MEDICAL NOTES

Lip
service

Most children Start speaking fluently by the age of six or seven. It is only about five per cent of children who have diffi­culties in some aspects of the spoken language. These children are said to have specific language impair­ment, says a recent issue of the New England Journal of Medicine. This defect was found to be hereditary. Children with de­fective speech most likely have an elder in the family with the same disorder and, in case of twins it is possible that both may have the problem. Many susceptible areas have been identified in the brain and this has brought up the question as to which genes are involved. Since all the speech defects are not the same, the causes that have been proposed in­clude deficits in short-term hearing memory, sequencing of hearing and rapid process­ing. Children with differentspeech disorders can belong to different genetic types. They may have difficulty in repeat­ing some particular words due to a short-term memory impair­ment or may have pronouncing disabilities- Others may have difficulty in coordinating be­tween hearing and speech when asked to repeat some spoken words. Such children ark classed as having speech dys°fluencv, dyspraxia or stut­ter. In 1990 some researchers made an attempt to discover the gene that causes speech defects when they came across a British family with three gen­erations affected with speech dyspraxia. They also had low IQ level and learning disorders. It was identified that F'OXY2 protein which had many targets in the brain, suppressed a gene which lead to language im­pairment. It is difficult to exclusively identify the cause for different clinical pictures of speech dis­orders and the relationship with other neurological defi­cits. How genetic and environ­mental factors affect language and language disorders is still not fully understood.