Reading Disability as a Deficit in Functional Coordination

Reading disability (dyslexia) is introduced as a failure in learning to optimize the coordination of the subfunctions involved in reading with the consequence of errors or delays in integrating reading related information represented in working memory (Functional Coordination Deficit model). Within this multicausal model, so-called reversal errors, such as those typically found in beginning readers and in a subgroup of reading disabled children, are explained as a result of a failure in optimally integrating visual and auditory information during reading. “Symmetry generalization” is introduced to describe a mechanism in visual object recognition. It is argued that symmetrically related objects (all axis) are represented in the brain by similar patterns of neural activity (cell assembly). Symmetry generalization, as an result of evolutionary and individual development, is assumed to be learned as an infant to warrant behavioral advantages (object constancy). However, this mechanism may be a hindrance in reading, because graphemes are visual symbols, and as such they have to have a non-ambiguous relation to the respective verbal information (label) they represent. It is argued that learning to read is comprised of learning to treat graphemes as symbols instead of objects, which is assumed to be learned very early during the first stage of reading acquisition. A failure in complete suppression of visually symmetrical information in the representation of visual symbols during reading produces ambiguous relations between visual and phonological information and disturbs the functional coordination, and thus may cause problems in learning to read. It is emphasized that reversal errors do not reflect a visual deficit, an incomplete hemispheric dominance nor the one and only cardinal symptom of dyslexia. 1. THE BEGINNING OF A SCIENTIFIC INTEREST IN READING DISABILITY 1.1 The Educational Concept of Reading Disability The beginning of the scientific interest in reading disability started about 100 years ago and can be seen as a consequence of the advances in two originally distinctive fields, educational and neurological science. At the beginning of the 20 century, psychoeducational testing became more important, not only for measuring general intelligence (Binet, 1905; Stern, 1912) but also for testing separate techniques like reading and writing (Gates, 1921, 1927; Thorndike, 1919). The main interest in doing so was to predict a students learning performance and to identify students whose performance in school differed greatly to what the test results suggested. The main intention of the reading tests was to optimize educational guidance for acquiring these techniques. Gates, Bond and Russell (1939) later pointed out that reading ability is something that children acquire in varying degrees; “it must be taught and is not a series of attributes for the development of which a teacher can do nothing but wait”. The reading test battery compiled by Gates (1927) includes most of the aspects that are considered today as important for reading: visual as well as auditory perception, word-recognition,