Dyslexia diagnosis & screening
So, how do you know if your child is dyslexic or just a slow learner?
Difficult one, because children are rarely assessed for a learning difficulty before the age of seven. Only then, when they fail to make the required progress in reading (being more than 18 to 24 months behind their classmates in literacy) is an educational psychologist normally consulted for an assessment and a series of tests.
In adults, the condition will be self-evident. They will have experienced learning difficulties all their lives, struggling with literacy, a lack of concentration, unreliable short-term memory, sometimes with poor coordination, communication and social skills. By adulthood, it will undoubtedly have affected their self-confidence too.
Putting it to the test
To identify dyslexia, in adults or children, an IQ intelligence test is taken to see if the level is within the normal range. When a child has verbal difficulties, this can be difficult to assess fully, so both verbal and non-verbal intelligence is measured. Again, results must be within the normal range to allow a diagnosis of dyslexia to be made.
Those with an overall IQ below the normal range will be classified as generally poor readers rather than dyslexics. However, there is much controversy over the approach of differentiating the conditions based on IQ levels.
For this reason, educational psychologists will assess reading and spelling skills using a range of different tests, alongside an assessment of intelligence. The main tests used by most psychologists to determine intelligence levels in both children and adults are the various Wechsler Intelligence Scale assessments, which measure all kinds of aptitude and abilities, from verbal comprehension to perceptual reasoning, processing speed to working memory.
This will include testing vocabulary, comprehension, general knowledge, perceptual reasoning awareness, visual awareness, letter-number sequencing and arithmetic.
There are other ways to diagnose difficulties in literacy, based on medical definitions and criteria. The commonest systems are from the World Health Organisation using a system called the ICD 10 classification and the other is that used by the American Psychiatric Association called the DSM IV classification.