Comparing Central Auditory Processing Performance in Bilinguals Using L1 vs. L2 Materials

Auditory processing disorder (APD) is a disorder caused by a disruption within the central auditory pathway that impairs processing of complex or degraded auditory inputs. Patients with this condition often present with normal hearing but still report problems understanding speech. This commonly manifests as individuals having difficulty understanding speech in challenging listening environments (e.g., noisy backgrounds, reverberant environments, rapid speech), localizing sounds, and following complex auditory directions. An underlying auditory skill vital to these processes is binaural processing, or the ability to utilize auditory cues from both ears. Binaural processing aids in identifying a talker in the midst of background noise and allows us to better separate relevant from irrelevant inputs.

While auditory processing evaluations assess specific auditory skills (like binaural processing) necessary for efficient processing and understanding of complex auditory signals, many of the tests rely heavily on language. This poses an issue for individuals for whom English is not their native language. Because the tests are linguistically loaded, the obtained results do not clearly identify whether an issue should be attributed to a central auditory problem or to the language used in the test materials. Thus, audiologists are often hesitant to test bilingual patients who demonstrate features of APD.

It is possible that bilingual individuals would perform more favorably when tested in their native language (L1). Indeed, differences in complex auditory task performance have been seen in Spanish-English bilinguals when materials were presented in Spanish versus English. Recent studies have evaluated test-language effects in bilingual education and described significant improvements in performance when bilinguals were instructed and tested in their native language (L1) compared to performance in their later acquired language (L2). Numerous studies have also assessed monolingual vs. bilingual performance in complex auditory tasks including listening in noise, auditory memory, and competing speech. While much research in auditory processing of bilingual speakers compares performance between monolinguals and bilinguals, evidence to inform best clinical practice in the assessment of APD in bilinguals is lacking. To date, relatively few studies investigate performance within the same participant with testing language being the differential factor.

Therefore, the purpose of this study is to compare binaural processing performance in Spanish-English bilingual participants when tested in Spanish (L1) versus in English (L2). Based on prior literature, we suspect that bilingual participants will perform better when they are instructed and presented with assessments in their native language versus when they are assessed in their later acquired language (L2). However, it is possible that our participants, who will be proficient in both L1 and L2, will show no difference in task performance. Regardless, by comparing binaural processing performance in bilingual participants, we will clarify whether testing bilingual individuals in a secondary language (when proficient in that language) results in valid and reliable measures of their auditory processing abilities. Thus, our results will provide evidence to establish best clinical practice when evaluating bilingual listeners for auditory processing deficits. This will enable clinicians to more confidently evaluate and diagnose auditory processing disorders in bilingual populations.