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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Appreciation of metaphoric and nonmetaphoric alternative word meanings was assessed in 19 aphasic, left (LHD) and 15 non-aphasic, right (RHD) hemisphere brain-damaged stroke patients. With the one exception in the aphasic group, all patients were male. In an unspeeded sorting task, subjects responded on the basis of less frequent, alternative meanings of polysemous target words. Targets were either polysemous adjectives (e.g. "warm") having metaphoric alternative meanings (loving) or polysemous nouns (e.g., "pen") having non-metaphoric alternative meanings (writing implement, cage). Both patient groups performed worse overall than a group of nonbrain-damaged control subjects. Relative to the RHD patients, LHD patients showed a spared appreciation of metaphoric alternative meanings. In addition, LHD, but not RHD, patients performed better on metaphoric adjective trials when there was high similarity between a word's dominant and (metaphoric) alternative meaning. The results suggest a pervasive insensitivity of RHD patients to alternative interpretations of linguistic units, and a special role for the intact right hemisphere in lexical-semantic processes related to metaphor comprehension.
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PMID:Appreciation of metaphoric alternative word meanings by left and right brain-damaged patients. 169 80

Seventy-two stroke patients, 43 with right hemisphere (RHD) and 29 with left hemisphere damage (LHD), and 7 coronary infarct controls with no evidence of cerebral damage, were neuropsychologically tested as part of an assessment program for driver's license. Mean age in the group was 53 years. Stroke patients were tested on average 4 months post injury. The groups did not differ on major demographic variables except that RHD patients were more often hemiplegic than LHD patients. The test battery was factor analyzed into 4 valid principal components: (I) visual perception, (II) spatial attention, (III) visuospatial processing, and (IV) language/praxis. The presence of hemianopia (factor I) excludes driving. In addition, measures of neglect and reduced speed of mental processing from factor II, III and IV, were found to be the most discriminating variables when classifying patients for driving. Even though neglect was more frequently observed among RHD than LHD patients, the two hemisphere groups did not differ significantly in number of patients denied driving, 58% RHD compared to 41% LHD patients. The need for comprehensive neuropsychological assessment is underlined.
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PMID:To drive or not to drive: neuropsychological assessment for driver's license among stroke patients. 772 76

The frequency and characteristics of apraxia in 63 stroke patients with left- or right-hemisphere damage were examined. Analyses focussing on five dimensions of gestural performance revealed an overall frequency of apraxia of 54% in patients with LHD and 30% in patients with RHD. Although both groups were impaired on the orientation and hand posture dimensions of performance, the patients with RHD exhibited significantly poorer performance on the location dimension and the patients with LHD on the action dimension. Analyses of intrahemispheric lesion localization implicated damage to subcortical areas involving periventricular white matter tracts at the temporoparietal junction with apraxia.
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PMID:Analyses of deficits in gestural pantomime. 1007 40

The production of transitive limb gestures is optimized when the appropriate tool can be physically manipulated. Little research has addressed the independent contributions of visual and nonvisual sources of sensory information to this phenomenon. In this study, 12 control, 37 LHD, and 50 RHD stroke patients performed transitive limb gestures to pantomime (to verbal command with the object visible) and object manipulation. Performance was more accurate in the object manipulation condition, suggesting that haptic and kinesthetic cues are important for transitive gesture production. Various patterns of performance were observed in the stroke groups, indicating that selective damage to the haptic/kinesthetic processing system is possible and common following unilateral stroke.
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PMID:Transitive gesture production in apraxia: visual and nonvisual sensory contributions. 1152 54

While language facility was once considered to be the sole province of the "dominant" left hemisphere, clinical and experimental findings suggest the right hemisphere plays an equally important role in many language tasks. To elucidate differential hemispheric language processes, Right Hemisphere Language Battery and Western Aphasia Battery data from left (LHD) and right (RHD) hemisphere cerebral vascular accident (CVA) patients and controls were subjected to multivariate discriminant analysis. The highly significant group differences and overall 95% classification rate obtained confirms the utility of the dependent measures in differential diagnosis. Results suggest CVA patients experience disparate language deficits, with the LHD group experiencing concordant-convergent language deficits and the RHD group displaying discordant-divergent deficits that interfere with the receptive and expressive language skills necessary for successful social discourse.
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PMID:Differential effects of left and right cerebral vascular accidents on language competency. 1157 87

Apraxia is the loss of the ability to perform learned, skilled movements correctly, and is frequently attributed to left hemisphere damage (Heilman & Rothi, 1985). Recent work (Dumont, Ska, & Schiavetto, 1999) has shown a dissociation between transitive (tool based; e.g., hammering a nail) and intransitive (expressive/ communicative; e.g., waving goodbye) actions; however, few group studies have specifically addressed apraxia for intransitive gestures. The present investigation examined the frequency and severity of praxis errors related to the production of intransitive gestures in left (LHD) or right hemisphere stroke (RHD) patients in the context of Roy's (1996) model of limb praxis. A total of 119 consecutive stroke patients (LHD = 57, RHD = 62) and 20 healthy age-matched controls performed eight intransitive gestures to pantomime and imitation. Performance was quantified via a multi-dimensional error notation system, providing detail about specific elements of performance (e.g., location), and a composite score reflecting overall gestural accuracy. Analyses of pantomime and imitation performance revealed an equal percentage of apraxic patients in each stroke group, and the severity of apraxia in these groups was also equivalent. Further, analyses of the patterns of apraxia specified by Roy (1996) revealed that patients in each stroke group demonstrated selective impairments in pantomime (LHD = 38%, RHD = 42%), or imitation (LHD = 9%, RHD = 5%) conditions, whereas others demonstrated concurrent impairments (LHD = 30%, RHD = 22%) indicating that stroke to either hemisphere can selectively impair each stage in the production of an intransitive action.
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PMID:Intransitive limb gestures and apraxia following unilateral stroke. 1177 40

Kinematic analyses of reaching have suggested that the left hemisphere is dominant for controlling the open loop component of the movement, which is more dependent on motor programmes; and the right hemisphere is dominant for controlling the closed loop component, which is more dependent on sensory feedback. This open and closed loop hypothesis of hemispheric asymmetry would also predict that advance planning should be dependent on the left hemisphere, and on-line response modification, which defines closed loop processes, should be dependent on the right hemisphere. Using kinematic analyses of reaching in patients with left or right hemisphere damage (LHD or RHD), we examined the ability: (i) to plan reaching movements in advance by examining changes in reaction time (RT) when response amplitude and visual feedback were cued prior to the response; and (ii) to modify the response during implementation when target location changed at the RT. Performance was compared between the stroke groups, using the ipsilesional arm, and age-matched control groups using their right (RNC) or left (LNC) arm. Aiming movements to a target that moved once or twice, with the second step occurring at the RT, were performed with or without visual feedback of hand position. There were no deficits in advance planning in either stroke group, as evidenced by comparable group changes in RT with changes in amplitude and visual feedback. Response modification deficits were seen for the LHD group in secondary velocity only. In addition, LHD produced slower initial peak velocity with prolongation of the deceleration phase and faster secondary peak velocities, and the RHD group produced deficits in final error only. These differences are more consistent with the dynamic dominance hypothesis, which links left hemisphere specialization to movement trajectory control and right hemisphere specialization to position control, rather than to global deficits in open and closed loop processing.
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PMID:Hemispheric asymmetries for kinematic and positional aspects of reaching. 1503 98

Some potassium channel openers (KCOs) are potent vasodilators that mainly target the ATP-sensitive potassium channels in vascular smooth muscle cells. Their lack of tissue selectivity limits their clinical use in hypertension therapy. Iptakalim [2,3-dimethyl-n-(1-methylethyl)-2-butylamine], which belongs to a novel chemical type of KCO, possesses unique pharmacological characteristics. In vitro experiments have shown that iptakalim could limit its vasorelaxing actions to resistance vessels. In this study, we investigate the antihypertensive effects of iptakalim on two different experimental hypertensive models: stroke-prone, spontaneously hypertensive rats (SHRsps) and two-kidney with one-clip renal hypertensive dogs (2K1C RHD). In acute hypotensive tests, iptakalim showed stable, long-lasting antihypertensive effects in SHRsps and 2K1C RHDs. Mean-while, it had little effect on heart rate when compared with pinacidil, nifedipine, captopril, or bisoprolol. In experimental therapeutic tests, repeated doses in SHRsps for 30 days or in 2K1C RHDs for 14 days produced consistent antihypertensive effects without causing tolerance. In separate experiments, chronic administration of iptakalim resulted in reversing hypertensive vascular remodeling in spontaneously hypertensive rats and hypertensive cardiac remodeling in SHRsps. These results suggest that iptakalim is a promising antihypertensive drug.
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PMID:A new ATP-sensitive potassium channel opener reduces blood pressure and reverses cardiovascular remodeling in experimental hypertension. 1552 92

Previous studies have demonstrated that following unilateral stroke, motor impairment occurs both contralateral, as well as ipsilateral, to the lesion. Although ipsilesional impairments can be functionally limiting, they can also provide important insight into the role of the ipsilateral hemisphere in controlling movement and the lateralization of specific motor control mechanisms, given that unilateral arm movements are thought to recruit processes in each hemisphere. The purpose of this study was to examine whether left and right hemisphere damage following stroke produces different ipsilesional deficits, and whether our dynamic dominance model of motor lateralization can predict such deficits. Specifically, the dynamic dominance model attributes control of multijoint dynamics to the left hemisphere, and control of steady-state position to the right hemisphere. Chronic stroke patients with either left or right hemisphere damage (LHD or RHD) used their ipsilesional arm, and the control subjects used either their left or right arm (LHC or RHC), to perform targeted reaching movements in different directions within the workspace ipsilateral to their reaching arm. We found that the LHD group showed deficits in controlling the arm's trajectory due to impaired multijoint coordination, but no deficits in achieving accurate final positions. In contrast, the RHD group showed deficits in final position accuracy but not in the ability to coordinate multiple joints during movement, thereby providing additional evidence for the hemisphere-specific nature of motor deficits. Furthermore, while both the LHD and RHD groups were functionally impaired to the same degree on the Jebsen Hand Function Test (JHFT), our results suggest that the underlying mechanisms for such impairment may be hemisphere-dependent.
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PMID:Hemispheric specialization and functional impact of ipsilesional deficits in movement coordination and accuracy. 1957 44

The study investigated performance on pantomime and imitation of transitive and intransitive gestures in 80 stroke patients, 42 with left (LHD) and 38 with right (RHD) hemisphere damage. Patients were also categorized in two groups based on the time that has elapsed between their stroke and the apraxia assessment: acute-subacute (n=42) and chronic (n=38). In addition, patterns of performance in apraxia were examined. We expected that acute-subacute patients would be more impaired than chronic patients and that LHD patients would be more impaired than RHD patients, relative to controls. The hemisphere prediction was confirmed, replicating previous findings. The frequency of apraxia was also higher in all LHD time post-stroke groups. The most common impairment after LHD was impairment in both pantomime and imitation in both transitive and intransitive gestures. Selective deficits in imitation were more frequent after RHD for transitive gestures but for intransitive gestures they were more frequent after LHD. Patients were more impaired on imitation than pantomime, relative to controls. In addition, after looking at both gesture types concurrently, we have described cases of patients who suffered deficits in pantomime of intransitive gestures with preserved performance on transitive gestures. Such cases show that the right hemisphere may be in some cases critical for the successful pantomime of intransitive gestures and the neural networks subserving them may be distinct. Chronic patients were also less impaired than acute-subacute patients, even though the difference did not reach significance. A longitudinal study is needed to examine the recovery patterns in both LHD and RHD patients.
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PMID:Associations and dissociations of transitive and intransitive gestures in left and right hemisphere stroke patients. 2016 14


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