Chapter 33. Motor Skills Disorder & Communication Disorders

Essentials of Diagnosis

DSM-IV-TR Diagnostic Criteria

1. Performance in daily activities that require motor coordination is substantially below that expected given the person's chronological age and measured intelligence. This may be manifested by marked delays in achieving motor milestones (e.g., walking, crawling, sitting), dropping things, “clumsiness,” poor performance in sports, or poor handwriting.

2. The disturbance in Criterion A significantly interferes with academic achievement or activities of daily living.

3. The disturbance is not due to a general medical condition (e.g., cerebral palsy, hemiplegia, or muscular dystrophy) and does not meet criteria for a pervasive developmental disorder.

4. If mental retardation is present, the motor difficulties are in excess of those usually associated with it.

(Reprinted, with permission, from Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Text Revision Copyright 2000 American Psychiatric Association.)

General Considerations

Recent research suggests that developmental coordination disorder can be divided into several subcategories (Table 33–1).

Epidemiology

It is estimated that 6% of schoolchildren have developmental coordination disorder. Children with perceptual motor defects have a high incidence of educational problems and psychological maladjustment.

Etiology

Motor development involves the gradual acquisition of central control over reflex movement. There is controversy over whether this acquisition involves the suppression of reflex and spontaneous cyclic movements of early infancy or whether infantile movements are incorporated into the elements that become voluntary motor skills.

Skilled movement requires a program of action with a specified objective or set goal. The program is composed of a sequence of hierarchically organized subroutines under executive control. Once acquired, motor skills are flexible. For example, the child who has learned to walk can do so on smooth, rugged, soft, or hard surfaces. The adaptation to different situations of the programmed subroutines requires accurate perception, central processing, executive control, and progressive feedback. Feedback monitors the approximation of the program to the set goal and modifies the timing, speed, force, and direction of movement until the desired endpoint is achieved. Initially, feedback produces jerky movements, as the child struggles to master the skill. Eventually, the skill is regulated centrally and the subroutines automated. A variety of skills can be built up from a limited number of practiced subroutines deployed in accordance with combinatorial rules. The combinatorial rules act as a kind of grammar, organizing the subroutines in hierarchical fashion. Skilled performance can be delayed or disrupted if basic reflexes are not suppressed or incorporated into the program, or if the following functions are delayed, defective, or disrupted: Perception, central processing and programming, motor function, or feedback.

The hypothesis of minimal brain damage or minimal brain dysfunction was formerly invoked to explain minor sensorimotor abnormalities or immaturities, however, there is no way to prove this hypothesis. It is unclear whether the defects or delays occur in the peripheral or in the central apparatus or, if so, how they relate to developmental coordination disorder.

Genetics

Like many other neurodevelopmental disorders of childhood onset, it is likely that there are multiple vulnerability genes associated with this condition. None, however, have been identified as yet.

Clinical Findings

Signs & Symptoms

Clumsiness

The clumsy child is slow, jerky, and inefficient in fine-motor performance. Agonist and antagonist muscles are poorly coordinated. Motor milestones are delayed. The child drops things, tends to lose his or her balance, and is poor at activities requiring hand-eye coordination. Clumsiness can affect a particular set of muscles (e.g., orofacial, hand and finger, shoulder girdle), several sets, or the entire body musculature. The child's social development is likely to be affected, particularly if clumsiness is associated with learning problems.

Adventitious Movements

These movements involve one or more of the following unwilled movements during a purposeful motor activity: synkinesis, chorea, tremor, or tic.

Synkinesis refers to movement in a set of muscles other than that in which the primary motor action takes place. It may be homologous (i.e., symmetrical) or heterologous (i.e., asymmetrical). For example, while drawing with the right hand, the child with synkinesis moves his or her left hand (homologous) or tongue (heterologous). Chorea refers to repetitive abrupt movements of the limbs or face. Tremor refers to rhythmic oscillations of a body part. A tic is an abrupt, involuntary, repetitive movement of a particular set of muscles, usually in the face, mouth, head, neck, or diaphragm.

Dyspraxia

Despite normal strength, coordination, and perception, the dyspraxic child is unable to learn or perform motor skills. Dyspraxia may involve all effector muscles or may affect mainly the orofacial musculature, hand, or trunk and lower limb. The components of the motor skill are intact, but they are combined in an incoherent manner. A clumsy child will slowly get the job done. The dyspraxic child will not get the job done at all.

Material-Specific Dyspraxia

Children with material-specific dyspraxia exhibit defective motor performance in regard to specific tasks such as handwriting (specific dysgraphia), drawing and construction (constructional dyspraxia), or the articulation of words (verbal dyspraxia).

Neurologic Soft Signs

Found normally in younger children, neurologic soft signs represent a heterogeneous group of phenomena that disappear with normal development. Soft signs are regarded as abnormal if detected beyond a normative cut-off age (8–10 years). They are usually found incidentally unless tested for specifically. Their reliability, validity, and significance are disputed. A number of studies have suggested an association with cognitive dysfunction, learning problems, and psychiatric disturbance. In some cases soft signs may be related to mild brain damage; in other cases they may be related to a genetically determined factor that also correlates with a nonspecific vulnerability to psychiatric disturbance.

Pathologic Handedness

Pathologic left-handedness occurs following damage during early development to the left hemisphere, causing a shift from right- to left-handedness. Right-sided hypoplasia, impaired visuospatial functioning, and language impairment are often found in association with this condition.

Assessment Procedures

After taking a developmental history, processing questions directed at elucidating motor performance, and administering a neurologic examination, the clinician can apply the specific assessment procedures described in the following sections:

Clumsiness

Gubbay's standardized test battery for the assessment of clumsy children, Denckla's Finger Tapping Test, and Rapin et al.'s Peg-Moving Procedures Test for Clumsiness are useful screening instruments.

Adventitious Movements

The Fog Test and Wolff et al.'s procedure screen for synkinesis are useful. In order to elicit choreiform movements, Wolff and Hurwitz had children stand with their eyes closed; arm, wrists, and fingers extended; and wrists pronated.

Dyspraxia

The Lincoln-Oseretsky Test includes a subtest for dyspraxia. Dyspraxia can be tested by having the child imitate hand postures, pantomime manual activities, and use actual objects (e.g., pen, cup) in an appropriate way.

Material-Specific Dyspraxia

Dysgraphia is tested by observing handwriting. Constructional dyspraxia is tested by having the child copy drawings (e.g., the Bender-Gestalt Test) or block designs. Verbal dyspraxia is screened for using the Reynell Developmental Language Scales.

Neurologic Soft Signs

Neurologic soft signs can be screened for with the Physical and Neurological Examination for Soft Signs or the Examination for Minor Neurological Signs in Children. The Examination for Minor Neurological Signs tests the following: Digit span, visual tracking, speech, nystagmus, eye symmetry, hand dominance, crossed dominance of arm and leg, right-left self-identification, right-left identification on examiner, bilateral hand stimulation, face-hand apposition, finger localization, graphesthesia, stereognosis, synkinesis, finger-to-nose apposition, diadochokinesis, and passive head turning.

Psychological Testing

Additional psychological testing should be undertaken if there is evidence of attentional difficulties or specific areas learning disability.

Laboratory Findings

Laboratory tests are seldom necessary in the evaluation of clumsiness unless there are abnormal findings on neurologic examination or a history of acute changes in motor skills. However, measurement of creatine kinase and lactate dehydrogenase should be performed with children who have reduced muscle mass or limited capacity for physical exertion.

Neuorimaging

Abnormal findings on neurological examination suggestive of a focal brain abnormality should have magnetic resonance imaging studies or computed tomography as part of their evaluation.

Course of Illness

Typically, mild and moderate degrees of clumsiness in early childhood improve over development. More severe clumsiness has a less favorable outcome only in regard to motor proficiencies.

Differential Diagnosis

Clumsiness is observed in chronic intoxication with neuroleptic and anticonvulsant drugs, in neuromuscular disorders (e.g., Charcot-Marie-Tooth disease, Duchenne's disease), and in upper motor neuron disorders (e.g., cerebral palsy, degenerative disorders). Children with Down syndrome, autism, Asperger's syndrome, specific dyslexia, and ADHD are sometimes more clumsy than is appropriate for their mental age.

Synkinesis is associated with agenesis of the corpus callosum, Klippel-Feil syndrome, hypogonadism, midline facial defects, and a rare familial syndrome. It may be associated with ADHD and conduct disorder. Chorea is observed in Sydenham's chorea (anti-streptolysin titer and electrocardiogram should be ordered to test for rheumatic fever), hyperthyroidism, benign familial chorea, CNS degenerations (e.g., Wilson's disease, Hallervorden-Spatz disease, homocystinuria, Huntington's disease), and tardive dyskinesia. Tremor is associated with posterior fossa tumors; neuroleptic, lithium, or phenytoin toxicity; hyperthyroidism; and benign familial tremor. Simple motor tics should be distinguished from Tourette's syndrome.

Dyspraxia is associated with subacute sclerosing panencephalitis, HIV encephalopathy, Rett's disorder, and degenerative disorders of the CNS, whether inborn or acquired. Dyspraxia can be associated with learning disorders and possibly ADHD and autism. Dysgraphia and oral-motor dyspraxia may be associated with neurofibromatosis, congenital heart disease, and homocystinuria. Constructional dyspraxia is observed in William's disease. Verbal dyspraxia has been described in galactosemia and fragile-X syndrome.

Treatment

A number of treatment methods have been proposed, but it is not clear whether any of them is effective. Ayres designed a motor training program based on the theory that motor skills disorders are caused by a failure to inhibit primitive reflexes. Kephart's motor training targets posture, balance, locomotion, manipulation, catching, and propulsion. Bobath and Connolly have designed physiotherapy and occupational therapy techniques for the remediation of motor handicaps.

Complications/Adverse Outcomes of Treatment

All children with developmental difficulties in motor coordination should receive supportive care failure to do so may lead to with increased academic, emotional, and behavioral problems.

Prognosis

Children with motor deficits that continue into adolescence and adulthood are more likely than their peers to have poor social competence, reduced academic motivation, lower self-esteem, obesity, and poorer physical fitness in part due to their reluctance to engage in physical activity and sports.

Essentials of Diagnosis

Diagnostic Criteria

DSM-IV-TR identifies the following categories of communication disorder:

• Expressive language disorder: A disturbance manifested by symptoms such as markedly limited vocabulary, errors in grammatical relationships, or difficulties with word recall or sentence production
• Mixed receptive-expressive language disorder: A disturbance that includes the symptoms of an expressive language disorder together with deficits involving the processing or understanding of spoken words and sentences
• Phonological disorder: A disturbance, formerly known as a developmental articulation disorder, manifested by developmentally inappropriate production, use, representation, or organization of speech sounds, such as sound substitutions or sound omissions
• Stuttering: A disturbance in the normal fluency and temporal patterning of speech characterized by one or more of the following: Sound and syllable repetitions, whole-word repetitions, prolongations, interjections, broken words, blocking, circumlocutions, and excess tension in word production

In each disorder, the problem must be severe enough to interfere with the patient's school or occupational achievement or with social communication. The problem also must exceed what would be expected based on the patient's age, intelligence, or dialect and on the presence of environmental deprivation or speech-motor or sensory deficits (if a sensory, speech-motor, or known neurologic deficit is present, it should be coded as an Axis III disorder). In addition, the diagnosis of either an expressive language disorder or mixed receptive-expressive language disorder requires that the criteria for a pervasive developmental disorder are not met.

The DSM-IV-TR category communication disorder not otherwise specified refers to any disturbance in communication that does not meet the criteria for a specific disorder of communication as noted in this section. Such disorders include voice disorders, cluttering (in which excessive wordiness interferes with idea expression), and so on. Although not specifically mentioned in DSM-IV-TR, deficits in pragmatic language abilities are included in this category. The term “pragmatics” refers to the use of language in a social context, with respect to either the understanding or expression of intended meanings. “Getting the message” entails more than simply a literal decoding and processing of words according to syntactic rules. It relies on the incorporation of a broader range of features, many of them nonverbal, such as prosodic and gestural cues. The interpretation of indirect meaning, humor, or sarcasm often depends heavily on these features. The same is true with respect to effective expression within a social context, which from a psychiatric standpoint is an especially important dimension of language functioning, as it often may relate to problems with interpersonal relationships and social skills development.

General Considerations

DSM-IV-TR criteria reflect a number of advancements in the conceptualization and definition of communication disorders in childhood. Many discussions on the topic make a distinction between acquired and developmental language disorders. An acquired language disorder, or acquired aphasia in childhood, is a syndrome involving impairment in one or more language abilities after the normal onset of speech. It usually has an identifiable neurologic basis and in general can be classified using the same terms used to classify adult aphasias. By contrast, a developmental language disorder (sometimes referred to as congenital aphasia) impedes the normal acquisition of language. It has no obvious point of onset, and although a neurologic basis may be suspected, it may not be verifiable. Earlier versions of DSM criteria specifically referred to developmental speech and language disorders. This distinction was dropped in DSM-IV, where the criteria were treated purely on functional grounds without implicit reference to type of onset.

Another improvement was the elimination of a category of communication disorders in childhood referring solely to receptive language impairment. The possibility of a specific disorder of receptive language, similar to Wernicke's aphasia, cannot exist in a child who has never learned to speak. Any disorder affecting receptive language, which would interfere with a child's ability to process and understand spoken input, will necessarily impede the child's ability to produce spoken language. Thus language disorders in children generally are either global or primarily expressive in nature.

Epidemiology

Prevalence rates for childhood speech and language deficits vary according to the classification criteria and cutoff points used in defining abnormality. Such deficits can be defined strictly on statistical grounds, as when impaired performance is defined as falling below a particular score on a standardized test. For example, if the cutoff is set at two standard deviations (SDs) below the mean, then by definition, 2% of the reference group would fall in the impaired range; this impairment rate would rise to roughly 7% if the cutoff were set at 1.5 SDs, and so forth. Shrinkage in the estimates would result if exclusionary criteria were considered.

There also appears to be an elevated rate of comorbidity with childhood psychopathology. For example, in one study 60% of children with language disorders met diagnostic criteria for ADHD.

Etiology

Speech and language disorder have multiple etiologies, some genetic, some congenital, and some arising from perinatal trauma such as prematurity and anoxia. Some form of underlying brain dysfunction has generally been assumed, even in disorders of the so-called developmental variety, although evidence to support this assumption may be lacking. Many studies examining children with language disorders—especially earlier studies—failed to document the presence of any CNS abnormalities.

New and important insights have begun to unfold, especially with recent technological advances in the study of brain function. For example, electrophysiologic features in the newborn—specifically involving auditory evoked responses over the left hemisphere—are predictive of language skills at 3 years of age. Such findings support a general presumption of left-hemispheric dysfunction in many speech and language disorders. Pragmatic language functions, and their dependence on various nonverbal abilities, are thought to be influenced strongly by right-hemispheric processes.

Genetics

Language disorders occur more frequently in families with a history of language or learning problems than in the general population and are about four times more likely in boys than girls. As genetically complex disorders it is likely that interactive relationships between multiple genetic loci will be important and lead to the degree of affectedness within specific domains of disability. However, there has been at least one autosomal dominant gene, FOXP2, on chromosome 7q31 that has been identified through the study of three generations of one family with a severe communication disorder.

Clinical Findings

Signs and Symptoms

Communication disorder is a broad term used to describe a variety of developmental disorders including those associated with cognitive impairment, in which speech and language also are affected. Specific disorders must be distinguished because of important differences in the approach to treatment and prognosis.

Psychological Testing

Several key issues must be addressed in the diagnosis and evaluation of communication disorders. First, a child's speech or language functioning must be assessed through the use of standardized, individually administrated tests. Basing the diagnosis on clinical observations alone is generally insufficient, except when the nature or severity of the disorder prevents formal testing. Table 33–2 describes sample measures and instruments.

Second, cutoff points should be set in determining abnormality or impairment on specific measures. In other words, what constitutes a significant deficit? This is somewhat arbitrary, although the cutoff is typically set at about 2 SDs below the mean on any particular measure, at or below which the obtained score would be considered to reflect impairment. A slightly higher cutoff may be used (e.g., 1–1.5 SDs) if the goal pertains more to initial screening than to formal diagnosis. A more liberal cutoff may also be used when it reflects a level of performance that is clearly discrepant with the child's more general functioning. Thus a score of 85 on a standardized language measure—which technically falls in a low average range—could be viewed as reflecting a significant problem in a child with an intelligence quotient of 115 or more.

Finally, how is an unbiased estimate of a child's global abilities obtained, against which his or her language performance can be compared? DSM-IV-TR requires that this estimate be based specifically on a nonverbal measure of intellectual capacity. This is because many intelligence measures depend heavily on verbal abilities; thus their results would be unduly lowered when a specific language impairment is involved. Measures of nonverbal intelligence include the Test of Nonverbal Intelligence, the Leiter International Performance Scale, and the Performance section of the Wechsler Intelligence Scales.

Laboratory Findings

All children with a communication disorder should have a complete medical evaluation and formal audiologic testing to detect medical conditions or hearing loss that may contribute to their condition.

Neuroimaging

Abnormal findings on neurological examination suggestive of a focal brain abnormality should have magnetic resonance imaging studies or computed tomography as part of their evaluation. Functional neuroimaging in this area has also accelerated in recent years. Typically dyslexic children exhibit altered patterns of brain activation in a variety of brain regions including the left parietotemporal cortex as well as frontal regions. At present the diagnostic value of these studies has yet to be established.

Course of Illness

Communication disorders are usually detectable before 4 years. Severe forms may be apparent by 2 years of age. Children with communication disorders are at high risk for developing learning disabilities and experiencing academic difficulties when they enter school. Parents should develop skills to advocate for their children in order to ensure that they receive the services they need.

Differential Diagnosis

The valid diagnosis of a communication disorder requires that it be differentiated from other factors that could interfere with effective communication. Language acquisition can be impeded by environmental deprivation, although such deprivation rarely would constitute the primary cause of a language disorder. Hearing-impaired children and children with neuromotor dysfunction may exhibit slow oral language growth. However, a specific language impairment may also be inferred if the degree of impairment exceeds what would be expected due to the sensory or sensorimotor deficit(s) alone. The same is true with respect to mental retardation, if present.

It is especially difficult to distinguish language disorders from autism or other pervasive developmental disorders. A communication impairment of one kind or another is a defining characteristic in various forms of pervasive developmental disorders. Important differences that may distinguish pervasive developmental disorders include the idiosyncratic use of words, aprosodic features, deviant eye contact, and an apparent disinterest in communication as reflected in the absence of a gestural language system or other nonverbal means of communication. Also, unlike the poor auditory memory often observed in language-impaired children, many children with pervasive developmental disorders exhibit superior memory.

It is also difficult sometimes to distinguish language impairment and ADHD. In both disorders, the child may have difficulties following spoken language or in expressing ideas in a focused and goal-directed manner. In ADHD, however, the problems with efficient focusing would not be limited to verbal areas. Both disorders may coexist (indeed the comorbidity rate appears fairly high), in which case the attention deficits may be especially pronounced when verbal processing is involved.

Many forms of learning disabilities can be viewed as the extension of language processing problems into the school-age period, especially when skills such as reading, spelling, and writing are involved. These problems can be considered language-based forms of learning disorders, particularly if accompanied by broader problems with language comprehension or production. The range of learning disabilities is varied, however, in that nonverbal types of learning disabilities also exist.

Treatment

Therapeutic services in the area of communication disorders are provided by appropriately certified speech and language pathologists. Services may focus on speech impediments, including problems with voice quality, oral-motor control, and phonologic and fluency weaknesses. Receptive and expressive language processing problems may also be addressed, with exercises aimed at improving word comprehension, naming abilities, syntactic awareness, and higher-order listening comprehension and formulation skills.

Depending on the therapist's qualifications, services may be directed toward facilitating pragmatic language abilities such as interpreting indirect meanings, utilizing nonverbal cues, and applying associated skills necessary for effective social communication (e.g., taking turns, maintaining eye contact). Treating pragmatic deficits is a more specialized aspect of language intervention that is related closely to behaviorally oriented treatment approaches focusing on social skills development. Such approaches are not necessarily emphasized in the training and experience of all speech and language pathologists; thus it must be considered specifically when exploring potential referral options. The same is true with respect to identifying speech and language pathologists who are suited for remedial work in areas such as mnemonics and language-based learning disabilities.