Kathleen S. Arnos and Arti Pandya
Genetic factors are believed to account for more than half of all cases of congenital or early-onset moderate to profound deafness. The identification of several dozen genes for deafness, one of which accounts for a high proportion of all childhood deafness, has enabled the identification of the exact cause of deafness in many children through genetic testing. Parents, family members, deaf and hard-of-hearing adults, as well as health care and educational professionals often are unaware of the exact process and goals of genetic evaluation and may have questions about the usefulness of genetic testing. Sensitive and appropriate genetic evaluation and testing, coupled with appropriate interpretation and information through genetic counseling, can be invaluable to many families. Health professionals and those who work with deaf children in educational and service settings play an important role in helping parents and family members understand the value of a genetic evaluation and making referrals to genetics professionals.
Bert De Smedt and Roland H. Grabner
In this chapter, we explore three types of applications of neuroscience to mathematics education: neurounderstanding, neuroprediction, and neurointervention. Neurounderstanding refers to the idea that neuroscience is generating knowledge on how people acquire mathematical skills and how this learning is reflected at the biological level. Such knowledge might yield a better understanding of the typical and atypical development of school-taught mathematical competencies. Neuroprediction deals with the potential of neuroimaging data to predict future mathematical skill acquisition and response to educational interventions. In neurointervention, we discuss how brain imaging data have been used to ground interventions targeted at mathematics learning and how education shapes the neural circuitry that underlies school-taught mathematics. We additionally elaborate on recently developed neurophysiological interventions that have been shown to affect mathematical learning. While these applications offer exciting opportunities for mathematics education, some potential caveats should be considered, which are discussed at the end of this chapter.
Children and Youth Who Are Hard of Hearing:: Hearing Accessibility, Acoustical Context, and Development
Janet R. Jamieson
Children and youth who are hard of hearing comprise a substantial proportion of the birth to young adult population with hearing loss, but in spite of this, researchers have paid scant attention to this group, in comparison to their peers who are deaf. However, there is currently a growing interest in the development of children whose hearing losses range from mild to severe. This focus has come about in part because of the widespread implementation of early hearing detection and intervention (EHDI), which is resulting in far earlier diagnosis and intervention—and improved outcomes across domains—than was evident in the past, and in part because of improved amplification technologies. Taken together, the overall impact of EHDI and improved amplification options is that there appears to be an increase in the population of children who are now able to develop functional communication skills more characteristic of hard-of-hearing children than of deaf children.
The aims of this chapter are to consider (1) the challenges inherent in interpreting research on individuals who are hard of hearing in the absence of a consistent definition, (2) outcomes in terms of speech and language development in children who are hard of hearing, (3) the vital role of acoustic ecology and hearing accessibility in the lives of children and youth who are hard of hearing, (4) the relationship between hearing accessibility and identity construction in hard-of-hearing adolescents, and (5) the actual and anticipated impact of newborn hearing screening and early intervention for this population.
Marc Marschark and Loes Wauters
Recent studies have obtained findings of significant theoretical and practical importance for parents and educators of deaf children and others who seek to discover how hearing loss and the use of a visuospatial language might influence language, cognitive, and social functioning. This work has led to a more objective understanding of deaf individuals and signed languages, and offers great hope for improving deaf education. This chapter offers a historical review of cognitive research involving deaf individuals through the stages of “the deaf as inferior,” “the deaf as concrete,” and “the deaf as intellectually normal.” It argues for an additional, contemporary stage of “different does not mean deficient.” Findings with regard to attention and perception, mental representation, visuospatial imagery and cognition, memory, and problem solving all point to the probability that deaf and hearing individuals differ cognitively in several subtle and not-so-subtle ways that might affect learning and other psychological domains. Whether a function of their language experiences, variable educational backgrounds, nature, or nurture, it is essential that such differences be understood in order to accommodate the needs of deaf learners while utilizing their strengths.
For more than a century we have known that the left hemisphere of the human brain is critical for producing and comprehending spoken languages. Evidence from brain-injured deaf signers and from neuroimaging studies indicates that the left cerebral hemisphere is also critical to processing signed languages. This chapter presents evidence that the left hemisphere specialization for language can be dissociated from symbolic gesture, motor control, and spatial cognitive abilities. Damage to distinct left perisylvian areas causes specific types of language impairment for both signers and speakers, and damage outside of these areas does not give rise to aphasic deficits. Specifically, neuroimaging and lesion data indicate that Broca’s area and Wernicke’s area play critical roles in sign language production and comprehension. Data from right hemisphere–damaged signers and speakers indicates that the right hemisphere is involved in discourse processing. In addition, the right hemisphere appears to be uniquely involved in the production and comprehension of spatial descriptions in sign language. Overall, both neural plasticity and invariance are observed for the neural organization of sign language. Neural plasticity is observed for auditory-related cortex (Wernicke’s area), which has received little or no auditory input, but nonetheless is engaged in processing the visual input of sign language. Neural invariance within left perisylvian structures points to a biological or developmental bias for these neural structures to mediate language at a more abstract level, divorced from the sensory and motoric systems that perceive and transmit language.
Young children who find mathematics very difficult are likely to encounter profound problems later on. Previous small-scale studies have indicated that early intervention can help them, but have provided insubstantial evidence. This chapter discusses the key features of a new mathematics intervention in England, Numbers Count, and analyzes the findings of a large-scale impact study of 8000 low-achieving 6- and 7-year-old children. After an average of 43 half-hour, one-to-one lessons in 3 months, their number age test scores had risen by 14 months with an effect size of .85. Their attitudes towards learning mathematics also improved substantially, with an effect size of .7. Children made strong progress irrespective of their background characteristics. It is suggested that the success of the intervention was due to its design, to its teachers’ professional development program, and to rigorous quality assurance. Subsequent changes are discussed.
David F. Armstrong and Sherman Wilcox
This chapter maintains that human languages emerge from purposeful human behavior, the most common of which are visible gestural behaviors. We further suggest that sign languages were probably the first human languages. These assertions are based on the observation that gestural communication is exhibited by all of the Hominoidea, the primate superfamily that includes apes and human beings; the fact that iconic and indexic gestures have been identified in the behavior of feral chimpanzees; and by noting that this sort of behavior was probably part of the repertoire of the common ancestors of chimpanzees and humans, thus of the earliest hominids. We propose an evolutionary model for the emergence of language based on semantic phonology and further demonstrate how spoken languages developed subsequently out of vocal gestures. Rationales are provided for the eventual predominance of speech as the primary medium for human language and for the maintenance of sign systems and gestural systems in conjunction with speech by hearing communities. Finally, we discuss evidence for the emergence of full sign languages whenever numbers of deaf people reach critical mass. Key aspects of this discussion include homesigns and sign systems used in small scale societies with significant numbers of deaf members; the earliest evidence for deaf communities with sign languages; the origin of Langue des Signes Française and ASL; and the origin and elaboration of Nicaraguan Sign Language, especially with respect to what the emergence of a new language tells us about the human language faculty.
Patricia Elizabeth Spencer
Play and Theory of Mind (ToM) result from a combination of maturation and experience. Play behaviors have often been used to index cognitive development in young deaf and hard-of-hearing (DHH) children, although relatively few reports are available on those under the age of 3 years. Available data indicate that the order of development of play behaviors in children with hearing loss parallels that of hearing children; however, delays occur at the symbolic level when language development and early communicative experiences are restricted. With the exception of a single report at 12 months, potentially explained by deaf mothers’ accommodation of age-expected visual attention limitations, hearing status itself has not been shown to affect play development. Like play, behaviors indicating attainment of ToM have been found to correlate with language levels and differences in early opportunities to participate in conversational interactions. Differences in the development of ToM are more readily explained by common effects from hearing loss on experience than from hearing status or language modality alone. Like play, ToM abilities reflect cognitive attainments in taking and representing multiple perspectives, integrating information across time and contexts, and creating as well as retrieving from memory symbolic representations of objects and events. Activities in which play behaviors and ToM problem solving occur, therefore, provide highly conducive contexts for the development of more advanced cognitive concepts and abilities. Intervention to assure “on time” attainment of these two abilities thus may be critical for children’s later abilities to acquire and synthesize information in typical learning environments.
Matthew L. Hall and Daphne Bavelier
Working memory (WM) refers to the human capacity to encode, store, manipulate, and recall information. A proper understanding of WM therefore provides essential insights into human cognition. This chapter reviews available research concerning the impact of deafness and sign language use on WM, much of which comes from the study of a single subcomponent of WM termed short-term memory (STM). We argue that excessive focus on STM (the ability to encode, store, and retrieve a sequence of unrelated words in serial order) to the exclusion of other WM subprocesses has caused an extreme interest in phonological coding at the expense of other known codes used in WM, in particular visual but also episodic codes. Deafness and use of a sign language may result in greater reliance on not only visual but also episodic coding, as compared to what is typically observed in hearing nonsigners. This multiple coding hypothesis calls into question whether the robust phonological bias described in hearing individuals should be taken by researchers, clinicians, and educators as the gold standard for deaf populations.
This chapter focuses on the concept of working memory and how it relates to visual language processing in deaf and hard-of-hearing individuals. It discusses modality-free and modality-specific aspects of signed and spoken language processing from a variety of behavioral and neuroscience data. The chapter concludes by addressing some abstract working memory processes that constitute general features across language modality and modes of speech understanding