'Dyslexia' is a meaningless label applied to children who are simply struggling to read, a new book claims.
Author Professor Julian Elliott, a former teacher of children with learning difficulties, said the term should be dropped because it probably doesn't even exist, yet millions of children may have been wrongly diagnosed with the condition.
In his book The Dyslexia Debate, the author, a professor of education at Durham University, said: "Parents are being woefully misled about the value of a dyslexia diagnosis. "In every country, and in every language, a significant proportion of children struggle to master the skill of reading and some will continue to find it difficult throughout their childhood and into adulthood.
"Typically, we search for a diagnostic label when we encounter problems because we believe that this will point to the best form of treatment.
"It is hardly surprising, therefore, that the parents and teachers of children with reading difficulties believe that if the child is diagnosed as dyslexic, clear ways to help them will result.
"Research in this field clearly demonstrates that this is a grave misunderstanding."
However, charities have challenged their assessment claiming that the term is important and should not be dropped.
Dr John Rack, head of research, development and policy, for Dyslexia Action insisted the term retained a scientific and educational value.
He said: "We don't buy the argument that it is wasteful to try to understand the different reasons why different people struggle.
"And for very many, those reasons fall into a consistent and recognisable pattern that it is helpful to call dyslexia.
"Helpful for individuals because it makes sense out of past struggles and helpful for teachers who can plan the way they teach to overcome or find ways around the particular blocks that are there."
And a statement from the British Dyslexia Association said: "We refute any suggestion that the definition of dyslexia is misleading and irrelevant.
"Dyslexia is a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling.
"Dyslexia is a specific learning difficulty. Difficulty with the acquisition of literacy is just one aspect of dyslexia.
"In adults who have had effective intervention at school, literacy difficulties can be less prominent, and organisational and time management skills can present the main issue.
"Dyslexia can affect the way information is processed, stored and retrieved, with problems of memory, speed of processing, time perception, organisation and sequencing."
In his book, Professor Elliott argues that more focus should be put on helping children to read, rather than finding a label for their difficulty.
He and his researchers found that symptoms found in one person leading to a diagnosis of dyslexia are often absent in another person similarly diagnosed.
Therefore a typical education invention for one pupil may not help another who has also been diagnosed with dyslexia.
While the researchers do not question the existence of the real, sometimes complex, problems some people have with reading, they are critical of the term 'dyslexia' because it is too imprecise.
They suggest the key task for professionals is to spot reading difficulties early in any child and intervene as quickly as possible rather than search for a questionable diagnosis.
Children are diagnosed with dyslexia for a range of reasons including those whose difficulty in reading is unexpected, those who show a discrepancy between reading and listening comprehension or pupils who do not make meaningful progress in reading even when provided with high-quality support.