Current State of Knowledge: Perceptual Processing by Children with Hearing Impairment

In Brief Perception concerns the identification and interpretation of sensory stimuli in our external environment. The purpose of this review is to survey contemporary views about effects of mild to severe sensorineural hearing impairment (HI) in children on perceptual processing. The review is one of a series of papers resulting from a workshop on Outcomes Research in Children with Hearing Loss sponsored by The National Institute on Deafness and Other Communication Disorders/National Institutes of Health. Children with HI exhibit heterogeneous patterns of results. In general, however, perceptual processing of the (a) auditory properties of nonspeech reveals some problems in processing spectral information, but not temporal information; (b) auditory properties of speech reveals some problems in processing temporal sequences, variation in spatial location, and voice onset times, but not in processing talker-gender, weighting acoustic cues, or covertly orienting to the spatial location of sound; (c) linguistic properties of speech reveals some problems in processing general linguistic content, semantic content, and phonological content. The normalcy/abnormalcy of results varies as a function of degree of loss and task demands. As a general rule, children with severe HI have more abnormalities than children with mild to moderate HI. Auditory linguistic properties are also generally processed more abnormally than auditory nonverbal properties. This outcome implies that childhood HI has less effect on more physical, developmentally earlier properties that are characterized by less contingent processing. Some perceptual properties that are processed in a more automatic manner by normal listeners are processed in a more controlled manner by children with HI. This outcome implies that deliberate perceptual processing in the presence of childhood HI requires extra effort and more mental resources, thus limiting the availability of processing resources for other tasks. This review synthesizes the evidence on perceptual processing by children with mild to severe sensorineural hearing impairment. An interdisciplinary perspective is adopted to examine the effects of hearing loss on the perceptual organization of the external world into auditory objects and of speech into auditory and linguistic channels of information. The section also considers the extent to which some perceptual properties that are processed in a more automatic manner by normal listeners may be processed in a more controlled or effortful manner by children with hearing loss. Effects of age and degree of hearing impairment are examined when possible.