Difficulty in reading or learning to read. It is always accompanied by difficulty in writing, and particularly in spelling. In an individual child, reading difficulties might be due to various factors – for example, a general learning problem, bad teaching or understimulation, or a perceptive problem such as poor eyesight. Specific dyslexia (‘word blindness’) unrelated to the above conditions affects 4–8 per cent of otherwise normal children. It is three times more common in boys than in girls, and there is often a family history. The condition is sometimes missed and, when a child has difficulty with reading, dyslexia should be considered as a possible cause.