Intelligence and hypoxemia in children with congenital heart disease: fact or artifact?

Previous studies have reported lower intelligence for cyanotic than for acyanotic children with congenital heart disorders, a finding attributed to the degree of hypoxemia present. Several important variables have not been examined consistently, however, including coexisting neurologic or genetic disorders, definitive surgery, degree of sickness, age at testing sex and social class. The present study examined the relation of these variables to obtained intelligence measures for 82 consecutively admitted children, excluding children with abnormal neurologic examinations and those having received definitive surgery. Consistent with earlier reports, intelligence quotients for the acyanotic children (112.81 +/- 14.52 mean +/- SD) were significantly higher (t = 2.60; p = 0.006) than for the cyanotic group (103.50 +/- 15.81). Although sex, race and social class were not significantly different between the 28 cyanotic and the 54 acyanotic children, the cyanotic children were significantly sicker (x2 = 9.12; p = 0.005) and younger (t = 4.10; p = 0.001). However, when young and old children and the degree of sickness within cyanotic and acyanotic groups were compared, no significant differences were found. These findings demonstrate that intelligence differences between cyanotic and acyanotic children persist when the effect of neurologic abnormalities and definitive surgery is removed and remain despite the severity of sickness or child's age at testing.

Muteness of cerebellar origin.

Acute bilateral damage to large areas of both cerebellar hemispheres including the dentate nuclei led to temporary loss of speech in six children. In each case muteness was unassociated with motor paralysis, loss of higher cognitive functions, or cranial nerve dysfunction. Muteness lasted one to three months. All patients were severely dysarthric during recovery. We conclude that transient muteness may result from acute bilateral cerebellar injury.

Acquired capsular/striatal aphasia in childhood.

We studied a case of language loss caused by an acquired vascular lesion in the putamen, anterior limb of the internal capsule, and lateral aspect of the head of the caudate nucleus in a 7-year-old right-handed girl. Acute right-sided hemiplegia, mutism, oral apraxia, and disturbance in language comprehension but no dysarthria were present. During recovery, a nonfluent aphasia with anomia was evident. After six months, only mild hemiparesis and minor spelling difficulties persisted. We compared this patient with an 11-year-old right-handed girl with right-sided hemiparesis and dysarthria but no language loss following a lesion in the globus pallidus, a portion of the posterior limb of the internal capsule, and the body of the caudate. The presence of a language disturbance in the first but not the second patient was attributed to the difference in lesion location. The symptoms and lesions were similar to those in recent reports of adult patients. To our knowledge, this is the first report of these findings in a child with a left-hemisphere lesion.

Scholastic aptitude and achievement among children with unilateral brain lesions.

Cognitive abilities, scholastic aptitude and academic achievement were studied for 20 left hemisphere lesioned (LL) and 12 right hemisphere lesioned (RL) children in comparison with matched peers. On the Cognitive clusters, both LL and RL children performed significantly poorer than controls on the reasoning, perceptual speed and memory clusters. For the Scholastic Aptitude clusters, lesioned subjects performed significantly lower than controls on all clusters except for the knowledge cluster. On the Academic Achievement clusters, LL performed significantly poorer on the written language cluster while RL performed lower on the reading, math and written language clusters. Age of lesion onset, site of lesion and IQ differences are discussed in relationship to the ability clusters measured.

Auditory temporal perception of children with left or right brain lesions.

Twenty left and 12 right brain lesioned children were administered Tallal's Repetition Task in which they were required to discriminate, associate and sequence two nonverbal auditory stimuli. Unlike adults with left hemisphere injury or children with developmental language disorders previously described by Tallal, neither left nor right brain-lesioned children differ significantly from control subjects matched by age, sex, race and social class. These results contrast with earlier reports of impaired spoken syntax and delayed lexical retrieval among many of these same left lesioned children, suggesting that prelinguistic auditory processing and higher language deficits may be dissociable among young left hemisphere impaired children. The findings demonstrate that the higher level language deficits seen in the left brain lesioned children cannot be attributed to difficulty in more preliminary analyses of the acoustic stimuli.

Intellectual stability in children with unilateral brain lesions.

In this paper we report on the longitudinal stability of IQ in 26 children with unilateral left (LL N = 18) or right (RL N = 8) hemisphere damage. Results revealed (i) normal or near normal levels of intellectual performance in both LL and RL groups, and, (ii) hemispheric differences in the level and stability of intellectual performance. RL children achieved lower IQ scores than LL children and were more likely to decrease in VIQ over time. Cross-sectional analyses revealed a tendency for injury sustained earlier (e.g. during the first 5 years of age), rather than later in development to be associated with lower IQ scores.

Presentation, clinical course, and outcome of childhood stroke.

We reviewed the presentations, clinical courses, and outcomes of 42 children with unilateral hemispheric stroke. Infants with strokes identified within the first few days of life usually presented with seizures. These infants had few abnormal neurologic findings as neonates, but hemiparesis became evident as gross motor development proceeded. Infants with strokes identified later in the first year of life usually presented with pathologic early hand preference without a history of an ictus. During subsequent development, the motor deficits in these children became more evident, producing an apparent progression of the neurologic abnormalities. Strokes identified in older children typically presented as sudden hemiparesis, often associated with seizures. The hemiparesis in these children was most severe at the onset, followed by some improvement in strength in all patients. Functional outcome was variable. At last follow-up, all children were ambulatory, some with clinically apparent hemiparesis. Eight of the 42 children (19%) developed recurrent seizures with an onset ranging from 4 months to more than 10 years (median: 26 months) after the stroke.

Hyperlexia and dyslexia: A family study.

The condition of hyperlexia, often associated with autism, is a rare disorder in which children read words precociously but show little comprehension, markedly poor language, behavioral, and interpersonal skills. The relationship of hyperlexia and dyslexia has never been investigated, although suggestions have been made that the two conditions may be related. In light of current research on familial factors in autism, language disorder, dyslexia, and, recently, hyperlexia, this study investigated family histories of twelve hyperlexic children in regard to language, reading, writing, spelling, and other learning problems, handedness, and presence of allergies. Results suggest a distinct familial tendency to disorders of language, reading, writing, and spelling in male relatives, along with an unusually high instance of nonleft-handedness. Allergy information is inconclusive. Descriptive data are presented, and the relationship of symptomatology in hyperlexia and dyslexia is described and discussed. It is suggested that hyperlexia may represent a point of convergence of several genetically-linked developmental disorders.

Unilateral brain lesions in childhood: performance on the Revised Token Test.

Comprehension of connected language as assessed by the Revised Token Test (RTT) was studied in 17 children with left hemisphere lesions (LL) and 11 with right hemisphere lesions (RL). LL children's significantly lower performance on several subtests than left controls (LC) matched by age, sex, race, and social class appeared to be related to the memory demands of these subtests rather than the limited syntactic elements assessed by the RTT. LL subjects requested significantly more command repetitions than control or RL subjects and when a repetition was not requested LL subjects often responded with immediacy. Although RL children tended to perform lower than right matched controls (RC), these differences were not significant nor readily related to either the memory or specific linguistic structures assessed. RL subjects required fewer command repetitions than LL subjects and exhibited a significantly greater frequency of immediate responses than controls or LL subjects. While based on few children, a trend for LL children with retrorolandic lesions to perform more poorly than those with left prerolandic lesions was suggested. No systematic difference in performance was apparent for children with left cortical vs. left subcortical lesions or among discrete sites of lesions within the right hemisphere. Children with left lesions prior to 1 year of age performed no better and, in several instances, significantly poorer than LL patients sustaining lesions after 1 year of age. Among RL subjects, those sustaining lesions after 1 year of age had greater difficulty than those with lesion onset before 1 year of age, especially on linguistic elements which seemed to be dependent upon visual spatial properties. Further studies are needed to evaluate the comprehension of more complex linguistic structures among children with unilateral brain lesions as well as to study the role of more basic factors such as memory and attention in explaining the present findings.

Comprehension and imitation of syntax following early hemisphere damage.

Twenty-five children with early left (LL = 16) or right (RL = 9) hemisphere damage and 25 age-matched controls were tested on their comprehension and imitation of complex coordinate, passive, and relative clause structures using a matched experimental design. The predominant deficit exhibited by left-injured children was one of significantly impaired imitation coupled with relatively preserved comprehension. For RL subjects the deficit was less pronounced in either comprehension or imitation. Manipulation of surface and configurational features of sentence structure revealed task differences in the pattern of correct performance; however, error strategies observed across the two methodologies were shown to converge in a number of critical ways, as well as to replicate those previously obtained with adult aphasics. The results are interpreted as consistent with an early and continuous left hemisphere specialization for expressive syntax.

Handedness and sex of children with developmental language disorders.

The handedness and sex of 4- and 5-year-old children with developmental language disorders were studied through a comparison of language disordered children and a normal control group and through a comparison of six linguistically homogeneous subgroups of language disordered children. Differences between the handedness of a generalized language disordered group and a normal control group were not found, possibly due to the multiple etiologies of developmental language disorders. Children with severe language disorders, however, were non-right-handed more often than children with mild language disorders. Furthermore, certain types of linguistic deficits were associated with non-right-handedness, whereas age and cognitive abilities were not. Males were more often language disordered than females; however, sex ratios did not significantly differ among the subgroups, possibly due to the small number of language disordered females in this study. Implications for cerebral laterality in developmental language disorders are discussed.

Presupposition and implication of truth: linguistic deficits following early brain lesions.

Twenty-four children (4-17 years) with unilateral left (N = 14) or right (N = 10) hemisphere damage and 24 age-matched controls were tested on their ability to presuppose the truth of factive sentences e.g., "Max knew that he locked the door," and to infer the truth or falsity of implicative sentences "Max remembered to lock the door." Experimental sentence types varied according to the type of inference, the semantic features of the verb (factive vs. implicative), the presence and type of negation (lexical or syntactic), and the syntax of the complement (tensed or infinitive). Relative to age-matched controls, left lesion subjects were deficient in both their presupposition and implication performance, particularly when such inferences required the computation of negation scope. Right lesion subjects exhibited a somewhat more selective deficit; one limited to implication, but not presupposition, and one limited to lexical but not syntactic forms of negation.

Lexical retrieval in left and right brain lesioned children.

Performance on two measures of lexical retrieval for 19 left and 13 right brain lesioned children was compared to that of control subjects matched by age, sex, race, and social class. On the Word-Finding Test, left lesioned subjects were significantly slower in response time than left controls when given semantic and visual cues and made more errors when given rhyming cues. On the Rapid Automatized Naming Test, left lesioned subjects were significantly slower than left controls in naming all semantic categories, including colors, numbers, objects, and letters. In contrast, right lesioned subjects responded as quickly as or more quickly than did right controls in all access conditions and in naming semantic categories yet tended to produce more errors than their controls, suggesting a speed-accuracy tradeoff. Children sustaining left brain lesions before 1 year of age appeared to be as impaired as those whose lesions occurred after 1 year of age. Diverse lesion sites within the left hemisphere were associated with increased lexical retrieval latencies.

Fluency of conversational speech in children with unilateral brain lesions.

The spontaneous conversational speech of 20 children with unilateral left hemisphere lesions and 13 with right lesions was compared to normally developing peers matched by age, sex, race, and social class for instances of stuttering type nonfluencies, normal nonfluencies, and rate of speech. Both left and right lesioned children provided quantitatively more and qualitatively different patterns of nonfluencies than their neurologically normal peers. Left and right lesioned children produced more stuttering types of nonfluencies than their controls, but neither lesioned group produced a greater number of normal nonfluencies than controls. Left lesioned children also had a slower rate of speech as measured by number of syllables per second during either stuttered or fluent speech. Considerable variability was observed among lesioned children. Implications for neurogenic theories of developmental fluency disorders are discussed.

Spoken syntax in children with acquired unilateral hemisphere lesions.

The spoken syntax of eight left hemisphere lesioned and eight right hemisphere lesioned children were compared to matched controls. The children's lesions were acquired between 0.08 and 6.17 years of age (mean = 1.33 years), and at the time of testing they were between 1.67 and 8.15 years of age (mean = 4.19). Based on analyses of spontaneous language samples, left hemisphere lesioned subjects performed more poorly than did their controls on most measures of simple and complex sentence structure. In contrast right lesioned subjects performed similarly to their controls on these measures, except for a tendency to make more errors in simple sentence structures. These findings provide further evidence that the left and right hemispheres are not comparable in supporting syntactic abilities.

Developmental apraxia of speech: I. Descriptive and theoretical perspectives.

Developmental apraxia of speech (DAS) is a putative diagnostic category for children whose speech errors presumedly (a) differ from the errors of children with developmental speech delay (SD) and (b) resemble the errors of adults with acquired apraxia of speech. The studies reported in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) concern both premises, with primary focus on the first--that children with DAS can be differentiated from children with SD on the basis of one or more reliable differences in their speech error profiles. Immediate goals are to identify a diagnostic marker for DAS and to consider implications for research and clinical practice. A long-term goal is to identify the phenotype marker for DAS, on the assumption that it may be a genetically transmitted disorder. This first paper reviews relevant descriptive and theoretical perspectives. Findings from a local ascertainment study support the clinical functionality of the term suspected DAS.

Developmental apraxia of speech: II. Toward a diagnostic marker.

This second paper in a series on developmental apraxia of speech (DAS) (Shriberg, Aram, & Kwiatkowski, 1997a) reports findings from two studies. Study I compares speech and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with speech delay (SD). Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. Study II cross-validates these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. Discussion considers methodological and conceptual issues in the measurement of linguistic stress. Theoretical issues and implications for research and clinical practice are deferred for synthesis of the present findings with those from a multi-site cross-validation project (Shriberg, Aram, & Kwiatkowski, 1997b).

Developmental apraxia of speech: III. A subtype marked by inappropriate stress.

Two prior studies in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) address the premise that children with developmental apraxia of speech (DAS) can be differentiated from children with speech delay (SD) on the basis of one or more reliable differences in their speech. The first study compared segmental and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with SD. Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. The second study cross-validated these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. The present study is of particular interest because it cross-validates the prior stress findings, using conversational speech samples from 19 children with suspected DAS provided by five DAS researchers at geographically diverse diagnostic facilities in North America. Summed across the three studies, 52% of 48 eligible samples from 53 children with suspected DAS had inappropriate stress, compared to 10% of 71 eligible samples from 73 age-matched children with speech delay of unknown origin. Discussion first focuses on the implications of stress findings for theories of the origin and nature of DAS. Perspectives in psycholinguistics, neurolinguistics, and developmental biolinguistics lead to five working hypotheses pending validation in ongoing studies: (a) inappropriate stress is a diagnostic marker for at least one subtype of DAS, (b) the psycholinguistic loci of inappropriate stress in this subtype of DAS are in phonological representational processes, (c) the proximal origin of this subtype of DAS is a neurogenically specific deficit, (d) the distal origin of this form of DAS is an inherited genetic polymorphism, and (e) significant differences between acquired apraxia of speech in adults and findings for this subtype of DAS call into question the inference that it is an apractic, motor speech disorder. Concluding discussion considers implications of these findings for research in DAS and for clinical practice.

The validity of discrepancy criteria for identifying children with developmental language disorders.

Empirical data from two studies address the clinical validity of discrepancy criteria for identification of children with developmental language disorders (DLD). Study 1 involved 256 preschoolers clinically defined as DLD and meeting inclusionary criteria for normal hearing, intellectual, neurological, and psychiatric status. Application of alternative psychometrically derived discrepancy criteria identified only 40% to 60% of the clinically defined group as language disordered. Study 2 applied nonverbal IQ-language performance discrepancy criteria to 368 eight-year-old, randomly selected control subjects, resulting in over 45% of the controls being identified as DLD. Factors contributing to underidentification in Study 1 and over-identification in Study 2 are discussed, raising questions regarding the validity of discrepancy criteria for identification of DLD children.

Preschool language disorders and subsequent language and academic difficulties.

Sixty-three language-disordered children first evaluated in their preschool years were followed four to five years after initial diagnosis. At follow-up approximately 40% of these children continued to present speech and language problems and approximately 40% presented other learning problems. Preschool levels of language comprehension, formulation, semantics, syntax, phonology, and speech production were found to be moderately correlated to subsequent class placement in the elementary grades. Duration of preschool therapy was not related to either the severity of preschool language disorder or to any subsequent speech, language, or academic abilities. Duration of school therapy was related to severity of phonologic deficit as rated during the preschool years and to all follow-up ratings for speech, language, and academic abilities.