HEARING LOSS IN CHILDREN Resident : Nhung Pham Thi Trang DR: Uyen Nguyen Thi To TOPICS TYPES AND CAUSES OF HEARING LOSS AUDIOGRAM AND HEARING SCREENING MANAGEMENT OF A CHILDREN WITH HEARING LOSS How do we hear? Childhood Hearing Loss - Hearing loss is the result of impaired auditory sensitivity and/or diminished speech intelligibility of the physiological auditory system - Moderate to profound congenital hearing impairment occurs in 4 per 1000 live births - 14.9% of children between 6 and 19 years of age had a hearing loss - Impact on the speech, language, and psychoeducational development of children Other descriptors associated with hearing loss Bilateral versus Unilateral - Hearing loss in both ears or Hearing loss in one ear and normal in other ear. Symmetrical versus Asymmetrical - In symmetrical hearing loss the degree and configuration are similar in both ears. - In asymmetrical hearing loss the degree and configuration are different in both ears. Progressive versus sudden - In progressive hearing loss the loss becomes worse over time where as in sudden the loss happens quickly. Fluctuating versus stable - Fluctuating hearing loss changes over time, sometimes getting better sometimes getting worse. Stable hearing loss does not change over time and remains the same. TYPES OF HEARING LOSS The type of hearing loss depends up on where in the ear problem occur. The four main types are: Conductive hearing loss. Sensorineural hearing loss. Mixed hearing loss Central hearing loss Types of Hearing Loss 7 CONDUCTIVE SENSORINEURAL MIXED HEARING LOSS CENTRAL Central ear TYPES OF HEARING LOSS Central hearing loss: - Auditory nerve, Brainstem Auditory Pathways or Auditory centers of Brain - Cause is disease or malfunction of nerve transmission of signal and possible impaired analysis and interpretation of sounds TYPES OF HEARING LOSS Mixed hearing loss - Outer/middle ear and inner ear involved - Both conductive and sensorineural hearing - Typically permanent SNHL overlaid with temporary conductive disease TYPES OF HEARING LOSS Conductive hearing loss - A problem in the outer or middle ear causes conductive hearing loss. - A decrease in strength of a sound is called attenuation. - Conductive hearing loss involves reduction in sound level, or the ability to hear faint sounds. - The inner ear and other sensorineural structures will be unimpaired and hearing by bone conduction will be normal. - This problem can be fixed through simple surgical procedures. TYPES OF HEARING LOSS Sensorineural hearing loss A problem in the inner ear can cause sensorineural hearing loss . It is also known as nerve-related hearing loss as the damaged nerves in the inner ear can cause the loss. These losses cannot be fixed through surgical procedures. Sensorineural hearing loss involves reduction in sound level, inability to hear sounds and also affects speech understanding . CAUSES OF HEARING LOSS Causes of conductive hearing loss Malformation of outer ear, ear canal or middle ear structures. Problems associated with middle ear pathology such as fluid in the middle ear from colds and allergies Poor Eustachian tube function Ear infection, perforated eardrum and benign tumors. Impacted earwax Foreign body in the ear Otosclerosis which is abnormal growth of bone of the middle ear The most common cause of intermittent, mild-to-moderate acquired hearing loss in infants and young children is conductive hearing loss associated with otitis media. CAUSES OF HEARING LOSS Delayed 34% GeneticNonsyndromic 37% Genetic-Syndromic 13% Neonatal 16% CAUSES OF HEARING LOSS Causes of sensorineural hearing loss There are two types of causes Prenatal or Perinatal causes Postnatal causes CAUSES OF HEARING LOSS PRENATAL OR PERINATAL CAUSES Infections such as rubella, herpes, toxoplasmosis, syphilis and cytomegalovirus (TORCHES) Asphyxia or lack of oxygen at birth. Birth weight of less than 1500 grams. Defects of head and neck. Malformation of inner ear CAUSES OF HEARING LOSS POSTNATAL CAUSES Exposure to loud noise. Bacterial Meningitis Ototoxicity caused by exposure to drugs Physical damage to head or ear Hyperbilirubinemia Cytomegalovirus Infection - - Most prevalent cause of intrauterine viral infection Primary infection can lead to months or years of viral shedding in saliva, urine, semen & cervical or vaginal fluids Particular CMV => VIII nerve 10% - 15% symptomatic CMV: 90% having cytomegalic inclusion disease (CID): pneumonitis, slow weight gain, adenopathy, rash, jaundice, anemia & atypical lymphocytosis Definitive Dx - viral isolation from urine or saliva e.g PCR within the first 2 weeks of life Antiviral therapy (ganciclovir) Cytomegalovirus Infection - Congenital CMV infection – 1/3 of sensorineural impairments in young children Develop permanent CMV - related hearing impairment, which can be delayed months or years Fluctuate & progress in severity over time Inner Ear Malformations The majority of congenital hearing loss causes (80%) are membranous malformations. Here, the pathology involves inner ear hair cells The remaining 20% have various malformations involving the bony labyrinth and can be radiologically demonstrated by CT and MRI Majority of these patients have bilateral severe to profound hearing loss. Inner Ear Malformations Cochlear malformations: A classification first proposed in 1987 by Jackler et al. 2 has become widely accepted which divides congenital cochlear anomalies according to the timing of the developmental arrest. - Complete labyrinthine aplasia or Michel deformity : 3rd week - Cochlear aplasia: 4th week - Common cavity malformation to the cochlea and vestibule: early 5th week - Cochlear incomplete partition type I including cystic cochleovestibular anomaly: late 5th week - Cochlear hypoplasia: 6th week - Cochlear incomplete partition type II including Mondini dysplasia: 7th week Normal cochlear: Enlarged vestibular aqueduct or semicircular malformation. Bacterial Meningitis - Permanent neurologic sequelae, including SNHL, in 10% to 15% of survivors - 15%- 20%, most = permanent, bilateral, often asymmetric, severe to profound losses - Onset early in the clinical course and does not appear to be ameliorated by any specific antibiotic - Dexamethasone administered 2 hrs before initiate ATB therapy => preventing moderate to severe hearing loss in pediatric patients with Hib meningitis but not in cases of pneumococcal etiology - Heptavalent pneumococcal vaccine is recommend for all children aged 2 to 23 month & also for patients having cochlear implant. GENETIC SNHL Syndromic - Autosomal-Dominant Syndromic: Branchio-OtoRenal Syndrome, Waardenburg Syndrome , Stickler Syndrome, Treacher-Collins - Autosomal-Recessive Syndromic: Pendred Syndrome, Jervell and Lange-Nielsen Syndrome, Usher Syndrome - X-Linked Syndromes: Alport Syndrome Nonsyndromic Branchio-Oto-Renal Syndrome Autosomal dominant disease characterized by: - hearing loss of early onset - preauricular pits - branchial clefts (abnormal passages from the throat to the outside surface of the neck) - and early progressive chronic renal failure in up to 40 Mutations in the EYA1 gene that maps on chromosome 8q13.3 Branchio-Oto-Renal Syndrome - - External ear anomalies : preauricular pits (82%), preauricular tags, auricular malformations (32%), microtia & EAC narrowing Middle ear anomalies: ossicular malformation , facial nerve dehiscence, absence of the oval window & reduction in size of the middle ear cleft Inner ear anomalies : cochlear hypoplasia & dysplasia Enlargement of the cochlear or vestibular aqueducts may be hypoplasia of the lateral semicircular canal Branchio-Oto-Renal Syndrome Hearing impairment is the most common feature of BOR syndrome (close to 90%) - conductive (30%) - sensorineural (20%) - mixed (50%) Severe: 1/3 of persons Progressive: 1/4 Branchial anomalies occur in laterocervical fistulas, sinuses & cysts & renal anomalies ranging from agenesis to dysplasia (25% of persons) Waardenburg Syndrome WS type I : SNHL, white forelock, pigmentary disturbances of the iris, & dystopia canthorum, displacement of the inner canthi & lacrimal puncti WS type II: is distinguished from WS type I by the absence of dystopia canthorum Waardenburg Syndrome - WS type I : 36% to 66.7% hearing loss - WS type II : 57% to 85% hearing loss - Most commonly, the loss affects persons with more than one pigmentation abnormality & profound, bilateral, and stable - Audiogram = variable, with low-frequency loss (more common) Treacher-Collins Syndrome Abnormalities of craniofacial development Maldevelopment of the maxilla & mandible, with abnormal canthi placement, ocular colobomas, choanal atresia & CHL secondary to ossicular fixation Pendred Syndrome Associate congenital deafness with thyroid goiter 7.5 to 10 per 100.000 persons, Up to 10% of hereditary deafness Develop in second decade Pendred Syndrome Usually prelingual , bilateral & profound, although it can be progressive Radiologic studies : - temporal bone anomaly, either dilated vestibular aqueducts (DVAs) or - Mondini dysplasia Jervell & Lange-Nielsen Syndrome Congenital deafness, prolonged QT interval & syncopal attacks The dominant disease(Romano-Ward syndrome) does not include the deafness phenotype The recessive disease is Jervell and Lange-Nielsen syndrome (JLNS) Congenital, bilateral & severe to profound The prolonged QT interval can lead to ventricular arrhythmias, syncopal episodes & death in childhood Usher Syndrome SNHL, retinitis pigmentosa & often vestibular dysfunction Prevalence 4.4/ 100,000 USA - 3% to 6% of congenitally deaf persons - cause of 50% of deafblindness in the US Usher Syndrome Type I = severe-to-profound SNHL, vestibular dysfunction, retinitis pigmentosa Type II = moderate-to-severe congenital SNHL, with uncertainty related to progression, no vestibular dysfunction, and retinal degeneration that begins in the third to fourth decade Type III = progressive hearing loss, variable vestibular dysfunction, and variable onset of retinitis pigmentosa Alport Syndrome Hematuric nephritis, hearing impairment & ocular changes Symmetric, high-frequency SNHL that can be detected by late childhood & progresses => all frequencies Alport Syndrome - Diagnostic criteria include at least three of the following four characteristics (1) positive FH of hematuria with or without CRF (2) progressive high-tone SN deafness (3) typical eye lesion (anterior lenticonus, and/or macular flecks) (4) histologic changes of the glomerular BM of the kidney - Controlling high BP & restricting salt, protein & phosphate in the diet => dialysis and kidney transplant may be necessary Nonsyndromic hearing loss Gene mutation “DeaFNess” gene loci: - AR (77%): DFNB loci (1-33) - AD (22%): DFNA loci (1-41) - X-linked (1%): DFN loci (1-8) The GJB2 gene encodes for the protein Connexin 26 (Cx26) and the most common cause of nonsyndromic autosomal recessive deafness is mutation in Cx26, which is responsible for approximately 20% of hereditary hearing loss in children Management of a children with hearing loss - Multidisciplinary team - History: + Prenatal, birth& postnatal history & FH for hearing loss + Speech or language disorders; ENT disorders & craniofacial deformities, such syndromic features ( kidney disorders, sudden death of a family member at a young age, thyroid disease, intracranial tumors, progressive blindness and cafe aulait spots ) + Marital pedigree - ECG, hemato & chem, TFT, tests for congenital infection, renal U/S & vision test and temporal bone imaging - Childhood deafness, confirm lab within first 2 - 3 weeks of life SIGNS AND SYMPTOMS SIGNS AND SYMPTOMS SIGNS AND SYMPTOMS Management of a patient with hearing loss Physical Exam Examination of the pinna and external auditory canal. Otoscopy: Management of a patient with hearing loss Physical Exam Examination of the pinna and external auditory canal. Otoscopy: Management of a patient with hearing loss Physical Exam Examination of the pinna and external auditory canal. Otoscopy: Management of a patient with hearing loss Physical Exam Examination of the pinna and external auditory canal. Otoscopy: Management of a patient with hearing loss Hearing tests - Behavioural observation audiometry (BOA) - Visual reinforce audiometry (VRA) - Play audiometry - Pure tone audiometry - Auditory brainstem response (ABR) - Otoacoustic emissions (OAEs) - Auditory Steady State Response (ASSR) - Tympanometry Imagine - CT scan temporal bones/ MRI cpa Degree of hearing loss Newborn Hearing Screening Identify newborns who are likely to have hearing loss and who require further evaluation Identify newborns with medical conditions that can cause late-onset hearing loss and to establish a plan for continued monitoring of their hearing status Passing a screening does not mean that a child has normal hearing across the frequency range. Newborn Hearing Screening The EHDI guidelines include: - Hearing screening completion by 1 month of age. NICU newborns are screened when they are ready for discharge and/or when they are medically stable. - Diagnosis of any hearing loss by 3 months of age - Hearing aid selection and fitting within 1 month of confirmation of hearing loss if parents choose that option - Entry into early intervention (EI) services by 6 months of age. Newborn Hearing Screening Pass/Refer Indications - “pass” = pass the screening in both ears during one session - Otherwise => rescreening in both ears. - Pass the screening or the rescreening + no risk factors for late-onset or progressive hearing loss => complete. - Has risk factors for late-onset or progressive hearing loss => important to monitor the newborn's hearing during early childhood Technology - Auditory brainstem response (ABR) - Otoacoustic emissions (OAEs) Newborn Hearing Screening ABR - Measure the neural response to sound from the level of the cochlea and through the VIII nerve and pontine-level of the brainstem and that correlates with behavioral hearing measures in the mid- to high-frequency region. - ABR measurements are sensitive to neural auditory disorders (i.e., auditory neuropathy). - ABR screening is less sensitive to outer ear debris than OAE screening, resulting in lower referral rates. Newborn Hearing Screening ABR - Using surface electrodes that are attached to the infant's head. Click stimuli are presented through insert or muff-style earphones that are worn on both ears. - The infant should be asleep or resting quietly for the test and positioned to reduce muscle artifact. The screener visually inspects the outer part of the ear canal to ensure that the canal is clear of debris and places the transducer. Both ears are screened during each session. Newborn Hearing Screening OAEs - Measure of outer hair cell and cochlear function in response to acoustic stimulation. - Using a sensitive probe microphone inserted into the infant's ear canal. - OAEs are not sensitive to disorders central to the outer hair cells, such as auditory neuropathy. - OAEs will be absent when there is outer or middle ear dysfunction or debris/blockage in the ear canal. MANAGEMENT - Team of health care - Directed at providing appropriate amplification as soon as possible - Cochlear implantation => option for persons with severe-to-profound deafness - Deaf culture Cochlear implant (CI) A surgically implanted, electronic prosthetic device that provides electric stimulation directly to auditory nerve fibers in the cochlea. Interprofessional CI team: audiologist, otolaryngologist/otologist (implant surgeon), speech-language pathologist (SLP), pediatrician/primary care physician, mental health professional, developmental specialist, occupational therapist, educator, vocational counselor,… Cochlear implant (CI) Two components: - Internal (implanted) device - External sound processor. The sound processor (external) receives sound from a microphone, processes the digital sound signal, and transmits it to the CI (internal) electrodes in the cochlea. The signal is then received by the auditory nerve and transmitted to the brain as an electrical signal.