Dyslexia may be defined as " a specific language based disorder of constitutional origi
n characterized by difficulties in reading and/or spelling which are unexpected in relation to age and other cognitive abilities" (Bonte et al 2004). Currently there is a vast array of research focusing on trying to define and explain dyslexia, however there still lies some disputes as to what causes this disability. Central to these arguments are the fact that the deficits that can be found in dyslexics are varied, it is not just reading and spelling problem, it is clear "that a significant proportion of dyslexics present sensory/and or motor deficits" (Ramus, 2003), the contrasting nature of certain deficits that have been found to be present in dyslexics has led to a variety of theories to be comprised.
The Phonological theory has been predominant for around 20 years, this states that dyslexia is a form of language impairment which is "exclusively caused by a cognitive deficit that is specific to the representation and processing of speech sounds, this cognitive deficit would arise from a congenital dysfunction of certain cortical areas involved on phonology and reading" (Ramus 2003).
The phonological problems found in dyslexics include phonological awareness which was demonstrated in research conducted by Baddeley et al (1992), it was shown that poor readers were worse than reading age controls at nonword reading, it is believed that the use of alphabetic strategy may be impaired in dyslexics. Further research has highlighted possible short term phonological memory deficits and rapid naming problems, Shankweiler et al (1979) demonstrated poor readers were less likely to show phonological similarity effect (PSE) in recall, perhaps the phonological code in dyslexics is impaired or they are simply not trying to use it. Hall et al (1981) identified floor effects in previous studies however,