Susan J. Maller and Jeffery P. Braden
This chapter addresses cognitive assessment of deaf children and adults. Emphasis is placed on the psychometric properties (e.g., reliability, validity, norms, item analysis) of published intelligence tests when administered to this population. The use of intelligence tests with deaf people has a long history that can be traced back to the early years of formal intelligence testing aimed at identifying those students in need of special education due to “mental retardation.” Intelligence tests continue to serve as a primary component of the assessment process for special education. Practitioners who serve deaf children regularly are faced with the dilemma of choosing from a variety of published tests that often lack sufficient evidence of validity (i.e., that the test score represents what it claims to represent) for this population. There are several potential reasons psychometric evidence is lacking for tests when administered to deaf people. First, deaf people constitute a low-incidence population, and sufficient sample sizes are difficult to obtain to conduct the necessary investigations. Second, the deaf population is composed of a diverse group in terms of a variety of variables, such as communication modalities, degree of hearing loss, parental hearing loss, age of onset, etiology, presence of additional disabilities, race/gender, socioeconomic status (SES), and educational placement. Third, funding is often not available to support investigations by test publishers and independent researchers for low-incidence populations. Finally, many independent researchers may lack the skills both for working with deaf people and in psychometrics that are required to conduct the necessary studies. Thus, valid cognitive assessment remains a difficult dilemma for practitioners whose goals may include helping educators understand a deaf child’s intellectual abilities and educational needs.
This chapter starts with a brief historical overview of research on the cognitive abilities of deaf children, to provide a context for understanding learning disabilities in this group of children. Working definitions of learning disabilities will be presented, distinguishing between global disability and specific difficulties. Although much has been written about deaf children’s cognitive abilities, good empirical evidence is patchy and findings are frequently contradictory. This makes it difficult to determine whether apparent specific difficulties are genuinely associated with hearing impairment, or the result of assessment methods or some other factor. However, some consistent findings have emerged and will be highlighted. Current research and views on established disorders such as dyslexia, dyspraxia, and auditory processing disorder (APD) in deaf children will be presented, as will the available knowledge base for other areas of cognitive functioning, for example executive function, memory, problem solving, and sequencing. Areas of overlap among the underlying cognitive processes will be emphasized. Despite a lengthy history of debate on the issue, assessment of learning disabilities in deaf children is in its infancy in terms of agreed methods, and the use of tests standardized on hearing children remains contentious. Issues relating to the use of neuropsychological and other tests are discussed, and a range of possible approaches are considered and appraised. Finally, suggestions for specific areas in need of further research spanning the whole field of learning disabilities in deaf children are outlined.