Nuances in Pediatric Single-Sided Deafness
There are many considerations in the medical workup for pediatric unilateral hearing loss, and each child may need a different approach.
Anita S. Jeyakumar, MD, MS, on behalf of the Pediatric Otolaryngology Education Committee
The estimated incidence of sensorineural hearing impairment (>40 dB HL) at birth is 1.86 per 1,000 newborns in developed countries, and 30% – 40% of these are unilateral.1 Congenital unilateral hearing loss (UHL) affects 0.3 to 1 in 1,000 newborns.1 The prevalence increases to 15% in ages six to 19 years. Profound unilateral sensorineural hearing loss (SNHL), also known as single-sided deafness (SSD), affects two to five in 1,000 school-aged children.1 Historically, despite the plethora of data, the clinical significance of UHL (the most severe of which is SSD), has been grossly underappreciated by patients, families, and healthcare practitioners. The effects of unilateral auditory deprivation can be more subtle to perceive, which often leads to decreased urgency in obtaining needed binaural input and therapy for the child.2
“Deaf [hard of hearing] people are not a monolith.” —Paul Raci, actor in the Oscar-nominated film Sound of Metal
Unilateral hearing loss, even in mild forms, can result in decreased hearing-related quality of life.2 Children with UHL face wide-ranging difficulties versus normally hearing peers, including decreased speech understanding, problems with sound localization, neurocognitive development challenges, language and grammar errors, and decreased scholastic performance.3 Children with UHL have a seven times-increased risk of failure in school than their normally hearing peers.3 Children with SSD have poor spatial hearing and need a higher signal-to-noise ratio for comparable hearing to their normally hearing peers. Unfortunately, these children are often labeled as having attention deficit disorder or a learning disability.
There are several considerations in the medical workup for pediatric UHL, and each child may need a different approach. Children with UHL, particularly SSD, benefit from an MRI owing to the higher incidence of cochlear nerve hypoplasia or aplasia in this population.4 If the child is identified young enough or there is access to the blood spot from birth, congenital CMV (cCMV) testing should be considered.4 If the MRI is negative, a CT scan can be an adjunct to help detect bony structural abnormalities. Currently, the routine and initial use of genetic testing is not recommended but can be done when the most common nongenetic etiologies of UHL (cCMV and cochlear nerve abnormality) have been excluded. The status of the cochlear nerve should be factored into the treatment options discussed with the family.4
Several management strategies are available.5 One management option is observation. However, this option means the child needs educational support at school. (In the public schools, this entails a 504 plan or Individualized Education Plan (IEP), preferential seating, and possibly an FM system to give them access to the teacher.) And the child needs to be intentionally monitored to ensure they are not falling behind educationally.
If the affected ear is aidable, a traditional hearing aid can provide the child with access to binaural hearing. If the affected ear has profound hearing loss, a traditional hearing aid will likely not be beneficial.5 In such cases, especially under age 5, a CROS hearing aid or bone-conduction device can be considered. The CROS and bone-conduction devices route the sound to the nonaffected ear but do not provide binaural hearing or good sound localization. And their benefits for children can be questionable. CROS hearing aids require the child to wear a receiver device in the good ear and there have been reports of sound attenuation in the good ear, which could lead to poor outcomes in children. Bone-conduction devices can be worn on a soft band until surgical decisions are made, but insurance will often not cover soft band bone-conduction devices. The only option for SSD that provides binaural hearing is cochlear implantation.6 The FDA approved pediatric cochlear implantation in 2019 for pediatric SSD in children 5 years and older.6 Although this was a step in the right direction, data suggests that extended monaural hearing leads to monaural preference (where the auditory cortex rearranges and “prefers” and pays attention to the good ear and not the affected ear).7 The monaural preference is a form of neural plasticity and appears to be difficult to reverse after 36 months of age, which is younger than the FDA approval cut-off.7
Finally, even when a younger child with SSD receives a cochlear implantation, intentional learning is needed. What does that mean? A child with SSD has a normal hearing ear with good quality sound. When a cochlear implant is first activated in a child with SSD, the sound is unnatural and unrecognizable. Despite this, a child needs to wear the device during all waking hours. But wearing the device alone is not enough, because the brain prefers the good ear. To get true binaural benefit, intentional learning with streaming (offered by all three cochlear implant manufacturers) is needed. This helps the patient receive good quality sound in the implanted ear to help them become binaural listeners. Without intentional learning, they can have sound awareness but not true binaural benefit.
There are a plethora of options to care for children with UHL, and even more so for the child with SSD. Each child deserves a thoughtful, individual approach to decide what is best for the child and their family.
References
- van Wieringen A, Boudewyns A, Sangen A, Wouters J, Desloovere C. Unilateral congenital hearing loss in children: Challenges and potentials. Hear Res. 2019 Feb;372:29-41. doi: 10.1016/j.heares.2018.01.010. Epub 2018 Jan 31. PMID: 29395617.
- Huttunen K, Erixon E, Löfkvist U, Mäki-Torkko E. The impact of permanent early-onset unilateral hearing impairment in children - A systematic review. Int J Pediatr Otorhinolaryngol. 2019 May;120:173-183. doi: 10.1016/j.ijporl.2019.02.029. Epub 2019 Feb 19. PMID: 30836274.
- Kuppler K, Lewis M, Evans AK. A review of unilateral hearing loss and academic performance: is it time to reassess traditional dogmata? Int J Pediatr Otorhinolaryngol. 2013 May;77(5):617-22. doi: 10.1016/j.ijporl.2013.01.014. Epub 2013 Mar 7. PMID: 23474216.
- Propst EJ, Greinwald JH, Schmithorst V. Neuroanatomic differences in children with unilateral sensorineural hearing loss detected using functional magnetic resonance imaging. Arch Otolaryngol Head Neck Surg. 2010 Jan;136(1):22-6. doi: 10.1001/archoto.2009.208. PMID: 20083773.
- Greaver L, Eskridge H, Teagle HFB. Considerations for Pediatric Cochlear Implant Recipients With Unilateral or Asymmetric Hearing Loss: Assessment, Device Fitting, and Habilitation. Am J Audiol. 2017 Jun 13;26(2):91-98. doi: 10.1044/2016_AJA-16-0051. PMID: 28291986.
- https://www.accessdata.fda.gov/cdrh_docs/pdf/P000025S104B.pdf Accessed June 17, 2024
- Jung ME, Colletta M, Coalson R, Schlaggar BL, Lieu JEC. Differences in interregional brain connectivity in children with unilateral hearing loss. Laryngoscope. 2017 Nov;127(11):2636-2645. doi: 10.1002/lary.26587. Epub 2017 Apr 20. PMID: 28425563; PMCID: PMC5650569.