Amblyaudia

Children with amblyaudia experience difficulties in speech perception,{{cite journal |vauthors=Miccio AW, Gallagher E, Grossman CB, Yont KM, Vernon-Feagans L |s2cid=35288270 |title=Influence of chronic otitis media on phonological acquisition |journal=Clin Linguist Phon |volume=15 |issue=1–2 |pages=47–51 |year=2001 |pmid=21269097 |doi=10.3109/02699200109167629}} particularly in noisy environments, sound localization,{{cite journal |vauthors=Besing JM, Koehnke J |s2cid=15538878 |title=A test of virtual auditory localization |journal=Ear Hear |volume=16 |issue=2 |pages=220–9 |date=April 1995 |pmid=7789673 |doi=10.1097/00003446-199504000-00009}} and binaural unmasking{{cite journal |vauthors=Hall JW, Grose JH, Pillsbury HC |title=Long-term effects of chronic otitis media on binaural hearing in children |journal=Arch. Otolaryngol. Head Neck Surg. |volume=121 |issue=8 |pages=847–52 |date=August 1995 |pmid=7619408 |doi=10.1001/archotol.1995.01890080017003 }}{{cite journal |vauthors=Moore DR, Hutchings ME, Meyer SE |title=Binaural masking level differences in children with a history of otitis media |journal=Audiology |volume=30 |issue=2 |pages=91–101 |year=1991 |pmid=1877902 |doi=10.3109/00206099109072874}}{{cite journal |vauthors=Gravel JS, Wallace IF, Ruben RJ |title=Auditory consequences of early mild hearing loss associated with otitis media |journal=Acta Otolaryngol. |volume=116 |issue=2 |pages=219–21 |date=March 1996 |pmid=8725518 |doi= 10.3109/00016489609137827}}{{cite journal |vauthors=Pillsbury HC, Grose JH, Hall JW |title=Otitis media with effusion in children. Binaural hearing before and after corrective surgery |journal=Arch. Otolaryngol. Head Neck Surg. |volume=117 |issue=7 |pages=718–23 |date=July 1991 |pmid=1863436 |doi=10.1001/archotol.1991.01870190030008}}{{cite journal |vauthors=Hogan SC, Moore DR |title=Impaired binaural hearing in children produced by a threshold level of middle ear disease |journal=J. Assoc. Res. Otolaryngol. |volume=4 |issue=2 |pages=123–9 |date=June 2003 |pmid=12943367 |pmc=3202709 |doi=10.1007/s10162-002-3007-9}} (using interaural cues to hear better in noise) despite having normal hearing sensitivity (as indexed through pure tone audiometry). These symptoms may lead to difficulty attending to auditory information causing many to speculate that language acquisition and academic achievement may be deleteriously affected in children with amblyaudia. A significant deficit in a child's ability to use and comprehend expressive language may be seen in children who lacked auditory stimulation throughout the critical periods of auditory system development. A child suffering from amblyaudia may have trouble in appropriate vocabulary comprehension and production and the use of past, present and future tenses. Amblyaudia has been diagnosed in many children with reported difficulties understanding and learning from listening{{Cite journal|title = Interaural asymmetries revealed by dichotic listening tests in normal and dyslexic children.|last = Moncrieff|first = DW|date = Sep 2002|journal = J Am Acad Audiol|pmid = 12371660|volume=13|issue = 8|pages=428–37|doi = 10.1055/s-0040-1716006}}{{Cite journal|title = Identification of binaural integration deficits in children with the Competing Words Subtest: standard score versus interaural asymmetry.|last = Moncrieff|first = DW|s2cid = 22794514|date = Sep 2006|journal = Int J Audiol|doi = 10.1080/14992020601003196|pmid = 17005498|volume=45|issue = 9|pages=546–54; discussion 554–8}}{{Cite journal|title = Dichotic listening deficits in children with dyslexia|last = Moncrieff|first = DW|date = Feb 2008|journal = Dyslexia|doi = 10.1002/dys.344|pmid = 17647215|volume=14|issue = 1|pages=54–75}} and adjudicated adolescents are at a significantly high risk for amblyaudia (Moncrieff, et al., 2013, Seminars in Hearing).

Families report the presence of amblyaudia in several individuals, suggesting that it may be genetic in nature. It is possible that abnormal auditory input during the first two years of life may increase a child's risk for amblyaudia, although the precise relationship between deprivation timing and development of amblyaudia is still unclear. Recurrent ear infections (otitis media) are the leading cause of temporary auditory deprivation in young children.{{cite journal |author =Pennie RA |title=Prospective study of antibiotic prescribing for children |journal=Can Fam Physician |volume=44 |pages=1850–6 |date=September 1998 |pmid=9789665 |pmc=2277846}}{{cite journal |vauthors=Teele DW, Klein JO, Rosner B |title=Epidemiology of otitis media during the first seven years of life in children in greater Boston: a prospective, cohort study |journal=J. Infect. Dis. |volume=160 |issue=1 |pages=83–94 |date=July 1989 |pmid=2732519 |doi=10.1093/infdis/160.1.83}}{{cite journal |vauthors=Freid VM, Makuc DM, Rooks RN |title=Ambulatory health care visits by children: principal diagnosis and place of visit |journal=Vital Health Stat 13 |issue=137 |pages=1–23 |date=May 1998 |pmid=9631643 |url=https://www.cdc.gov/nchs/data/series/sr_13/sr13_137.pdf}} During ear infection bouts, the quality of the signal that reaches the auditory regions of the brains of a subset of children with OM is degraded in both timing and magnitude.{{cite journal |vauthors=Owen MJ, Norcross-Nechay K, Howie VM |title=Brainstem auditory evoked potentials in young children before and after tympanostomy tube placement |journal=Int. J. Pediatr. Otorhinolaryngol. |volume=25 |issue=1–3 |pages=105–17 |date=January 1993 |pmid=8436453 |doi=10.1016/0165-5876(93)90014-T }}{{cite journal |vauthors=Eric Lupo J, Koka K, Thornton JL, Tollin DJ |title=The effects of experimentally induced conductive hearing loss on spectral and temporal aspects of sound transmission through the ear |journal=Hear. Res. |volume=272 |issue=1–2 |pages=30–41 |date=February 2011 |pmid=21073935 |pmc=3073683 |doi=10.1016/j.heares.2010.11.003 }} When this degradation is asymmetric (worse in one ear than the other) the binaural cues associated with sound localization can also be degraded. Aural atresia (a closed external auditory canal) also causes temporary auditory deprivation in young children. Hearing can be restored to children with ear infections and aural atresia through surgical intervention (although ear infections will also resolve spontaneously). Nevertheless, children with histories of auditory deprivation secondary to these diseases can experience amblyaudia for years after their hearing has been restored.{{cite journal |vauthors=Wilmington D, Gray L, Jahrsdoerfer R |s2cid=4762842 |title=Binaural processing after corrected congenital unilateral conductive hearing loss |journal=Hear. Res. |volume=74 |issue=1–2 |pages=99–114 |date=April 1994 |pmid=8040103 |doi=10.1016/0378-5955(94)90179-1}}

Amblyaudia is a deficit in binaural integration of environmental information entering the auditory system. It is a disorder related to brain organization and function rather than what is typically considered a “hearing loss” (damage to the cochlea). It may be genetic or developmentally acquired or both. When animals are temporarily deprived of hearing from an early age, profound changes occur in the brain. Specifically, cell sizes in brainstem nuclei are reduced,{{cite journal |vauthors=Webster DB, Webster M |title=Neonatal sound deprivation affects brain stem auditory nuclei |journal=Arch Otolaryngol |volume=103 |issue=7 |pages=392–6 |date=July 1977 |pmid=880104 |doi=10.1001/archotol.1977.00780240050006 }}{{cite journal |vauthors=Webster DB, Webster M |s2cid=10194727 |title=Effects of neonatal conductive hearing loss on brain stem auditory nuclei |journal=Ann. Otol. Rhinol. Laryngol. |volume=88 |issue=5 Pt 1 |pages=684–8 |year=1979 |pmid=496200 |doi= 10.1177/000348947908800515}}{{cite journal |vauthors=Coleman JR, O'Connor P |s2cid=38143118 |title=Effects of monaural and binaural sound deprivation on cell development in the anteroventral cochlear nucleus of rats |journal=Exp. Neurol. |volume=64 |issue=3 |pages=553–66 |date=June 1979 |pmid=467549 |doi=10.1016/0014-4886(79)90231-0 }}{{cite journal|last1=Conlee|first1=John W.|last2=Parks|first2=Thomas N.|title=Age- and position-dependent effects of monaural acoustic deprivation in nucleus magnocellularis of the chicken|journal=The Journal of Comparative Neurology|volume=202|issue=3|year=1981|pages=373–384|pmid=7298905|doi=10.1002/cne.902020307 |s2cid=27428850}} the configuration of brainstem dendrites are altered{{cite journal |vauthors=Conlee JW, Parks TN |title=Late appearance and deprivation-sensitive growth of permanent dendrites in the avian cochlear nucleus (nuc. magnocellularis) |journal=J. Comp. Neurol. |volume=217 |issue=2 |pages=216–26 |date=June 1983 |pmid=6886053 |doi=10.1002/cne.902170208 |s2cid=9227670 }}{{cite journal |vauthors=Gray L, Smith Z, Rubel EW |s2cid=33997388 |title=Developmental and experimental changes in dendritic symmetry in n. laminaris of the chick |journal=Brain Res. |volume=244 |issue=2 |pages=360–4 |date=July 1982 |pmid=7116181 |doi=10.1016/0006-8993(82)90098-1 }}{{cite journal |vauthors=Smith ZD, Gray L, Rubel EW |title=Afferent influences on brainstem auditory nuclei of the chicken: n. laminaris dendritic length following monaural conductive hearing loss |journal=J. Comp. Neurol. |volume=220 |issue=2 |pages=199–205 |date=October 1983 |pmid=6315783 |doi=10.1002/cne.902200207 |s2cid=1640696 }} and neurons respond in different ways to sounds presented to both the deprived and non-deprived ears.{{cite journal |vauthors=Silverman MS, Clopton BM |title=Plasticity of binaural interaction. I. Effect of early auditory deprivation |journal=J. Neurophysiol. |volume=40 |issue=6 |pages=1266–74 |date=November 1977 |pmid=925728 |doi=10.1152/jn.1977.40.6.1266 }}{{cite journal |vauthors=Clopton BM, Silverman MS |title=Plasticity of binaural interaction. II. Critical period and changes in midline response |journal=J. Neurophysiol. |volume=40 |issue=6 |pages=1275–80 |date=November 1977 |pmid=925729 |doi=10.1152/jn.1977.40.6.1275 }}{{cite journal |vauthors=Moore DR, Irvine DR |s2cid=6730028 |title=Plasticity of binaural interaction in the cat inferior colliculus |journal=Brain Res. |volume=208 |issue=1 |pages=198–202 |date=March 1981 |pmid=7470922 |doi=10.1016/0006-8993(81)90632-6 }}{{cite journal |vauthors=Popescu MV, Polley DB |title=Monaural deprivation disrupts development of binaural selectivity in auditory midbrain and cortex |journal=Neuron |volume=65 |issue=5 |pages=718–31 |date=March 2010 |pmid=20223206 |pmc=2849994 |doi=10.1016/j.neuron.2010.02.019 }}

An electrophysiologic study demonstrated that children with amblyaudia (referred to then as a "left-ear deficit") were less able to process information from their non-dominant ears when competing information is arriving at their dominant ears. The N400-P800 complex{{Cite journal|title = ERP evidence of a dichotic left-ear deficit in some dyslexic children|last = Moncrieff|first = DW|date = Jul 2004|journal = J Am Acad Audiol|doi = 10.3766/jaaa.15.7.6|pmid = 15484601|volume=15|issue = 7|pages=518–34}} showed a strong and highly correlated response from the dominant and non-dominant ears among normal children while the response from children with amblyaudia was uncorrelated and indicated an inability to separate information arriving at the non-dominant ear from the information arriving at the dominant ear. The same children also produced weaker fMRI responses from their non-dominant left ears when processing dichotic material in the scanner.{{Cite journal|title = Hemodynamic differences in children with dichotic listening deficits: preliminary results from an fMRI study during a cued listening task.|last = Moncrieff|first = D|date = Jan 2008|journal = J Am Acad Audiol|doi = 10.3766/jaaa.19.1.4|pmid = 18637408|volume=19|issue = 1|pages=33–45}}

A clinical diagnosis of amblyaudia is made following dichotic listening testing as part of an auditory processing evaluation. Clinicians are advised to use newly developed dichotic listening tests that provide normative cut-off scores for the listener's dominant and non-dominant ears. These are the Randomized Dichotic Digits Test{{Cite journal|title = Recognition of randomly presented one-, two-, and three-pair dichotic digits by children and young adults.|last = Moncrieff|first = DW|date = Jan 2009|journal = J Am Acad Audiol|doi = 10.3766/jaaa.20.1.6|pmid = 19927683|volume=20|issue = 1|pages=58–70}} and the Dichotic Words Test.{{Cite journal|title = Age- and Gender-Specific Normative Information from Children Assessed with a Dichotic Words Test.|last = Moncrieff|first = D|date = Jul 2015|journal = J Am Acad Audiol|doi = 10.3766/jaaa.14096|pmid = 26218052|volume=26|issue = 7|pages=632–44}} Older dichotic listening tests that provide normative information for the right and left ears can be used to supplement these two tests for support of the diagnosis (). If performance across two or more dichotic listening tests is normal in the dominant ear and significantly below normal in the non-dominant ear, a diagnosis of amblyaudia can be made.{{cite journal |author =Moncrieff DW |s2cid=37665256 |title=Dichotic listening in children: age-related changes in direction and magnitude of ear advantage |journal=Brain Cogn |volume=76 |issue=2 |pages=316–22 |date=July 2011 |pmid=21530051 |doi=10.1016/j.bandc.2011.03.013 }}

A number of computer-based auditory training programs exist for children with generalized Auditory Processing Disorders (APD). In the visual system, it has been proven that adults with amblyopia can improve their visual acuity with targeted brain training programs (perceptual learning).{{cite journal |vauthors=Levi DM, Li RW |title=Perceptual learning as a potential treatment for amblyopia: a mini-review |journal=Vision Res. |volume=49 |issue=21 |pages=2535–49 |date=October 2009 |pmid=19250947 |pmc=2764839 |doi=10.1016/j.visres.2009.02.010 }} A focused perceptual training protocol for children with amblyaudia called Auditory Rehabilitation for Interaural Asymmetry (ARIA) was developed in 2001{{cite journal |vauthors=Moncrieff DW, Wertz D |s2cid=22268018 |title=Auditory rehabilitation for interaural asymmetry: preliminary evidence of improved dichotic listening performance following intensive training |journal=Int J Audiol |volume=47 |issue=2 |pages=84–97 |date=February 2008 |pmid=18236240 |doi=10.1080/14992020701770835}} which has been found to improve dichotic listening performance in the non-dominant ear and enhance general listening skills.

• Amblyopia
• Auditory processing disorder
• Binaural fusion
• Hearing
• Otitis media
• Aural atresia

{{Reflist|30em}}

• [https://www.npr.org/templates/story/story.php?storyId=124684675 Temporary Hearing Loss Affects Brain's Wiring]

Category:Neurobiological brain disorders

Category:Neurological disorders in children

Category:Audiology