Just to share

Recently i start to be worry about mikkiel cos until now he is going to be 18 month but than he seem not speaking much although everyone is saying is alright i just to find some research and ease my worries.he can only managed to speak much start from 10 month onwards but he become more lesser in talking when he is growing day by day.Parent is not easy to be,we start to worry when kids cannot this way cannot that way but than for my views dun compare children by children,every kid has their own talent and have their own way to pick up any skills (take some times)..

SPEECH AND LANGUAGE DISORDERS IN CHILDREN

Dr Chong Shang Chee

Associate Consultant, The Children's Medical Institute, National University Hospital

Introduction

The development of speech and language is an important basis for meaningful and symbolic human communication. At the Child Development Unit, National University Hospital, speech and language disorders encompass 11.0% to 20.0% of cases referred (data from 2006 and 2007) and are among the commonest causes of referrals for evaluation and intervention. Studies have suggested that the prevalence rates of combined speech and language delay to be 5%-8% in the population,¹ and untreated speech and language delay in pre-school children to be 40% to 60%.² Language disorders are also the basis for learning difficulties and school difficulties, and is an indicator of a child's cognitive abilities. It is hence important to recognise and diagnose such disorders.

Development of speech and communication

The rate of language acquisition varies among individuals and is also affected by biological and environmental factors. Boys are more predisposed to language disorders. Brain activation appears to be lateralised to the left inferior frontal gyrus in males, but to bilateral regions in females during phonological processing tasks. This bilateral representation may account for why girls are less likely to manifest language problems.³

During the prelinguistic stage (birth to 12 months), communicative intents are non-verbal but social use of language emerges (eg. peek-a-boo game). Vocalisations begin at 3-4 months, and then babbling at 8 months evolve into use of single words at 12 months. During the early linguistic period (1 to 3 years), children use words to code what they know through concepts eg.: "more", "no". The two-word stage starts at 18 to 24 months and vocabulary expands to several hundred words. Three-to four-word stage from 24 to 36 months mark the period of expansion of vocabulary and using specific words to communicate feelings and desires. Complex language evolves at 3 to 5 years including the use of preposition, conditionals, connectors. Pre-school children should be able to tell stories, anticipate future events, and follow three-component demands. Upon school entry, language demands are extensive and applied through academic and social situations. By 7 to 8 years, the child uses language symbolically. The emergence of semantics (words and their meanings), syntax (grammar and rules), pragmatics (social language use) and metalinguistics (understanding of language) at school-going age places new demands on the child.

Warning signs of speech and language disorders which prompt referral for evaluation are as shown in Table 1.⁴

Medical and neurological causes of speech or language impairment

Some diagnosable medical conditions which may lead to speech or language impairment include hearing loss, genetic and chromosomal disorders (eg. Down syndrome, Fragile X, Williams syndrome), autism, seizure disorders (eg. Landau-Kleffner) and cognitive impairment. Child abuse and neglect can lead to poor quantities and qualities of child-directed verbal language in their environment. Additionally, it is important for the paediatrician to recognise that behavioural disorders can emerge in children who are language-impaired because of poor communication, frustration at work and social difficulties.

Receptive and expressive aphasia can result from damage to specific areas of the left side of the brain, which is usually the dominant hemisphere for language and communication. Receptive aphasia (Wernicke's aphasia) results from damage to the Wernicke's area (eg. stroke, tumour) This disorder causes major impairment in language comprehension and jargon or largely meaningless speech. Expressive aphasia (Broca's aphasia) involves damage to the Broca's area, and sufferers find it difficult to initiate speech. Their speech is usually non-fluent and halting, and reduced to disjointed words. Though these are the major areas involved in speech and language, separate brain areas are involved in subtasks of hearing words (receptive language), seeing words (reading), speaking words (expressive language) and generating words (metalinguistic skills). What remains undetermined is how some people may move effortlessly from speaking, writing and listening—closely related skills represented by separate brain areas, while some do not and may need discrete exercises to promote each component skill.⁵

Table 1: Warning signs of Speech or Language Disorders⁴

Age Range	Signs
First 12 months	Does not smile at familiar faces or voices by 2 months Does not imitate any sounds by 4 months Does not babble by 8 monthsNo ability or interest in games eg. "peek-a-boo" by 8 months No single words by 12 months Does not use any gestures eg. "bye-bye" or shaking head by 12 months Does not point to objects or pictures by 12 months
12-24 months	Does not use at least 15 words by 18 months Prefers gestures instead of vocalising words or needs by 18 months Sequences of sounds in familiar words are unclear and not understood by 2 years No two-word utterances by 2 years Does not imitate words or actions by 2 years Does not follow simple instructions by 2 years
24-36 months	Does not combine words into short phrases or sentences by 3 years Does not initiate any interactions with others by 3 years Not able to use the sounds /p, h, m, n, t, d, k, g/ correctly before 3 years Restricted or repetitive play with toysUnable to understand and answer simple questions Frustration in communicative situations
4 years	Unable to be understood by people outside of family Cannot retell simple stories or recall recent events clearly Sentences are disorganised with a lot of errors Sentences contain many sound errors eg. substitution or deletions

Auditory processing disorders encompass a group of disorders where there are deficits in the processing of verbal and non-verbal acoustic stimuli. Children with such disorders may present with difficulties with oral instruction, rapid speech, in background noise, and with language, reading and spelling disorders. The auditory system and pathways including peripheral and central nervous systems may be involved. The human auditory system is fully developed at birth, though myelination continues until 10-12 years. This myelination is sound dependant and may vary in individuals. Central auditory tests are hence maturationally-dependant and improve with age.

Unknown causes of delays in speech and language

In most cases of speech and language delay, no organic or medical cause is found. In one study, it was found that half of children with language delay at 2 years will eventually function normally at 3 to 4 years, though in the other half the delays persisted.⁶ Currently, more research needs to be done on predictors and risk factors for long-standing communication difficulties. Children with persistent language problems at school entry which limit age-appropriate learning, communication and social abilities are classified to have a language disorder. Some children whose early delays in speech and language apparently resolve during the pre-school years demonstrate reading disorders in later years, implying the presence of a subtle but underlying fundamental disorder.⁷ Speech sound disorders have also been associated with reading disability.⁸

Bilingualism and speech and language delay?

Generally, being raised in bilingual environments does not slow the process of language learning. Studies have shown that the bilingual children have similar combined vocabularies if two languages are assessed, when compared to monolingual children. ^9,10 Other research have also found that monolingual and bilingual children achieve their linguistic milestones in each of their languages at the same time.¹⁰ It is hence untrue that exposing a child to two languages may confuse the child and interrupt normal language development. Conversely, other studies in the US involving language minority children who speak Spanish reveal that decoding, word identification and spelling skills of bilingual children are similar to monolingual children. However, reading comprehension and writing skills may lag behind monolingual peers.¹¹ Though there are many controversies surrounding this "bilingual paradox", it is currently believed that bilingual education has cognitive advantages, and these include cognitive flexibility, divergent thinking, and general reasoning and verbal abilities.^12,13

Bilingual children, when acquiring both languages in early development, may perform code switching (switching back and forth between both languages). This is a natural developmental process and should not be perceived as manifesting language delay. Code switching can in fact represent bilingual proficiency as a reflection of the child's language use in different contexts.⁹ Children from bilingual families may however show uneven skills in the two languages, depending on the amount of exposure. They are also capable of being proficient in both. Therefore, children from bilingual families with speech and language delay should be evaluated appropriately, and their delays not attributed to bilingualism. There is currently no evidence that children with language delays should only learn one language. However, children with language difficulties which are significant can be exempted from written examinations involving a second language, but continue to learn and use the oral form of second language in their native environments.

Disorders of articulation and phonology

Articulation disorders involve inability to produce sounds correctly in words or speech. The child is unable to produce the speech sounds correctly in all contexts. Though most cases have unknown causes, it is believed that this disorder is the result of mistaken learning and oromotor deficits.

Phonological deficits involve not being able to sound words based on patterns or implicit rules, but the child produces sounds correctly in some contexts but not others. Many of these children have concurrent deficits in receptive and expressive language skills. They are at high risks of reading and spelling difficulties. Children with cleft palates and velopharyngeal insufficiency are also at high risks of phonological disorders.¹⁴

Development verbal apraxia (Speech dyspraxia)

Children with speech dyspraxia have difficulties with controlled production of speech sounds, or motor speech planning or programming. There is discrepancy between receptive and expressive abilities. They demonstrate great difficulties with speech imitation, and are inconsistent with vowel and consonant production across a variety of situations. They also have unusual intonation, pausing and stress patterns of speech. Commonly, they have associated cognitive, behavioural and motor abnormalities. In recent years, several cases of developmental verbal apraxia in humans have been linked to mutations in the FOXP2 gene.¹⁵ Further work has revealed that the gene not only affects motor control but also other areas of linguistic processing including grammar, comprehension, receptive and expressive language.¹⁶

Disorders of fluency

Stuttering is the commonest form of dysfluency in speech, and affects boys to girls in the ratio 4:1. Children of ages 2.5 to 4 can have dyscoordination of thought and language affecting fluency of speech. Eighty-five percent of cases start in pre-school years. Stuttering involves inappropriate pauses, sound prolongation and repetition. Though mild dysfluency is acceptable developmentally, danger signs include repetitive facial expressions and other motor mannerisms (eg. Eye blinking, jaw jerking), social avoidance behaviours, and frequent repetitions or prolongation that interferes with speech intelligibility. The prognosis for most young children is good, and spontaneous recovery varies from 40 to 80%. However, in a child who is older than 6 years of age, spontaneous recovery is less likely.¹⁷ It is also associated with anxiety, though it is often unknown if anxiety is the cause or effect. Interventions include encouraging patients to talk slowly, fluency-shaping mechanisms eg. delayed auditory feedback devices to slow the speech rate, providing pauses for children to communicate, and active listening which involves removing pressure when the child tries to formulate thoughts.

Language Disorders

Language acquisition and development involve complex components of semantics, pragmatics, syntax, morphology, discourse, pragmatics and metalinguistic awareness.¹⁸ Some symptoms and signs of language dysfunction in school children include:

• Not able to follow instructions of need for repeated instructions

• Difficulties with concentrating in verbal settings (eg. classroom instruction) but not other settings (music, art, sport)

• Verbal hesitance or lack of verbal participation

• Expressive repetition or lack of cohesion in speech

• Word finding difficulties and excessive use of pause words

• Difficulties with word problems in Math but not arithmetic

• Poor written expression

• Poor comprehension despite good sight vocabulary.

Parental interviews, school reports and examples of school work are useful in aiding the diagnosis. Though each symptom may indicate other developmental disorders, a large number of symptoms increases the likelihood of a language disorder.

In specific language impairment, a child demonstrates discrepancies between cognitive function (Performance IQ) and language function (Verbal IQ). These children have unexplained difficulties with acquiring and learning language, but are otherwise cognitively normal. There appears to be a genetic basis for this disorder.¹⁹ Speech out put is poorly articulated and comprehension is poor. These children show problems with non-word repetition, acoustic processing, and grammatical problems.

Screening and Evaluation of Language Disorders

Currently, screening for speech delay occurs as part of a child's visit for well-baby checks or for routine immunisation. It is not known how consistently primary care physicians screen for speech or language delay when a child presents with other medical problems. One study has shown that 43% of parents report that their children aged 10-35 months did not receive any form of developmental assessment at well-child visits, and 30% of physicians had not discussed how the child communicates.²⁰ Language issues are otherwise usually detected when a parent presents to the medical caregiver raising concerns, or when a child attends pre-school or primary school. In view that language intervention is most useful when started early, the benefits of early detection are evident.

A systematic review of screening for speech and language in pre-school children in US sought to evaluate the benefits and effectiveness of routine screening in primary care settings.²¹ Identified risk factors from studies for selective screening programmes consistently included the following -- a family history of speech and language delay, male gender, and perinatal factors (prematurity, low birth weight, sucking habits) Other risk factors included educational levels of parents, childhood illnesses, birth order and family size.

Studies which evaluated screening instruments which took less than 10 minutes to administer had a wide range of sensitivity (17-100%) and specificity (45-100%). Most of the instruments were, however, not designed for screening in primary care settings. There is currently no gold standard screening tool used and evaluated in different populations. What remains unanswered are the optimal intervals for screening and the adverse effects of screening (eg. anxiety, unnecessary therapy).

In Singapore, there are currently no standardised screening tools used routinely for speech disorders in young children in pre-school settings. Pre-school readiness assessments which include language evaluation items are currently adopted in some schools and centres. It is currently unknown the prevalence of such disorders nationwide and if we are successful in detecting these cases early.

Therapy for speech and language disorders

Therapy for speech and language disorders usually involves a "child-centred, child-initiated and child-directed approach". A language programme is only useful if incorporated into a language-facilitated environment, involving teachers, parents and therapists.

Intervention has been found to be largely effective in many studies. Most studies demonstrated improvements in articulation, phonology, expressive and receptive language, and syntax. Some studies also revealed improvements in social outcomes and self-esteem. In a Cochrane study evaluating language therapy interventions, it was found that language therapy was least effective for receptive deficits. Interventions involving clinician versus trained parents revealed no differences in outcomes. There was apparently no difference between group and individual therapy approaches.²² In terms of economic models, another study supported indirect group therapy as the most cost-effective form of language intervention.²³ Interventions however varied widely and may not be generalised for all populations (eg. home based, centre based or school programmes). Characteristics of children who may best benefit from the different approaches needs to be evaluated, and a refined model suitable for curriculum needs to be planned.

How parents can help in language development

Parental and caregiver involvement is important in reinforcement of language development in a child. Studies have demonstrated that parental input is positively correlated with rates of language development. The Hanen programme is an example of a parent training programme that develops a child's conversational strategies through maximising language learning opportunities in everyday situations.²⁴ Simple steps to promoting language development in children also include

• Listening attentively to the child

• Talking with child and expanding on child's speech topics

• Being a good model ie. Avoid talking down or using baby talk

• Talking about what one is doing in everyday situations

• Encouraging a child to ask questions

• Reading to the child ²⁵

A child with speech or language difficulties should never be coerced to speak or shamed for not speaking properly.

Conclusions

Speech and language disorders form a significant proportion of cases seen for evaluation and therapy in the tertiary setting. Such cases may represent only a proportion of more significant numbers among school-going children. Screening awareness among parents, teachers and doctors may need to be increased, and cost-effective programmes may need to be refined to suit the educational and therapeutic needs of such children in our population.