Verb and noun morphology in the spoken and written language of children with language learning disabilities

The purpose of this study was to investigate the use of verb and noun morphology in school-age children's spoken and written language. Sixty children, with and without language learning disabilities (LLD), each produced 2 spoken and 2 written language samples. The children's accuracy in using morphemes that mark verb finiteness (regular past tense, 3rd person singular present tense, copula, and auxiliary BE) was compared with their accuracy in using noun morphology (regular plural, possessive, articles). As would be expected, the typically achieving children, who were aged 7 to 12 years, had mastered the verb and noun morphology in spoken and written samples. The children with LLD, aged 10 to 12 years, also showed high accuracy in the spoken samples. On the other hand, they showed substantial difficulty in the written samples with the regular past tense, with errors in 26% of obligatory contexts. However, the children with LLD also had difficulty with the regular plural, with errors in 12% of obligatory contexts. For both the regular past tense and plural, all errors were errors of omission. These results indicate that finiteness marking remains an area of relative difficulty, but perhaps not the only grammatical difficulty, for children with language impairments in the school years.

An attenuated influenza virus vaccine: protection against homologous and heterologous strains of virus

An effective influenza virus vaccine should be capable of inducing protection against both the homologous strain of virus and the heterologous strains representing antigenic drift. For evaluation of the protection provided by an attenuated influenza virus vaccine, volunteers were immunized intranasally with either placebo or influenza A/England/42/72 (H3N2) virus vaccine in a double-blind fashion in two doses administered two weeks apart. Forty-seven subjects were challenged 30-100 days after the second dose with either the homologous or a virulent heterologous strain of virus [A/Dunedin/73 (H3N2)]. The vaccine resulted in good clinical protection against challenge with both the homologous and heterologous strains of virus. The rates of protection against infection (as judged by antibody responses, irrespective of signs and symptoms) were also good (72% and 60% against the homologous and heterologous strains, respectively). Thus, immunity induced by this attenuated influenza virus vaccine extends to provide protection against a related but nonidentical influenza virus.