavioral state of the child and to the environmental noise levels. Whether OAE or ABR methods are used, accuracy will be poor if the child is not resting quietly (preferably sleeping). The primary problem associated with OAE is physical movement of the stimulus probe in the ear canal; for the AABR, electromyogenic interference associated with gross body movement may decrease sensitivity. A similar deterioration of specificity is expected if environmental noise levels are too high, and a limit of about 55 dBA (55dB sound pressure level with a so-called "A-weighting" of energy at various frequencies that approximates the sensitivity characteristics of the human ear) has been suggested.The requirement of a sleeping infant means that accurate, objective, physiologic audiometry by OAE or ABR methods is increasingly difficult to obtain in a child older than 6 months of age. If the risk of hearing impairment is substantial, testing under mild sedation or light general anesthesia may be considered. Sedation or anesthesia probably would be used for full, objective diagnostic assessment immediately following screening failure in infants older than about 6 months or in younger infants who are found to be untestable in natural sleep.It is fortunate that behavorial screening by VRA or related methods such as conditioned play audiometry (CPA) is increasingly feasible for many children older than 6 months of age who have no substantive cognitive deficit. The skill and experience required for accurate and consistent VRA and CPA are substantial. Informal office behavioral screening using various kinds of noisemakers and observing behavioral response is notoriously inaccurate and has little if any place in a high-quality system for childhood hearing health care. Definitive audiologic assessment of children who have significant cognitive disabilities can be a long-term challenge that requires careful longitudinal integration of various types of objective, physiologic evidence (otoacoustic emissions, evoked potentials, middle ear muscle reflexes) as well as behavioral data from formal tests and real-world observations.When a child fails an objective screen, one of the first questions is whether the failure is attributable to middle ear disease.One goal of screening children in the age range of 3 to 5 years is to identify preschoolers who may have developed hearing impairment that is likely to interfere with communication and educational development. In the context of an integrated system for EHDI, such impairments are likely to be late-onset, progressive, or adventitious (hearing loss associated with diseases or traumatic events occurring in early childhood such as meningitis or head trauma). Risk indicators include family history, specific infections, trauma, and parent/caregiver or clinician concerns about hearing, speech, language, or developmental delay.Middle ear disorders are common in this age group, and it can be efficient to screen for both hearing loss and middle ear abnormality. If the child is cooperative, OAE screening is feasible and attractive because of its objectivity. The latest devices incorporate both measurement of OAE and otoacoustic immittance capabilities. This allows simultaneous detection of any hearing impairment of at least 30 dB hearing loss (with OAE) and limited differential diagnosis of the type of impairment (conductive or sensorineural).If a skilled tester and facilities are available and the child is cooperative and responsive, many children in this age group can be screened by CPA under earphones. This technique has the advantage of assessing the full perceptual system of a child, whereas objective procedures such as OAE and AABR measure only physiologic correlates of true hearing. Children who cannot perform adequately on CPA may be able to be tested successfully with VRA. It may be useful to conduct both objective and behavioral screening, where feasible, to guard against screening errors. Failure on either screening tool normally should be followed by full audiologic assessment.When a child fails an objective screen, such as an OAE screen, one of the first questions is whether the failure is attributable to middle ear disease. Tympanometry (immittance testing) can be helpful; when results are normal, the index of suspicion for significant SNHL is increased significantly. Full and prompt diagnostic audiologic assessment is indicated. If the tympanometry result is abnormal, there is a substantial likelihood that the screening failure is attributable to middle ear disease. The presence of a sensorineural component is not ruled out by abnormal tympanometric findings.Detailed guidelines for screening protocols for children of various age groups are published in the Joint Committee on Infant Hearing 2000 position statement and the Guidelines for Audiologic Screening developed by the American Speech-Language-Hearing Association (see Suggested Reading).

Year 2000 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs.

The Big Screen Difference

Advances in the Hearing Sciences: Current Research and Clinical Applications

Access to Pediatric Audiological Evaluation Facilities: Urgent Needs and Why They Matter

Background Rubella infection in pregnancy can cause congenital rubella syndrome (CRS), and one common defect of CRS is hearing loss. However, hearing screening is not routinely performed in Indonesia. While the number of reported cases of CRS in Indonesia is increasing, it is still difficult to identify all CRS cases. This study aims to identify CRS cases through a newborn hearing screening. Materials and Methods This descriptive study was conducted at Dr. Sardjito Hospital, Yogyakarta, Indonesia. The subjects were recruited from September 1, 2013 to November 19, 2013. The study period was from September 1, 2013 to January 31, 2014. Newborn subjects underwent the first otoacoustic emissions (OAEs) test. Subjects with the first OAEs test REFER results underwent the second OAEs test 2 months later. Subjects with REFER result in the second OAEs test then underwent auditory brainstem response (ABR) and detection of rubella IgM in blood serum. Result There were 151 subjects who underwent the first OAEs test. Ninety subjects (60%) had REFER results, but only 29 subjects underwent the second OAEs test. In the second OAEs test, 9/151 (5%) subjects were REFER. There were 6/151 (3.9%) subjects who underwent ABR and all subjects had sensory neural hearing loss. Of them, one subject was positive for rubella IgM with a titer of 11.86 at 2.5 months of age. We found nine suspected CRS cases, one clinically-confirmed and one laboratory-confirmed CRS case. The incidence of laboratory-confirmed CRS was 1/151 (6.62/1,000) live births. Conclusion Due to the low incidence we found and the cost of screening, we recommend to strengthen surveillance of CRS. All infants less than 1 year of age with suspected CRS should be checked with rubella IgM to identify CRS cases. While universal newborn hearing screening is not mandatory in Indonesia, targeted newborn hearing screening should be performed to detect children with permanent congenital hearing loss due to CRS.

Objective. Although previous studies have documented the feasibility and benefits of universal newborn hearing screening in selected hospitals, none have reviewed the effectiveness of regionally mandated participation of large numbers of hospitals with variable levels of motivation to succeed. The purpose of this study was to measure hospital participation and overall screening success in a statewide program for universal newborn hearing screening and to track improvements in program establishment and outpatient follow-up over time. Methods. Four Colorado hospitals began voluntarily performing hearing screening before hospital discharge on all newborns in 1992. By 1996, 26 Colorado hospitals were participating in universal newborn hearing screening. The publication of screening results from these early years served as a catalyst for legislation requiring increased hospital participation in establishing universal screening programs. Data systems were subsequently developed to improve statistical tracking and follow-up. Eight years’ worth of cumulative study data as well as the results from calendar year 1999 (the year of greatest hospital participation) were reviewed for collective measures of successful screening and follow-up. Three hospitals did not initiate newborn hearing screening programs until after the study period ended in 1999. Of the 57 hospitals that were screening newborns in 1999, the chosen method of screening at 52 hospitals was automated auditory brainstem response testing; 3 hospitals used otoacoustic emission testing, and the remaining 2 hospitals used 2-stage screening. Hearing loss was defined as a threshold of 35 decibels or greater in 1 or both ears at the time of confirmatory testing. Results. During the full 8-year study period, 1992 to 1999, 148 240 newborns were screened. A total of 291 infants who were born during the study period received a diagnosis of congenital hearing loss. In this cohort of 291 children, the cumulative frequency of bilateral hearing loss was 71% (range: 48%–94% by calendar year), the frequency of sensorineural hearing loss was 82% (range: 67%–88%), and the frequency of 1 or more risk factors was 47% (range: 37%–61%). During calendar year 1999, a total of 63 590 births were recorded at 60 birthing hospitals in Colorado. The families of 263 (0.4%) of these newborns refused newborn hearing screening. Of the remaining 63 327 newborns, 87% (55 324 infants) were screened for hearing acuity before hospital discharge, a far greater percentage than the 19% of all newborns screened during the first 5 years of voluntary hospital participation, and approaching the American Academy of Pediatrics’s recommendation of 95% of newborns completing hospital-based testing in a successful screening program. As a result of this statewide hearing screening program, congenital hearing loss was diagnosed in 86 Colorado newborns during 1999, representing an occurrence rate of approximately 1 affected child in every 650 newborns. In this group of 86 infants, 59 had bilateral sensorineural hearing loss, 17 had unilateral sensorineural hearing loss, 4 had bilateral conductive hearing loss, and 6 had unilateral conductive hearing loss. Mild hearing loss was present in 6 infants, moderate hearing loss was present in 42 infants, severe hearing loss was present in 33 infants, and profound hearing loss was present in the remaining 5 infants. Only 32 of the 86 affected newborns in 1999 had 1 or more risk factors for hearing loss subsequently identified. After failing an initial hospital-based screening at 1 of the 57 participating hospitals in 1999, 2.3% of infants screened (1283 newborns) were referred for follow-up testing, easily exceeding the standard of Conclusions. Universal screening for congenital hearing loss is demonstrated to be feasible in a large regional effort of legislatively mandated participation. The success of such an endeavor is dependent on educational efforts for community professionals, commitment on the part of program planners, and data systems that more accurately track and recall infants who fail initial hospital-based screening.

Meningioma in the Middle Ear: An Unusual Case of Hearing Loss

Community-based newborn hearing screening program in Taiwan

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.

Objectives: Demonstrate the role of the innate immune response in a mouse model for Cytomegalovirus (CMV) induced sensorineural hearing loss (SNHL). Methods: Forty C57BL/6 and BALB/c mice underwent intracranial injection at postnatal day 3 with 200 pfu of green fluorescent protein (GFP) expressing murine (m) CMV; 10 controls received either saline or no injection. Hearing thresholds were assessed using distortion product otoacoustic emission (DPOAE) and auditory brain stem response testing (ABR). Temporal bones were harvested and sectioned for histologic analysis. A subset of BALB/c and C57B/6 temporal bones were harvested for histologic analysis 3 and 7 days after inoculation. Results: Fifty-five percent of the BALB/c mice had profound hearing loss (≥80 dB) at 4 weeks of age, while 45% initially showed moderate hearing loss that progressed to profound hearing loss by 6 weeks. The green fluorescent protein (GFP)-labeled virus was abundant in the spiral ganglion and adjacent to the scala tympani at 7 days post-injection and absent by 4 weeks. In contrast to what was seen in BALB/c mice, the C57/B6 mice showed mild hearing loss. Moreover, temporal bone histology also showed no evidence of mCMV infiltration of the cochlea 3 and 7 days post-inoculation when peak mCMV infection was expected. Conclusions: Since C57BL/6 mice have been shown to possess a Ly-49H receptor that triggers natural killer cell activation which is not present in BALB/c mice, these results suggest that CMV mediated hearing loss severity may be influenced by the innate immune response.

Hearing Loss, Congenital HIV, and Medulloblastoma: A Case Report

Functional Mutation of SMAC/DIABLO, Encoding a Mitochondrial Proapoptotic Protein, Causes Human Progressive Hearing Loss DFNA64

To systematically assess the data on the prevalence and causes of hearing impairment in Africa. Systematic review on the prevalence and causes of hearing loss in Africa. We undertook a literature search of seven electronic databases (EMBASE, PubMed, Medline, Global Health, Web of Knowledge, Academic Search Complete and Africa Wide Information) and manually searched bibliographies of included articles. The search was restricted to population-based studies on hearing impairment in Africa. Data were extracted using a standard protocol. We identified 232 articles and included 28 articles in the final analysis. The most common cut-offs used for hearing impairment were 25 and 30 dB HL, but this ranged between 15 and 40 dB HL. For a cut-off of 25 dB, the median was 7.7% for the children- or school-based studies and 17% for population-based studies. For a cut-off of 30 dB HL, the median was 6.6% for the children or school-based studies and 31% for population-based studies. In schools for the deaf, the most common cause of hearing impairment was cryptogenic deafness (50%) followed by infectious causes (43%). In mainstream schools and general population, the most common cause of hearing impairment was middle ear disease (36%), followed by undetermined causes (35%) and cerumen impaction (24%). There are very few population-based studies available to estimate the prevalence of hearing impairment in Africa. Those studies that are available use different cut-offs, making comparison difficult. However, the evidence suggests that the prevalence of hearing impairment is high and that much of it is avoidable or treatable.

Background. The incidence of hearing loss is constantly increasing and according to the World Health Organization, by 2050, 900 million people will suffer from hearing loss. The main Objective of the study was to determine the differences between the severity of the symptoms of stress, anxiety and depression in participants with varying degrees of sensorineural hearing loss during the COVID-19 pandemic. An additional aim was to examine the extent and manner in which protective face masks impact the communication of people with hearing loss. Matrials and Methods: A cross-sectional study was conducted, which included 160 patients (81 men and 79 women) with bilateral sensorineural hearing loss. The patients’ age range was 50 to 80 years. Depending on the degree of hearing loss or pure-tone threshold, the participants were divided into four groups: mild hearing loss, moderate hearing loss, severe hearing loss and profound hearing loss. The research used the Depression, Anxiety and Stress Scale (DASS-21) and a questionnaire in which the participants reported whether surgical face masks (medical three-layer masks) worn by speakers makes communication difficult, to what extent and in what way. Results: The average age of the patients was 67.97 ± 8.16. A significant correlation was found between the degree of hearing loss and communication difficulties caused by the use of protective face masks (p < 0.001). For patients with severe and profound hearing loss, communication is significantly more difficult (50.0% and 45.0% respectively) when the interlocutor wears a face mask. There is a significant correlation between the degree of hearing loss and the way in which communication is made more difficult when the interlocutor wears a face mask (p < 0.001). A statistically significant difference was determined between the degrees of hearing loss in all measured subscales: stress (p = 0.024), anxiety (p = 0.026) and depression (p = 0.016). Conclusions: We have determined that face masks used during the COVID-19 pandemic significantly hamper communication among the study groups (p = 0.007) and there is a significant correlation between the degree of sensorineural hearing loss and the presence of symptoms in all three DASS-21 subscales, meaning that the symptoms of stress, anxiety and depression were more intense in severe and profound hearing loss.