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Biomedical subjects

D M Aram

Publications and source records attributed to D M Aram.

At least 19 recordsLinked to original sources
PubMed1998

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.

Analysis of Variance↗
PubMed1997

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.

Adolescent↗
PubMed1997

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).

Apraxias↗
PubMed1997

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.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1994

Limits to a left hemisphere explanation for specific language impairment.

The hypothesis of unilateral left hemisphere damage as an explanatory model for the neurological basis of specific language impairment (SLI) does not appear to be sufficient for most children with SLI. Children with unilateral brain lesions have been shown to function significantly lower than their neurologically intact peers on a variety of language measures, yet few of the deficits noted are as persistent or severe as those seen in SLI. In at least two instances, however, language symptomatology following unilateral lesions in children does parallel some types of SLI. The first occurs following subcortical damage to anterior grey and white matter structures that typically results in pronounced language and learning disorders. The second parallel lies in the similar developmental course shared by children with "delayed" language and children with known unilateral lesions, whereby language onset and development is slow in the preschool years but normalizes by school age, with minimal long-term language-learning deficits.

Brain↗
PubMed1993

Relationship between language and fluency in children with developmental language disorders.

The present investigation addresses two primary hypotheses: (a) that a subset of children with developmental language disorders exhibits significantly more disfluencies than other children with language disorders and (b) that differences between the disfluent and nondisfluent groups observed in fluency may be related to differences in language deficits. Spontaneous language samples from 60 preschool children with developmental language disorders were analyzed for frequency and type of disfluencies. Comparisons of the frequency of disfluencies across subjects revealed that a subset of 10 subjects exhibited significantly more disfluencies than the other subjects with language disorders. Demographic, intelligence, and language variables were compared across the two groups to determine whether such factors could account for the differences in fluency. The subjects with greater percentages of disfluencies were found to be significantly older and demonstrated significantly higher scores on two standard measures of vocabulary. These findings were interpreted in light of two models of disfluencies: the neuropsycholinguistic (Perkins, Kent, & Curlee, 1991) and Demands and Capacities (Adams, 1990; Starkweather, 1987). This suggests that some children with language disorders are at risk for fluency breakdown because of dysynchronies in the development of lexical and syntactic aspects of language or as a result of mismathces between speaking demands and capacities.

Age Factors↗
PubMed1993

Clinical and research congruence in identifying children with specific language impairment.

This paper reports on the results of a large multicenter project designed to develop an empirically based classification of preschool children with language impairments. A clinically selected population of 252 children with specific language impairments (SLI) was used to evaluate the reliability, coverage, and usefulness of both standard clinical and research definitions of such children. Varying degrees of congruence were found between the clinically identified children with SLI and those identified as SLI using discrepancy, deficit, and standardized operational criteria. Such mismatch between the original clinical identification and more standardized operational criteria may be related to different clinical perspectives, professional training, and limited assessment measures. These results suggest that there is a significant gulf between the clinical diagnosis of children with specific language impairment and more standardized operational criteria. It is suggested that the global concept of a "specific language impairment" may not be a useful concept for either clinical or research activities.

Age Factors↗
PubMed1992

Mathematics performance in left and right brain-lesioned children and adolescents.

Children and adolescents with unilateral left- or right-hemisphere lesions were administered a standardized test of mathematics ability and a battery of experimental tests that examined the components of numerical and arithmetic processing. All lesioned groups showed at least marginally lower scores on the standardized test than the controls. More importantly, lesion-related deficits in performance were observed, especially for younger left-lesioned subjects (ages 7-12), on the verbal counting, digit matching, speeded addition, and written subtraction tasks; deficits among younger right-lesioned subjects were similar in nature, yet less pronounced than in the left-hemisphere group. Older left-lesioned subjects showed differences from their controls only on complex verbal counting and speeded addition. Correlations among the various measures indicated two further points. First, earlier onset of left-hemisphere lesion is associated with more serious disruption of mathematical processing. Second, these disruptions are not well assessed by a typical standardized test of mathematical performance, but are clearly in evidence with more precise, focused tasks.

Adolescent↗
PubMed1992

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.

Achievement↗
PubMed1991

Very-low-birthweight children and speech and language development.

Very low birthweight (VLBW) is often considered to be a risk factor for speech and language disorders, yet data are equivocal. The present study compared speech and language comprehension and production between 249 very-low-birthweight (VLBW: less than 1.5 kg) and 363 normal-birthweight 8-year-olds, randomly sampled in a geographic area. Mean performance for the entire group of VLBW children and for the group when 24 VLBW children with major neurologic abnormalities were excluded, was significantly lower than for controls on the majority of speech and language measures. Further analyses addressed the clinical significance of these statistically significant differences. Test scores were converted to standard scores and grouped according to standard deviation intervals, thus portraying each child's performance in terms of the magnitude of discrepancy from each test's mean. When the 24 children with major neurological abnormalities were excluded, no significant differences between the VLBW and control children were observed. Using discrepancy between WISC-R performance IQ and language to define specific language impairment (SLI), a higher percentage of control than VLBW children were identified as having SLI. Neonatal risk factors did not differentiate between VLBW children with or without SLI. A higher proportion of VLBW than control children did present subnormal language associated with IQ less than 85, hearing deficits, and/or major neurological impairments. Thus, SLI is not more common among VLBW than control children. Language deficits accompanied by more general developmental problems, however, are more frequent.

Chi-Square Distribution↗
PubMed1990

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.

Aphasia, Broca↗
PubMed1989

A familial study of severe phonological disorders.

The present study examined the familial basis for severe phonological disorders. Twenty children with severe phonological disorders and their siblings were compared to 20 normally developing children and their siblings on measures of phonology, language, reading, and motor ability. Results revealed that the siblings of the disordered children performed more poorly than control siblings on phonology and reading measures. Disordered subjects' phonological skills correlated significantly and positively with their siblings', whereas controls' scores did not. Families of disordered children reported significantly more members with speech and language disorders and dyslexia than did families of controls. Sex differences were reflected in the incidence but not the severity or type of disorder present. These findings suggest a familial basis for at least some forms of severe phonological disorders.

Child↗
PubMed1989

Language and motor findings in benign megalencephaly.

9 children between the ages of 5 and 12 yr. whose head circumferences were greater than the 98th percentile and showed negative CT scans and histories for disease associated with increased brain size were studied. A battery of language, articulation, intelligence, and motor tests were administered to subjects and in each case to a sibling whose head circumference was normal. Analysis showed few differences in intelligence and language comprehension between the megalencephalic children and their siblings. Significant differences were observed in motor proficiency, with over 50% of the megalencephalic children scoring below the 10th percentile for their age group. Three megalencephalic children displayed articulation errors. All subjects had at least one parent whose head circumference exceeded the 98th percentile. These results suggest a relationship between benign megalencephaly and developmental motor difficulties.

Cephalometry↗
PubMed1988

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.

Achievement↗
PubMed1988

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.

Auditory Pathways↗