Auditory Nerve Disease of Both Ears Revealed by Auditory Brainstem Responses, Electrocochleography and Otoacoustic Emissions

Abstract

We report on two patients who showed absence of auditory brainstem response (ABR) but broad compound action potentials on electrocochleograms and almost normal otoacoustic emissions, together with absence of caloric response and preservation of per rotatory nystagmus for both ears. Patient 1, a 53-year-old woman, had noted auditory and vestibular problems since the age of 15 years, and Patient 2, a 68-year-old woman, had noted problems of the same age of 30 years. They could hear words and understand sentences if spoken slowly, but they could not discriminate monosyllables very well. Their auditory examinations disclosed mild threshold elevation in pure-tone audiometry and markedly poor scores in speech audiometry and good scores in auditory comprehension test. They were diagnosed as having auditory nerve disease of unknown cause.

Cochlear Receptor (Microphonic and Summating Potentials, Otoacoustic Emissions) and Auditory Pathway (Auditory Brain Stem Potentials) Activity in Auditory Neuropathy

“…The preservation of OAEs and CMs in AN has been considered evidence that cochlear outer hair cell function is normal in this disorder (Deltenre, Mansbach, Bozet, Clercx, & Hecox, 1997;Kaga, Nakamura, Shinogami, Tzuzuku, Yamada, & Shindo, 1996;Starr et al, 1996;Stein, Tremblay, Pasternak, Banerjee, Lindemann, & Kraus, 1996). However, there are several findings that could represent abnormal cochlear outer hair cell function.…”

Auditory nerve disease and auditory neuropathy spectrum disorders

“…In 1996 a new type of bilateral hearing disorder was discerned and published almost simultaneously by Kaga et al [1] and Starr et al [2]. Although the pathophysiology of this disorder as reported by each author was essentially identical, Kaga used the term ''auditory nerve disease'' and Starr used the term ''auditory neuropathy''.…”

Auditory Neuropathy/Dys-synchrony and Its Perceptual Consequences

“…Similarly, Sininger and Oba (2001) reported speech discrimination scores (CID W-22 lists) for 36 of their (mostly adult) auditory neuropathy/dys-synchrony patients that showed 25 (69%) fell below the Yellin et al (1989) normative range. Other examples of auditory neuropathy adults with extreme speech perception difficulties have been presented by Jerger et al, 1992;Berlin et al, 1993;Sininger et al, 1995;Widen et al, 1995;Berlin et al, 1996;Kaga et al, 1996;Starr et al, 2000;Zeng et al, 2001a;Mason et al, 2003;Starr et al, 2003;and Zeng and Liu, in press. The data presented in these studies demonstrate that in many cases of adult auditory neuropathy/dys-synchrony, speech signal disruption can occur that is more extreme than that observed in sensorineural hearing loss.…”

“…Localization ability based on interaural timing differences is another aspect of binaural auditory processing affected by auditory neuropathy/dys-synchrony-type hearing loss (Starr et al, 1991;Kaga et al, 1996;Zeng et al, in press). Subjects in the Zeng et al, study, for example were significantly impaired in their ability to make lateralization judgements from temporal cues.…”