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Biomedical subjects

E Bates

Publications and source records attributed to E Bates.

At least 55 records · Page 3Linked to original sources
PubMed1993

Acute effects of dobutamine on myocardial oxygen consumption and cardiac efficiency measured using carbon-11 acetate kinetics in patients with dilated cardiomyopathy.

OBJECTIVES: The aim of this study was to use positron emission tomography (PET)-derived carbon (C)-11 acetate kinetics to determine the effects of dobutamine on oxidative metabolism and its effects on myocardial efficiency in a group of patients with dilated cardiomyopathy. BACKGROUND: Dobutamine is known to improve myocardial function but may do so at the expense of myocardial oxygen consumption, which could be a potential deleterious effect. Carbon-11 acetate kinetics correlate with myocardial oxygen consumption as shown in animal models. Combining these scintigraphic measurements of oxygen consumption with estimates of cardiac work results in a work-metabolic index, which reflects cardiac efficiency. METHODS: Eight patients with nonischemic dilated cardiomyopathy underwent dynamic PET imaging, echocardiography and hemodynamic measurements. Seven of these patients were also studied while receiving dobutamine. Direct measurements of myocardial oxygen consumption using coronary sinus catheterization were obtained with eight of the PET studies to validate C-11 acetate in patients with cardiomyopathy. RESULTS: The mean (+/- SD) C-11 clearance rate significantly increased with dobutamine from 0.105 +/- 0.027 to 0.155 +/- 0.023 min-1 (p = 0.001). Directly measured myocardial oxygen consumption had a linear relation to the mean C-11 clearance rate (r = 0.8, p = 0.018). Dobutamine was noted to significantly reduce systemic vascular resistance as well as the severity of mitral regurgitation. The work-metabolic index determined using hemodynamic variables and PET data increased from 2 +/- 0.7 x 10(4) to 2.6 +/- 0.6 x 10(4) (p = 0.04). Efficiency, estimated by employing the oxygen consumption to k2 relation, also increased from 13 +/- 4.5% to 16.9 +/- 6.4% (p = 0.04). CONCLUSIONS: Despite an increase in myocardial oxygen consumption, dobutamine led to an increase in work-metabolic index in patients with dilated nonischemic cardiomyopathy. Dobutamine reduced systemic vascular resistance and mitral regurgitation, suggesting that in this group of patients, it had important vasodilatory action in addition to its inotropic effects. The use of the C-11 acetate PET for determining myocardial oxygen consumption and estimating efficiency could potentially complement existing clinical measures of ventricular performance and may allow improved and objective evaluation of therapy in patients with heart failure.

Adult↗
PubMed1993

Early lexical development in Spanish-speaking infants and toddlers.

This paper describes the early lexical development of a group of 328 normal Spanish-speaking children aged 0;8 to 2;7. First the development and structure of a new parent report instrument, Inventario del Desarollo de Habilidades Communicativas is described. Then five studies carried out with the instrument are presented. In the first study vocabulary development of Spanish-speaking infants and toddlers is compared to that of English-speaking infants and toddlers. The English data were gathered using a comparable parental report, the MacArthur Communicative Development Inventories. In the second study the general characteristics of Spanish language acquisition, and the effects of various demographic factors on that process, are examined. Study 3 examines the differential effects of three methods of collecting the data (mail-in, personal interview, and clinic waiting room administration). Studies 4 and 5 document the reliability and validity of the instrument. Results show that the trajectories of development are very similar for Spanish- and English-speaking children in this age range, that children from varying social groups develop similarly, and that mail-in and personal interview administration techniques produce comparable results. Inventories administered in a medical clinic waiting room, on the other hand, produced lower estimates of toddler vocabulary than the other two models.

Child Development↗
PubMed1993

Subglottic plasmacytoma: the use of jet ventilation and contact Nd:YAG laser for tissue diagnosis.

Extramedullary plasmacytomas (EMP) constitute only 1% of all head and neck malignancies, with the vast majority occurring in the upper respiratory tract. The diagnosis of laryngeal EMP can be difficult since the symptoms are non-specific and the tumor usually mucosally covered. This paper discusses the successful combination of jet Venturi ventilation technique with suspension microlaryngoscopy and contact Nd:YAG laser for tissue diagnosis in a patient presenting with a large subglottic mass. Previous attempts using standard endotracheal intubation and forceps technique for biopsy failed to reach the diagnosis and resulted in significant bleeding from the biopsy site. A review of the disease and technique is presented.

Biopsy↗
PubMed1992

Language development.

Recent research suggests that our ability to learn language is innate, but not necessarily domain-specific. That is, language development appears to be based on a relatively plastic mix of neural systems that also serve other cognitive and perceptual functions. Evidence in support of this conclusion includes neural network simulations of language learning, event-related brain potential studies of normal language development, and studies of language development in several clinical populations of subjects suffering focal brain injury, specific language impairment, and contrasting forms of mental retardation.

Humans↗
PubMed1991

A maximum likelihood procedure for the analysis of group and individual data in aphasia research.

The limitations inherent in group versus case studies appear to lie in a complementary distribution, underscoring the importance of combining both strategies within a single research program. However, this compromise approach requires analytic tools that permit us to combine and evaluate individual and group data in a common format. Maximum likelihood estimation (MLE) belongs to a family of procedures for determining goodness of fit. MLE can be used in conjunction with a linear or nonlinear model of the way that sources of information combine to determine a given behavioral outcome; such models can be used to estimate the distance between two groups, the degree to which an individual case deviates from a given empirically or theoretically defined group profile, and the degree to which one individual case resembles another. We offer a demonstration of how MLE can be used to evaluate group and individual profiles, in a cross-linguistic study of sentence comprehension in nonfluent aphasic speakers of English, Italian, and German. This includes a demonstration in which the MLE models for each language are "lesioned" to simulate several competing accounts of receptive agrammatism.

Aphasia↗
PubMed1991

Statistical constraints on the use of single cases in neuropsychological research.

In a recent study by Miceli, Silveri, Romani, and Caramazza (Brain and Language, 1989, 36, 447-492), free speech records for 20 unselected Italian-speaking agrammatic patients were analyzed along a variety of linguistic parameters, with particular emphasis on substitution and omission errors within traditional "part of speech" categories. The authors draw two strong conclusions: (1) the variability observed in this sample is too great to justify grouping these patients (or any coherent subset of the patients) into the "same" clinical category; (2) the extensive variability displayed by these patients reflects meaningful and very specific patterns of dissociation that would be lost if patients were grouped together in a common category called "aggrammatism." In a reanalysis of the Miceli et al. data, we conclude that the evidence does not justify either of these conclusions. First, we provide a set of mathematical simulations demonstrating that the dissociations claimed by Miceli et al. could have occurred entirely by chance, if samples of speech were drawn randomly from a "universe of discourse" characterized by error rates similar to those displayed by patients in this study. This randomization method has considerable generality, and could prove useful to other investigators interested in determining the number and type of dissociations that are likely to occur by chance in individual and/or group studies. Second, we demonstrate that there are many confounding factors that could account for the variability observed by Miceli et al., including differences in neurological status, education, and the strategies that patients elect to deal with their limitations.

Aphasia, Broca↗
PubMed1991

Early lexical development in children with focal brain injury.

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.

Brain Injuries↗
PubMed1991

The noun-verb problem in Chinese aphasia.

Previous studies have shown that Broca's aphasics experience a selective difficulty with action naming inside or outside of a sentence context. Conversely, it has been suggested that Wernicke's aphasics are particularly impaired in object naming. A number of explanations have been offered to account for this double dissociation, including grammatical accounts according to which the main verb problem in agrammatic Broca's aphasics is viewed as a by-product of their syntactic and/or morphological impairment, due perhaps to the greater morphological load carried by verbs (compared with nouns). In the Chinese language, there are no verb conjugations and no declensions. Hence there is no reason to expect a relationship between morphological impairment and deficits in action naming. We examined comprehension and production of object and action names, outside of a sentence context, in a sample of Chinese-speaking Broca's and Wernicke's aphasics. There was an interaction between patient group and object/action naming, but no corresponding interaction on the comprehension task. We conclude that action-naming deficits in Broca's aphasia (and/or the corresponding sparing of action names in Wernicke's aphasia) cannot be attributed to morphological differences between nouns and verbs. We also found a sublexical variant of the noun/verb dissociation applied to the internal structure of compound words made up of a verbal and a nominal element: Broca's aphasics tended to lexicalize the verbal portion of these words more often than the nominal compound, while Wernicke's showed the opposite pattern. These sublexical effects are difficult to explain in syntactic terms nor do they fit the standard lexical view. A modified lexical account is proposed, emphasizing semantic/conceptual effects in a distributed lexicon.

Adult↗
PubMed1991

A crosslinguistic study of grammaticality judgments in Broca's aphasia.

Crosslinguistic studies of sentence comprehension and production in Broca's aphasia have yielded two complementary findings: (1) grammatical morphology appears to be more impaired than word order principles in every language studied, but (2) the degree to which grammatical morphology is retained by aphasic patients depends upon the "strength" or importance of those morphemes in the patient's premorbid language. In an earlier study comparing violations of word order and agreement, we found that English-speaking Broca's aphasics showed greater sensitivity to errors of ordering than to errors of agreement, providing further evidence for the selective vulnerability of morphology. However, because English is a rigid word order language with a relatively weak inflectional system, it could be argued that word order is resilient to brain damage because it is the strongest source of information in this language. The present study compared the performance of English-speaking Broca's aphasics and normal controls with their Italian counterparts in the same grammaticality judgment experiment. Four predictions relating to our previous work were confirmed. (1) Italian aphasics, like their English-speaking counterparts, showed general preservation of grammatical knowledge and (2) they were able to use this knowledge in an "on-line" fashion. (3) Within each language, Broca's aphasics showed greater impairment in their ability to recognize errors of morphological selection (i.e., agreement) compared with errors made by moving the same words to an incorrect position downstream. Nevertheless (4), crosslinguistic differences observed in previous studies of comprehension and production were also observed in this grammaticality judgment task: a processing advantage for agreement errors in Italian normals and aphasics, and a processing advantage for ordering errors in English normals and aphasics.

Adult↗
PubMed1989

The validity of a parent report instrument of child language at twenty months.

When carefully assessed and analysed, parent report can provide a valuable overall evaluation of children's language at 20 months. Norming information and validity coefficients are presented here for a vocabulary checklist assessment included in the Early Language Inventory. Normative data are provided for fullterm, preterm, and precocious samples, including selected vocabulatory subsets that are indicative of early language learning style. The vocabulary checklist has substantial validity as indexed by correlations with the Bayley Scales of Infant Development and particularly with a language subscale derived from that test.

Child Language↗
PubMed1989

Language and cognition in two children with Williams syndrome.

In this study, aspects of language, single-gesture retrieval, combinatorial play, and visual-spatial cognition are reported in two children with Williams syndrome who were in the single-word stage of language acquisition. Williams syndrome children are of particular interest because, when older (10-15 years), they display an unusual profile of abilities that may include superior linguistic performance compared with other aspects of cognition. The two children in the present study are compared to a group of normal children in the single-word stage of language acquisition with a mean age of 14.8 months, a group of single-word stage children who are 6-18 months delayed, and a group of older normal children with a mean age of 23.5 months. Results are compatible with the unusual cognitive profile displayed by older Williams syndrome children. We discuss the possibility that this profile involves mechanisms that extend beyond the boundaries of language proper.

Child, Preschool↗
PubMed1988

Language and gesture in late talkers.

The relationship between language and symbolic gesture was studied in a group of young children who were in the lowest 10% for language production for their age based on information obtained from language inventories filled out by their parents. On a single scheme imitation task, designed to be a gestural analog of lexical production, subjects performed like controls matched for language production. On a multischeme imitation task, designed to be a gestural analog of syntax, subjects performed like age-matched controls, and significantly better than language-matched controls. Potential reasons for this dissociation are discussed in the context of predictors of early language success or impairment.

Child, Preschool↗