A reliable and practical measure of listening effort is crucial in the aural rehabilitation of children with communication disorders. In this article, we propose a novel behavioral paradigm designed to measure listening effort in school-age children based on different depths and levels of verbal processing. The paradigm consists of a classic word recognition task performed in quiet and in noise coupled to one of three additional tasks asking the children to judge the color of simple pictures or a certain semantic category of the presented words. The response time (RT) from the categorization tasks is considered the primary indicator of listening effort.
The listening effort paradigm was evaluated in a group of 31 normal-hearing, normal-developing children 7 to 12 years of age. A total of 146 Dutch nouns were selected for the experiment after surveying 14 local Dutch-speaking children. Windows-based custom software was developed to administer the behavioral paradigm from a conventional laptop computer. A separate touch screen was used as a response interface to gather the RT data from the participants. Verbal repetition of each presented word was scored by the tester and a percentage-correct word recognition score (WRS) was calculated for each condition. Randomized lists of target words were presented in one of three signal to noise ratios (SNR) to examine the effect of background noise on the two outcome measures of WRS and RT. Three novel categorization tasks, each corresponding to a different depth or elaboration level of semantic processing, were developed to examine the effect of processing level on either WRS or RT. It was hypothesized that, while listening effort as measured by RT would be affected by both noise and processing level, WRS performance would be affected by changes in noise level only. The RT measure was also hypothesized to increase more from an increase in noise level in categorization conditions demanding a deeper or more elaborate form of semantic processing.
There was a significant effect of SNR level on school-age children’s WRS: their word recognition performance tended to decrease with increasing background noise level. However, depth of processing did not seem to affect WRS. Moreover, a repeated-measure analysis of variance fitted to transformed RT data revealed that this measure of listening effort in normal-hearing school-age children was significantly affected by both SNR level and the depth of semantic processing. There was no significant interaction between noise level and the type of categorization task with regard to RT.
The observed patterns of WRS and RT supported the hypotheses regarding the effects of background noise and depth of processing on word recognition performance and a behavioral measure of listening effort. The magnitude of noise-induced change in RT did not differ between categorization tasks, however. Our findings point to future research directions regarding the potential effects of age, working memory capacity, and cross-modality interaction when measuring listening effort in different levels of semantic processing.