Performance of the ABCD2 score for stroke risk post TIA: meta-analysis and probability modeling.

OBJECTIVE: To study the accuracy of the ABCD2 score in predicting early stroke risk following TIA and to model post-test probability of stroke for varying cutoff scores and baseline stroke risk. METHODS: Medline, PubMed, Embase, conference proceedings, and manuscript references up to October 2010 were searched for studies reporting ABCD2 score and stroke outcome after TIA. Additional data were requested from authors. Meta-analysis, meta-regression, and post-test probability modeling were undertaken to assess prediction of stroke at 2, 7, and 90 days. RESULTS: Of 44 eligible studies, data were available for 33 (16,070 patients): 26/33 reported stroke at 2 days (533 strokes), 32/33 at 7 days (781 strokes), and 28/33 at 90 days (1,028 strokes) after TIA. Using scores 0-3 ("low risk") and 4-7 ("high risk") for stroke at 7 days, pooled measures were sensitivity 0.89 (0.87-0.91), specificity 0.34 (0.33-0.35), positive predictive value 0.08 (0.07-0.09), negative predictive value 0.98 (0.98-0.98), positive likelihood ratio (PLR) 1.43 (1.33-1.54), negative likelihood ratio (NLR) 0.40 (0.33-0.50), and area under the curve (AUC) 0.70 (0.62-0.78). Results were similar at days 2 and 90. There was moderate heterogeneity while pooling PLR (p < 0.01, I(2) >50%), with stroke specialist TIA diagnosis associated with slightly higher PLR. At 5% baseline stroke risk, ABCD2 >3 indicated an absolute increase in 7-day stroke risk of only 2.0% while a score ≤3 indicated a 2.9% decrease in risk. Changes in risk were very small when baseline stroke risk was lower. CONCLUSIONS: The ABCD2 score leads to only small revisions of baseline stroke risk particularly in settings of very low baseline risk and when used by nonspecialists.

Structural and functional correlates of unilateral mesial temporal lobe spatial memory impairment.

The aim of this study was to explore the effects of preoperative and postoperative lateralized mesial temporal damage on three measures of spatial learning: navigation, object location and plan drawing, and to determine the relationship between volumetry of the hippocampus and memory performance. Fifteen patients with well-characterized unilateral hippocampal sclerosis, 15 patients who had undergone unilateral anterior temporal lobectomy (ATL), and a comparison group consisting of 15 patients with idiopathic generalized epilepsy and 25 neurologically healthy participants explored a novel virtual environment. Volumetric analyses of both hippocampi were conducted on unilateral hippocampal sclerosis and idiopathic generalized epilepsy patients' T(1)-weighted magnetic resonance imaging scans. Performance of temporal lobe epilepsy (TLE) patients (either unilateral hippocampal sclerosis or anterior temporal lobectomy) on the different spatial memory variables, namely navigation, object location and plan drawing, was significantly worse relative to the comparison groups (either idiopathic generalized epilepsy or controls). Patients with right TLE did not differ from patients with left TLE on any of the spatial memory measures. An index of absolute hippocampal asymmetry did not correlate with any of the spatial memory measures. Together, our lesion and volumetry findings suggest that the domain of spatial memory is systematically related to the integrity of both right and left mesial temporal lobe, and is unlikely to be a strongly lateralized function. From the standpoint of cerebral organization (lateralization), the notion of material-specificity, which postulates that all components of verbal and spatial memory are lateralized in their entirety to the left and right hemispheres, respectively, requires modification. Instead it would appear that the notion of task-specificity is a more accurate description of patterns of lateralization of spatial memory.