Showing papers by "David C. Reutens published in 2006"
TL;DR: GM has a higher infarction threshold for CBF, CBV, and ADC than WM in patients within 24 hours of ischemic stroke onset, and when assessing patients for potential therapies, tissue-specific rather than whole-brain thresholds may be a more precise measure of predicting the likelihood of infarctions.
Abstract: Background and Purpose— Although gray matter (GM) and white matter (WM) have differing neurochemical responses to ischemia in animal models, it is unclear whether this translates into differing thresholds for infarction. We studied this issue in ischemic stroke patients using magnetic resonance (MR) techniques. Methods— MR studies were performed in patients with acute hemispheric ischemic stroke occurring within 24 hours and at 3 months. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and apparent diffusion coefficient (ADC) were calculated. After segmentation based on a probabilistic map of GM and WM, tissue-specific diffusion and perfusion thresholds for infarction were established. Results— Twenty-one patients were studied. Infarction thresholds for CBF were significantly higher in GM (median 34.6 mL/100 g per minute, interquartile range 26.0 to 38.8) than in WM (20.8 mL/100 g per minute; interquartile range 18.0 to 25.9; P<0.0001). Thresholds were also significantly hi...
136 citations
TL;DR: In this paper, the authors examined the efficacy of Melodic Intonation Therapy (MIT) in a male singer with severe Broca's aphasia, and found that melody and speech through rehearsal promoted separate storage and/or access to the phrase representation.
Abstract: This study examined the efficacy of Melodic Intonation Therapy (MIT) in a male singer (KL) with severe Broca’s aphasia. Thirty novel phrases were allocated to one of three experimental conditions: unrehearsed, rehearsed verbal production (repetition), and rehearsed verbal production with melody (MIT). The results showed superior production of MIT phrases during therapy. Comparison of performance at baseline, 1 week, and 5 weeks after therapy revealed an initial beneficial effect of both types of rehearsal; however, MIT was more durable, facilitating longer-term phrase production. Our findings suggest that MIT facilitated KL’s speech praxis, and that combining melody and speech through rehearsal promoted separate storage and/or access to the phrase representation.
87 citations
TL;DR: Findings indicate that serotonin receptor availability is increased in sleep compared to wakefulness in narcoleptic humans.
46 citations
TL;DR: The extent of cerebral infarction correlates with increased risk of intracerebral hemorrhage (ICH) following recombinant tissue plasminogen activator (rt-PA) administration and this findings should provide impetus for research to develop a scoring system explicitly based on regional hemorrhage risk as an aid to selecting patients for thrombolysis.
44 citations
TL;DR: In vivo evidence of reduced benzodiazepine receptor binding in subjects with the GABRG2(R43Q) mutation is provided, likely to represent an important clue to the mechanisms linking this gene defect and the epilepsy phenotype.
36 citations
TL;DR: The findings from this detailed study can be interpreted differently and it is proposed that the cortical borderzone (CBZ) hypothesis was questioned when it was questioned about borderzone infarction.
Abstract: To the Editor:
We congratulate Yong and colleagues on their recent article about borderzone infarction.1 However, the findings from this detailed study can be interpreted differently and we would like to propose an alternative conclusion.
Originally, the interest in these stroke syndromes was that their recognition potentially suggested a hemodynamic mechanism and hence direction for medical therapy.2 Investigators emphasized the importance of severe carotid artery stenosis/occlusion coupled with hemodynamic compromise to the mechanism of internal borderzone (IBZ) infarction.3,4 However, this is not a constant finding, and others have found IBZ infarction occurring in the setting of mild, moderate and severe carotid artery stenosis.5 The cortical borderzone (CBZ) hypothesis was also questioned when it was …
9 citations
01 Jan 2006
5 citations
Journal Article•
1 citations
TL;DR: The claim that echocardiography is an essential test in all ischemic stroke patients including those in sinus rhythm needs to be supported by strong evidence for a benefit from therapy, namely prophylactic anticoagulation.
Abstract: To the Editor:
We read with great interest the article by de Abreu et al1 on the topic of identifying the stroke mechanism in patients with sinus rhythm. These investigators raise 2 important issues: (1) the need to identify the mechanisms of stroke, and (2) therapy of patients with abnormal cardiac echo findings. The rationale for this study appears to be a lack of emphasis in the current guidelines that echocardiography is “an essential test.”2,3 They have identified a significant proportion of hospitalized stroke patients with some echocardiographic abnormalities. However, based only on a prevalence study of echocardiographic features, they draw rather strong conclusions regarding the need for routine echocardiography in acute ischemic stroke patients.
We agree that echocardiography can assist in clarifying the mechanism of ischemic stroke. However, we dispute the claim that echocardiography is an essential test in all ischemic stroke patients including those in sinus rhythm. The need for routine echocardiography ischemic stroke needs to be supported by strong evidence for a benefit from therapy, namely prophylactic anticoagulation. Of all the cardiac conditions listed in Table 2 of the article, only anterior wall dyskinesis or reduced ejection fraction from a recent anterior myocardial infarction can justify the use of warfarin, albeit for 3 months only.4 Although there is level I evidence that anticoagulation prevents stroke in …
1 citations