Speech Perception Results for Children Using Cochlear Implants Who Have Additional Special Needs

Article excerpt

Speech perception outcomes in young children with cochlear implants are affected by a number of variables including the age of implantation, duration of implantation, mode of communication, and the presence of a developmental delay or additional disability. The aim of this study is to examine the association between degree of developmental delay and speech perception outcomes for a group of young children using cochlear implants.

Forty-nine children who received cochlear implants at the Royal Victorian Eye and Ear Hospital between 1993 and 2001 were assessed by an educational psychologist. The choice of test used for the psychological, cognitive, and motor evaluations depended on the age and development of each child participant. In order to collate results across five different tests of cognitive development, three groups were defined. There were 27 children in Group 1 who demonstrated cognitive development within the normal range. There were 14 children placed in Group 2 who demonstrated a mild delay in cognitive development. There were 8 children placed in Group 3 who demonstrated a severe cognitive delay. Open-set and closed-set word and sentence tests of speech perception were completed when appropriate. For children too young or unable to perform formal tests, a 7-category speech perception classification system was applied to provide an assessment of auditory skills.

Results suggested that there was a significant association between cognitive development and speech perception based on the categorical scale of outcomes. There was insufficient data available from the formal speech perception test scores for children with a range of cognitive delay to enable valid statistical analysis.

Some children with significant cognitive delay demonstrated speech perception benefit from the cochlear implant. This result suggests that presence of a cognitive delay should not preclude children from being considered for receiving cochlear implants. The degree of cognitive impairment should be carefully evaluated and appropriate counseling regarding expectations is essential.

Introduction

The use of multi-channel cochlear implants for children with significant hearing loss has been established as a safe and effective means for improving auditory detection and discrimination when benefit from conventional amplification is limited (Cheng & Niparko, 2000; Geers & Moog, 1994; Osberger et al., 1991; Staller, Beiter, Brimacombe, Mecklenburg, & Arndt, 1991b; Tyler, 1993; Waltzman et al., 1994). Research has demonstrated that young children using cochlear implants, including those with prelingual and congenital hearing loss, can demonstrate speech perception skills commensurate with children who use hearing aids within the severe hearing loss range (Boothroyd & Eran, 1994; Kishon-Rabin et al., 2000; Snik, Vermeulen, & Groenen, 2000) and achieve results comparable to those obtained by adults with post-lingual deafness (Dowell, Blarney, & Clark, 1995; Dowell, Dettman, Blarney, Barker, & Clark, 2002; Sarant, Blarney, Dowell, Clark, & Gibson, 2001; Tyler et al., 2000). Children using cochlear implants have acquired language at rates greater than that previously reported for children with profound hearing loss who use hearing aids (Dawson, Blarney, & Dettman, 1995; Geers & Moog, 1994; Robbins, Svirsky, & Miyamoto, 2000; Svirsky, Robbins, Kirk, Pisoni, & Miyamoto, 2000; Tomblin, Spencer, Flock, Tyler, & Gantz, 1999). In addition, children using cochlear implants have demonstrated significant improvements in speech production and overall intelligibility overtime (Alien, Nikolopoulos, & O'Donoghue, 1998; Geers & Moog, 1992; Grogan, Barker, Dettman, & Blarney, 1995; Serry & Blarney, 1999). A number of variables have been identified that contribute to speech perception outcomes for children using cochlear implants. These variables include the age at onset of deafness, duration of deafness (Mitchell, Psarros, Pegg, Rennie, & Gibson, 2000), amount of residual hearing, duration after receiving the cochlear implant, (Isaacson, Hasenstab, Wohl, & Williams, 1996; Pyman, Blamey, Lacy, Clark, & Dowell, 2000), etiology, communication mode (Bertram, Lenarz, Meyer, Battmer, & Hartrampf, 1995; Geers, Brenner, & Davidson, 2003; Hellman et al. …