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Language plays an important role in the cognitive, social, emotional, and behavioural development of children. Therefore, impairment in language development may have a serious impact on cognitive and psychosocial development. Language development disorders (LDD) are very often apparent in preschool children. Epidemiologic surveys suggest a prevalence figure in the range of 6% to 8% among children of this age (1). According to DSM-IV (2), an LDD is signaled by impairment of expressive and (or) receptive language development not caused by sensory deficits, deficits in nonverbal intellectual capacity, a neurological condition, or environmental deprivation. The linguistic features of expressive language disorder include a limited amount of speech, a limited vocabulary range, difficulty in acquiring new words, word finding or vocabulary errors, shortened sentences, simplified grammatical structures, limited varieties of grammatical structures (for example, verb forms), limited varieties of sentence structures (for example, imperatives and questions), the omission of critical parts of sentences, and the use of unusual word orders. The most common feature associated with an expressive language disorder in younger children is a phonological disorder. The linguistic features of a mixed receptive–expressive language disorder include difficulty understanding words, sentences, or specific types of words in combination with phonological and expressive language problems. Problems in language development may be linked to other basic disabilities, such as delays in reaching other developmental milestones (3), impaired verbal and nonverbal intellectual capacities (4), reading and spelling difficulties (5,6), psychiatric diagnoses (7,8), and behavioural problems (9,10). Evidence for associations between emotional and behavioural problems and communication difficulties has been reported by investigations into the prevalence rate of behavioural problems among children with speech and language disorders as well as by evaluations of the prevalence rate of language problems among children with psychiatric disorders. Beitchman and others (11) found that, based on parent and teacher reports, 50% of children with speech and language problems showed behavioural problems in comparison with 12% of children without speech and language problems. Several studies suggest that children with psychiatric disorders (12–14) have previously undiagnosed speech and language difficulties. Cohen and others examined the prevalence of unsuspected language impairments in 4- to 12-year-old psychiatric outpatients (12). They reported that 34.4% of the children had a language impairment that had not been previously suspected and that these children had the most serious externalized behavioural problems. A longitudinal study regarding the follow-up of 2 groups of young men, 1 with autism and 1 with developmental receptive language disorder, who were first assessed at the ages of 7 to 8 years and then at the ages of 23 to 24 years, demonstrated that many of those children with the receptive language disorder still had few close friends and had moderate to severe social problems (15). The association between behaviour problems and language disorders has been documented extensively, although methodological problems have been found in terms of inadequate diagnostic classification and the heterogeneity of the groups studied (16). Many studies deal with language disorders in a broad sense. Diverse types of speech and language disorders, such as articulation problems, stuttering, and expressive and (or) receptive language disorders, are frequently grouped together; speech and language problems are often associated with intellectual impairment and autistic behaviour, but the differentiation into subgroups of language-impaired children is often neglected (17); and control groups are often omitted from the experimental design. The purpose of the present study was to investigate univariate and multivariate differences in behavioural problems among children with disorders in expressive and mixed receptive– expressive language development, using children with unimpaired language development as control subjects. MethodsSubjects The mean age was 57 (SD 8.8) months, the mean position in sibship was 1.7 (SD 0.8). Twenty-six (29%) children had no siblings, 48 (53%) had 1 sibling, 12 (13%) had 2 siblings, 3 (3%) had 3 siblings, and 1 (1%) had 4 siblings in the family. Ninety-two (98%) of the children had been in kindergarten (corresponds to “preschool” in the US) for a mean duration of 19.9 (SD 12.5) months, 2 children (2%) were not in a daycare program. The mean nonverbal IQ was 99.0 (SD 16.5). Sixty-nine (76%) had not received any treatment before they had been examined. Eighteen (32%) received speech therapy for a mean duration of 6.9 (SD 9.0) months, 2 children (4%) received occupational therapy for a mean duration of 2.5 (SD 0.7) months, and 1 child (2%) received physical therapy for a period of 3 months. The mean age of the patients’ mothers was 30.8 (SD 5.4) years. Regarding educational level, 17 (18%) of the mothers had left school after the compulsory 9-year school program, 50 (53%) had graduated from a 2- or 3-year high school program, 21 (22%) had obtained a 4- or 5-year high school diploma, and 6 (7%) mothers held a university degree. Ninety-four children without LDD were recruited as control subjects in Viennese kindergartens and were matched by age and sex to the patient sample. They were also examined with respect to their language development and their social– emotional behaviour. The mean position in sibship was 1.5 (SD 0.7). Thirty-four (36%) children had no siblings, 47 (50%) had 1 sibling, 6 (6%) had 2 siblings, and 7 (8%) had 3 siblings. Control subjects had been in kindergarten for a mean duration of 22.2 (SD 9.7) months. The mean nonverbal IQ was 100 (SD 16.8). No child had received any treatment before entering the study. The mean age of the control subjects’ mothers was 34.2 (SD 5.9) years. Regarding educational level, 20 (21%) of the mothers had left school after the compulsory 9-year school program, 24 (26%) had graduated from a 2- or 3-year high school program, 45 (48%) had a 4- or 5-year high school diploma, and 5 (5%) held a university degree. There were no significant differences between the patients’ mothers and the control subjects’ mothers with respect to the maternal age (t = –1.84; df 46; P = 0.072). A significant difference was found between the patients’ mothers and the control subjects’ mothers with respect to the distribution of the maternal education (c² = 18.2; df 3; P = 0.0004). It is not a systematic difference, because the distribution of the patients’ mothers showed a higher percentage of graduation from a 2- or 3-year high school program and an university degree but a lower percentage of the compulsory 9-year school program and a 4- or 5-year high school diploma than the distribution of the control subjects’ mothers. Moreover, the explained variance between maternal education and language development ranged from 1% to 10% in the children with LDD and from 1% to 9% in the control subjects. Therefore, both maternal age and maternal education were not used as covariates. Materials Child behaviour was measured by the German version (23) of the Child Behavior Checklist/4-18 (CBCL) (24), which consists of 2 sections: “child’s competence” and “child’s social–emotional problems.” The present study only considered the scales of the child’s social–emotional problems section. The 118 behaviour problem items, to be assessed by the parents, refer to the 8 syndromes: “withdrawn,” “somatic complaints,” “anxious–depressed,” “social problems,” “thought problems,” “attention problems,” “delinquent problems,” “aggressive behaviour,” and “other problems.” A t-score based on the normal population can be assigned to each syndrome. The t-scores of 67 and above have been designated by Achenbach (24) to define the clinically abnormal range. These t-scores correspond to the 95th percentile of the normal group. Statistics According to DSM-IV, a diagnosis of mixed receptive– expressive language disorder is defined by the child’s actual and tested abilities with respect to vocabulary (expressive and receptive), which were measured by the Active Vocabulary Test for 3- to 6-Year-Old Children (19) and the Peabody Picture Vocabulary Test (20) in this study, and grammar (expressive and receptive), which was measured by the subtests I, II, and XI of the Heidelberg Evaluation of Language Development (21). The data values had to be at least 1 SD below those of the normative sample of the tests used. Univariate group differences within the patient sample and between patients and control subjects were analyzed for significance using t-tests (paired and unpaired), and chi-square tests with Bonferroni correction for multiple testing. Stepwise discriminant analysis was used for multivariate group differences between patients and control subjects regarding the 8 syndromes and the other problems scale of the CBCL (24). Those children with at least 1 t-score within the clinical range (67 or greater) were considered to be behaviourally disturbed. The cut-off level for 2-tailed statistical significance was set at P < 0.05. Data handling and analyses were carried out using SPSS for Windows, version 10.0. ResultsForty-five patients (48%) fulfilled the DSM-IV criteria for expressive language disorder; 49 children (52%) met the criteria for mixed receptive–expressive language disorder. None of the patients and control subjects enrolled in the present study had a pure speech disorder, and none of the control subjects fulfilled the DSM-IV criteria for any language disorder. Thirty-two children (34%) with LDD, 14 (31%) with an expressive language disorder, and 18 (37%) with a mixed receptive–expressive language disorder showed behaviour problems within the clinical range, whereas only 6 control subjects (6%) had scores within this range. Those syndromes that most frequently occurred in the clinical range for the members of the entire combined LDD sample turned out to be attention problems (14%), withdrawal (13%), thought problems (12%), and aggressive behaviour (10%), as reported by their mothers. The syndromes most often specified (above 10%) by mothers of children with an expressive language disorder were thought problems (11%), attention problems (11%), and aggressive behaviour (11%). For children with a mixed expressive–receptive language disorder, withdrawal (17%), attention problems (16%), thought problems (12%), and social problems (10%) were most often noted. Details are given in Table 1.
Group comparisons between patients and control subjects showed significant differences in all 8 syndromes and the other problems scale, with patients having higher scores. Details are shown in Table 2. Within the patient sample, group comparisons between children with expressive language disorder and mixed receptive–expressive language disorder showed no significant differences in any of the 9 scales (Table 3).
Multivariate stepwise discriminant analysis showed a significant discriminant function (canonical correlation r = 0.8; Wilk’s Lambda = 0.4; c² = 125.0; df 6; P < 0.0001) for the scales other problems, social problems, anxious–depressed, thought problems, attention problems, and delinquent problems. Ninety-two percent of control subjectss (sensitivity) and 76% patients (specificity) were classified correctly in their respective categories, with an overall correct classification of 86.3% (Table 4).
DiscussionThirty-two children (34%) with LDD, 14 (31%) with an expressive language disorder, and 18 (37%) with a mixed receptive–expressive language disorder were reported as having behavioural problems by their mothers, whereas only 6 (6%) control subjects had CBCL scores within the clinical range. Considering those syndromes that are most prevalent (that is, with greater than 10% incidence within the clinical range among the children with LDD), attention problems (14%), withdrawal (13%), thought problems (12%), and aggressive behaviour (10%) were reported. Nearly the same most frequent CBCL syndromes (attention problems, 47%; withdrawal, 39%; delinquent behaviour, 34%; and aggressive behaviour, 33%) were reported by parents of children with disorders in language development in a study by Noterdaeme and Amorosa (9), although they found higher frequencies for behavioural problems. The higher frequencies may stem from different forms of patient recruitment, the difference in patient age, or the different composition of the patient sample. Their patients were selected from a sample of children referred for diagnosis to the unit for developmental and behavioural disorders at a child and adolescent psychiatry facility in Munich after demonstrating a developmental language disorder. Our sample of children with LDDs was recruited from a university ear, nose, and throat clinic and was examined for behavioural problems through a routine psychological diagnostic process regarding general (that is, cognitive, language, and emotional–social) child development. The mean age of their patients (8.2 years) was higher than the mean age of ours (4.8 years). This may explain the higher frequency of behavioural problems, since the gap between children with disorders in language development and their normally developing peers tends to widen over time in several areas, such as language abilities (25), and cognitive and academic functioning (26), as well as emotional–social functioning (27). Difficulties in several areas may become more evident as children grow older. Children aged 3 to 6 years with specific language impairment show fewer behavioural problems (28) than older children (29). In follow-up studies, children with disorders in language development in preschool had increased rates of behavioural problems when reassessed later in childhood (28). In the study by Noterdaeme and Amorosa (9), 41% of the patient sample were children with expressive language disorder and 59% were children with receptive disorders, whereas in our sample, 48% of the children had expressive language disorder and 52% had a mixed receptive– expressive disorder. It seems to be rather unlikely that the differences in the frequencies of behavioural problems were caused by different patient sample compositions. Children with mixed disorders in receptive and expressive language development were indeed more likely to show scores within the clinical range with respect to withdrawal and attention problems, whereas children with disorders in expressive language development more frequently reported “somatic complaints”; however, group comparisons within both the language disorder groups yielded no significant differences. The univariate group comparisons among all children with disorders in language development and age- and sex-matched children without problems in their language development showed significantly higher CBCL scores among the children with LDD. The multivariate stepwise discriminant analysis correctly classified 92% of control subjects as control subjects (sensitivity) and 76% of patients as patients (specificity); the overall correct classification was 86.3% by the CBCL scales other problems, social problems, anxious–depressed, thought problems, attention problems, and delinquent problems. Coster and others reported that children with specific language impairment did not demonstrate more externalized behaviour than children without language problems and suggested that the absence of aggressive behaviour might be a characteristic of children with specific language impairment (10). Our results could not confirm this hypothesis, because the univariate results yielded significant differences between the children with LDD and the control subjects with respect to aggressive behaviour and delinquent problems, and the multivariate stepwise discriminant analysis showed that higher scores in delinquent problems, in addition to other scales, contribute significantly to the classification of a child as having LDD. In general, our results agree with several studies that report that children with speech and language disorders are at special risk for developing behavioural problems (9,10). There are at least 3 possible explanations for the association between disorders in language development and behavioural problems.
Some of the early and more obvious effects of a neurodevelopmental immaturity could appear in the form of delays in speech or language development and in a lower mental age. Several studies reported verbal and nonverbal intellectual disabilities in children with disorders in language development (4). Further, it may emerge in the form of neurological signs (42). Slight structural and functional brain abnormalities, in contrast to serious ones, have been reported (43). Neuropathological studies of the brain of a 7-year-old girl with developmental dysphasia revealed atypical symmetry of the plana temporale and a dysplastic gyrus on the inferior surface of the left frontal cortex along the inferior surface of the sylvian fissure. According to Cohen and others, these abnormalities are likely related to midgestation, the period of neuronal migration from the germinal matrix to the cerebral cortex, and are consistent with a neurodevelopmental cause of developmental dysphasia (44). EEG studies showed epileptic abnormalities in 9 children (rare in 4 cases and frequent in 5 cases) with expressive developmental dysphasia, but according to Duvelleroy-Hommet and others, it is unlikely that EEG abnormalities could have produced dysphasia (45). Single photon emission computed tomography (SPECT) studies showed that functional specialization of both hemispheres is impaired in developmental dysphasia (46). High-resolution magnetic resonance imaging (MRI) revealed bilateral parietotemporal gray matter heterotopias in monozygotic male twins with a developmental language disorder, more frequently in the left hemisphere than in the right and more pronounced in the more affected twin (47). They suggested that neuronal migration defects and ensuing focal heterotopias might be causally related to developmental language disorder. Trauner and others reported neurological abnormalities in 70% of children with developmental language impairment; the most common abnormalities featured obligatory synkinesis, fine motor impairments, and hyperreflexia (48). Further, about one-third of these children had abnormal MRI scans, including ventricular enlargement, central volume loss, and white matter abnormalities. They suggested that language impairment is indicative of more widespread nervous system dysfunction. Preis and others found normal left–right asymmetry of the planum temporale and planum parietale in 21 right-handed children with developmental language disorder when compared with 21 matched control subjects (49). The planum temporale was bilaterally smaller in the affected children, which seems to account for their approximately 7% smaller forebrain sizes. They suggested that their findings do not support a role of gross visible unilateral abnormalities of posterior intrasylvian ontogenesis in this disorder. In contrast to the results of Preis and others (49), the neuroanatomical findings of Gauger and others (50) demonstrate that the areas of the brain subserving language function in the left hemisphere (the planum and pars triangularis) are significantly different in size and shape in children with LDD when compared with children without language deficits. The typical leftward asymmetry for the planum and pars triangularis was not found in most of the LDD children. The pars triangularis was significantly smaller in the left hemisphere, and children with LDD were more likely to have right-side asymmetry of language structures, which suggests a structure–function relation between the language structures of the brain and language ability. They suggested that atypical asymmetry of perisylvian structures may indicate an absence of the necessary establishment of neural networks required for specific functions, such as language (51). The limitations of this study are the collection of the cross- sectional and checklist-based child behaviour data using a clinical sample, which possibly limits the generalizability of the findings. For future studies, it would be very interesting to investigate child behaviour using an experimental design between a clinical and a nonclinical sample. Moreover, longitudinal studies exploring the association between LDD and child behaviour would be also very informative. To conclude, behavioural manifestations may be both direct and indirect expressions of a neurodevelopmental immaturity (41). The risk of psychiatric disorder among speech- or language-impaired children will increase as a function of the underlying severity of the neurodevelopmental immaturity— the more limited and specific the impairment, the milder the neurodevelopmental delay and the better the prognosis (7). 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Neuropathological abnormalities in developmental dysphasia. Ann Neurol 1989;25:567–70. 45. Duvelleroy-Hommet C, Billard C, Lucas B, Gillet P, Barthez MA, Santini JJ, and others. Sleep EEG and developmental dysphasia: lack of a consistent relationship with paroxysmal EEG activity during sleep. Neuropediatrics 1995;26:14–8. 46. Chiron C, Pinton F, Masure MC, Duvelleroy-Hommet C, Leon F, Billard C. Hemispheric specialization using SPECT and stimulation tasks in children with dysphasia and dystrophia. Developmental Medicine and Child Neurology 1999;41:512–20. 47. Preis S, Engelbrecht V, Huang Y, Steinmetz H. Focal grey matter heterotopias in monozygotic twins with developmental language disorder. European Journal of Pediatrics 1998;157:849–52. 48. Trauner D, Wulfeck B, Tallal P, Hesselink J. Neurological and MRI profiles of children with developmental language impairment. Developmental Medicine and Child Neurology 2000;42:470–5. 49. Preis S, Jäncke L, Scittler P, Huang Y, Steinmetz H. Normal intrasylvian anatomical asymmetry in children with developmental language disorder. Neuropsychologia 1998;36:849–55. 50. Gauger LM, Lombardino LJ, Leonard CM. Brain morphology in children with specific language impairment. Journal of Speech, Language, and Hearing Research 1997;40:1272–84. 51. Galaburda AM. Ordinary and extraordinary brain devleopment: anatomical variation in developmental dyslexia. Annals of Dyslexia 1989;39:67–79. Author(s)Manuscript received August 2002, revised, and accepted April 2003. 1. Associate Professor, Department of Phoniatrics and Logopedics, University Ear, Nose, and Throat Clinic, Vienna, Austria. 2. Research Scientist, Department of Neuropsychiatry of Children, LKH Klagenfurt, Austria. 3. University Assistant, Department of Phoniatrics and Logopedics, University Ear, Nose, and Throat Clinic, Vienna, Austria. 4. Research Scientist, Department of Phoniatrics and Logopedics, University Ear, Nose, and Throat Clinic, Vienna, Austria. 5. Assistant Professor, Department of Psychology, Vienna, Austria. 6. Associate Professor, Department of Medical Psychology, Vienna, Austria Address for correspondence: Dr U Willinger, Department of Phoniatrics and Logopedics, University Ear, Nose, and Throat Clinic, Waehringer Guertel 18-20, A-1090 Vienna, Austria e-mail: ulrike.willinger@univie.ac.at
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