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Biomedical subjects

J R Tweedy

Publications and source records attributed to J R Tweedy.

14 recordsLinked to original sources
PubMed2000

Verbal pragmatics following unilateral stroke: emotional content and valence.

Verbal pragmatic aspects of discourse production were examined in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD), and 16 normal control right-handed adults. The facilitation effect of emotional content, valence hypothesis, and relationship between pragmatics and emotion were evaluated. Participants produced monologues while recollecting emotional and nonemotional experiences. Transcribed monologues were rated for appropriateness on 6 pragmatic features: conciseness, lexical selection, quantity, relevancy, specificity, and topic maintenance. Overall, brain-damaged groups were rated as significantly less appropriate than normals. Consistent with the facilitation effect, emotional content enhanced pragmatic performance of LBD aphasic participants yet suppressed performance of RBD participants. Contrary to the valence hypothesis, RBD participants were more impaired for positive emotions and LBD participants for negative emotions. Pragmatic appropriateness was not strongly correlated with a measure of emotional intensity.

Adult↗
PubMed1999

Psychometric aspects of verbal pragmatic ratings.

This study examined the psychometric aspects of a verbal pragmatic rating scale. The scale contained six pragmatic features (i.e., Conciseness, Lexical Selection, Quantity, Relevancy, Specificity, and Topic Maintenance) based on Grice's cooperative principles. Fifteen right brain-damaged (RBD), 15 left brain-damaged (LBD), and 16 healthy normal control (NC) right-handed adult participants produced narratives while recollecting emotional and nonemotional experiences. Naive raters evaluated each pragmatic feature for appropriateness on a 5-point Likert scale. When reliability was examined, the overall internal consistency of the pragmatic scale was extremely high (alpha =.96). Factor analysis was conducted to examine the theoretical relations among the six pragmatic features. Three meaningful factors involving discourse content, conceptual unity, and parsimony were identified. Findings are discussed in light of Grice's model and the construct validity of the scale.

Aged↗
PubMed1996

Hemispheric specialization for discourse reports of emotional experiences: relationships to demographic, neurological, and perceptual variables.

This study examined hemispheric specialization for discourse reports of emotional and nonemotional experience in 16 right-brain-damaged (RBD), 16 left-brain-damaged (LBD), and 16 demographically-matched normal control (NC) right-handed adults. Patient groups did not differ on etiology, months post-CVA onset, and intrahemispheric lesion location. Subjects were requested to produce monologues about positive and negative emotional and nonemotional experiences. The lexical content of written transcriptions of these monologues was later rated for "emotionality" by naive judges. Overall, RBDs described experiences with less emotional intensity than did NCs and LBDs, providing support for right hemisphere involvement in lexical emotion. Although the RBDs in the current study demonstrated similar patterns of deficits in a prior study [9] on tasks involving lexical emotional perception, there were no significant relationships between the current measures of emotional expression and the previous measures of emotional perception. Finally, the expression and the perception data were examined with respect to intrahemispheric factors. Among the brain-damaged subjects, subcortical structures were more involved in reports of emotional experience, and cortical structures were more involved in the perception of emotion.

Age Factors↗
PubMed1992

Right hemisphere specialization for the identification of emotional words and sentences: evidence from stroke patients.

This study examines the contribution of the lexical/verbal channel to emotional processing in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD) and 16 normal control (NC) right-handed adults. Emotional lexical perception tasks were developed; analogous nonemotional tasks were created to control for cognitive and linguistic factors. The three subject groups were matched for gender, age and education. The brain-damaged groups were similar with respect to cerebrovascular etiology, months post-onset, sensory-motor status and lesion location. Parallel emotional and nonemotional tasks included word identification, sentence identification and word discrimination. For both word tasks, RBDs were significantly more impaired than LBDs and NCs in the emotional condition. For all three tasks, RBDs showed a significantly greater performance discrepancy between emotional and nonemotional conditions than did LBDs or NCs. Results were not affected by the valence (i.e. positive/negative) of the stimuli. These findings suggest a dominant role for the right hemisphere in the perception of lexically-based emotional stimuli.

Aged↗
PubMed1992

Set-shifting and spatial orientation in patients with Parkinson's disease.

Individuals with Parkinson's disease were compared to normal control subjects on a series of widely used neuropsychological measures. The two groups were matched for gender, handedness, age, education, and occupation. The neuropsychological tests were chosen to measure two specific functions: (a) spatial orientation (i.e., measures of personal orientation, extrapersonal orientation, right/left orientation, and mental rotation), and (b) the ability to shift mental set (e.g., generating responses from alternating categories). The tests chosen to measure spatial orientation had no set-shifting component, and the tests chosen to measure set-shifting had no spatial orientation component. Multivariate statistical analyses revealed a significant difference between the subjects with Parkinson's disease and the control subjects on the measures of set-shifting ability. In contrast, no significant difference between the groups was observed on the measures of spatial orientation. These results are discussed in terms of the current speculation in the literature regarding the relationship between set-shifting deficits and a disruption of dopaminergic fibers to the prefrontal cortex in Parkinson's disease.

Aged↗
PubMed1988

Evaluating evidence for automaticity in frequency of occurrence judgments: a bias for bias?

Frequency of occurrence judgments were evaluated in young adults recovering from closed-head injuries, normal elderly, and young adult controls. Impaired performance was observed in both head-injured and elderly subjects, a result contrary to Hasher and Zacks' 1979 hypothesis that this information accumulates in memory via automatic processes which are unaffected by age, but supporting their conjecture that damage to the central nervous system would be sufficient to interfere with this function. The head-injured subject's performance on the frequency judgment task was correlated with effortful memory capacity as measured by several widely used memory tests. Whether the obtained group differences reflect differences in memory capacity or response criteria effects is discussed, and several methods of analyzing the data are compared.

Adolescent↗
PubMed1987

Hand preference and performance effects on line bisection.

Right- and left-handed subjects performed a visual line bisection task with each hand. When bisecting horizontal lines, both groups bisected left of true center regardless of hand used. Regardless of hand preference, bisections were significantly left of center only when subjects performed with their left hand. Left-handed subjects using their left hand deviated significantly further left than right-handed subjects using their left hand. Regardless of hand used, right-handers bisected vertical lines significantly above veridical center. Left-handed subjects were not significantly above center with either hand. The results require both hemispheric advantage and lateralized activation effects for a complete explanation.

Adult↗
PubMed1987

Cerebral blood flow in severity-matched Alzheimer and multi-infarct patients.

Cerebral blood flow was studied in patients meeting research criteria for either Alzheimer's disease or multi-infarct dementia, matched for age and severity of dementia. In both groups, mean flow was less than in age-matched normal controls, but the Alzheimer patients also had significantly lower mean flow than the multi-infarct group. This result helps resolve discrepancies found in studies with inadequate control for severity. Either global flow or regional left parietal flow could be used to discriminate between these dementia categories with 87% accuracy.

Aged↗
PubMed1984

Underdiagnosis of cognitive impairment in a rehabilitation setting.

Of 100 patients consecutively admitted to a rehabilitation hospital, 25 were cognitively impaired. On two brief tests of intellectual function, they scored below the criteria selected by the originators of those tests for clinically significant mental impairment. Nineteen of the 25 had vascular disease of the heart, brain, or peripheral vessels; two had cardiac valvular disease; three had head trauma; and one was mentally retarded. Mental impairment appears to be relatively common among the hospitalized elderly who do not carry the primary diagnosis of "dementia" or "organic brain syndrome." It appears to be particularly common among those with cardiovascular disease, even without frank stroke. Brief mental status examinations should be part of the routine evaluation of such patients.

Adolescent↗
PubMed1982

The effect of semantic relations on the memory deficit associated with Parkinson's disease.

Analysis of a series of verbal memory experiments reveals a systematic performance deficit in subjects with Parkinson's disease, relative to matched normal and right-hemisphere stroke controls, in both recall and recognition tasks. Parkinson patients benefit less from semantic recall cues; they find semantically mediated synonym detections particularly difficult; and they show reduced benefits from the introduction of semantically novel material in a recall task. Their recall is as well organized semantically as that of normal controls, but reduced in amount. Recognition deficits arise principally from increases in false positive responses.

Aged↗
PubMed1982

Lecithin treatment of cognitively impaired Parkinson's patients.

To test the effects of lecithin on cognitive deficits associated with Parkinson's disease, sixteen elderly and mentally-impaired outpatients with Parkinson's disease participated in a 9-week double-blind placebo-controlled study. Each patient took a daily dose of approximately 32 g of a commercial lecithin preparation containing 25% phosphatidylcholine, or an equivalent amount of powdered skim milk placebo. Marked clinical improvement was not observed, but some indications of a positive treatment effect were obtained on memory, cognition, and motility tests.

Aged↗
PubMedDate not supplied

Effect of inversion on memory for faces in Parkinson's disease and right-hemisphere stroke patients.

Upright and upside-down photographs of faces, schematic drawings of faces, and photographs of houses were presented to patients with Parkinson's disease (PD), patients with right hemisphere stroke (RH), and age-matched normal control subjects (NC) in a forced-choice recognition paradigm. These slides were presented in four orientation conditions: upright at original presentation and at test, upside-down at both, upright initially and upside-down at test, and vice versa. NC subjects recognized faces most accurately when presented in the same orientation both times. This suggests that the information is resistant to mental rotation. Patients with PD recognized faces most accurately when they were presented upright both times, suggesting difficulty with any unusual orientation, consistent with an inability to shift mental set. RH patients, unlike the other groups, did not recognize faces presented upright both times more accurately than those in any other condition. This supports previous studies suggesting a right hemisphere specialization for recognition of upright faces.

Aged↗