Language Abilities After Left Hemisphere Brain Injury

This paper describes the language abilities of two twin pairs in which one twin (the experimental subject) suffered brain injury to the left cerebral hemisphere around the time of birth and one (the control) did not. One pair of twins was initially assessed at age 23 months, the other at about 30 months, and they were subsequently evaluated in their homes three times at about 6-month intervals. The results showed that subjects scored at or above the normal range on all formal tests. Their scores were similar to the controls' on the Bayley Scales of Infant Development, the Peabody Picture Vocabulary Test, and the receptive scale of the Sequenced Inventory of Communicative Development (SICD) but lower than the controls' on the Expressive One Word Test and the expressive scale of the SICD. Analysis of language samples revealed that the subject in one pair used a smaller vocabulary and shorter, less complex sentences than his twin, but progressed at a similar rate. In these cases the subtle differences in language abilities following perinatal left hemisphere brain injury were detected only through comparisons of brain-injured children to extremely well-matched controls. The relative difficulties experienced by one subject in syntactic skills were compatible with other studies on the sequelae of left hemispheric damage, but the difficulties in this case appeared to be a developmental delay, not deficit.