ABSTRACT
At a commonsense everyday level dyslexia is often defined as an unexpected difficulty in learning to read, write and spell. But like many definitions as soon as it is examined more closely it becomes more difficult to pin down and a number of problems and ambiguities arise. Who decides that the difficulty is unexpected, and on what basis? How behind does a child have to be for it to be counted as a difficulty and how is the difficulty judged or quantified? Do all children need to show the same sort of difficulty or can they show different types of difficulties and still be called dyslexic? In examining definitions of dyslexia it becomes apparent that different definitions highlight different aspects or levels of the problem. Frith (1992) has proposed that in looking at learning disabilities like autism and dyslexia it is important
to look at the links between the different levels of explanation so that we can begin to see the links between biological causation, cognitive impairments, and behaviours such as poor reading and spelling. Although at present there isn’t one agreed definition of dyslexia, the following, put forward by the World Federation of Neurology (1968) (cited in Critchley 1970), is one that is still widely used.
