INTELLECTUAL-PERFORMANCE AFTER PRESYMPTOMATIC CRANIAL RADIOTHERAPY FOR LEUKEMIA - EFFECTS OF AGE AND SEX

Cognitive outcome, as measured by verbal and performance IQs, was comp ared in 35 girls and 47 boys who were in first remission for acute lym phoblastic leukaemia. All children had received presymptomatic cranial radiotherapy and intrathecal methotrexate. The mean age at diagnosis was 4 . 2 years and the mean elapsed time from initial diagnosis to in tellectual assessment was 7 . 1 years. Results showed that children ir radiated before the age of 4 years were impaired in certain aspects of non-verbal ability, as well as in measures of short term memory and a ttention, calculated by factor scores derived from selected subtests o f the IQ test. Subtests requiring verbal and nonverbal reasoning showe d the greatest impairment after early diagnosis and treatment. In addi tion girls were selectively impaired in verbal IQ and other aspects of verbal ability, with the degree of impairment exacerbated by early tr eatment. No relationship was found between degree of impairment and ei ther time since treatment or number of methotrexate injections. It is concluded that early age at irradiation increases the risk of impaired intellectual outcome, particularly in girls.