a1 Hospital For Sick Children, Great Ormond Street, London
The prevalence of reading difficulties varies according to the definition of the problem used and the region in which the survey takes place. The methodologically sound epidemiological studies on the Isle of Wight (Rutter et al 1970) and in an Inner London Borough (Berger et al 1975), which investigated the presence of reading backwardness and specific reading retardation in 10 year olds, indicate the extent of reading problems in this country. Reading backwardness was defined as a level of reading attainment 28 months behind chronological age on the Neale Analysis of Reading Ability (Neale 1958). Specific reading retardation refers to level of attainment 28 months below that expected taking IQ as well as chronological age into account. On the Isle of Wight 8.3% and 3.9% of 10 year olds were reading backward and reading retarded respectively. The corresponding figures for the Inner London Borough were 19.0% and 9.9%.