A multi-level synthesis of dyslexia

Dyslexia has been studied from many angles. Researchers have obtained seemingly contradictory results and created widely varying theories and treatments. A complete understanding of dyslexia requires recognition of neurological and psychological components and their interaction, and could therefore benefit from a complex systems approach. This paper surveys and synthesizes results from many theoretical, experimental, and clinical approaches to dyslexia, including Galaburda, Davis, Geiger, and Merzenich. The magnocellular hypothesis combined with the Davis theory of "triggers" appear to explain nearly every experimental result, observation, and successful treatment of which the author is aware. Dyslexia can be understood as an accretion of simple symptoms in multiple sensory modalities, each symptom having the same neurological basis; each individual has a different combination of symptoms, and the symptoms are created and maintained through mental/psychological interaction with the individual's efforts to perform. There is strong observational evidence, confirmed by pilot studies carried out by the author, that the symptoms can change momentarily. Although such rapid change is not recognized by many dyslexia researchers, it has been demonstrated with PET scans in the case of stuttering; this finding is crucial to a full understanding of the interaction between neural function and mental state. The recognition of the diversity of symptoms, their common neurological basis, and their extreme plasticity in response to high-level mental state, may help to focus research and to develop increasingly effective and rapid treatments.