Diverse etiologies manifesting auditory neuropathy characteristics from infants with profound hearing loss and clinical implications.
OBJECTIVE
Auditory neuropathy spectrum disorder (ANSD) is a hearing disorder with impaired signal transmission from the inner ear to the brain. The electrophysiological characteristics of auditory neuropathy (AN characteristics) are marked with presence of otoacoustic emissions (OAE) or cochlear microphonics (CM) in the absence of auditory brainstem response (ABR). This study aimed to review etiologies related to AN characteristics from infants with profound hearing loss (HL), either unilaterally or bilaterally.


METHODS
Prospective cohort study for thirty infants with prelingual profound HL.


METHODS
ABR, OAE, and/or CM were analyzed to identify electrophysiological characteristics. Temporal bone computed tomography and/or internal acoustic canal magnetic resonance imaging were reviewed to identify anatomical abnormalities. The electrophysiological characteristics and cochlear nerve status were analyzed according to the laterality of deafness (unilateral vs bilateral).


RESULTS
Among the total 41 ears (from 30 infants) with profound HL, 13 ears (7 (36.8%) of 19 ears with unilateral HL and 6 (27.3%) of 22 ears associated with bilateral HL) showed AN characteristics (37.1%), and 21 ears showed cochlear nerve deficiency (CND) (51.2%). AN characteristics was detected about two times more frequently in cases with CND (38.1%) than with anatomically normal cochlear nerve (20.0%), the difference not reaching a statistical significance probably due to a small sample size. Detection of AN characteristics did not differ between unilateral and bilateral profound HL, even though presence of CND was more frequently detected in cases with unilateral profound HL than with bilateral cases. There were at least five types of etiologies related to AN characteristics in 13 ears (from 10 infants) in our series depending on the laterality of deafness and presence of CND.


CONCLUSIONS
This study demonstrates that there were diverse etiologies related to AN characteristics from infants with unilateral or bilateral profound HL. Association between CND and AN characteristics is suggestive but not solid at this moment and AN characteristics is not a fully penetrant feature of CND.
Department of Otorhinolaryngology - Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea; Department of Otorhinolaryngology - Head and Neck Surgery, Korea University Medical Center, Korea University College of Medicine, Seoul, Republic of Korea.
Shin Hye
SH
Kim
Department of Otorhinolaryngology - Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea.
Hyun Seok
HS
Choi
Department of Otorhinolaryngology - Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea.
Young Eun
YE
Han
Department of Otorhinolaryngology - Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea; Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea. Electronic address: choiby@snubh.org.
Byung Yoon
BY
Choi
D015331:Cohort Studies; D007758:Ear, Inner / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006313:Hearing Loss, Central / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D011446:Prospective Studies; D013701:Temporal Bone / Q000473:pathology; D014057:Tomography, X-Ray Computed
Auditory neuropathy; Cochlear nerve deficiency; Electrophysiological characteristics; Hearing loss; Infant