Association of laterality and size of perfusion lesions on neurological deficit in acute supratentorial stroke

Hyperintense vessels on imaging account for neurological function independent of lesion volume in acute ischemic stroke

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Studies have revealed variable significance of FLAIR hyperintense vessels (FHV).

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We found number and location of FHV are associated with functional deficits.

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Functional measures correlated with FHV independently of lesion volume.

In acute ischemic stroke, reported relationships between lesion metrics and behavior have largely focused on lesion volume and location. However, hypoperfusion has been shown to correlate with deficits in the acute stage. Hypoperfusion is typically identified using perfusion imaging in clinical settings, which requires contrast. Unfortunately, contrast is contraindicated for some individuals. An alternative method has been proposed to identify hypoperfusion using hyperintense vessels on fluid-attenuated inversion recovery (FLAIR) imaging. This study aimed to validate the clinical importance of considering hypoperfusion when accounting for behavior in acute stroke and demonstrate the clinical utility of scoring the presence of hyperintense vessels to quantify it.

One hundred and fifty-three participants with acute ischemic stroke completed a battery of commonly-used neurological and behavioral measures. Clinical MRIs were used to determine lesion volume and to score the presence of hyperintense vessels seen on FLAIR images to estimate severity of hypoperfusion in six different vascular regions. National Institutes of Health Stroke Scale (NIHSS) scores, naming accuracy (left hemisphere strokes), and language content produced during picture description were examined in relation to lesion volume, hypoperfusion, and demographic variables using correlational analyses and multivariable linear regression.

Results showed that lesion volume and hypoperfusion, in addition to demographic variables, were independently associated with performance on NIHSS, naming, and content production. Specifically, hypoperfusion in the frontal lobe independently correlated with NIHSS scores, while hypoperfusion in parietal areas independently correlated with naming accuracy and content production.

These results correspond to previous reports associating hypoperfusion with function, confirming that hypoperfusion is an important consideration—beyond lesion volume—when accounting for behavior in acute ischemic stroke. Quantifying hypoperfusion using FLAIR hyperintense vessels can be an essential clinical tool when other methods of identifying hypoperfusion are unavailable or time prohibitive.

National Institutes of Health Stroke Scale Correlates Well with Initial Intracerebral Hemorrhage Volume

OBJECTIVES

The US Centers for Medicare and Medicaid Services (CMS) currently publicly reports hospital-quality, risk-adjusted mortality measure for ischemic stroke but not intracerebral hemorrhage (ICH). The NIHSS, which is captured in CMS administrative claims data, is a candidate metric for use in ICH risk adjustment and has been shown to predict clinical outcome with accuracy similar to the ICH Score. Correlation between early NIHSS and initial ICH volume would further support use of the NIHSS for ICH risk adjustment.

MATERIALS AND METHODS

Among 372 ICH patients enrolled in a large multicenter trial (FAST-MAG), the relation between early NIHSS and early ICH volume was assessed with correlation and linear trend analysis.

RESULTS

Overall, there was strong correlation between NIHSS and ICH volume, r = 0.77 (p < 0.001), and for every 10cc increase in ICH the NIHSS increased by 4.5 points. Correlation coefficients were comparable in all subgroups, but magnitude of NIHSS increase with ICH unit volume increase was greater with left than right hemispheric ICH, with presence rather than absence of IVH, with imaging done within the first hour than second hour after last known well, with men than women, and with younger than older patients.

CONCLUSION

Early NIHSS neurologic deficit severity values correlate strongly with initial ICH hematoma volume. As with ischemic stroke, lesion volume increases produce greater NIHSS change in the left than right hemisphere, reflecting greater NIHSS sensitivity to left hemisphere function. These findings provide further support for the use of NIHSS in risk-adjusted mortality measures for intracerebral hemorrhage.

Psychiatric sequelae of stroke affecting the non-dominant cerebral hemisphere

There are a plethora of cognitive sequelae in addition to neglect and extinction that arise with unilateral right hemispheric stroke (RHS). Cognitive deficits following non-dominant (right) hemisphere stroke are common with unilateral neglect and extinction being the most recognized examples. The severity of RHS is usually underestimated by the National Institutes of Health Stroke Scale (NIHSS), which in terms of lateralized right hemisphere cognitive deficits, tests only for visual inattention/extinction. They account for 2 out of 42 total possible points. Additional neuropsychiatric sequelae include but are not limited to deficiencies in affective prosody comprehension and production (aprosodias), understanding and expressing facial emotions, empathy, recognition of familiar faces, anxiety, mania, apathy, and psychosis. These sequelae have a profound impact on patients' quality of life; affecting communication, interpersonal relationships, and the ability to fulfill social roles. They also pose additional challenges to recovery. There is presently a gap in the literature regarding a cohesive overview of the significant cognitive sequelae following RHS. This paper serves as a narrative survey of the current understanding of the subject, with particular emphasis on neuropsychiatric poststroke syndromes not predominantly associated with left hemisphere lesions (LHL), bilateral lesions, hemiplegia, or paralysis. A more comprehensive understanding of the neuropsychological consequences of RHS extending beyond the typical associations of unilateral neglect and extinction may have important implications for clinical practice, including the ways in which clinicians approach diagnostics, treatment, and rehabilitation.

Interhemispheric Asymmetry in Distribution of Infarct Lesions among Acute Ischemic Stroke Patients Presenting to Hospital

BACKGROUNDS

This study aimed to investigate the possible asymmetric distribution of acute ischemic infarct lesions between patients with right-sided stroke versus left-sided stroke.

METHODS

Acute ischemic stroke patients with unilateral infarct who underwent magnetic resonance imaging scan within 24 hours of onset were included. Infarct lesions were segmented on diffusion-weighted-imaging series and coregistered on the MNI-152 brain map. After flipping all lesions to the left side, voxel-based analysis was performed to evaluate for asymmetric distribution of infarct lesions using the stroke side as an independent variable. Symptom severity at admission was evaluated using the National Institutes of Health Stroke Scale score, and early clinical outcome with the modified Rankin Scale score at discharge.

RESULTS

Of the 218 patients included in this study, 110 had right-sided ischemic infarcts whereas 108 had left-sided ischemic infarcts. There was no significant difference between patients with right-sided stroke versus left-sided stroke in terms of admission symptom severity, rate of treatment, stroke risk factors, and early clinical outcome. However, voxel-based analysis showed that ischemic infarcts of insular ribbon and lentiform nucleus were asymmetrically more common on the left-sided stroke compared to the right-sided stroke. The admission symptoms were more severe among patients with left insular ribbon and lentiform nucleus infarct compared to those with infarction of mirrored right anatomical regions (P = .019).

CONCLUSIONS

Acute ischemic infarcts of the left insular ribbon and lentiform nucleus are asymmetrically more common compared to mirrored counterpart regions, presumably due to more severe symptoms at presentation. Otherwise, distribution of symptomatic infarcts to the rest of the brain is roughly symmetric.

Asymmetry of deep medullary veins on susceptibility weighted MRI in patients with acute MCA stroke is associated with poor outcome

BACKGROUND AND PURPOSE

Due to its sensitivity to deoxyhemoglobin, susceptibility weighted imaging (SWI) enables the visualization of deep medullary veins (DMV) in patients with acute stroke, which are difficult to depict under physiological circumstances. This study assesses the asymmetric appearance of prominent DMV as an independent predictor for stroke severity and outcome.

MATERIALS AND METHODS

SWI of 86 patients with acute middle cerebral artery (MCA) stroke were included. A scoring system from 0 (no visible DMV) to 3 (very prominent DMV) was applied for both hemispheres separately. A difference of scores between ipsi- and contralateral side was defined as asymmetric (AMV+). Occurrence of AMV+ was correlated with the National Institute of Health Stroke Scale (NIHSS) Score on admission and discharge, as well as the modified Rankin Scale (mRS) at discharge. Ordinal regression analysis was used to evaluate NIHSS and mRS as predictors of stroke severity, clinical course of disease and outcome.

RESULTS

55 patients displayed AMV+ while 31 did not show an asymmetry (AMV-). Median NIHSS on admission was 17 (11-21) in the AMV+ group and 9 (5-15) in the AMV- group (p = 0.001). On discharge median NIHSS was 11 (5-20) for AMV+ and 5 (2-14) for AMV- (p = 0.005). The median mRS at discharge was 4 (3-5) in the AMV+ group and 3 (1-4) in AMV- (p = 0.001). Odds ratio was 3.19 (95% CI: 1.24-8.21) for AMV+ to achieve a higher mRS than AMV- (p = 0.016).

CONCLUSION

The asymmetric appearance of DMV on SWI is a fast and easily evaluable parameter for the prediction of stroke severity and can be used as an additional imaging parameter in patients with acute MCA stroke.

Right hemisphere dysfunction is better predicted by emotional prosody impairments as compared to neglect

BACKGROUND

Neurologists generally consider hemispatial neglect to be the primary cognitive deficit following right hemisphere lesions. However, the right hemisphere has a critical role in many cognitive, communication and social functions; for example, in processing emotional prosody (tone of voice). We tested the hypothesis that impaired recognition of emotional prosody is a more accurate indicator of right hemisphere dysfunction than is neglect.

METHODS

We tested 28 right hemisphere stroke (RHS) patients and 24 hospitalized age and education matched controls with MRI, prosody testing and a hemispatial neglect battery. Emotion categorization tasks assessed recognition of emotions from prosodic cues. Receiver operating characteristic (ROC) analyses were used to compare tests in their ability to distinguish stroke patients from controls.

RESULTS

ROC analyses revealed that the Prosody Score was more effective than the Neglect Battery Score in distinguishing stroke patients from controls, as measured by area under the curve (AUC); Prosody Score = 0.84; Neglect Battery Score =0. 57. The Prosody Score correctly classified 78.9%, while Neglect Score correctly classified 55.8% of participants as patients versus controls. The Prosody Score was similar to the total NIH Stroke Scale in identifying RHS patients (AUC=0.86, correctly classifying 80.1% of patients versus controls), but the tests only partially overlapped in the patients identified.

CONCLUSIONS

Severe prosody impairment may be a better indicator of right hemisphere dysfunction than neglect. Larger studies are needed to determine if including a bedside test of Prosody with the NIH Stroke Scale would most efficiently and reliably identify right hemisphere ischemia.