Cochlear Implantation in Adults With Prelingual Deafness. Part II. Underlying Constraints That Affect Audiological Outcomes

Abstract

The reviewed evidence, although circumstantial, suggests that emphasizing aurally based educational programs before (with hearing aids) and after cochlear implantation could reduce the cortical colonization phenomenon and potentially improve postimplantation audiological performance of patients with long-term prelingual deafness.

Cochlear Implantation Outcome in Prelingually Deafened Young Adults

“…These findings support the existence of a sensitive period for language development declining with age and related to central plasticity [Johnson and Newport, 1991]. The development of normal language skills seems to require the presence of a robust auditory input guiding the organization of the secondary auditory cortex and association areas during the sensitive period [Kral et al, 2000;Naito et al, 1997;Teoh et al, 2004b;Truy et al, 1995].…”

“…These values are remarkably lower compared to those reported for postlingually deafened patients with cochlear implant [Bassim et al, 2005;Manrique et al, 1999;Teoh et al, 2004a]. This was explained by the existence of a sensitive period declining with age for the development of speech perception abilities, which is strictly related to the cortical plasticity processes and requires an auditory input to be accomplished [Kral et al, 2000;Naito et al, 1997;Teoh et al, 2004b;Truy et al, 1995].…”

Differential activity in Heschl's gyrus between deaf and hearing individuals is due to auditory deprivation rather than language modality

“…Characterising which of the components of plastic reorganisation in primary auditory areas of deaf individuals are caused by language modality and which by auditory deprivation is not only important for understanding the basic mechanisms of plastic reorganisation, but also because of its relevance in terms of approaches to language acquisition in deaf children, in particular those who have cochlear implants (CI) or are waiting to receive one. Even though several pieces of evidence show that crossmodal plasticity correlates with CI success (Giraud et al, 2001;Rouger et al, 2007;Mangus et al, 2012;Stevenson et al, 2012), and that speech acquisition in hearing individuals involves the integration of auditory and visual inputs (Mills, 1987;Lewkowicz and Hansen-Tift, 2012), some studies suggest that plastic reorganisation due to visual language can interfere with CI success, and that sign language and speechreading could make this interference worse (Teoh et al, 2004;Giraud and Lee, 2007). Here we dissociate the effects of language modality and auditory deprivation on visual crossmodal plasticity in HG, using a subject-specific anatomical definition, and also a subject-specific cytoarchitectonic definition of area Te1.0.…”

Cochlear Implantation in Adults with Prelingual Deafness - A Case Report

“…Unlike children with prelingual deafness and patients with post lingual deafness, the listening performance of adults with prelingual deafness was usually observed with enormous variability among individual and lower speech perception abilities [1] due to the cortical colonization and reorganization by other sensory modalities [2,3]. The slow progress of listening performance was shown in this 33 years old gentleman.…”

“…According to Teoh et al [2], they realized that patients' characteristics played a main role in determining the observed outcome measures instead of the implants brands Cochlear Limited, MED-EL or Advanced Bionics [1]. Our patient is willing to have the training done by his sister but not the other family members.…”