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Biomedical subjects

S W Anderson

Publications and source records attributed to S W Anderson.

33 records · Page 2Linked to original sources
PubMed1992

Acquisition of signs from American sign language in hearing individuals following left hemisphere damage and aphasia.

Three severely aphasic hearing patients with no prior knowledge of sign language were able to acquire competency in aspects of American Sign Language (ASL) lexicon and finger spelling, in contrast to a near complete inability to speak the English counterparts of these visuo-gestural signs. Two patients with damage in left postero-lateral temporal and inferior parietal cortices mastered production and comprehension of single signs and short meaningful sign sequences, but the one patient with damage to virtually all left temporal cortices was less accurate in single sign processing and was unable to produce sequences of signs at all. These findings suggest that conceptual knowledge is represented independently of the auditory-vocal records for the corresponding lexical entries, and that left anterior temporal cortices outside of traditional "language areas" are part of the neural network which supports the linkage between conceptual knowledge and linguistic signs, especially as they are used in the sequenced activations required for production or comprehension of meaningful sentences.

Adult↗
PubMed1991

Wisconsin Card Sorting Test performance as a measure of frontal lobe damage.

We examined the sensitivity and specificity of the Wisconsin Card Sorting Test (WCST) as a measure of frontal lobe damage in 91 subjects with stable focal brain lesions. Anatomical information about the location and extent of brain damage was obtained from MR and CT transparencies. No significant differences in WCST performance were found between subjects with frontal vs. nonfrontal damage. Some subjects with extensive frontal lobe damage performed well on the WCST, and some subjects with damage outside of the frontal lobes failed. The optimal cutoff scores for discriminating frontal from nonfrontal subjects correctly classified only 62% of the subjects. Further analysis of WCST performances associated with damage to various subregions of the frontal lobes also failed to reveal any reliable relationships. These findings indicate that performance on the WCST cannot be interpreted in isolation as an index of frontal lobe damage.

Aging↗
PubMed1990

Neuropsychological impairments associated with lesions caused by tumor or stroke.

Populations of patients with strokes or tumors constitute the most frequently used subjects in neuropsychological research, and these populations are often combined when the investigation aims at establishing brain-behavior relationships. We compared these two populations with respect to their neuropsychological profiles. Seventeen subjects with tumors were individually matched to subjects with unilateral strokes on the basis of lesion location. Despite close matching of lesions, there were major differences in the neuropsychological impairments of the two groups, eg, all subjects with stroke in the left hemisphere had more severe language defects than did their counterparts with tumors, and some tumor subjects performed normally on all neuropsychological tests. These findings demonstrate that the cognitive and/or behavioral consequences of tumors or strokes in similar locations can be radically different. The two patient types should be treated separately for the purpose of neuropsychological research.

Adult↗
PubMed1990

Troubled letters but not numbers. Domain specific cognitive impairments following focal damage in frontal cortex.

A well educated right-handed woman developed severe and stable alexia and agraphia following a circumscribed surgical lesion in the left premotor cortex. The lesion was located in Brodmann's field 6, above Broca's area, in the region traditionally referred to as Exner's area. The alexia and agraphia occurred in a pure form, that is, in the setting of otherwise normal cognitive and neurological function. She was not aphasic or hemiparetic and her visual perception, intellect, memory, oral spelling and drawing were normal. The patterns of impairment of reading and writing closely paralleled one another. Reading of single words and letters was severely impaired, and she was entirely unable to read sentences. She was virtually unable to write recognizable letters, could write no words, and her writing attempts were severely distorted spatially. By contrast, she could easily read all numbers and nonverbal symbols, and she was equally able to write numbers and perform written calculations without difficulty. These striking dissociations provide further evidence of the domain specificity of cognitive/neural representations. They also point to the possible role of premotor cortices in the coactivation of precise sequences of motor and sensory activity patterns involved in reading and writing.

Agraphia↗
PubMed1988

Serial position memory of boys with Duchenne muscular dystrophy.

Ten male patients with Duchenne muscular dystrophy (DMD) and 10 age-matched controls were tested with the WISC-R and a memory test requiring recall of the serial positions of drawings of easily named objects. After statistically controlling for differences in IQ, the two groups did not differ in their ability to recall the most recently presented items. However, the DMD patients were severely impaired in remembering items presented early in the list. The DMD patients also performed poorly on the WISC-R subtests Digit Span and Arithmetic. This pattern of impairment is discussed in terms of possible verbal mediation and attentional deficits.

Adolescent↗
PubMed1986

Fundamental frequency patterns during spontaneous picture description.

This study was conducted to determine if fundamental voice frequency (F0) decreases throughout the course of spontaneously produced sentences, and if so, to compare the declination pattern associated with spontaneously produced sentences to the declination pattern which is reliably found when speakers read isolated sentences aloud. A picture description task was used to elicit original sentences of the speakers' own formulation while still providing considerable experimental control over the semantic content and syntactic structure of the sentences. Five speakers each formulated and produced five sentences in the picture description task and read aloud five matched sentences. F0 declination reliably occurred in one- and two-clause sentences in spontaneous speech and oral reading. There were no differences between the declination slopes in the two speech modes. We concluded that the domain of F0 declination is not strictly limited to read speech. Comparison of these findings with other recent reports suggests that declination is characteristic of sentences spoken in isolation but not of lengthy passages, independent of whether the speaker is reading aloud or speaking spontaneously.

Adult↗
PubMed1985

Speed of color naming and degree of familial sinistrality: correlation in girls, no correlation in boys.

Twenty-nine male and 35 female right-handed children, aged 5 to 7, were assessed for the effect of familial sinistrality on a rapid color-naming task. Controlling for age and family size, a significant effect for degree of familial sinistrality was found in the girls but not in the boys. Among the girls, those with two or more left-handed or ambidextral relatives were the fastest on the color-naming task, those with no such relatives were the slowest, and those with only one left-handed or ambidextral relative scored between the other two groups in color-naming speed. It is suggested that a gene associated with left-handedness, when present in a right-hander, interacts with sex to produce the superior color-naming performance that we observed in girls but not in boys.

Age Factors↗
PubMed1985

Speed of color naming and intelligence: association in girls, dissociation in boys.

We administered a rapid naming test to a sample of prereaders. Slow performance on this task among older children is known to be associated with reading disability. Results showed a sex difference in the degree of correlation between naming performance and a test of general intelligence. The finding was replicated on an independent sample. This finding bears theoretically on the degree to which a learning disability can appear as an isolated deficit in the two sexes.

Child↗
PubMed1984

Timing analysis of coding and articulation processes in dyslexia.

Several investigators have found that the time required to perform serial naming tasks is a good predictor of dyslexia in children. Protracted overall time scores, such as are reported for the Rapid Automatized Naming (RAN) test of Denckla and Rudel, are, by themselves, insufficient to determine the extent to which the performance deficit is cognitive in nature, or is the articulatory consequence of an inability master the quickly changing acoustic formant patterns associated with consonants, as proposed by Tallal. We administered the RAN test to matched groups of dyslexic and normal control children, aged 8 to 11 years. Measurement of speech signal durations was performed by computer. We applied the Gould and Boies algorithm for extracting cognitive preparation time to these data, resulting in a partition of overall RAN test score into coding time and articulation time components. Differential performances between the groups on RAN subtests were examined for effects of postvocalic consonants and semantic load. It was found that both vocalization time and pause time means were significantly longer for the dyslexics on each of the four RAN subtests: objects, colors, numbers, letters. The Gould and Boies analysis showed very little preparation time during speech in both groups, attributing virtually all coding time to pauses, although reanalysis suggested somewhat less. Increased vowel length among the dyslexics occurred on all subtests, but was not maximized on subtests with more numerous postvocalic consonants. Vowel time differences between groups accounted for nearly all of the differences in vocalization time. Profiles were constructed on speech measures which, for each subtest, correctly identified each subject with his group. On the letters subtest it was found that vowel duration alone achieved a perfect discrimination between the dyslexic and control subjects.

Child↗
PubMed1983

Long-term effects of treatment on endocrine function in children with brain tumors.

Fourteen children with brain tumors received endocrine evaluations at least one year following completion of cranial irradiation. Treatment consisted of operation (13 patients), craniospinal irradiation (6), whole brain irradiation (5), posterior fossa irradiation (3), and chemotherapy (10). Endocrine evaluation included bone age roentgenography and measurement of growth hormone (using sequential arginine and insulin stimulation), thyroxine, thyroid-stimulating hormone, plasma cortisol, testosterone, prolactin, and urinary follicle-stimulating hormone and luteinizing hormone. Ten of 12 children (83%) had abnormal responses to both tests of growth hormone stimulation. All growth hormone-deficient patients treated prior to puberty and tested at least 2 years following completion of cranial irradiation had decelerated linear growth. Results of thyroid function tests were abnormal in 4 patients: 2 patients had evidence of primary hypothyroidism, and 2 showed secondary or tertiary hypothyroidism. Two patients had inadequate cortisol responses to insulin hypoglycemia. Urinary follicle-stimulating hormone and luteinizing hormone, serum prolactin, and serum testosterone levels were appropriate for age in all patients.

Adolescent↗
PubMedDate not supplied

Insensitivity to future consequences following damage to human prefrontal cortex.

Following damage to the ventromedial prefrontal cortex, humans develop a defect in real-life decision-making, which contrasts with otherwise normal intellectual functions. Currently, there is no neuropsychological probe to detect in the laboratory, and the cognitive and neural mechanisms responsible for this defect have resisted explanation. Here, using a novel task which simulates real-life decision-making in the way it factors uncertainty of premises and outcomes, as well as reward and punishment, we find that prefrontal patients, unlike controls, are oblivious to the future consequences of their actions, and seem to be guided by immediate prospects only. This finding offers, for the first time, the possibility of detecting these patients' elusive impairment in the laboratory, measuring it, and investigating its possible causes.

Adult↗