Multivariate lesion symptom mapping for predicting trajectories of recovery from aphasia.

Individuals with post-stroke aphasia tend to recover their language to some extent; however, it remains challenging to reliably predict the nature and extent of recovery that will occur in the long term. The aim of this study was to quantitatively predict language outcomes in the first year of recovery from aphasia across multiple domains of language and at multiple timepoints post-stroke. We recruited 217 patients with aphasia following acute left hemisphere ischaemic or haemorrhagic stroke and evaluated their speech and language function using the Quick Aphasia Battery acutely and then acquired longitudinal follow-up data at up to three timepoints post-stroke: 1 month (n = 102), 3 months (n = 98) and 1 year (n = 74). We used support vector regression to predict language outcomes at each timepoint using acute clinical imaging data, demographic variables and initial aphasia severity as input. We found that ∼60% of the variance in long-term (1 year) aphasia severity could be predicted using these models, with detailed information about lesion location importantly contributing to these predictions. Predictions at the 1- and 3-month timepoints were somewhat less accurate based on lesion location alone, but reached comparable accuracy to predictions at the 1-year timepoint when initial aphasia severity was included in the models. Specific subdomains of language besides overall severity were predicted with varying but often similar degrees of accuracy. Our findings demonstrate the feasibility of using support vector regression models with leave-one-out cross-validation to make personalized predictions about long-term recovery from aphasia and provide a valuable neuroanatomical baseline upon which to build future models incorporating information beyond neuroanatomical and demographic predictors.

Commentary on "Consciousness as a Memory System" by Budson, Richman, and Kensinger (2022).

Consciouness is a phenomenon that has eluded explanation by generations of physicians and scientists. Many discussions, experiments, and theories about consciousness have been published, but none has adequately explained the phenomenon. In the previous issue, Budson and colleagues (2022) present a theory of consciousness based on explicit memory processes, with consciousness developing in the context of memory function. In the authors' view, consciousness accompanying other cortical processes such as language or visual-spatial function developed only later in evolution. The evidence presented for this evolutionary sequence, however, is very limited. Furthermore, no discussion is directed toward the theory that consciousness involves the intersection between external perceptions and internal bodily states. The authors also develop the concept that most of our actions, and even our personality, are conscious only after the fact; immediate decisions are taken by the unconscious mind-the "horse" rather than the "rider." There is empirical evidence that rapid decisions and responses occur before they become conscious. However, Budson and colleagues (2022) extend the concept of unconscious decision-making to virtually all actions; in so doing, not only do they minimize the phenomenon of self-conscious awareness, but their theory has disturbing ethical implications for personal responsibility, criminal law, free will, and personality.

Recovery from aphasia in the first year after stroke.

Most individuals who experience aphasia after a stroke recover to some extent, with the majority of gains taking place in the first year. The nature and time course of this recovery process is only partially understood, especially its dependence on lesion location and extent, which are the most important determinants of outcome. The aim of this study was to provide a comprehensive description of patterns of recovery from aphasia in the first year after stroke. We recruited 334 patients with acute left hemisphere supratentorial ischaemic or haemorrhagic stroke and evaluated their speech and language function within 5 days using the Quick Aphasia Battery (QAB). At this initial time point, 218 patients presented with aphasia. Individuals with aphasia were followed longitudinally, with follow-up evaluations of speech and language at 1 month, 3 months, and 1 year post-stroke, wherever possible. Lesions were manually delineated based on acute clinical MRI or CT imaging. Patients with and without aphasia were divided into 13 groups of individuals with similar, commonly occurring patterns of brain damage. Trajectories of recovery were then investigated as a function of group (i.e. lesion location and extent) and speech/language domain (overall language function, word comprehension, sentence comprehension, word finding, grammatical construction, phonological encoding, speech motor programming, speech motor execution, and reading). We found that aphasia is dynamic, multidimensional, and gradated, with little explanatory role for aphasia subtypes or binary concepts such as fluency. Patients with circumscribed frontal lesions recovered well, consistent with some previous observations. More surprisingly, most patients with larger frontal lesions extending into the parietal or temporal lobes also recovered well, as did patients with relatively circumscribed temporal, temporoparietal, or parietal lesions. Persistent moderate or severe deficits were common only in patients with extensive damage throughout the middle cerebral artery distribution or extensive temporoparietal damage. There were striking differences between speech/language domains in their rates of recovery and relationships to overall language function, suggesting that specific domains differ in the extent to which they are redundantly represented throughout the language network, as opposed to depending on specialized cortical substrates. Our findings have an immediate clinical application in that they will enable clinicians to estimate the likely course of recovery for individual patients, as well as the uncertainty of these predictions, based on acutely observable neurological factors.

Patterns of Recovery From Aphasia in the First 2 Weeks After Stroke.

Purpose Recovery from aphasia after stroke has a decelerating trajectory, with the greatest gains taking place early and the slope of change decreasing over time. Despite its importance, little is known regarding evolution of language function in the early postonset period. The goal of this study was to characterize the dynamics and nature of recovery of language function in the acute and early subacute phases of stroke. Method Twenty-one patients with aphasia were evaluated every 2-3 days for the first 15 days after onset of acute ischemic or hemorrhagic stroke. Language function was assessed at each time point with the Quick Aphasia Battery (Wilson, Eriksson, Schneck, & Lucanie, 2018), which yields an overall summary score and a multidimensional profile of 7 different language domains. Results On a 10-point scale, overall language function improved by a mean of 1.07 points per week, confidence interval [0.46, 1.71], with 19 of 21 patients showing positive changes. The trajectory of recovery was approximately linear over this time period. There was significant variability across patients, and patients with more impaired language function at Day 2 poststroke experienced greater improvements over the subsequent 2 weeks. Patterns of recovery differed across language domains, with consistent improvements in word finding, grammatical construction, repetition, and reading, but less consistent improvements in word comprehension and sentence comprehension. Conclusion Overall language function typically improves substantially and steadily during the first 2 weeks after stroke, driven mostly by recovery of expressive language. Information on the trajectory of early recovery will increase the accuracy of prognoses and establish baseline expectations against which to evaluate the efficacy of interventions. Supplemental Material https://doi.org/10.23641/asha.7811876.

Clinical Use of Cerebrovascular Compliance Imaging to Evaluate Revascularization in Patients With Moyamoya.

BACKGROUND: Surgical revascularization is often performed in patients with moyamoya, however routine tools for efficacy evaluation are underdeveloped. The gold standard is digital subtraction angiography (DSA); however, DSA requires ionizing radiation and procedural risk, and therefore is suboptimal for routine surveillance of parenchymal health. OBJECTIVE: To determine whether parenchymal vascular compliance measures, obtained noninvasively using magnetic resonance imaging (MRI), provide surrogates to revascularization success by comparing measures with DSA before and after surgical revascularization. METHODS: Twenty surgical hemispheres with DSA and MRI performed before and after revascularization were evaluated. Cerebrovascular reactivity (CVR)-weighted images were acquired using hypercapnic 3-Tesla gradient echo blood oxygenation level-dependent MRI. Standard and novel analysis algorithms were applied (i) to quantify relative CVR (rCVRRAW), and decompose this response into (ii) relative maximum CVR (rCVRMAX) and (iii) a surrogate measure of the time for parenchyma to respond maximally to the stimulus, CVRDELAY. Measures between time points in patients with good and poor surgical outcomes based on DSA-visualized neoangiogenesis were contrasted (signed-rank test; significance: 2-sided P < .050). RESULTS: rCVRRAW increases (P = .010) and CVRDELAY decreases (P = .001) were observed pre- vs post-revascularization in hemispheres with DSA-confirmed collateral formation; no difference was found pre- vs post-revascularization in hemispheres with poor revascularization. No significant change in rCVRMAX post-revascularization was observed in either group, or between any of the MRI measures, in the nonsurgical hemisphere. CONCLUSION: Improvement in parenchymal compliance measures post-revascularization, primarily attributed to reductions in microvascular response time, is concurrent with collateral formation visualized on DSA, and may be useful for longitudinal monitoring of surgical outcomes.

Hemodynamic mechanisms underlying elevated oxygen extraction fraction (OEF) in moyamoya and sickle cell anemia patients.

Moyamoya is a bilateral, complex cerebrovascular condition characterized by progressive non-atherosclerotic intracranial stenosis and collateral vessel formation. Moyamoya treatment focuses on restoring cerebral blood flow (CBF) through surgical revascularization, however stratifying patients for revascularization requires abilities to quantify how well parenchyma is compensating for arterial steno-occlusion. Globally elevated oxygen extraction fraction (OEF) secondary to CBF reduction may serve as a biomarker for tissue health in moyamoya patients, as suggested in patients with sickle cell anemia (SCA) and reduced oxygen carrying capacity. Here, OEF was measured (TRUST-MRI) to test the hypothesis that OEF is globally elevated in patients with moyamoya (n = 18) and SCA (n = 18) relative to age-matched controls (n = 43). Mechanisms underlying the hypothesized OEF increases were evaluated by performing sequential CBF-weighted, cerebrovascular reactivity (CVR)-weighted, and structural MRI. Patients were stratified by treatment and non-parametric tests applied to compare study variables (significance: two-sided P < 0.05). OEF was significantly elevated in moyamoya participants (interquartile range = 0.38-0.45) compared to controls (interquartile range = 0.29-0.38), similar to participants with SCA (interquartile range = 0.37-0.45). CBF was inversely correlated with OEF in moyamoya participants. Elevated OEF was only weakly related to reductions in CVR, consistent with basal CBF level, rather than vascular reserve capacity, being most closely associated with OEF.

Transient Global Amnesia: Commentary on Trip Gabriel's First-Person Account.

This paper comments on a companion article, a first-person account of an episode of transient global amnesia written by New York Times reporter Trip Gabriel (Gabriel T. 2017. Cogn Behav Neurol. 30:1-4). Mr Gabriel describes having no memories of a cold, rainy day that he had spent on a sailboat competing in two races. The episode may have been triggered by his exposure to water. Afterward, the skipper recalled that Mr Gabriel had functioned fine on the boat, although after returning to shore he needed help finding his car. When he told his wife over the phone that he could not remember where he lived, she got him home and to the hospital. The staff excluded stroke and other causes of amnesia. He felt some awareness after about 9 hours, and the episode ended after about 23 hours. He has been left with a permanent memory gap of 12 hours.The commentary on the case outlines the state of knowledge about transient global amnesia. The diagnosis is well established: a witnessed sudden-onset retrograde and anterograde amnesia lasting <24 hours in a fully conscious person who knows who he/she is and has no other cause for amnesia. Triggers include exposure to water, stress, and sexual intercourse. A normal magnetic resonance imaging scan can help with the often challenging differential diagnosis. Apart from the gap in memory, patients recover fully and only 15% to 20% have recurrences. The underlying pathophysiology has not been explained.

Implementation of an institution-wide acute stroke algorithm: Improving stroke quality metrics.

BACKGROUND: In May 2012, an updated stroke algorithm was implemented at Vanderbilt University Medical Center. The current study objectives were to: (1) describe the process of implementing a new stroke algorithm and (2) compare pre- and post-algorithm quality improvement (QI) metrics, specificaly door to computed tomography time (DTCT), door to neurology time (DTN), and door to tPA administration time (DTT). METHODS: Our institutional stroke algorithm underwent extensive revision, with a focus on removing variability, streamlining care, and improving time delays. The updated stroke algorithm was implemented in May 2012. Three primary stroke QI metrics were evaluated over four separate 3-month time points, one pre- and three post-algorithm periods. RESULTS: The following data points improved after algorithm implementation: average DTCT decreased from 39.9 to 12.8 min (P < 0.001); average DTN decreased from 34.1 to 8.2 min (P ≤ 0.001), and average DTT decreased from 62.5 to 43.5 min (P = 0.17). CONCLUSION: A new stroke protocol that prioritized neurointervention at our institution resulted in significant lowering in the DTCT and DTN, with a nonsignificant improvement in DTT.

The Inflammatory Form of Cerebral Amyloid Angiopathy or "Cerebral Amyloid Angiopathy-Related Inflammation" (CAARI).

Cerebral amyloid angiopathy-related inflammation (CAARI) is a recently recognized syndrome of reversible encephalopathy seen in a subset of patients with cerebral amyloid angiopathy (CAA). CAA is a disorder of the elderly in which amyloid peptides are deposited in the walls of cerebral arteries, leading to microhemorrhages, macrohemorrhages, and eventually dementia. In a few cases, the amyloid deposition is accompanied by inflammation or edema. The clinical syndrome of CAARI is distinguished by subacute neurobehavioral symptoms, headaches, seizures, and stroke-like signs, contrasting the acute intracranial hemorrhage typically seen in CAA. Magnetic resonance imaging findings may be symmetric or asymmetric and involve patchy or confluent T2 hyperintense lesions in the cortex and subcortical white matter. Recent diagnostic criteria have been proposed which help distinguish CAARI from alternative diagnoses. Improvement has been reported in most cases with immunosuppression, although a few cases have had recurrent symptoms. Here, we review the clinical and radiologic features of CAARI and compare these with CAA.