The authors first examined the influence of moderate to severe congenital hearing impairment (CHI) on the correctness
of samples of elicited spoken language. Then, the authors used this measure as an indicator of linguistic proficiency and
examined its effect on performance in language reception, independent of bottom-up auditory processing.
groups of adults with normal hearing (NH, n = 22), acquired hearing impairment (AHI, n = 22), and moderate to severe CHI (n
= 21), the authors assessed linguistic proficiency by analyzing the morphosyntactic correctness of their spoken language production.
Language reception skills were examined with a task for masked sentence recognition in the visual domain (text), at a readability
level of 50%, using grammatically correct sentences and sentences with distorted morphosyntactic cues. The actual performance
on the tasks was compared between groups.
Adults with CHI made more morphosyntactic errors in spoken
language production than adults with NH, while no differences were observed between the AHI and NH group. This outcome pattern
sustained when comparisons were restricted to subgroups of AHI and CHI adults, matched for current auditory speech reception
abilities. The data yielded no differences between groups in performance in masked text recognition of grammatically correct
sentences in a test condition in which subjects could fully take advantage of their linguistic knowledge. Also, no difference
between groups was found in the sensitivity to morphosyntactic distortions when processing short masked sentences, presented
These data showed that problems with the correct use of specific morphosyntactic knowledge
in spoken language production are a long-term effect of moderate to severe CHI, independent of current auditory processing
abilities. However, moderate to severe CHI generally does not impede performance in masked language reception in the visual
modality, as measured in this study with short, degraded sentences. Aspects of linguistic proficiency that are affected by
CHI thus do not seem to play a role in masked sentence recognition in the visual modality.