Annals of neurology
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Annals of neurology · Jul 2002
Comparative StudyAcute hyperglycemia adversely affects stroke outcome: a magnetic resonance imaging and spectroscopy study.
Controversy exists whether acute hyperglycemia is causally associated with worse stroke outcome or simply reflects a more severe stroke. In reversible ischemia models, hyperglycemia is associated with lactic acidosis and conversion of penumbral tissue to infarction. However, the relationship between hyperglycemia, lactic acidosis, and stroke outcome has not been explored in humans. ⋯ In contrast, acute blood glucose levels in nonmismatch patients did not independently correlate with outcome measures, nor was there any acute-subacute increase in lactate in this group. Acute hyperglycemia increases brain lactate production and facilitates conversion of hypoperfused at-risk tissue into infarction, which may adversely affect stroke outcome. These findings support the need for randomized controlled trials of aggressive glycemic control in acute stroke.
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Annals of neurology · Jul 2002
Comparative StudyApplication of the new McDonald criteria to patients with clinically isolated syndromes suggestive of multiple sclerosis.
Traditionally, multiple sclerosis (MS) has been diagnosed on the basis of clinical evidence of dissemination in time and space. Previously, it could not be diagnosed in patients with single clinical episodes of demyelination known as clinically isolated syndromes. New diagnostic criteria from the International Panel of McDonald and colleagues incorporate MRI evidence of dissemination in time and space to allow a diagnosis of MS in patients with clinically isolated syndromes. ⋯ The development of MS with the new MRI criteria after 1 year had a high sensitivity (83%), specificity (83%), positive predicative value (75%), negative predictive value (89%), and accuracy (83%) for clinically definite MS at 3 years. Use of the new McDonald criteria more than doubled the rate of diagnosis of MS within a year of presentation with a clinically isolated syndrome. The high specificity, positive predictive value, and accuracy of the new criteria for clinically definite MS support their clinical relevance.
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Annals of neurology · Jul 2002
Comparative StudyWorking memory after traumatic brain injury in children.
To investigate the effects of traumatic brain injury on working memory in children, we administered semantic (letter identity) and phonological (letter rhyme) N-back tasks to children who were on average 5 years post-mild (n = 54) or -severe (n = 26) traumatic brain injury and 44 typically developing children who were comparable in age. The correct detection of targets and false alarms were measured for each task. Memory load (which varied from 0 to 3 letters back) and age significantly affected the detection of targets and false alarms in both tasks. ⋯ Traumatic brain injury severity also interacted with memory load in its effect on false alarms on the rhyme task. Traumatic brain injury results in impaired working memory and diminished inhibition in children. The N-back working memory task is feasible for administration to brain-injured children and potentially could be useful for studying brain activation associated with working memory and effects of drug therapy in this group of patients.