Clinical Evaluation and Etiologic Diagnosis of Hearing Loss
- Deaf: a community with a distinct culture and visual language shaped by the experience of being deaf or hard of hearing, which may include deaf, hard-of-hearing, and hearing individuals
- deaf: an auditory phenotype characterized by a total or near-total loss of the ability to hear
- hard-of-hearing: an auditory phenotype characterized by a partial loss of the ability to hear
- hearing loss: an auditory phenotype characterized by any degree of loss of the ability to hear; depending on the cause, hearing loss can be temporary or permanent—this practice resource focuses on permanent hearing loss
Summary of Recommendations
- The medical and birth histories may be helpful in differentiating between acquired vs inherited causes of HL. Elements of medical and birth histories focused on HL include the following:
- Prenatal history, including maternal infections (eg, CMV, rubella) and illnesses (eg, syphilis), or medication or drug exposures (eg, thalidomide, retinoic acid)151,152
- Neonatal history, including premature birth, low birth weight, birth hypoxia, hyperbilirubinemia, sepsis, and exposure to ototoxic medications
- Postnatal history, including viral illnesses, bacterial meningitis, head trauma, noise exposure, and exposure to ototoxic medications (https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Meningitis-and-Encephalitis-Fact-Sheet. Accessed February 4, 2022)
- Audiometric assessment of HL, including sensorineural vs conductive or mixed HL; age of onset; progressive, nonprogressive, or fluctuating nature of HL; laterality, symmetry, severity, and configuration of HL; and presence or absence of vestibular dysfunction or auditory neuropathy
- The pedigree and family medical history should focus on identifying the following:
- First- and second-degree relatives with HL or with features commonly associated with HL (such as pigmentary, branchial, retinal, or renal anomalies) or sudden cardiac death
- A pattern of inheritance
- Ethnicity and country of origin
- A common origin from ethnically or geographically isolated areas
- The physical examination should focus on dysmorphic and other physical findings such as the following:
- Unusual facial appearance, with attention to asymmetry
- Pigmentary anomalies
- Neck, skin, facial, or ear anomalies
- Neurological abnormalities
- Balance disturbances
- Skeletal abnormalities
- Other unusual physical findings
- Pretest genetic counseling should be provided, and, with patient’s or caregiver’s informed consent, genetic testing should be ordered to confirm the diagnosis. This testing may include single-gene tests, HL multigene panels, ES, GS, chromosome analysis, or microarray- or NGS-based copy number analysis, depending on clinical findings;
- Appropriate studies should be undertaken to determine whether other organs are involved; and
- Appropriate near-term and long-term screening and management should be arranged, including referrals to specialists, as indicated by the associated manifestations of the particular syndrome.
- Unless clinical and/or family history suggests a specific genetic etiology, comprehensive HL gene panel testing should be initiated. If panel testing is negative, genome-wide testing, such as ES or GS, may be considered. However, issues related to genomic testing, such as the likelihood of incidental or secondary findings, will have to be addressed.
- The HL panel should include the genes recommended by the HL Gene Curation Expert Panel (https://clinicalgenome.org/affiliation/40007/#heading_documents).131 Because of the existing variations in gene number and content among currently available HL gene panels, clinicians must be aware of the genes included in the test (panel) chosen and the performance characteristics of the platform chosen, including coverage, analytic sensitivity, and what types of variants will be detected. Additional testing strategies may need to be adopted to address the technical challenges caused by highly homologous regions, including pseudogenes. It should be noted that the cost of these new genetic sequencing technologies is decreasing so rapidly that the use of large sequencing panels targeted toward HL-related genes as the initial test, may, in many cases, already be more cost-effective in the evaluation of HL.
- If genetic testing reveals variant(s) in an HL-related gene, gene-specific genetic counseling should be provided, followed by appropriate medical evaluations and referrals.
- If genetic testing fails to identify an etiology for a patient’s HL, the possibility of a genetic etiology remains. This point must be emphasized because it can be misunderstood by clinicians and by patients and their families. For interested patients and families, further genetic testing may be pursued on a research basis.
- Temporal bone imaging by computed tomography or magnetic resonance imaging should be considered as a complement to genetic testing, particularly if the diagnosis remains unclear; if cochlear implantation is being considered; if auditory neuropathy is noted, in cases of progressive HL; or if other clinical concerns exist. The anticipated clinical utility of imaging studies should be balanced against the risks associated with radiation exposure and sedation.
- CMV testing should be done as soon as possible after birth but within the first 3 weeks of life for infants with congenital HL. For later-onset or progressive HL, CMV testing can be obtained, but the likelihood that a positive test is caused by postnatal exposure increases with age.
- A team approach that includes otolaryngologists, clinical geneticists, genetic counselors, audiologists, speech and language specialists, early hearing intervention and family support specialists (which may include other individuals who are deaf or hard of hearing or other parents of deaf or hard-of-hearing children), and other appropriate specialists offers optimal opportunity to provide ongoing management and support of deaf and hard-of-hearing individuals and their families as their needs change over time.
- For cases in which the genetic evaluation failed to identify an underlying cause, periodic follow-up care every 3 years with a geneticist may be appropriate for several reasons. First, subtle features of syndromic forms of HL may not be apparent at birth or early in childhood but may appear as deaf or hard-of-hearing individuals grow into adulthood. These may prompt additional medical tests or referrals for specialty care. Second, follow-up visits offer the opportunity to inform individuals about new genetic tests that may have become available or changes in the interpretation of previous test results as medical knowledge advances. Finally, follow-up visits may also help identify clinical concerns unrelated to HL, for which referral for specialty care may be appropriate (Figure 1).
Audiometric and Clinical Aspects of HL
- Age of onset: congenital, prelingual (before the acquisition of speech), postlingual (after the acquisition of speech), adult onset, or presbycusis (age-related late-onset HL)
- Type of HL: sensorineural, conductive, mixed, or auditory neuropathy
- Laterality and symmetry of HL: unilateral or bilateral, symmetric or asymmetric
- Stability of HL: progressive, nonprogressive, or fluctuating
- Degree of HL: slight (16-25 decibels [dB]), mild (26-40 dB), moderate (41-55 dB), moderately severe (56-70 dB), severe (71-90 dB), or profound (91 dB or greater)
Figure 1Approach to clinical and diagnostic evaluation for hearing loss
Clinical Evaluation and Etiologic Diagnosis of Hearing Loss
May 10, 2022
External Publication Status
Country of Publication
Male, Female, Adolescent, Adult, Child, Infant, Older adult
Health Care Settings
Ambulatory, Childcare center, Long term care, Outpatient
Genetics, medical techologist technician
Counseling, Diagnosis, Assessment and screening, Management
D034381 - Hearing Loss, D003638 - Deafness
hearing loss, Etiologic, genetics evaluation, Deaf, geneting testing, geneting counseling