Pilot study of cognition in children with unilateral hearing loss

ObjectiveThe objective of this study was to obtain preliminary data on the cognitive function of children with unilateral hearing loss in order to identify, quantify, and interpret differences in cognitive and language functions between children with unilateral hearing loss and with normal hearing.MethodsFourteen children ages 9-14 years old (7 with severe-to-profound sensorineural unilateral hearing loss and 7 sibling controls with normal hearing) were administered five tests that assessed cognitive functions of working memory, processing speed, attention, and phonological processing.ResultsMean composite scores for phonological processing were significantly lower for the group with unilateral hearing loss than for controls on one composite and four subtests. The unilateral hearing loss group trended toward worse performance on one additional composite and on two additional phonological processing subtests. The unilateral hearing loss group also performed worse than the control group on the complex letter span task. Analysis examining performance on the two levels of task difficulty revealed a significant main effect of task difficulty and an interaction between task difficulty and group.ConclusionsCognitive function and phonological processing test results suggest two related deficits associated with unilateral hearing loss: (1) reduced accuracy and efficiency associated with phonological processing, and (2) impaired executive control function when engaged in maintaining verbal information in the face of processing incoming, irrelevant verbal information. These results provide a possible explanation for the educational difficulties experienced by children with unilateral hearing loss.