The chapter attempts to understand the enigma of late-onset auditory neuropathy spectrum disorder (ANSD) from a psychosocial perspective. The focus of research has always been on accurate diagnosis and management of individuals with ANSD. However, there are limited studies on the psychological problems faced by individuals with late-onset ANSD. In the present chapter, the studies on late-onset ANSD and the psycho-social problems faced by them are reviewed. They experience serious psychosocial issues which need to be addressed urgently for appropriate management of individuals with ANSD. It is highlighted that a psychologist/psychiatrist should be a part of the rehabilitation team for management of individuals with late-onset ANSD. In addition, the focus of rehabilitation should not be restricted to physiological problems, but the psychological problems should also be addressed. Thus, a patient-centric approach in management would definitely improve the quality of life of some individuals with ANSD.
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Auditory neuropathy spectrum disorder (ANSD) is a retro-cochlear pathology in which the outer hair cell functioning is normal but there is an abnormality in the auditory nerve (Berlin et al., 2010; Berlin, Hood, Morlet, Rose, and Brashears, 2003; Deltenre et al., 1999; Roush, Frymark, Venediktov, and Wang, 2011; Starr, Picton, Sininger, Hood, and Berlin, 1996). ANSD was first explained by Starr et al. (1991) as a single case study in detail. The condition was later described in detail on ten subjects and named as auditory neuropathy (Starr et al., 1996). The condition is also described using the terminology ‘auditory dys-synchrony’ as this would better indicate the pathophysiology of the disorder (Berlin, Hood, and Rose, 2001; Berlin, Jeanfreau, Hood, Morlet, and Keats, 2001).
The term ‘auditory neuropathy’ was not preferred as the eighth cranial nerve (Vestibulocochlear nerve/auditory nerve) itself may not be affected as the pathology can be at inner hair cells (IHC) level or at the level of the synapse of IHC and auditory nerve. In addition, the term auditory neuropathy may lead clinicians not to consider cochlear implant as a management option. It has been shown later that the individuals with auditory dys-synchrony benefit from cochlear implants (Berlin et al., 2003; Peterson et al., 2003). A group of audiologists, neonatologists, medical geneticists, hearing scientists and neurologists had a conference for the development of guidelines on identification and appropriate management of auditory neuropathy. One of the decisions taken in the conference was to replace the current terminology used for describing the clinical condition as auditory neuropathy spectrum disorder (ANSD).
ANSD can affect the functioning of inner hair cells, synapse between the inner hair cells and auditory nerve, or the auditory nerve itself (Starr, Sininger, and Pratt, 2000). Individuals with ANSD may manifest asynchronous firing of the auditory nerve fibers due to demyelinization (Starr, Picton, and Kim, 2001). The demyelinization leads to temporal asynchrony in the firing of the auditory nerve fibers and thus reducing the compound action potential of the auditory nerve. Asynchronization not only affects auditory brainstem responses, but also influences auditory perception dependent on temporal cues (Kraus et al., 2000; Rance, McKay, and Grayden, 2004; Starr, Zeng, Michalewski, and Moser, 2010; Zeng, Kong, Michalewski, and Starr, 2005; Zeng, Oba, Garde, Sininger, and Starr, 1999).