Semantic Processing in Deaf and Hard-of-Hearing Children: Large N400 Mismatch Effects in Brain Responses, Despite Poor Semantic Ability

Abstract

Difficulties in auditory and phonological processing affect semantic processing in speech comprehension for deaf and hard-of-hearing (DHH) children. However, little is known about brain responses related to semantic processing in this group. We investigated event-related potentials (ERPs) in DHH children with cochlear implants (CIs) and/or hearing aids (HAs), and in normally hearing controls (NH). We used a semantic priming task with spoken word primes followed by picture targets. In both DHH children and controls, cortical response differences between matching and mismatching targets revealed a typical N400 effect associated with semantic processing. Children with CI had the largest mismatch response despite poor semantic abilities overall; Children with CI also had the largest ERP differentiation between mismatch types, with small effects in within-category mismatch trials (target from same category as prime) and large effects in between-category mismatch trials (where target is from a different category than prime), compared to matching trials. Children with NH and HA had similar responses to both mismatch types. While the large and differentiated ERP responses in the CI group were unexpected and should be interpreted with caution, the results could reflect less precision in semantic processing among children with CI, or a stronger reliance on predictive processing.

Literacy development in children with cochlear implants

“…The N400 effect has been examined in numerous special populations, including those diagnosed with SLI (Cummings & Ceponiene, 2010), dyslexia (Helenius et al, 1999;Schulz et al, 2009), generalised learning disabilities (Fernandez, Silva-Pereyra, Prieto-Corona, Rodriguez-Camacho & Reynoso-Alcantara, 2014), autism spectrum disorder (McCleery et al, 2010) and William's syndrome (Pinheiro, Galdo-Álvarez, Sampaio, Niznikiewicz & Gonçalves, 2010). Some studies have also been conducted to explore the N400 effect in individuals with CIs (Hahne, Wolf, Müller, Mürbe & Friederici, 2012;Kallioinen et al, 2016;Key, Porter & Bradham, 2010;Vavatzanidis, Burbe, Friederici & Hahne, 2018). Such electrophysiological evidence has provided insight into the semantic processing capabilities of this population, thereby complementing behavioural evidence that highlights their spoken language difficulties (e.g., Geers, 2003;Nittrouer et al, 2012;2014;Weisi et al, 2013).…”

“…Compared with the research involving adults with CIs, there have been more studies investigating the N400 effect in children with CIs, although the results are arguably less conclusive. Kallioinen et al (2016) used a word-picture matching paradigm to elicit ERP responses in 5-to 7-year-old children with CIs. The task included three different conditions: stimulus pairs were either congruent (e.g., wolf-wolf), between-category incongruent (e.g., wolf-car), or within-category incongruent (e.g., wolf-bear).…”

“…Yet, the same aims have rarely been addressed using neurophysiological methods, and with attention to the N400 effect. Where CI users have been the focus of investigation, the N400 effect is reportedly significant (Hahne et al, 2012;Kallioinen et al, 2016;Key et al, 2010;Vavatzanidis et al, 2018), albeit with a different waveform shape to that elicited in typically hearing controls (Hahne et al, 2012;Kallioinen et al, 2016). Of the previous studies involving children with CIs, none has examined the N400 exclusively in users of spoken language.…”

“…Compared with the literature on adult CI users, relatively more research has been conducted to investigate the N400 effect in children with CIs (Key, Porter and Bradham, 2010;Kallioinen et al, 2016;Vavatzanidis, Murbe, Friederici & Hahne, 2018), although only one study to the author's knowledge has addressed this evidence gap on a group scale and with reference to typically hearing controls. Kallioinen and colleagues (2016) elicited ERP responses in a 5-to 7-year-old CI cohort, who used a combination of sign and spoken language.…”

“…The amplitude of the within-category N400 effect was also correlated with phonological processing, although this finding cannot easily be explained by shared lexical-semantic demands across ERP and behavioural tasks. Most importantly, Kallioinen et al (2016) did not include behavioural assessments of spoken language comprehension. Accordingly, it is not possible to know the degree to which the language difficulties exhibited by children with CIs relate to their underlying lexical-semantic functioning, as indexed by the N400 effect.…”