Impact of Leukoaraiosis Burden on Hemispheric Lateralization of the National Institutes of Health Stroke Scale Deficit in Acute Ischemic Stroke

Abstract

BACKGROUND AND PURPOSE: The National Institutes of Health Stroke Scale (NIHSS) awards higher deficit scores for infarcts in the dominant hemisphere when compared with otherwise similar infarcts in the nondominant hemisphere. This has been shown to adversely affect stroke recognition, therapeutic decisions, and outcome. However, factors modifying the association between infarct side and deficit severity are incompletely understood. Thus, we sought to determine whether age and age-related leukoaraiosis alter the relation between NIHSS deficit score and the side and volume of infarction. METHODS: We studied 238 patients with supratentorial, nonlacunar ischemic infarcts prospectively included in our stroke registry between January 2013 and January 2014. NIHSS deficit severity was assessed at the time of presentation. Infarct volumes were assessed by manual planimetry on diffusion-weighted imaging. Leukoaraiosis burden was graded on fluid-attenuated inversion recovery images according to the Fazekas scale and dichotomized to none-to-mild (0-2) versus severe (3-6). Multivariable linear regression with backward elimination was used to identify independent predictors of the admission NIHSS. RESULTS: Left-hemispheric infarction (P \u3c 0.001), severe leukoaraiosis (P=0.001), their interaction term (P=0.005), infarct volume (P \u3c 0.001), and sex (P=0.013) were independently associated with the NIHSS deficit. Analysis of the individual NIHSS components showed that severe leukoaraiosis was associated with an increase of the lateralizing components of the NIHSS in patients with right-hemispheric infarction (P\u3c0.05). CONCLUSIONS: Severe leukoaraiosis substantially attenuates the classic hemispheric lateralization of the NIHSS deficit by relating to greater NIHSS scores of components that are typically assigned to left hemisphere function

Time to Presentation Is Associated with Clinical Outcome in Hemispheric Stroke Patients Deemed Ineligible for Recanalization Therapy

“…Hence, excluded patients may have different outcomes from included patients because of differing vascular risk factor profiles as well as stroke severity and etiology. 17 Although this may affect the generalizability of our results our approach allowed for rigorous adjustment for the infarct volume, which is one of the most important predictors of the post-stroke outcome. 37 Lastly, since we excluded patients with infratentorial strokes it remains to be shown whether our results also apply to this population.…”

“…13–15 Included patients have been described as part of a previously published studies. 16,17 All patients were evaluated by stroke-trained physicians. Patient demographics, laboratory data, co-morbidities, pre-admission medications, and stroke etiology (using the Trial of Org 10 172 in Acute Stroke Treatment [TOAST] classification 16–18 ), after completion of diagnostic evaluation, were collected on all patients.…”

Leukoaraiosis Attenuates Diagnostic Accuracy of Large-Vessel Occlusion Scales

“…15,18 Patient demographics, laboratory data, comorbidities, preadmission medications, and stroke pathogenesis (using the Causative Classification System for Ischemic Stroke [CCS] as previously described 15,18 ) after completion of diagnostic evaluation, were collected on all patients. NIHSS scores were assessed at the time of presentation by members of the stroke team certified in NIHSS.…”

“…14,15 The total Fazekas score was calculated by adding the periventricular and subcortical scores. 14 We have previously shown substantial inter-rater reliability with an intra-class correlation coefficient of 0.969 (95% CI 0.943–0.983).…”

“…We used the following additional prespecified rules for derivation of the scores because we previously found that severe leukoaraiosis substantially attenuates the classic hemispheric lateralization of the NIHSS deficit: 15 If both sides were weak, the weaker side determined the sign scored and if both sides were equally weak presence of the sign was scored.…”