Tower Of Babel

Early detection and timely intervention 
can correct most speech disorders, says Biplab Das 

Arun is an 11-year-old boy. He was born deaf. He is doubly unfortunate because he cannot express his thoughts and feelings. This is because he was not taught sign language from an early age. Had he been formally trained in sign language during his early childhood, he could have mastered communication skills despite his handicap. 

Like Arun, many hearing impaired children reach adolescence burdened by this additional impairment. There are a host of other speech and language disorders that impair the communications of youngsters, and to overcome them, speech therapy is essential. "Early detection and therapeutic intervention are essential to correct speech and language disorders," says Dr. Amitav Choudhry, head, Linguistic Research Unit (LRU), Indian Statistical Institute (ISI). "Speech therapy often fails if it is started later than the age of seven years," he warns. 

In a seven-year-old child, the parts of the brain and the muscles that control language and speech are almost fully developed. "It then becomes hard to control the process," explains Choudhry. This is why older children have difficulty uttering words even after speech therapy. 

The central language-processing unit is known to lie in the left hemisphere of the brain. Wernicke's area and Broca's area, two regions in the left hemisphere, play significant roles in language processing. Wernicke's area decodes the sounds of language heard from outside and sends the decoded information to Broca's area. Broca's area then produces speech by triggering the brain regions which controls the movements of speech organs like the lungs, the larynx, soft palate, the lower jaw, the lips and the tongue. 

Recently, a research team supported by Dr. Milind Deogaonkar, neurosurgeon at National Neurosciences Centre has come up with an interesting insight. According to them, the right hemisphere of the brain also plays a pivotal role in language processing. "Studies with epileptic children have shown that surgical removal of the damaged hemisphere shifts the language functions to the other hemisphere," says Madhushree Chakraborty, a member of the ISI team. It will widen the scope of speech language therapy, says Chakraborty, as they think that new areas of the brain may be able to compensate for the non-functioning of a damaged area. 

Speech disorders arise either from wrong perception or processing of words, or defects in articulation. In hearing impaired children, the pathway that transmits sounds to the brain's language centres does not function properly. Sounds get distorted due to the damage to sensory cells or nerves in their inner ear. 

On the other hand, damage to the brain regions controlling muscular movements of speech organs causes problems in articulation. Congenital deformity in speech organs too hampers articulation. The palate plays an essential role in speech. In cleft palate, a congenital split in the roof of the mouth connects the mouth and the nasal cavities. A child with a cleft palate utters words dominated by nasal sounds. 

Gothic palate is another defect in which the palate is abnormally raised, distorting speech. Problems in articulation can be completely cured by speech therapy. "Children with cleft palate can be trained to reduce the dominance of nasal sounds during the delivery of speech," says Madhavi Indu, a speech therapist at LRU, ISI. 

Among the language disorders, dyslexia is the commonest one. Dyslexic children, despite having normal intelligence, fail to attain the language skills of reading, writing and spelling. "It has been revealed that the problems of children with dyslexia mainly originate from reading disability," says Chakraborty. "A dyslexic child fails to split words up into their constituent sounds." Reading therapy, a component of speech language therapy, is used to help these children. Madhavi Indu says, "In reading therapy, a dyslexic child is taught about rhymes and ways of building up words from their sounds." 

Whenever a case of speech disorder comes up, the first thing required is to rule out hearing impairment. This is done by various audiometric tests. Sign language and pictorial aids are used to develop language skills in hearing impaired children. 

"No matter what therapy is needed for your child, you should bring him to the clinic before he or she is seven," cautions Indu, echoing Choudhry. 

"Parents should have a fair idea about the stages of speaking or learning a language to provide early detection and therapy," says Choudhry. "If you listen carefully you will find tone variations in the crying of normal children. But in a deaf child the crying is monotonous," he explains. From two to nine months, a child coos and then babbles. "In a deaf child, cooing will not progress to babbling," says Choudhry. 

Apart from speech therapy, parent-child interaction plays a vital role in curing speech or learning disorders. "Reduced interactions with parents limits exposure to new words. It badly affects the communication and cognitive skills of children," says Choudhry.

    October 28, 2002.