polthype.blogg.se - Auditory neuropathy spectrum disorder in adults

AN can have either congenital or acquired causes. Īuditory neuropathy can occur spontaneously, or in combination with diseases like Charcot-Marie-Tooth disease and Friedreich's ataxia. Patients with auditory neuropathy spectrum disorders have to date never been shown to have normal middle ear muscle reflexes at 95 dB HL or less despite having normal otoacoustic emissions. AN patients can have a range of hearing thresholds with difficulty in speech perception. Other tests would include pure-tone and speech audiometry. The classic AN paradigm would include present OAEs indicating normal outer hair cell function, absent or abnormal ABR with presence of the cochlear microphonic, and absent acoustic reflexes. Īuditory Neuropathy can be diagnosed with a battery of tests including Otoacoustic Emissions (OAE), Auditory Brainstem Response (ABR), and acoustic reflexes. Auditory brainstem response should be tested with both polarities (helps in identifying cochlear microphonics). Diagnosing auditory neuropathy ĭiagnosis is possible after a test battery, that must necessarily include the following: the auditory brainstem response and otoacoustic emissions. Seminars in Hearing 2002: Copyright© 2002 by Thieme Medical Publishers, Inc.Based on clinical testing of subjects with auditory neuropathy, the disruption in the stream of sound information has been localized to one or more of three probable locations: the inner hair cells of the cochlea, the synapse between the inner hair cells and the auditory nerve, or a lesion of the ascending auditory nerve itself.

Sininger YS, editor Identification of auditory neuropathy in infants and children.

Recommended Procedure Assessment And Management of Auditory Neuropathy Spectrum Disorder (ANSD) in Young Infants.

Hypoxic ischaemic encephalopathy or intraventricular haemorrhage.

Prematurity (particularly extreme <28 weeks’ gestation).

Hyperbilirubinaemia (particularly extreme requiring exchange transfusion).

(1) ANSD has also been associated with a number of risk factors:(1,2) Several gene variants have been associated, including those of the DFNB9 gene which codes for otoferlin protein involved in synaptic functioning at the inner cochlear hair cells.(1) Other possible causes may include neurodegenerative, metabolic and mitochondrial conditions, and structural conditions, such as hydrocephalus, tumours, auditory nerve or brainstem anomalies. This term was considered to better reflect the fact that this is not a diagnosis with single aetiology, but a range of possible disorders and prognoses defined by a pattern of test results (1)Įarly studies indicated that around 40% of cases of ANSD may have genetic cause (2)

The condition was variably referred to as auditory dys-synchrony or de-synchrony, peri-synaptic audiopathy, auditory mismatch, neural hearing loss or persistent outer hair cell function, before ANSD was adopted by consensus in 2008. Absent or severely abnormal auditory brainstem response (ABR), demonstrating a disrupted auditory pathway.Present otoacoustic emissions (OAEs) and cochlear microphonics (CM) tests, demonstrating normal outer hair cell function.The term ‘auditory neuropathy’ was first used in 1996 when Starr et al (3) described 10 children and adults who presented with hearing impairment characterised by:

has been estimated that ANSD may account for around 1 in 10 children with permanent childhood hearing impairment (PCHI) (2).Last edited 07/2020 and last reviewed 07/2020Īuditory Neuropathy Spectrum Disorder (ANSD) is a term used for a pattern of test results that show normal function of the outer sensory hair cells of the cochlear, but abnormal transmission at some point from the inner hair cells of the cochlear along the auditory nerve pathway to the auditory brainstem (1)