Neurologic Outcome Predictors in Pediatric Intracerebral Hemorrhage: A Prospective Study.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage is a considerable source of morbidity and mortality. This 3-center study describes outcomes of pediatric intracerebral hemorrhage and identifies 2-year neurological outcome predictors. METHODS: Children 29 days to 18 years of age presenting with intracerebral hemorrhage from March 2007 to May 2015 were enrolled prospectively. Exclusion criteria included trauma; intracranial tumor; hemorrhagic transformation of arterial ischemic stroke or cerebral sinovenous thrombosis; isolated subdural, epidural, or subarachnoid hemorrhage; and abnormal baseline neurological function. Intracerebral hemorrhage and total brain volumes were measured on neuroimaging. The Pediatric Stroke Outcome Measure assessed outcomes. RESULTS: Sixty-nine children were included (median age: 9.7 years; interquartile range: 2.2-14). Six children (9%) died during hospitalization. Outcomes in survivors were assessed at early follow-up in 98% (median 3.1 months; interquartile range: 3.1-3.8) and at later follow-up in 94% (median: 2.1 years; interquartile range: 1.3-2.8). Over a third had a significant disability at 2 years (Pediatric Stroke Outcome Measure >2). Total Pediatric Stroke Outcome Measure score improved over time (P=0.0003), paralleling improvements in the sensorimotor subscore (P=0.0004). Altered mental status (odds ratio, 13; 95% confidence interval, 3.9-46; P<0.001), hemorrhage volume ≥4% of total brain volume (odds ratio, 17; 95% confidence interval, 1.9-156; P=0.01), and intensive care unit length of stay (odds ratio, 1.1; 95% confidence interval, 1.0-1.2; P=0.002) were significantly associated with poor 2-year outcome. CONCLUSIONS: Over one third of children experienced significant disability at 2 years. Improvements in outcomes were driven by recovery of sensorimotor function. Altered mental status, hemorrhage volume ≥4% of total brain volume, and intensive care unit length of stay were independent predictors of significant disability at 2 years.

Yield of CT perfusion for the evaluation of transient ischaemic attack.

BACKGROUND: Magnetic resonance diffusion-weighted imaging and perfusion-weighted imaging are able to identify ischaemic 'footprints' in transient ischaemic attack. Computed tomography perfusion (CTP) may be useful for patient triage and subsequent management. To date, less than 100 cases have been reported, and none have compared computed tomography perfusion to perfusion-weighted imaging (PWI). We sought to define the yield of computed tomography perfusion for the evaluation of transient ischaemic attack. METHODS: Consecutive patients with a discharge diagnosis of possible or definite transient ischaemic event who underwent computed tomography perfusion were included in this study. The presence of an ischaemic lesion was assessed on noncontrast computed tomography, automatically deconvolved CTPTMax (Time till the residue function reaches its maximum), and when available on diffusion-weighted imaging and PWITMax maps. RESULTS: Thirty-four patients were included and 17 underwent magnetic resonance imaging. Median delay between onset and computed tomography perfusion was 4·4 h (Interquartile range [IQR]: 1·9-9·6), and between computed tomography perfusion and magnetic resonance imaging was 11 h (Interquartile range: 3·8-22). Noncontrast computed tomography was negative in all cases, while CTPTMax identified an ischaemic lesion in 12/34 patients (35%). In the subgroup of patients with multimodal magnetic resonance imaging, an ischaemic lesion was found in six (35%) patients using CTPTMax versus nine (53%) on magnetic resonance imaging (five diffusion-weighted imaging, nine perfusion-weighted imaging). The additional yield of CTPTMax over computed tomography angiography was significant in the evaluation of transient ischaemic attack (12 vs. 3, McNemar, P = 0·004). CONCLUSIONS: CTPTMax found an ischaemic lesion in one-third of acute transient ischaemic attack patients. Computed tomography perfusion may be an acceptable substitute when magnetic resonance imaging is unavailable or contraindicated, and has additional yield over computed tomography angiography. Further studies evaluating the outcome of patients with computed tomography perfusion lesions in transient ischaemic attack are justified at this time.

Pediatric intracerebral hemorrhage score: a simple grading scale for intracerebral hemorrhage in children.

BACKGROUND AND PURPOSE: The intracerebral hemorrhage (ICH) score is the most commonly used clinical grading scale for outcome prediction after adult ICH. We created a similar scale in children to inform clinical care and assist in clinical research. METHODS: Children, full-term newborns to 18 years, with spontaneous ICH were prospectively enrolled from 2007 to 2012 at 3 centers. The pediatric ICH score was created by identifying factors associated with poor outcome. The score's ability to detect moderate disability or worse and severe disability or death was examined with sensitivity, specificity, and area under the receiver operating characteristic curve. RESULTS: The pediatric ICH score components include ICH volume>2% to 3.99% of total brain volume (TBV): 1 point; ICH volume≥4% TBV: 2 points; acute hydrocephalus: 1 point; herniation: 1 point; and infratentorial location: 1 point. The score ranges from 0 to 5. At 3-month follow-up of 60 children, 10 were severely disabled or dead, 30 had moderate disability, and 20 had good recovery. A pediatric ICH score≥1 predicted moderate disability or worse with a sensitivity of 75% (95% confidence interval [CI], 59% to 87%) and a specificity of 70% (95% CI, 46% to 88%). A pediatric ICH score≥2 predicted severe disability or death with a sensitivity and specificity of 90% (95% CI, 55% to 99%) and 68% (95% CI, 53% to 80%), respectively. The area under the receiver operating characteristic curve for classifying outcome as severe disability or death was 0.88 (95% CI, 0.78-0.97). CONCLUSIONS: The pediatric ICH score is a simple clinical grading scale that may ultimately be used for risk stratification, clinical care, and research.

Frequency of hematoma expansion after spontaneous intracerebral hemorrhage in children.

IMPORTANCE: Hematoma expansion is the only modifiable predictor of outcome in adult intracerebral hemorrhage; however, the frequency and clinical significance of hematoma expansion after childhood intracerebral hemorrhage are unknown. OBJECTIVE: To assess the frequency and extent of hematoma expansion in children with nontraumatic intracerebral hemorrhage. DESIGN, SETTING, AND PARTICIPANTS: Prospective observational cohort study at 3 tertiary care pediatric hospitals. Children (≥ 37 weeks' gestation to 18 years) with nontraumatic intracerebral hemorrhage were enrolled in a study from 2007 to 2012 focused on predictors of outcome. For this planned substudy of hematoma expansion, neonates 28 days or younger and participants with isolated intraventricular hemorrhage were excluded. Children with 2 head computed tomography (CT) scans within 48 hours were evaluated for hematoma expansion and were compared with children with only 1 head CT scan. Consent for the primary cohort was obtained from 73 of 87 eligible participants (84%); 41 of 73 children enrolled in the primary cohort met all inclusion/exclusion criteria for this substudy, in whom 22 had 2 head CT scans obtained within 48 hours that could be evaluated for hematoma expansion. Within our substudy cohort, 21 of 41 (51%) were male, 25 of 41 (61%) were white, 16 of 41 (39%) were black, and median age was 7.7 years (interquartile range, 2.0-13.4 years). MAIN OUTCOME AND MEASURE: Primary outcome was prevalence of hematoma expansion. RESULTS: Of 73 children, 41 (56%) met inclusion criteria, and 22 (30%) had 2 head CT scans to evaluate expansion. Among these 22 children, median time from symptom onset to first CT was 2 hours (interquartile range, 1.3-6.5 hours). Median baseline hemorrhage volume was 19.5 mL, 1.6% of brain volume. Hematoma expansion occurred in 7 of 22 (32%). Median expansion was 4 mL (interquartile range, 1-11 mL). Three children had significant (>33%) expansion; 2 required urgent hematoma evacuation. Expansion was not associated with poorer outcome. Compared with children with only 1 head CT scan within 48 hours, children with 2 head CT scans had larger baseline hemorrhage volumes (P = .05) and were more likely to receive treatment for elevated intracranial pressure (P < .001). CONCLUSIONS AND RELEVANCE: Hematoma expansion occurs in children with intracerebral hemorrhage and may require urgent treatment. Repeat CT should be considered in children with either large hemorrhage or increased intracranial pressure.

Natural history and prognostic value of corticospinal tract Wallerian degeneration in intracerebral hemorrhage.

BACKGROUND: The purpose of this study was to define the incidence, imaging characteristics, natural history, and prognostic implication of corticospinal tract Wallerian degeneration (CST-WD) in spontaneous intracerebral hemorrhage (ICH) using serial MR imaging. METHODS AND RESULTS: Consecutive ICH patients with supratentorial ICH prospectively underwent serial MRIs at 2, 7, 14, and 21 days. MRIs were analyzed by independent raters for the presence and topographical distribution of CST-WD on diffusion-weighted imaging (DWI). Baseline demographics, hematoma characteristics, ICH score, and admission National Institute of Health Stroke Score (NIHSS) were systematically recorded. Functional outcome at 3 months was assessed by the modified Rankin Scale (mRS) and the motor-NIHSS. Twenty-seven patients underwent 93 MRIs; 88 of these were serially obtained in the first month. In 13 patients (48%), all with deep ICH, CST-WD changes were observed after a median of 7 days (interquartile range, 7 to 8) as reduced diffusion on DWI and progressed rostrocaudally along the CST. CST-WD changes evolved into T2-hyperintense areas after a median of 11 days (interquartile range, 6 to 14) and became atrophic on MRIs obtained after 3 months. In univariate analyses, the presence of CST-WD was associated with poor functional outcome (ie, mRS 4 to 6; P=0.046) and worse motor-NIHSS (5 versus 1, P=0.001) at 3 months. CONCLUSIONS: Wallerian degeneration along the CST is common in spontaneous supratentorial ICH, particularly in deep ICH. It can be detected 1 week after ICH on DWI and progresses rostrocaudally along the CST over time. The presence of CST-WD is associated with poor motor and functional recovery after ICH.

Disentangling the neuroanatomical correlates of perseveration from unilateral spatial neglect.

Perseverative behavior, manifest as re-cancelling or re-visiting targets, is distinct from spatial neglect. Perseveration is thought to reflect frontal or parietal lobe dysfunction, but the neuroanatomical correlates remain poorly defined and the interplay between neglect and perseveration is incompletely understood. We enrolled 87 consecutive patients with diffusion-weighted, perfusion-weighted imaging, and spatial neglect testing within 24 hours of right hemisphere ischemic stroke. The degrees of spatial neglect and perseveration were analyzed. Perseveration was apparent in 46% (40/87) of the patients; 28% (24/87) showed perseveration only; 18% (16/87) showed both perseveration and neglect; and 3% (3/87) showed neglect only. Perseverative behaviors occur in an inverted "U" shape: little neglect was associated with few perseverations; moderate neglect with high perseverations; and in severe neglect targets may not enter consciousness and perseverative responses decrease. Brodmann areas of dysfunction, and the caudate and putament, were assessed and volumetrically measured. In this study, the caudate and putamen were not associated with perseveration. After controlling for neglect, and volume of dysfunctional tissue, only Brodmann area 46 was associated with perseveration. Our results further support the notion that perseveration and neglect are distinct entities; while they often co-occur, acute dorsolateral prefrontal cortex ischemia is associated with perseveration specifically.

Arterial spin labeling imaging findings in transient ischemic attack patients: comparison with diffusion- and bolus perfusion-weighted imaging.

BACKGROUND: Since transient ischemic attacks (TIAs) can predict future stroke, it is important to distinguish true vascular events from non-vascular etiologies. Arterial spin labeling (ASL) is a non-contrast magnetic resonance (MR) method that is sensitive to cerebral perfusion and arterial arrival delays. Due to its high sensitivity to minor perfusion alterations, we hypothesized that ASL abnormalities would be identified frequently in TIA patients, and could therefore help increase clinicians' confidence in the diagnosis. METHODS: We acquired diffusion-weighted imaging (DWI), intracranial MR angiography (MRA), and ASL in a prospective cohort of TIA patients. A subset of these patients also received bolus contrast perfusion-weighted imaging (PWI). Two neuroradiologists evaluated the images in a blinded fashion to determine the frequency of abnormalities on each imaging sequence. Kappa (ĸ) statistics were used to assess agreement, and the χ(2) test was used to detect differences in the proportions of abnormal studies. RESULTS: 76 patients met the inclusion criteria, 48 (63%) of whom received PWI. ASL was abnormal in 62%, a much higher frequency compared with DWI (24%) and intracranial MRA (13%). ASL significantly increased the MR imaging yield above the combined DWI and MRA yield (62 vs. 32%, p < 0.05). Arterial transit artifact in vascular borderzones was the most common ASL abnormality (present in 51%); other abnormalities included focal high or low ASL signal (11%). PWI was abnormal in 31% of patients, and in these, ASL was abnormal in 14 out of 15 cases (93%). In hemispheric TIA patients, both PWI and ASL findings were more common in the symptomatic hemisphere. Agreement between neuroradiologists regarding abnormal studies was good for ASL and PWI [ĸ = 0.69 (95% CI 0.53-0.86) and ĸ = 0.66 (95% CI 0.43-0.89), respectively]. CONCLUSION: In TIA patients, perfusion-related alterations on ASL were more frequently detected compared with PWI or intracranial MRA and were most frequently associated with the symptomatic hemisphere. Almost all cases with a PWI lesion also had an ASL lesion. These results suggest that ASL may aid in the workup and triage of TIA patients, particularly those who cannot undergo a contrast study.

Automated perfusion imaging for the evaluation of transient ischemic attack.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) is recommended for the evaluation of transient ischemic attack. Perfusion imaging can increase the yield of MRI in transient ischemic attack. We evaluated automated bolus perfusion (the time when the residue function reaches its maximum [TMax] and mean transit time [MTT]) and arterial spin labeling (ASL) sequences for the detection of ischemic lesions in patients with transient ischemic attack. METHODS: We enrolled consecutive patients evaluated for suspicion of acute transient ischemic attack by multimodal MRI within 36 hours of symptom onset. Two independent raters assessed the presence and location of ischemic lesions blinded to the clinical presentation. The prevalence of ischemic lesions and the interrater agreement were 1,410 assessed. RESULTS: From January 2010 to 2011, 93 patients were enrolled and 90 underwent perfusion imaging (69 bolus perfusion and 76 ASL). Overall, 25 of 93 patients (27%) were DWI-positive and 14 (15%) were perfusion-positive but DWI-negative (ASL n=9; TMax n=9; MTT n=2). MTT revealed an ischemic lesion in fewer patients than TMax (7 versus 20, P=0.004). Raters agreed on 89% of diffusion-weighted imaging cases, 89% of TMax, 87% o10f010 MTT, and 90% of ASL cases. The interrater agreement was good for DWI, TMax, and ASL (κ=0.73, 0.72, and 0.74, respectively) and fair for MTT (κ=0.43). Diffusion and/or perfusion were positive in 39 of 69 (57%) patients with a discharge diagnosis of possible ischemic event. CONCLUSIONS: Our results suggest that in patients referred for suspicion of transient ischemic attack, automated TMax is more sensitive than MTT, and both ASL and TMax increase the yield of MRI for the detection of ischemic lesions.

Evaluation of intraventricular hemorrhage in pediatric intracerebral hemorrhage.

Previous studies of pediatric intracerebral hemorrhage have investigated isolated intraparenchymal hemorrhage. The authors investigated whether detailed assessment of intraventricular hemorrhage enhanced outcome prediction after intracerebral hemorrhage. They prospectively enrolled 46 children, full-term to 17 years, median age 2.7 years, with spontaneous intraparenchymal hemorrhage and/or intraventricular hemorrhage. Outcome was assessed with the King's Outcome Scale for Childhood Head Injury. Twenty-six (57%) had intraparenchymal hemorrhage, 10 (22%) had pure intraventricular hemorrhage, and 10 (22%) had both. There were 2 deaths, both with intraparenchymal hemorrhage and intraventricular hemorrhage volume ≥4% of total brain volume. Presence of intraventricular hemorrhage was not associated with poor outcome, but hydrocephalus showed a trend (P = .09) toward poor outcome. In receiver operating characteristic curve analysis, combined intraparenchymal hemorrhage and intraventricular hemorrhage volume also showed a trend toward better outcome prediction than intraparenchymal hemorrhage volume alone. Although not an independent outcome predictor, future studies should assess intraventricular hemorrhage qualitatively and quantitatively.

ABC/2: estimating intracerebral haemorrhage volume and total brain volume, and predicting outcome in children.

AIM: Few data exist to aid the clinician in prognosis after paediatric intracerebral haemorrhages (ICHs). Recently, ICH volume as a per cent of total brain volume (TBV) was shown to help predict outcomes in children. Thus, we sought to develop a bedside method of TBV estimation using typical hospital imaging software, and to validate the ABC/2 method for children in order to determine ICH volume and aid prognosis. METHOD: The study group comprised 23 children and adolescents with non-traumatic, acute ICH who had undergone head computed tomography and who were available for analysis. The median age of participants, 14 males (61%) and nine females (39%), was 6 years (range 0-16 y; mean 7.8 y; SD 5.3 y). Preterm infants born at less than 37 weeks' gestation and term infants with pure intraventricular haemorrhages were excluded. Manual segmentation, which is the criterion standard for measurement of ICH volume and TBV, requires specialized software and is time-consuming. We therefore used the well-known 'ABC/2 × slice thickness' method to calculate ICH volume and TBV, thus allowing ICH size to be reported as a percentage of TBV regardless of the absolute size of ICH. RESULTS: The estimated ICH volume was highly accurate compared with the criterion standard (R(2) =0.97 and R(2) =0.93; combined R(2) =0.96), as was the estimated TBV (R(2) =0.89 and R(2) =0.77; combined R(2) =0.89). The interrater reliability was high for both ICH volume and TBV, with an intraclass correlation coefficient of 0.94 and 0.80 respectively. Therefore, using no specialized software, we accurately measured ICH volume as a percentage of TBV. INTERPRETATION: The ABC/2 × slice thickness method is a possible bedside tool for the clinician that can aid prognosis after paediatric ICH.

MRI profile of the perihematomal region in acute intracerebral hemorrhage.

BACKGROUND AND PURPOSE: The pathophysiology of the presumed perihematomal edema immediately surrounding an acute intracerebral hemorrhage is poorly understood, and its composition may influence clinical outcome. Method-Twenty-three patients from the Diagnostic Accuracy of MRI in Spontaneous intracerebral Hemorrhage (DASH) study were prospectively enrolled and studied with MRI. Perfusion-weighted imaging, diffusion-weighted imaging, and fluid-attenuated inversion recovery sequences were coregistered. TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient values in the presumed perihematomal edema regions of interest were compared with contralateral mirror and remote ipsilateral hemispheric regions of interest. RESULTS: Compared with mirror and ipsilateral hemispheric regions of interest, TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient were consistently increased in the presumed perihematomal edema. Two thirds of the patients also exhibited patchy regions of restricted diffusion in the presumed perihematomal edema. CONCLUSIONS: The MRI profile of the presumed perihematomal edema in acute intracerebral hemorrhage exhibits delayed perfusion and increased diffusivity mixed with areas of reduced diffusion.

The NIHSS-plus: improving cognitive assessment with the NIHSS.

BACKGROUND: The National Institutes of Health Stroke Scale (NIHSS) has been criticized for limited representation of cognitive dysfunction and bias towards dominant hemisphere functions. Patients may therefore receive a low NIHSS score despite a fairly large stroke. A broader scale including simple cognitive tests would improve the clinical and research utility of the NIHSS. METHODS: We studied 200 patients with acute non-dominant hemispheric stroke who underwent cognitive testing and had MRI with diffusion-weighted imaging (DWI) within 5 days of presentation. We measured DWI volumes and retrospectively calculated NIHSS scores. We used linear regression to determine the role of selected cognitive tests, when added to the NIHSS, in predicting DWI volume. RESULTS: The NIHSS predicted DWI volume in a univariate analysis, as did total line cancellation and a visual perception task. In a multivariate model, using log-transformed variables, the NIHSS (p=0.0002), line cancellation errors (p=0.02) and visual perception (p=0.004) each improved prediction of total infarct volume. CONCLUSION: The addition of line cancellation and visual perception tasks significantly adds to the model of NIHSS alone in predicting DWI volume. We propose that these two cognitive tests, which together can be completed in 2-3 minutes, could be combined with the NIHSS to create an "NIHSS-plus" that more accurately represents a patient's ischemic tissue volume after a stroke. This scale requires further validation in a prospective study.

Recovery from spatial neglect and hemiplegia in a child despite a large anterior circulation stroke and Wallerian degeneration.

Prognosis after stroke in children is difficult given the paucity of literature regarding motor and cognitive recovery. Spatial neglect has been described in children after stroke, yet little evidence exists to guide clinicians and parents regarding its resolution. Wallerian degeneration on magnetic resonance imaging (MRI) suggests poor recovery in neonates and adults. We report near complete resolution of spatial neglect in 4 weeks and significant improvement in hemiplegia in a 9-year-old boy with a right anterior cerebral artery and middle cerebral artery infarction, despite Wallerian degeneration apparent on diffusion-weighted imaging. Serial assessment of neglect documenting the rapid course of recovery is the unique feature of this case and may help serve as a guide to pediatricians and neurologists in assessment of young patients and counseling of parents. The lack of published outcome data suggests a need for larger studies about the recovery of spatial neglect and other cognitive symptoms following pediatric stroke.

Intracerebral hemorrhage volume predicts poor neurologic outcome in children.

BACKGROUND AND PURPOSE: Although intracerebral hemorrhage (ICH) volume and location are important predictors of outcome in adults, few data exist in children. METHODS: A consecutive cohort of children, including full-term newborns to those younger than 18 years of age with nontraumatic, acute ICH and head CT available for analysis were studied. Clinical information was abstracted via chart review. Hemorrhage volume was expressed as percentage of total brain volume (TBV) with large hemorrhage defined as >or=4% of TBV. Hemorrhages were manually traced on each head CT slice and volumes were calculated by multiplying by slice thickness. Location was classified as supratentorial or infratentorial. Logistic regression was used to identify predictors of poor neurological outcome, defined as a Glasgow outcome scale or=4% of TBV (P=0.03). In multivariate analysis, hemorrhage >or=4% of TBV (OR, 22.5; 95% CI, 1.4-354; P=0.03) independently predicted poor outcome 30 days after ICH. In this small sample, infratentorial hemorrhage location and the presence of intraventricular hemorrhage did not predict poor outcome. CONCLUSIONS: ICH volume predicts neurological outcome at 30 days in children, with worst outcome when hemorrhage is >or=4% of TBV. Location and ICH etiology may also be important. These findings identify children with ICH who are candidates for aggressive management and may influence counseling regarding prognosis.

Neural substrates of visuospatial processing in distinct reference frames: evidence from unilateral spatial neglect.

There is evidence for different levels of visuospatial processing with their own frames of reference: viewer-centered, stimulus-centered, and object-centered. The neural locus of these levels can be explored by examining lesion location in subjects with unilateral spatial neglect (USN) manifest in these reference frames. Most studies regarding the neural locus of USN have treated it as a homogenous syndrome, resulting in conflicting results. In order to further explore the neural locus of visuospatial processes differentiated by frame of reference, we presented a battery of tests to 171 subjects within 48 hr after right supratentorial ischemic stroke before possible structural and/or functional reorganization. The battery included MR perfusion weighted imaging (which shows hypoperfused regions that may be dysfunctional), diffusion weighted imaging (which reveals areas of infarct or dense ischemia shortly after stroke onset), and tests designed to disambiguate between various types of neglect. Results were consistent with a dorsal/ventral stream distinction in egocentric/allocentric processing. We provide evidence that portions of the dorsal stream of visual processing, including the right supramarginal gyrus, are involved in spatial encoding in egocentric coordinates, whereas parts of the ventral stream (including the posterior inferior temporal gyrus) are involved in allocentric encoding.

Hemispherectomy sustained before adulthood does not cause persistent hemispatial neglect.

INTRODUCTION: Hemispatial neglect has been well established in adults following acute ischemic stroke, but has rarely been investigated in children and young adults following brain injury. It is known that young brains have a tremendous potential for reorganization; however, there is controversy as to whether functions are assumed by the opposite hemisphere, or perilesional areas in the same hemisphere. Patients with intractable epilepsy who undergo hemispherectomy for treatment are missing the entire cortex on one side following surgery. In these patients, only the opposite hemisphere is available to assume function. Therefore, they provide the unique opportunity to determine in what cases the left or right hemisphere can take over the spatial attention functions of the opposite hemisphere following damage. The objective of this study was to determine the incidence and types of hemispatial neglect in children and young adults following both right- and left-sided hemispherectomy; which types of spatial attention functions can be assumed by the opposite hemisphere; and whether factors like their age at time of surgery, handedness, or gender influence recovery. METHODS: Thirty-two children and young adults who had previously undergone hemispherectomy were administered two tests to evaluate for two types of hemispatial neglect: a gap detection test and a line cancellation test. Egocentric neglect was defined as significantly more omissions of targets on the contralesional versus ipsilesional side of the page (by chi square analysis; p<.05). Allocentric neglect was defined as significantly more errors in detecting contralesional versus ipsilesional gaps in circles. RESULTS: Only one of the patients displayed statistically significant hemispatial egocentric neglect on the line cancellation test, and none of the patients displayed statistically significant egocentric or allocentric neglect on the gap detection test. CONCLUSIONS: These results imply that reorganization to the contralateral hemisphere occurs peri-hemispherectomy, as there are no perilesional areas to assume function.

Where (in the brain) do semantic errors come from?

BACKGROUND: Semantic errors result from the disruption of access either to semantics or to lexical representations. One way to determine the origins of these errors is to evaluate comprehension of words that elicit semantic errors in naming. We hypothesized that in acute stroke there are different brain regions where dysfunction results in semantic errors in both naming and comprehension versus those with semantic errors in oral naming alone. METHODS: A consecutive series of 196 patients with acute left hemispheric stroke who met inclusion criteria were evaluated with oral naming and spoken word/picture verification tasks and magnetic resonance imaging within 48 h of stroke onset. We evaluated the relationship between tissue dysfunction in 10 pre-specified Brodmann's areas (BA) and the production of coordinate semantic errors resulting from (1) semantic deficits or (2) lexical access deficits. RESULTS: Semantic errors arising from semantic deficits were most associated with tissue dysfunction/infarct of left BA 22. Semantic errors resulting from lexical access deficits were associated with hypoperfusion/infarct of left BA 37. CONCLUSION: Our study shows that semantic errors arising from damage to distinct cognitive processes reflect dysfunction of different brain regions.