Kliegman: Nelson Textbook of Pediatrics, 18th ed.

Copyright © 2007 Saunders, An Imprint of Elsevier

32.2 Language Development and Communication Disorders

Mark D. Simms Robert L. Schum

For most children, learning to communicate in their native language is a naturally acquired skill, whose potential is present at birth. No specific instruction is required, although children must be exposed to a language-rich environment. Normal development of speech and language is predicated on the infant's ability to hear, see, comprehend, and remember. Equally important are sufficient motor skills to imitate oral motor movements and the social ability to interact with others.

NORMAL LANGUAGE DEVELOPMENT.

For the purposes of analysis, language is subdivided into several essential components. Communication consists of a wide range of behaviors and skills. At the level of basic verbal ability, phonology refers to the correct use of speech sounds to form words, semantics refers to the correct use of words, and syntax refers to the appropriate use of grammar to make sentences. At a more abstract level, verbal skills include the ability to link thoughts in a coherent fashion and to maintain a topic of conversation. Pragmatic abilities include verbal and nonverbal skills that facilitate the exchange of ideas, including the appropriate choice of language for the situation and circumstance and the appropriate use of body language (posture, eye contact, gestures). Social pragmatic and behavioral skills also play an important role in effective interactions with communication partners (engaging, responding, maintaining reciprocal exchanges).

It is customary to divide language skills into receptive (hearing and understanding) and expressive (talking) abilities. Language development usually follows a fairly predictable pattern and parallels general intellectual development ( Table 32-1 ).

TABLE 32-1 -- Normal Language Milestones

HEARING AND UNDERSTANDING

TALKING

BIRTH–3 MO

Startles to loud sounds

Makes pleasure sounds (cooing, gooing)

Quiets or smiles when spoken to

Cries differently for different needs

Seems to recognize your voice and quiets if crying

Smiles when sees you

Increases or decreases sucking behavior in response to sound

4–6 MO

Moves eyes in direction of sounds

Babbling sounds more speech-like, with many different sounds, including p, b, and m

Responds to changes in tone of your voice

Vocalizes excitement and displeasure

Notices toys that make sounds

Makes gurgling sounds when left alone and when playing with you

Pays attention to music

7 MO–1 YR

Enjoys games such as peekaboo and pat-a-cake

Babbling has both long and short groups of sounds, such as tata upup bibibibi.

Turns and looks in direction of sounds

Uses speech or noncrying sounds to get and keep attention

Listens when spoken to

Imitates different speech sounds

Recognizes words for common items, such as cup, shoe, and juice

Has 1 or 2 words (bye-bye, Dada, Mama), although they may not be clear

Begins to respond to requests (Come here.Want more?)

1–2 YR

Points to a few body parts when asked

Says more words every month

Follows simple commands and understands simple questions (Roll the ball. Kiss the baby.)

Uses some 1–2 word questions (Where kitty? Go bye-bye? your shoe?)

Listens to simple stories, songs, and rhymes

Puts 2 words together (more cookie, no juice, mommy book)

Points to pictures in a book when named

Uses many different consonant sounds at the beginning of words

2–3 YR

Understands differences in meaning (e.g., go-stop, in-on, big-little, up-down)

Has a word for almost everything

Follows 2-step requests (Get the book and put it on the table.)

Uses 2–3 word “sentences”to talk about and ask for things

Speech is understood by familiar listeners most of the time

Often asks for or directs attention to objects by naming them

3–4 YR

Hears you when you call from another room

Talks about activities at school or at

Hears television or radio at the same loudness level as other family members

Usually understood by people outside the family

Understands simple who, what, where, why questions

Uses a lot of sentences that have ≥4 words

Usually talks easily without repeating syllables or words

4–5 YR

Pays attention to a short story and answers simple questions about it

Voice sounds as clear as other

Hears and understands most of what is said at home and in school

Uses sentences that include details (I like to read my books.)

Tells stories that stick to a topic

Communicates easily with other children and adults

Says most sounds correctly except a few, such as l, s, r, v, z, ch, sh, and th

Uses the same grammar as the rest of the family

From:American Speech-Language-Hearing Association, 2005; http://professional.asha.org

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Receptive Language Development.

From birth, newborns show preferential response to human voices over inanimate sounds. The infant will alert and turn toward the direction of an adult who speaks in a soft, high-pitched voice. Over the 1st 3 mo, infants appear to recognize their parent's voice and will quiet if crying. Between 4 and 6 mo, infants will visually search for the source of sounds, again showing a preference for the human voice over other environmental sounds. By 5 mo, infants can passively follow the adult's line of visual regard, resulting in a “joint reference” to the same objects and events in the environment. The ability to share the same experience is critical to the development of further language, social, and cognitive skills. By 8 mo, the infant can actively show, give, and point to objects. Comprehension of words often becomes apparent by 9 mo, when the infant selectively responds to his or her name and appears to comprehend the word no. Social games, such as “peek-a-boo,” “so big,” and waving “bye-bye” can be elicited by simply mentioning the words. At 12 mo, many children can follow a simple, 1-step request without a gesture (“Give it to me”). Between 1 and 2 yr, comprehension of language accelerates rapidly. Toddlers can point to body parts on command, identify pictures in books when named, and respond to simple questions (“Where's your shoe?”). The 2 yr old is able to follow a 2-step command involving unrelated tasks (“Take off your shoes, then go sit at the table”)

and can point to objects described by their use (“Give me the one we drink from”). By 3 yr of age, children typically understand simple wh- question forms (who, what, where, why). By 4 yr of age, most children can follow adult conversation. They can listen to a short story and answer simple questions about it. Typically, 5 yr olds have a receptive vocabulary of >2,000 words and can follow 3- to 4-step commands.

Expressive Language Development.

Cooing noises are established by 4–6 wk of age. Over the 1st 3 mo of life, parents may distinguish their infant's different vocal sounds for pleasure, pain, fussing, or tiredness. Many 3 mo old infants vocalize in a reciprocal fashion with an adult to maintain a social interaction (“vocal tennis”). By 4 mo, infants begin to make bilabial (“raspberry”) sounds, and by 5 mo, monosyllables and laughing are noticeable. At 6–8 mo, polysyllabic babbling (“lalala,” “mamama”) is heard and the infant may begin to communicate with gestures. At 8–10 mo, babbling makes a phonologic shift toward the particular sound patterns of the child's native language (the child produces more native sounds than non-native sounds). At 9–10 mo, babbling becomes truncated into specific words (“mama,” “dada”) for their parents.

Over the next several months, infants learn 1 or 2 words for common objects and begin to imitate words presented by an adult. These words may appear to come and go from the child's repertoire until a stable group of 10 or more words is established. The rate of acquisition of new words is approximately 1/wk at 12 mo, but accelerates to approximately 1/day by 2 yr. The first words to appear are used primarily to label objects (nouns) or to ask for objects and people (requests). By 18–20 mo, toddlers should use a minimum of 20 words and produce jargon (strings of wordlike sounds) with language-like inflection patterns (rising and falling speech patterns). This jargon usually contains some embedded true words. Spontaneous 2-word phrases (pivotal speech), consisting of the flexible juxtaposition of words with clear intention (“Want juice!,” “Me down!”) are characteristic of a 2 yr old and reflect the emergence of grammatical ability (syntax). Two-word, combinational phrases do not usually emerge until the child has acquired a lexicon of 50–100 words. Thereafter, the acquisition of new words accelerates rapidly. As knowledge of grammar increases, there is a proportional increase in the use of verbs, adjectives, and other words that serve to define the relationship between objects and people (predicates). By 3 yr, sentence length increases and the child uses pronouns and simple present tense verb forms. These 3–5 word sentences typically have a subject and verb, but lack conjunctions, articles, and complex verb forms. The Sesame Street character Cookie Monster (“Me want cookie!”) typifies the “telegraphic” nature of 3 yr old sentences. By 4 to 5 yr, children should be able to carry on conversations using adult-like grammatical forms and to use sentences that provide details (“I like to read my books”).

VARIATIONS OF NORMAL.

Language milestones have been found to be largely universal across languages and cultures, with some variations, depending on the complexity of the grammatical structure of individual languages. In Italian (where verbs often occupy a prominent position at the beginning or end of sentences), 14 mo olds produce a greater proportion of verbs compared with English-speaking infants. Within a given language, development usually follows a fairly predictable pattern, paralleling general cognitive development. Although the sequences are predictable, the exact timing of achievement is not. There are marked variations among normal children in the rate of development of babbling,

comprehension of words, production of single words, and use of combinational forms within the first 2–3 yr of life.

Two basic patterns of language learning have been identified: analytic and holistic. The analytic pattern is the most common and reflects the mastery of increasingly larger units of language forms. As reflected in the earlier discussion of milestones, the child's analytic skills proceed from simple to more complex and lengthy forms. Children who follow a holistic, or “gestalt,” learning pattern may start by using relatively large chunks of speech in familiar contexts. They may memorize familiar phrases or dialog from movies or stories and repeat them in an overgeneralized fashion. Their sentences often have a formulaic pattern, reflecting inadequate mastery of the use of grammar to flexibly and spontaneously combine words appropriately in the child's own unique utterance. Over time, these children gradually break down the meaning of phrases and sentences into their component parts, and they learn to analyze the linguistic units of these memorized forms. As this occurs, more original speech productions emerge and the child is able to assemble thoughts in a more flexible manner. Both analytic and holistic learning processes are necessary for normal language development to occur.

LANGUAGE AND COMMUNICATION DISORDERSEPIDEMIOLOGY.

Disorders of speech and language affect up to 8% of preschool children. Nearly 20% of 2 yr olds are thought to have delayed onset of speech. By age 5 yr, 19% of children are identified as having a speech and language disorder (6.4% speech impairment, 4.6% speech and language impairment, and 8% language impairment). Developmental stuttering occurs in 4–5% of 3–5 yr olds and 1% of adolescents. Boys are nearly twice as likely as girls to have an identified speech or language impairment.

ETIOLOGY.

Normal language ability is a complex function that is widely distributed across the brain through interconnected neural networks that are synchronized for specific activities. Although early researchers in language disorders, noting what appeared to be clinical parallels between acquired aphasia in adults and childhood language disorders, expected to find similar lesions in the brains of affected children, for the most part, unilateral, focal lesions acquired in early life do not seem to have the same effects in children as in adults. Risk factors for neurologic injury are absent in the majority of children with language impairment. Genetic factors appear to play a major role in influencing how children learn to talk. Language disorders appear to cluster in families. A careful family history may identify current or past speech or language problems in up to 30% of 1st-degree relatives of proband children. Children who are exposed to parents with language difficulty might be expected to experience poor language stimulation and inappropriate language modeling. Studies of twins have shown the concordance rate for low language test scores and/or a history of speech therapy to be approximately 50% in dizygotic pairs, increasing to >90% in monozygotic pairs. A number of potential gene loci have been identified, but no consistent genetic markers have been established. The most plausible genetic mechanism involves a disruption in the timing of early prenatal neurodevelopmental events affecting migration of nerve cells from the germinal matrix to the cerebral cortex.

Severe expressive language delay is rarely associated with a duplication of the locus for Williams syndrome. Microdeletions, in contrast, cause Williams syndrome, which leads to normal articulation and fluent expressive language in affected patients.

PATHOGENESIS.

Language disorders are associated with a fundamental deficit in the brain's capacity to process complex information rapidly. Simultaneous evaluation of words (semantics), sentences (syntax), prosody (tone of voice), and social cues may overtax the child's ability to comprehend and respond appropriately in a verbal setting. Limitations in the amount of information that can be stored in verbal working memory may further limit the rate at which language information is processed. Electrophysiologic studies show abnormal latency in the early phase of auditory processing in children with language disorders. Neuroimaging studies have identified an array of anatomic abnormalities in regions of the brain that are central to language processing. MRI scans in children with specific language impairment (SLI) may show white matter lesions, white matter volume loss, ventricular enlargement, focal gray matter heterotopia within the right and left parietotemporal white matter, abnormal morphology of the inferior frontal gyrus, atypical patterns of asymmetry of the language cortex, or increased thickness of the corpus callosum. Postmortem studies of children with language disorders have found evidence of atypical symmetry in the plana temporale and cortical dysplasia in the region of the sylvian fissure. Some researchers have identified a high incidence of paroxysmal electroencephalogram (EEG) anomalies during sleep in children with SLI. Although these findings may represent a mild variant of Landau-Kleffner syndrome (acquired verbal auditory agnosia), they likely represent an epiphenomenon in which paroxysmal activity is related to architectural dysplasia. In support of a genetic mechanism affecting cerebral development, a high rate of atypical perisylvian asymmetries has also been documented in parents of children with SLI.

CLINICAL MANIFESTATIONS.

Primary disorders of speech and language development are frequently found in the absence of broader cognitive or motor dysfunction. Disorders of communication are the most common comorbid condition in individuals with generalized cognitive disorders (autism or mental retardation; see Chapters 29 and 38 ), structural anomalies of the organs of speech (velopharyngeal insufficiency from cleft palate), and neuromotor conditions affecting oral motor coordination (dysarthria from cerebral palsy or other neuromuscular disorders).

Classification.

There is no universally accepted classification of childhood communication disorders. Each professional discipline has adopted a somewhat different classification system, based on cluster patterns of symptoms. One of the simplest classifications is that adopted by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). This system recognizes 4 types of communication disorders: expressive language disorder, mixed receptive-expressive language disorder, phonologic disorder, and stuttering ( Table 32-2 ). In clinical practice, childhood speech and language disorders occur as a number of distinct entities.

TABLE 32-2 -- DSM-IV Diagnostic Criteria for Communication Disorders

EXPRESSIVE LANGUAGE DISORDER

A.

The scores obtained from standardized individually administered measures of expressive language development are substantially below those obtained from standardized measures of both nonverbal intellectual capacity and receptive language development. The disturbance may be manifest clinically by symptoms that include having a markedly limited vocabulary, making errors in tense, or having difficulty recalling words or producing sentences with developmentally appropriate length or complexity

B.

The difficulties with expressive language interfere with academic or occupational achievement or with social communication

C.

Criteria are not met for mixed receptive-expressive language disorder or a pervasive developmental disorder

D.

If mental retardation, a speech-motor or sensory deficit, or environmental deprivation is present, the language difficulties are i n excess of those usually associated with these problems

Coding note: If a speech-motor or sensory deficit or a neurologic condition is present, code the condition on Axis III

MIXED RECEPTIVE-EXPRESSIVE LANGUAGE DISORDER

A.

The scores obtained from a battery of standardized individually administered measures of both receptive and expressive language development are substantially below those obtained from standardized measures of nonverbal intellectual capacity. Symptoms include those for expressive language disorder as well as difficulty understanding word s, sentences, or specific types of words, such as spatial terms

B.

The difficulties with receptive and expressive language significantly interfere with academic or occupational achievement or wi th social communication

C.

Criteria are not met for a pervasive developmental disorder

D.

If mental retardation, a speech-motor or sensory deficit, or environmental deprivation is present, the language difficulties are i n excess of those usually associated with these problems

Coding note: If a speech-motor or sensory deficit or a neurologic condition is present, code the condition on Axis III

PHONOLOGICAL DISORDER

A.

Failure to use developmentally expected speech sounds that are appropriate for age and dialect (e.g., errors in sound production, use, representation, or organization such as, but not limited to, substitutions of 1 sound for another [use of /t/for target /k/sound] or omissions of sounds such as final consonants)

B.

The difficulties in speech sound production interfere with academic or occupational achievement or with social communication

C.

If mental retardation, a speech-motor or sensory deficit, or environmental deprivation is present, the speech difficulties are in excess of those usually associated with these problems

Coding note: If a speech-motor a sensory deficit or a neurologic condition is present, code the condition on Axis III

STUTTERING

A.

Disturbance in the normal fluency and time patterning of speech (inappropriate for the individual's age), characterized by frequent occurrences of ≥1 of the following:

1.

Sound and syllable repetitions

2.

Sound prolongations

3.

Interjections

4.

Broken words (e.g., pauses within a word)

5.

Audible or silent blocking (filled or unfilled pauses in speech)

6.

Circumlocutions (word substitutions to avoid problematic words)

7.

Words produced with an excess of physical tension

8.

Monosyllabic whole-word repetitions (e.g., I-I-I-I see him)

B.

The disturbance in fluency interferes with academic or occupational achievement or with social communication

C.

If a speech-motor or sensory deficit is present, the speech difficulties are in excess of those usually associated with these pr oblems

Coding note: If a speech-motor or sensory deficit or a neurologic condition is present, code the condition on Axis III

COMMUNICATION DISORDER NOT OTHERWISE SPECIFIED

This category is for disorders in communication that do not meet the criteria for any specific communication disorder; for exampl e, a voice disorder (i.e., an abnormality of vocal pitch, loudness, quality, tone, or resonance)

Reprinted with permission from the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Washington, DC, American Psychiatric Association, 1994, pp.58,60–61,63,65. Copyright 1994, American Psychiatric Association.

Specific Language Impairment (SLI).

Also referred to as developmental dysphasia or developmental language disorder, SLI is characterized by a significant discrepancy between the child's overall cognitive level (typically nonverbal measures of intelligence) and functional language level. These children follow an atypical pattern of language acquisition and use. Closer examination of the child's skills may show deficits in the understanding and use of word knowledge (semantics) and grammatical understanding (syntax). Children with SLI are often delayed in starting to talk and usually have difficulty understanding spoken language. The problem may stem from insufficient understanding of single words or from the inability to deconstruct and analyze the meaning of sentences. Many affected children show a “holistic” pattern of language development, repeating memorized phrases or dialog from movies or stories (echolalia). In contrast to their difficulty with spoken language, children with SLI appear to learn visually and demonstrate their ability on nonverbal tests of intelligence. Although they have difficulty interacting with peers who are more verbally adept, many children with SLI play appropriately with younger or older children. Despite their communication impairment, they engage in pretend play, show imagination, share emotions (affective reciprocity), and demonstrate joint referencing behaviors appropriate to their age. There is a high incidence of difficulty with fine motor coordination in these children. A combination of increased joint mobility and mild muscular hypotonia often results in motor clumsiness. Although children with SLI respond to therapeutic and educational interventions and show a trend toward improvement of communication skills, adults with a history of childhood language disorder continue to show evidence of impaired language ability, even when surface features of the communication difficulty may have improved considerably. This suggests that many individuals find successful ways of adapting to their impairment.

Many children with SLI show difficulties with social interaction, particularly with same-aged peers. Social interaction is mediated by oral communication, and a child deficient in communication is at a distinct social disadvantage. Children with SLI tend to be more dependent on older children or adults, who can adapt their communication to match the child's level of function. At times, these children may gravitate toward younger children who communicate at a level they can comprehend. Generally, social interaction skills are more closely correlated with language level than with nonverbal cognitive level; a developmental progression of increasingly sophisticated social interaction is usually seen as the child's language abilities improve. In this context, social ineptitude is not necessarily a sign of asocial distancing (autism), but rather a delay in the ability to negotiate social interactions.

Pragmatic Language Disorder.

The ability to communicate effectively with others depends on mastery of a range of skills that go beyond basic understanding of words and rules of grammar. These higher-order abilities include knowledge of the conversational partner, knowledge of the social context in which the conversation is taking place, and general knowledge of the world. Social and linguistic aspects of communication are often difficult to tease apart, and individuals who have trouble interpreting these relatively

abstract aspects of communication typically have difficulty forming and maintaining relationships. Symptoms of pragmatic difficulty include extreme literalness and inappropriate verbal and social interactions. Proper use and understanding of humor, slang, and sarcasm depend on correct interpretation of both the meaning and the context of language and the ability to draw proper inferences. Failure to provide a sufficient referential base to one's conversational partner—to take the perspective of another person—results in the appearance of talking or behaving randomly or incoherently. Pragmatic language impairment often occurs in the context of specific language impairment, but it has been recognized as a symptom of a wide range of disorders, including damage to the right hemisphere of the brain, autism, Asperger syndrome, Williams syndrome, and nonverbal learning disabilities.

Mental Retardation.

(See Chapter 38 .) Most children with a mild degree of mental retardation learn to talk at a slower than normal rate, although they follow a normal sequence of language acquisition and eventually master basic communication skills. Difficulties may be encountered with higher-level language concepts and usage. Individuals with moderate to severe degrees of cognitive retardation may have great difficulty in acquisition of basic communication skills. Approximately ½ of individuals with IQ <50 are able to communicate using single words or simple phrases; the rest are typically nonverbal.

Autism and Pervasive Developmental Disorders.

(See Chapter 29 .) A disordered pattern of language development is one of the core features of autism and other pervasive developmental disorders. The language profile of children with autism is indistinguishable from that of children with specific language impairments. The key points of distinction between these conditions are the lack of reciprocal social relationships that characterizes individuals with autism; limitation in the ability to develop functional, symbolic, or pretend play; and an obsessive need for sameness and resistance to change. Approximately 75–80% of children with autism are also mentally retarded, and this may limit their ability to develop functional communication skills. Language abilities may range from absent to grammatically intact, but with limited pragmatic features and/or odd prosody patterns. Some autistic individuals have highly specialized, but isolated, “savant” skills, such as calendar calculations and hyperlexia (the precocious ability to recognize written words beyond expectation based on general intellectual ability). Regression in language and social skills (autistic regression) occurs in approximately 30% of children with autism, usually before 2 yr of age. No explanation for this phenomenon has been identified. Once the regression has “stabilized,” recovery of function does not usually occur ( Fig. 32-2 ). Other causes of language regression include acquired brain lesions, neurodegenerative disorders, disintegrative disorders (autistic behavior, cognitive deficit seen in older children), or acquired epileptic aphasia (Landau-Kleffner syndrome).

Figure 32-2 Relationship of autism, language disorders, and mental retardation. (From Simms MD, Schum RL: Preschool children who have atypical patterns of development. Pediatr Rev 2000; 21:147–158.)

Asperger Disorder.

(See Chapter 29.2 .) Although sharing many characteristics of autism (deficits in social relatedness, restricted range of interests), individuals with Asperger syndrome typically show normal early language development (syntax, semantics). As they mature, higher-order social and language pragmatic impairments become prominent. These children have an unusually circumscribed range of interests that are all-absorbing and that interfere with learning other skills and social adaptation. They may engage in long-winded, verbose monologues about their topics of special interest, with little regard to the reaction of others. Their inflection pattern (prosody) may be inappropriate to the content of their conversation, and they may not adjust their rate of speech or vocal volume to the setting.

Selective Mutism.

(See Chapter 24 .) Selective mutism is defined as a failure to speak in specific social situations, despite speaking in other situations; it is typically a symptom of an underlying anxiety disorder. Children with selective mutism can speak normally in certain settings, such as within their home or when they are alone with their parents, but do not speak in other social settings, such as at school or at other places outside their home. Other symptoms associated with selective mutism can include excessive shyness, withdrawal, dependency on parents, and oppositional behavior. Most cases of selective mutism are not the result of a single traumatic event, but rather are the manifestation of a chronic pattern of anxiety. Mutism is not passive-aggressive behavior. Mute children report that they want to speak in social settings, but are afraid to do so. It is important to emphasize that the underlying anxiety disorder is the likely origin of selective mutism. Often, one or both parents of a child with selective mutism have a history of anxiety symptoms, including childhood shyness, social anxiety, or panic attacks. This suggests that the child's anxiety represents a familial trait. For an unknown reason, the child converts the anxiety into mutism. The mutism is highly functional for the child in that it reduces anxiety and protects the child from the perceived challenge of social interaction. Treatment of selective mutism should focus on reduction of the general anxiety, rather than focusing only on the mute behaviors. Selective mutism reflects a difficulty with social interaction and not a disorder of language processing.

Isolated Expressive Language Disorder.

More commonly seen in boys than in girls, isolated expressive language disorder (late talker syndrome) is a diagnosis best made in retrospect. These children have age-appropriate receptive language and social ability. Once they start talking, their speech is clear. There is no increased risk of language or learning disability as they progress through school. A family history of other males with a similar developmental pattern is often reported. This pattern of language development likely reflects a variation of normal.

MOTOR SPEECH DISORDERS.Dysarthria.

Motor speech disorders may originate from neuromotor disorders, such as cerebral palsy, muscular dystrophy, myopathy, or facial palsy. The resulting dysarthria affects both speech and nonspeech functions (smiling, chewing). Lack of strength and muscular control manifests as slurring of words and distortion of vowels. Speech patterns are often slow and labored. Poor velopharyngeal function may result in mixed nasal resonance (hyper- or hyponasal speech). In many cases, feeding difficulty, drooling, an open-mouth posture, and a protruding tongue accompany the dysarthric speech.

Verbal Apraxia.

Difficulty in planning and coordinating movements for speech production may result in inconsistent distortion of speech sounds. The same word may be pronounced differently each time. Intelligibility tends to decrease as the length and complexity of the child's speech increase. Consonants may be deleted and sounds transposed. As they try to talk spontaneously or imitate another's speech, children with verbal apraxia may display oral groping or struggling behaviors. Children with verbal apraxia often have a history of early feeding difficulty, limited sound production as infants, and delayed onset of spoken words. They may point, grunt, or develop an elaborate gestural communication system in an attempt to overcome their verbal difficulty. Apraxia may be limited to oral-motor function, or it may be a more generalized problem affecting fine and/or gross motor coordination.

Phonologic Disorder.

Children with phonologic speech disorder are frequently unintelligible, even to their parents. Articulation errors are not the result of neuromotor impairment, but seem to reflect an inability to process correctly the words they hear. As a result, they lack understanding of how to fit sounds together properly to create words. In contrast to children with apraxia, those with phonologic disorder are fluent—although unintelligible—and produce a consistent, highly predictable pattern of articulation errors. Children with phonologic speech disorder are at high risk for later reading and learning disability.

Hearing Impairment.

Hearing loss can be a major cause of delayed or disordered language development. Approximately 16–30/1,000 children have mild to severe hearing loss that is significant enough to affect educational progress (see Chapter 636 ). An additional 1/1,000 children are deaf (profound bilateral hearing loss). Hearing loss can be present at birth or acquired postnatally. Newborn screening programs can identify many forms of congenital hearing loss, but progressive hearing loss or acquired deafness may develop after birth.

The most common types of hearing loss are due to a conductive (middle ear) or sensorineural deficit. Although it is not possible to predict accurately the effect of hearing loss on a child's language development, the type and degree of hearing loss, the age of onset, and the duration of the auditory impairment clearly play important roles. Children with significant hearing impairment frequently have problems developing facility with language and often have related academic difficulties. Presumably, the language impairment is caused by lack of exposure to fluent language models starting in infancy.

Approximately 30% of hearing impaired children have at least 1 other disability that often affects the development of speech and language (mental retardation, cerebral palsy, craniofacial anomalies). Accordingly, any child who shows developmental warning signs of a speech and language problem should have a hearing assessment by an audiologist and an examination by a geneticist as part of a comprehensive evaluation.

Hydrocephalus.

Some children with hydrocephalus are described as having “cocktail party syndrome.” Although they may use sophisticated words, their comprehension of abstract concepts may be limited, and their pragmatic conversational skills may be weak, resulting in superficial discussion of topics or the appearance of a monologue.

Dysfluency (Stuttering).[*]

Fluent speech requires timely synchronization of phonatory and articulatory muscle groups. There is also an important interaction between speech and language skills. Stuttering involves involuntary frequent repetitions, lengthenings (prolongations) or arrests (blocks, pauses) of syllables, or sounds that are exacerbated by emotionally or syntactically demanding speech. The World Health Organization's definition of stuttering is a disorder in the rhythm of speech in which the individual knows precisely what he/she wishes to say, but at the same time may have difficulty saying it because of an involuntary repetition, prolongation, or cessation of sound. Stuttering often leads to frustration and avoidance of speaking situations.

* R.M. Kliegman contributed to this topic.

EPIDEMIOLOGY/ETIOLOGY.

Stuttering usually begins at 3–4 yr of age and is seen more often in males (4:1). Approximately 3–5% of preschool children stutter to some degree; only 0.7–1% of young adults stutter. Stuttering is common in families. Females and those with a history of recovery in the family are most likely to have spontaneous recovery by adolescence. This recovery is not related to the severity of the stuttering.

Stuttering may be due to impaired timing between areas of the brain involved in language preparation and execution. Adults who stutter and those with fluent speech activate similar areas of the brain. In addition, adults who stutter overactivate parts of the motor cortex and cerebellar vermis, show right-sided laterality, and have no auditory activation on hearing their own speech.

DIAGNOSIS.

Stuttering must be differentiated from the normal developmental dysfluency of preschool children (Tables 32-3 and 32-4 [3] [4]). Developmental dysfluency is characterized by brief periods of stuttering that resolve by school age, and it usually involves whole words, with <10 dysfluences/100 words. The DSM-IV diagnostic criteria for stuttering are noted in Table 32-2 . Stuttering that persists and is associated with tics may be a manifestation of Tourette syndrome (see Chapters 24 and 597.4 ).

TABLE 32-3 -- Differences Between Stuttering and Developmental Dysfluency

BEHAVIOR

STUTTERING

DEVELOPMENTAL DYSFLUENCY

Frequency of syllable repetition per word

≥2

≤1

Tempo

Faster than normal

Normal

Airflow

Often interrupted

Rarely interrupted

Vocal tension

Often apparent

Absent

Frequency of prolongations per 100 words

≥2

≤1

Duration of prolongation

≥2 sec

≤1 sec

Tension

Often present

Absent

Silent pauses within a word

May be present

Absent

Silent pauses before a speech attempt

Unusually long

Not marked

Silent pauses after the dysfluency

May be present

Absent

Articulating postures

May be inappropriate

Appropriate

Reaction to stress

More broken words

No change in dysfluency

Frustration

May be present

Absent

Eye contact

May waver

Normal

Adapted with permission from Van Riper C: The Nature of Stuttering. Englewood Cliffs, NJ, Prentice-Hall, 1971, p 28. From Lawrence M, Barclay DM III:Stuttering:A brief review.Am Family Physician 1998;57:2175–2178. http://www.aafp.org/afp/980501ap/lawrence.html

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TABLE 32-4 -- Examples of Normal Dysfluency in Preschoolers

TYPE OF DYSFLUENCY

EXAMPLES

Voiced repetitions

Occasionally 2 word parts (mi … milk)

Single-syllable words (I … I see you)

Multisyllabic words (Barney … Barney is coming!)

Phrases (I want … I want Elmo.)

Interjections

We went to the … uh … cottage.

Revisions:incomplete phrases

I lost my… . Where is Daddy going?

Prologations

I am Toooommy Baker.

Tense pauses

Lips together, no sound produced

From Costa D, Kroll R:Stuttering:An update for physicians. CMAJ 2000;162:1849–1855.

TREATMENT.

Preschool children with developmental dysfluency (see Table 32-3 ) can be observed with parental education and reassurance. Parents should not reprimand the child or create undue anxiety. Preschool or older children with stuttering should be referred to a speech pathologist. Therapy is most effective if started during the preschool period. In addition to the risks noted in Table 32-3 , indications for referral include 3 or more dysfluencies/100 syllables (b-b-but; th-th-the; you, you, you); avoidances or escapes (pauses, head nod, blinking); discomfort or anxiety while speaking; and suspicion of an associated neurologic or psychotic disorder.

Most preschool children respond to interventions taught by speech pathologists and to behavioral feedback by parents. Parents shouldn't yell at the child, but should calmly praise periods of fluency (“That was smooth”) or nonjudgmentally note episodes of stuttering (“That was a bit bumpy”). The child can be involved with self-correction and respond to requests (“Can you say that again?”) made by a calm parent.

Older children, adolescents, and adults have also been treated with risperidone or olanzapine with varying but usually positive results if behavioral speech therapy is unsuccessful.

RARE CAUSES OF LANGUAGE IMPAIRMENTHyperlexia.

Hyperlexia is the precocious development of reading single words that spontaneously occurs in some young children (2–5 yr of age) without specific instruction. It is typically associated with developmental disorders such as pervasive developmental disorder (PDD) or SLI. It stands in contrast to precocious reading development in young children who do not have any other developmental disorders. Although hyperlexia has been considered a rare and peculiar symptom associated with autism, it is recognized as a variation seen in young children with disordered language who do not have the social deficits or restricted or repetitive behaviors associated with autism. A typical manifestation is for a child with SLI to read single words orally or to match pictures with single words. Although hyperlexic children show early and well-developed word decoding skills, they usually have no precocious ability for comprehension of text. Rather, text comprehension is closely intertwined with oral comprehension, and children who have difficulty decoding the syntax of language are also at risk for reading comprehension problems.

Landau-Kleffner Syndrome (Verbal Auditory Agnosia).

Children with Landau-Kleffner syndrome have a history of normal language development until they experience a regression in their ability to comprehend spoken language (verbal auditory agnosia). The regression may be sudden or gradual, and it usually occurs at 3–7 yr of age. Expressive language skills typically deteriorate, and some children may become mute. Despite their language regression, these children typically retain appropriate play patterns and the ability to interact in a socially appropriate manner. An EEG may show a distinct pattern of status epilepticus in sleep (continuous spike wave in slow-wave sleep); up to 80% of children with this condition eventually have clinical seizures. A number of treatment approaches have been reported, including antiepileptic medication, steroids, and intravenous gamma globulin, with varying results. The prognosis for return of normal language ability is uncertain, even with resolution of the EEG abnormality, which may represent an epiphenomenon of an underlying brain abnormality.

Metabolic and Neurodegenerative Disorders.

(See Part X.) Regression of language development may accompany loss of neuromotor function at the outset of a number of metabolic diseases, including lysosomal storage disorders (metachromatic leukodystrophy), peroxisomal disorders (adrenal leukodystrophy), ceroid lipofuscinosis (Batten disease), and mucopolysaccharidosis (Hunter disease, Hurler disease). Recently, creatine transporter deficiency was identified as an X-linked disorder that presents with language delay in boys and mild learning disability in female carriers.

SCREENING.

At each well child visit, developmental surveillance should include specific questions about normal language developmental milestones and observations of the child's behavior. Clinical judgment, defined as eliciting and responding to parental concerns, can detect the majority of speech and language problems. Many clinicians use standardized developmental screening questionnaires and observation checklists designed for use in a pediatric setting (see Chapter 15 ). All general developmental screening instruments include items about language development (Denver Developmental Screening Test II [DDST-II], Child Development Inventory [CDI], Ages and Stages Questionnaire [ASQ], Parents' Evaluations of Developmental Status [PEDS]). Specific language screening tools are also available, such as the Early Language Milestone (ELM) Scale and the Clinical Linguistic and Auditory Milestone Scale (CLAMS). Because of the high prevalence of speech and language disorders in the general population, referral to a speech and language pathologist for further evaluation and treatment should be made whenever there is suspicion of delay. Specific warning signs that should always prompt referral for comprehensive multidisciplinary developmental evaluation are shown in Table 32-5 .

TABLE 32-5 -- Warning Signs of Language Problems

Not babbling, pointing, or gesturing by 10–12 mo Not understanding simple commands by 18 mo Not using any words by 18–21 mo

No word combinations by 24 mo Speech is difficult for parents to understand by 24–36 mo Speech is difficult for others to understand by 36–48 mo Child avoids talking situations Stuttering of more than tension-free, whole-word repetition Any regression in language or social skills at any age

NONCAUSES OF LANGUAGE DELAY.

Twinning, birth order, “laziness,” exposure to multiple languages (bilingualism), tongue-tie, and otitis media are not adequate explanations for significant language delay. Normal twins learn to talk at the same age as normal single-born children, and effects of birth order on language development have not been consistently found. The drive to communicate and the rewards for successful verbal interaction are so strong that children who let others talk for them usually cannot talk for themselves and are not “lazy.” Toddlers who are exposed to >1 language may show a mild delay in starting to talk, and they may initially mix elements (vocabulary and syntax) of the different languages they are learning (code switching). However, they learn to segregate the languages by 24–30 mo and are equal to their monolingual peers by 3 yr of age. An extremely tight lingual frenulum (tongue-tie) may affect feeding and speech articulation, but will not prevent the acquisition of language abilities. Frequent ear infections and/or serous otitis media in early childhood do not result in language disorder.

DIAGNOSTIC EVALUATION.

It is important to distinguish developmental delay (abnormal timing) from developmental disorder (abnormal patterns or sequences). A child's language and communication skills must also be interpreted within the context of his or her overall cognitive and physical abilities. It is important to evaluate the child's use of language to communicate with others in the broadest sense (communicative intent). Thus, a multidisciplinary evaluation is often warranted. At a minimum, this should include psychologic evaluation, neurologic assessment, and speech and language examination.

Psychologic Evaluation.

There are 2 main goals for the psychologic evaluation of a young child with a communication disorder. Nonverbal cognitive ability must be assessed to determine if the child is mentally retarded, and the child's social behaviors must be assessed to determine whether autism or a form of PDD is present. Additional diagnostic considerations may include emotional disorders such as anxiety,

depression, mood disorders, obsessive-compulsive disorder, academic learning disorders, and attention-deficit/hyperactivity disorder.

COGNITIVE ASSESSMENT.

Mental retardation is defined as retardation in the development of cognitive abilities and adaptive behaviors. Children with mental retardation show delayed development of communication skills; delayed communication does not necessarily signal mental retardation. Therefore, a broad-based cognitive assessment is an important component of the evaluation of children with language delays, including evaluation of both verbal and nonverbal skills. If a child has mental retardation, both verbal and nonverbal scores will be low compared with norms (≤2nd percentile). In contrast, a typical cognitive profile for a child with SLI will include a significant difference between nonverbal and verbal abilities, with nonverbal IQ > verbal IQ and the nonverbal score within the average range.

EVALUATION OF SOCIAL BEHAVIORS.

Social interest is the key difference between children with a primary language disorder (e.g., SLI) and those with a communication disorder secondary to autism or PDD. Children with SLI have an interest in social interaction, but may have difficulty acting on this interest because of their limitations to communication. In contrast, autistic children show little social interest. Four key nonverbal behaviors that are often shown by children with SLI—but not autistic children (especially toddlers and preschoolers)—are joint attention, affective reciprocity, pretend play, and direct imitation.

RELATIONSHIP OF LANGUAGE AND SOCIAL BEHAVIORS TO MENTAL AGE.

Cognitive assessment provides a mental age for the child, and the child's behavior must be evaluated in that context. Whereas most 4 yr old children engage peers in interactive play, most 2 yr olds are playful, but primarily focused on interactions with adult caretakers. A 4 yr old with mild to moderate mental retardation and a mental age of 2 yr may not play with peers; however, this is because of cognitive limitation, not a lack of desire for social interaction.

Speech and Language Evaluation.

A certified speech-language pathologist should perform a speech and language evaluation. A typical evaluation includes assessment of language, speech, and the physical mechanisms associated with speech production. Both expressive and receptive language is assessed by a combination of standardized measures and informal interactions and observations. All components of language are assessed, including syntax, semantics, pragmatics, and fluency. Speech assessment similarly uses a combination of standardized measures and informal observations. Assessment of physical structures includes oral structures and function, respiratory function, and vocal quality. A speech-language pathologist often works with an audiologist, who can perform an appropriate hearing evaluation. If an audiologist is not available in that setting, then a separate referral should be made. No child is too young for a speech-language or hearing evaluation. A referral for evaluation is appropriate whenever language impairment is suspected.

Medical Evaluation.

A careful history and physical examination should focus on the identification of potential contributors to the child's language and communication difficulties. A family history of delay in talking, the need for speech and language therapy, or academic difficulty may suggest a genetic predisposition to language disorders. Pregnancy history may show risk factors for prenatal developmental anomalies, such as polyhydramnios or decreased fetal movement patterns. Speech and language difficulty is more likely to occur in a child who is small-for-gestational-age at birth, who has symptoms of neonatal encephalopathy, or who has early and persistent oral-motor feeding difficulty. The developmental history should focus both on the age at which various language skills were mastered and on the sequences and patterns of milestone acquisition. Regression or loss of acquired skills should raise immediate concern. Physical examination should include measurement of height (length), weight, and head circumference. The skin should be examined for lesions consistent with phakomatosis (tuberous sclerosis, neurofibromatosis, Sturge-Weber syndrome) and other disruptions of pigment (hypomelanosis of Ito). Anomalies of the head and neck, such as white forelock and hypertelorism (Waardenburg syndrome), ear malformations (Goldenhar syndrome), facial and cardiac anomalies (Williams syndrome, velocardiofacial syndrome), retrognathism of the chin (Pierre-Robin anomaly), or cleft lip and/or palate, are associated with hearing and speech abnormalities. Neurologic examination may show muscular hypertonia or hypotonia, both of which may affect neuromuscular control of speech. Generalized muscular hypotonia, with increased range of motion of the joints, is commonly seen in children with SLI. The reason for this association is not clear, but it may account for the fine and gross motor clumsiness often seen in these children. Mild hypotonia is not a sufficient explanation for the impairments of expressive and receptive language.

No routine diagnostic studies are indicated for SLI or isolated language disorders. When language delay is part of a generalized cognitive or physical disorder, referral for further genetic evaluation, chromosome testing (including fragile X testing), neuroimaging studies, and EEG may be considered, if clinically indicated.

TREATMENT.

The federal IDEA laws (Individuals with Disabilities Education Act) require that schools provide special education services to children who have learning difficulties. This includes children with speech and language disorders. Services are provided to children from birth through 21 yr of age. Each state has various methods for providing services, and for young children, these can include birth–3, early childhood, and early learning programs. These programs provide speech-language therapy as part of public education, in conjunction with other special education resources. Children can also receive therapy from nonprofit service agencies, hospital and rehabilitation centers, and speech pathologists in private practice.

Speech-language therapy includes a variety of goals. Sometimes both speech and language activities are incorporated into therapy. Speech goals focus on the development of more intelligible speech. Language goals can focus on expanding vocabulary (lexicon) and understanding of the meaning of words (semantics), improving syntax by using proper forms or learning to expand single words into sentences, and social use of language (pragmatics). Therapy can include individual sessions, group sessions, and mainstream classroom integration. Individual sessions may use either drill activities for older children or play activities for younger children, to target specific goals. Group sessions can include several children with similar language goals to help them practice peer communication

activities and bridge the gap into more naturalistic communication situations. Classroom integration may include the therapist team-teaching or consulting with the teacher to facilitate the child's use of language in common academic situations.

For children with severe language impairment, alternative methods of communication are often included in therapy. These may include the use of manual sign language or the use of pictures (Picture Exchange Communication System [PECS]). Often the ultimate goal is to achieve better spoken language. Early use of sign language or pictures can help the child to establish better functional communication and understand the symbolic nature of words to facilitate the language process. There is no evidence that the use of signs or pictures will interfere with the development of oral language if the child has the capacity to speak. Furthermore, many clinicians believe that these alternative methods accelerate the learning of language. They also reduce the frustration of parents and children who cannot communicate for basic needs.

Parents can consult with their child's speech-language therapist about home activities to enhance language development and extend therapy activities through appropriate language stimulation activities and recreational reading. Parent language activities should focus on emerging communication skills that are within the child's repertoire, rather than teaching the child new skills. The speech pathologist can guide parents in effective modeling and eliciting communication from their child.

Recreational reading focuses on expanding the child's comprehension of language. Sometimes the child's avoidance of reading is a sign that the parent is presenting material that is too complex. The speech-language therapist can guide the parent in selecting an appropriate level of reading material.

PROGNOSIS.

Although the majority of children improve their communication ability with time, 50–80% of preschoolers with language delay and normal nonverbal intelligence continue to show language difficulties up to 20 yr beyond the initial diagnosis. Early language difficulty is strongly related to later reading disorders. Approximately 50% of children with early language difficulty later have a reading disorder, and 55% of children with a reading disorder have a history of impaired early oral language development. Children who eventually manifest a specific reading disorder produced fewer words per utterance, expressed less complicated sentences, and showed more pronunciation difficulties at 2–3 yr of age compared with non–reading-disordered peers. By 5 yr of age, verbal sentence complexity has little predictive power, but expressive vocabulary and phonologic awareness of words (the ability to manipulate the component sounds of words) are highly correlated with later reading achievement.

Comorbid Psychiatric Disorders.

Early language disorders, particularly difficulty with auditory comprehension, appear to be a specific risk factor for later emotional dysfunction. Boys and girls with language disorders have a higher than expected rate of anxiety disorders (principally social phobia). Boys with language disorders are more likely to have symptoms of attention-deficit/hyperactivity disorder, conduct disorder, and antisocial personality disorder compared with normally developing peers. Language disorders are common in

children referred for psychiatric services, but they are frequently underdiagnosed and their effect on children's behavior and emotional development is often overlooked.

Preschoolers with language difficulty commonly express their frustration through anxious, socially withdrawn, or aggressive behaviors. As their ability to communicate improves, parallel improvements are usually noted in their behavior, suggesting a cause and effect relationship between language and behavior. However, the persistence of emotional and behavioral problems over the life span of individuals with early language disability is suggestive of a strong biologic or genetic connection between language development and subsequent emotional disorders.

ROLE OF PEDIATRICIANS.

Evaluation of children's language development should be an important component of every well child supervision visit. All children who appear to have delayed speech or language should be referred for further assessment and treatment.

Children with symptoms of mental retardation, birth defect syndromes, or neuromotor impairment should be referred for comprehensive multidisciplinary evaluation to identify a specific etiology for their developmental disorder. The child with speech and language disorder may experience social and behavioral difficulties interacting with peers. These difficulties should be evaluated in the context of the child's functional language and mental age. Anxiety disorders may require behavioral and/or psychopharmacologic interventions. Throughout the school years, children should be monitored for evidence of reading disorders.

Most children with language disorders can improve their communication ability through a process of educational programs and speech-language therapy. The physician can help the parents to understand that improvement is a long developmental process guided by teachers and therapists. Many parents question if the child will catch up to his or her peers. Sometimes that occurs, but not all the time. Although most children show significant improvement in communication ability as they grow, language disorders appear to persist over the life span in the majority of affected individuals.

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