How long is the recovery of global aphasia? Twenty-five years of follow-up in a patient with left hemisphere stroke

Investigating Aphasia Recovery: Demographic and Clinical Factors

Post-stroke language recovery remains one of the main unresolved topics in the field of aphasia. In recent years, there have been efforts to identify specific factors that could potentially lead to improved language recovery. However, the exact relationship between the recovery of particular language functions and possible predictors, such as demographic or lesion variables, is yet to be fully understood. In the present study, we attempted to investigate such relationships in 42 patients with aphasia after left hemisphere stroke, focusing on three language domains: auditory comprehension, naming and speech fluency. Structural imaging data were also obtained for the identification of the lesion sites. According to our findings, patients demonstrated an overall improvement in all three language domains, while no demographic factor significantly contributed to aphasia recovery. Interestingly, specific lesion loci seemed to have a differential effect on language performance, depending on the time of testing (i.e., acute/subacute vs. chronic phase). We argue that this variability concerning lesion-deficit associations reflects the dynamic nature of aphasia and further discuss possible explanations in the framework of neuroplastic changes during aphasia recovery.

Current and Emerging Endovascular and Neurocritical Care Management Strategies in Large-Core Ischemic Stroke

The volume of infarcted tissue in patients with ischemic stroke is consistently associated with increased morbidity and mortality. Initial studies of endovascular thrombectomy for large-vessel occlusion excluded patients with established large-core infarcts, even when large volumes of salvageable brain tissue were present, due to the high risk of hemorrhagic transformation and reperfusion injury. However, recent retrospective and prospective studies have shown improved outcomes with endovascular thrombectomy, and several clinical trials were recently published to evaluate the efficacy of endovascular management of patients presenting with large-core infarcts. With or without thrombectomy, patients with large-core infarcts remain at high risk of in-hospital complications such as hemorrhagic transformation, malignant cerebral edema, seizures, and others. Expert neurocritical care management is necessary to optimize blood pressure control, mitigate secondary brain injury, manage cerebral edema and elevated intracranial pressure, and implement various neuroprotective measures. Herein, we present an overview of the current and emerging evidence pertaining to endovascular treatment for large-core infarcts, recent advances in neurocritical care strategies, and their impact on optimizing patient outcomes.

Repetition Priming Treatment for Anomia: Effects of Single- and Multiple-Exemplar Protocols

INTRODUCTION

Repetition priming can lead to improved naming ability in people with aphasia, but concerns have arisen from prior research about using only a single picture exemplar for each target. Specifically, it is unclear whether the observed improvements were due to learning simple correspondences between particular words and pictures rather than changes at a deeper level of lexical-semantic processing. In addition, implications for generalization after training with single exemplars were unclear. This study replicated and extended previous work to address these questions.

METHOD

Five participants with chronic aphasia participated in this repeated-measures design study, which repeatedly paired words and pictures with no feedback provided. Two participants engaged in a single-exemplar condition, with a single picture exemplar of each target used for every presentation of that target. The remaining three participants engaged in a multiple-exemplar condition, with several different pictures used for each target. Half of these targets used training pictures during naming probes, whereas half did not.

RESULTS

Primed items led to greater improvements in naming than items that were practiced but not primed. The data indicate that improvements may extend beyond stimulus-specific correspondences. Maintenance and generalization effects were mixed.

CONCLUSIONS

These data provide further support for the efficacy of repetition priming treatment for anomia. Implications and future directions are discussed.

Electrophysiological Changes in Patients with Post-stroke Aphasia: A Systematic Review

Background Magnetoencephalography (MEG) and electroencephalography (EEG) record two main types of data: continuous measurements at rest or during sleep, and event-related potentials/evoked magnetic fields (ERPs/EMFs) that involve specific and repetitive tasks. In this systematic review, we summarized longitudinal studies on recovery from post-stroke aphasia that used continuous or event-related temporal imaging (EEG or MEG). Methods We searched PubMed and Scopus for English articles published from 1950 to May 31, 2022. Results 34 studies were included in this review: 11 were non-interventional studies and 23 were clinical trials that used specific rehabilitation methods, neuromodulation, or drugs. The results of the non-interventional studies suggested that poor language recovery was associated with slow-wave activity persisting over time. The results of some clinical trials indicated that behavioral improvements were correlated with significant modulation of the N400 component. Discussion Compared with continuous EEG, ERP/EMF may more reliably identify biomarkers of therapy-induced effects. Electrophysiology should be used more often to explore language processes that are impaired after a stroke, as it may highlight treatment challenges for patients with post-stroke aphasia.

Clinical Predictors for Upper Limb Recovery after Stroke Rehabilitation: Retrospective Cohort Study

After stroke, recovery of upper limb (UL) motor function is enhanced by a high dose of rehabilitation and is supposed to be supported by attentive functions. However, their mutual influence during rehabilitation is not well known yet. The aim of this retrospective observational cohort study was to investigate the association between rehabilitation dose and motor and cognitive functions, during UL motor recovery. Inpatients with first unilateral stroke, without time restrictions from onset, and undergoing at least 15 h of rehabilitation were enrolled. Data on dose and modalities of rehabilitation received, together with motor and cognitive outcomes before and after therapy, were collected. Fugl-Meyer values for the Upper Extremity were the primary outcome measure. Logistic regression models were used to detect any associations between UL motor improvement and motor and cognitive-linguistic features at acceptance, regarding dose of rehabilitation received. Thirty-five patients were enrolled and received 80.57 ± 30.1 h of rehabilitation on average. Manual dexterity, level of independence and UL motor function improved after rehabilitation, with no influence of attentive functions on motor recovery. The total amount of rehabilitation delivered was the strongest factor (p = 0.031) influencing the recovery of UL motor function after stroke, whereas cognitive-linguistic characteristics were not found to influence UL motor gains.

Motivation Theory and Practice in Aphasia Rehabilitation: A Scoping Review

PURPOSE

In the aphasia literature, motivation has been described as potentially influencing rehabilitation outcomes, and there are reports that researchers and clinicians have acted to promote it. However, studies directly investigating the range of beliefs and practices surrounding motivation do not exist currently. The purpose of this scoping review is to develop themes related to the beliefs and practices appearing in the recent aphasia literature.

METHOD

Four databases (CINAHL, PsycINFO, PubMed, and Google Scholar) were searched using keywords aphasia and motivation (including derivatives such as motiv*) for articles published between 2009 and 2020. Searches returned 19,731 articles; after deleting duplicates and applying inclusionary criteria, 365 articles remained. In each article, text surrounding the term motivation was highlighted and thematic analysis was applied to these quotations.

RESULTS

Sixteen themes were developed through thematic analysis and placed into two groups. The first group contained five themes suggesting that researchers believed that motivation should be studied and recognized the value of motivation in person(s) with aphasia when participating in research or clinical activities. The second group contained 11 themes reporting diverse beliefs and practices in how motivation is incorporated in research and clinical activities.

CONCLUSIONS

Results from this scoping review suggest that aphasia researchers, clinicians, and persons with aphasia hold beliefs about motivation that can influence clinical and research decisions. In general, beliefs and decisions related to motivation appeared to be guided by intuition rather than theories of motivation. These themes are discussed within the context of three psychological needs proposed by self-determination theory: competency, autonomy, and relatedness. Applying theories of motivation to future study in aphasia rehabilitation will guide work that can provide empirical support for these beliefs.

Plasticity of the language system in children and adults

The language system is perhaps the most unique feature of the human brain's cognitive architecture. It has long been a quest of cognitive neuroscience to understand the neural components that contribute to the hierarchical pattern processing and advanced rule learning required for language. The most important goal of this research is to understand how language becomes impaired when these neural components malfunction or are lost to stroke, and ultimately how we might recover language abilities under these circumstances. Additionally, understanding how the language system develops and how it can reorganize in the face of brain injury or dysfunction could help us to understand brain plasticity in cognitive networks more broadly. In this chapter we will discuss the earliest features of language organization in infants, and how deviations in typical development can-but in some cases, do not-lead to disordered language. We will then survey findings from adult stroke and aphasia research on the potential for recovering language processing in both the remaining left hemisphere tissue and in the non-dominant right hemisphere. Altogether, we hope to present a clear picture of what is known about the capacity for plastic change in the neurobiology of the human language system.

Is There a Research-Practice Dosage Gap in Aphasia Rehabilitation?

Purpose Aphasia intervention research aims to improve communication and quality of life outcomes for people with aphasia. However, few studies have evaluated the translation and implementation of evidence-based aphasia interventions to clinical practice. Treatment dosage may be difficult to translate to clinical settings, and a mismatch between dosage in research and clinical practice threatens to attenuate intervention effectiveness. The purpose of this study is to quantify a potential research-practice dosage gap in outpatient aphasia rehabilitation. Method This study utilized a two-part approach. First, we estimated clinical treatment dosage in an episode of care (i.e., treatment provided from outpatient assessment to discharge) via utilization in a regional provider in the United States. Second, we undertook a scoping review of aphasia interventions published from 2009 to 2019 to estimate the typical dosage used in the current aphasia literature. Results Outpatient clinical episodes of care included a median of 10 treatment sessions and a mean of 14.8 sessions (interquartile range: 5-20 sessions). Sessions occurred 1-2 times a week over 4-14 weeks. The median total hours of treatment was 7.5 hr (interquartile range: 3.75-15 hr). In contrast, published interventions administered a greater treatment dosage, consisting of a median of 20 hr of treatment (interquartile range: 12-30 hr) over the course of 15 sessions (interquartile range: 10-24 sessions) approximately 3 times per week. Conclusions Results demonstrate a meaningful research-practice dosage gap, particularly in total treatment hours and weekly treatment intensity. This gap highlights the potential for attenuation of effectiveness from research to outpatient settings. Future translational research should consider clinical dosage constraints and take steps to facilitate intervention implementation, particularly with regard to dosage. Conversely, health care advocacy and continued development of alternative delivery methods are necessary for the successful implementation of treatments with dosage that is incompatible with current clinical contexts. Pragmatic, implementation-focused trials are recommended to evaluate and optimize treatment effectiveness in outpatient clinical settings. Supplemental Material https://doi.org/10.23641/asha.15161568.

Current Approaches to the Treatment of Post-Stroke Aphasia

Aphasia, impairment of language after stroke or other neurological insult, is a common and often devastating condition that affects nearly every social activity and interaction. Behavioral speech and language therapy is the mainstay of treatment, although other interventions have been introduced to augment the effects of the behavioral therapy. In this narrative review, we discuss advances in aphasia therapy in the last 5 years and focus primarily on properly powered, randomized, controlled trials of both behavioral therapies and interventions to augment therapy for post-stroke aphasia. These trials include evaluation of behavioral therapies and computer-delivered language therapies. We also discuss outcome prediction trials as well as interventional trials that have employed noninvasive brain stimulation, or medications to augment language therapy. Supported by evidence from Phase III trials and large meta-analyses, it is now generally accepted that aphasia therapy can improve language processing for many patients. Not all patients respond similarly to aphasia therapy with the most severe patients being the least likely responders. Nevertheless, it is imperative that all patients, regardless of severity, receive aphasia management focused on direct therapy of language deficits, counseling, or both. Emerging evidence from Phase II trials suggests transcranial brain stimulation is a promising method to boost aphasia therapy outcomes.

Decompressive Hemicraniectomy for Large Hemispheric Strokes

Large hemispheric infarcts occur in up to 10% of all ischemic strokes and can cause devastating disability. Significant research and clinical efforts have been made in hopes of mitigating the morbidity and mortality of this disease. Areas of interest include identifying predictors of malignant edema, optimizing medical and surgical techniques, selecting the patient population that would benefit most from decompressive hemicraniectomy, and studying the impact on quality of life of those who survive. Decompressive surgery can be a life-saving measure, and here we discuss the most up-to-date literature and provide a review on the surgical management of large hemispheric ischemic strokes.

Clinical Implementation of Transcranial Direct Current Stimulation in Aphasia: A Survey of Speech-Language Pathologists

Purpose The objectives of this study are to (a) identify speech-language pathologists' (SLPs') familiarity with transcranial direct current stimulation (tDCS), (b) quantify what SLPs consider necessary tDCS-related improvement in aphasia severity (i.e., tDCS enhancement; desired improvement above and beyond traditional behavioral therapy) to implement this adjuvant therapy for the clinical management of aphasia, and (c) identify concerns that could potentially hinder the clinical adoption of tDCS. Method A brief (14-question) survey was disseminated via e-mail and social media outlets targeting SLPs working with individuals with aphasia. Results Two hundred twenty-one individuals responded, and 155 valid surveys were analyzed. Seventy-one percent of participants reported familiarity with tDCS prior to taking the survey. Clinicians reported a desired mean enhancement of 22.9% additional points on the Western Aphasia Battery-Revised Aphasia Quotient. Importantly, 94.2% of SLPs reported concerns regarding the implementation of tDCS in clinical settings (i.e., safety, cost, administrative approval, reimbursement and training). Conclusions This is the first study to identify SLPs' perspectives regarding the clinical adoption of tDCS. Results suggest the majority of queried SLPs were familiar with tDCS prior to taking the survey. Although SLPs report a desired improvement of approximately 23% additional points on the Western Aphasia Battery-Revised Aphasia Quotient to consider adopting tDCS into practice, many SLPs reported concerns regarding clinical adoption. Responses from the current survey offer important preliminary evidence to begin bridging the research-to-practice gap as it relates to the clinical implementation of tDCS. Relatedly, these results will inform future clinical trials.

Cortical stimulation in aphasia following ischemic stroke: toward model-guided electrical neuromodulation

The aim of this paper is to integrate different bodies of research including brain traveling waves, brain neuromodulation, neural field modeling and post-stroke language disorders in order to explore the opportunity of implementing model-guided, cortical neuromodulation for the treatment of post-stroke aphasia. Worldwide according to WHO, strokes are the second leading cause of death and the third leading cause of disability. In ischemic stroke, there is not enough blood supply to provide enough oxygen and nutrients to parts of the brain, while in hemorrhagic stroke, there is bleeding within the enclosed cranial cavity. The present paper focuses on ischemic stroke. We first review accumulating observations of traveling waves occurring spontaneously or triggered by external stimuli in healthy subjects as well as in patients with brain disorders. We examine the putative functions of these waves and focus on post-stroke aphasia observed when brain language networks become fragmented and/or partly silent, thus perturbing the progression of traveling waves across perilesional areas. Secondly, we focus on a simplified model based on the current literature in the field and describe cortical traveling wave dynamics and their modulation. This model uses a biophysically realistic integro-differential equation describing spatially distributed and synaptically coupled neural networks producing traveling wave solutions. The model is used to calculate wave parameters (speed, amplitude and/or frequency) and to guide the reconstruction of the perturbed wave. A stimulation term is included in the model to restore wave propagation to a reasonably good level. Thirdly, we examine various issues related to the implementation model-guided neuromodulation in the treatment of post-stroke aphasia given that closed-loop invasive brain stimulation studies have recently produced encouraging results. Finally, we suggest that modulating traveling waves by acting selectively and dynamically across space and time to facilitate wave propagation is a promising therapeutic strategy especially at a time when a new generation of closed-loop cortical stimulation systems is about to arrive on the market.

[Combined neuroprotection in the treatment of post-stroke aphasia]

AIM

To evaluate the efficacy of combined neuroprotection in the restoration of speech function in patients with acute ischemic stroke in the carotid region.

MATERIAL AND METHODS

The study included 257 patients (median age 60 (55; 72) years) with ischemic stroke and motor or sensorimotor aphasia. The degree of speech recovery was characterized by an increase in the score on the scale of the speech questionnaire (SQ) on the 21st day from the beginning of the disease. Patients were divided into low recovery (ΔSQ ≤6) and high recovery (ΔSQ >6) groups. All patients received neuroprotectors of different groups.

RESULTS

The greatest efficacy was shown for cortexin in combination with mexidol: the ΔSQ >6 group included 24 (70.6%) and the group ΔSQ ≤6 10 (29.4%) patients out of 34 patients. The lowest efficacy was observed for gliatilin in monotherapy: an increase was ≤6 points in 24 (68.6%) patients and >6 points in 11 (31.4%), and for combinations of ceraxon and mexidol: 26 (61.9%) and 6 (38.1%) patients with low- and high level of speech recovery, respectively (p=0.041).

CONCLUSION

Combined neuroprotective therapy using drugs with neuromodulatory and antioxidant effects (cortexin and mexidol) in the acute period of ischemic stroke is effective in the treatment of post-stroke aphasia.

Progression of Aphasia Severity in the Chronic Stages of Stroke

Background and Purpose The severity of aphasic impairment in chronic stroke survivors is typically thought to be stable by 6 months postonset. However, a recent study showed that stroke survivors with aphasia experience language improvement or decline in the chronic phase, years beyond onset. Little is known about why some individuals improve whereas others remain stable or decline. Additionally, no study has tracked changes in aphasia from assessments completed at multiple time points across many years. The current study offers a comprehensive analysis of potential predictive demographic and health information to determine which factors predict dynamic changes in aphasia severity in chronic stroke. Methods Individuals in the chronic stage of a single-event, left-hemisphere ischemic stroke were identified from an archival database and included for study ( N = 39). Participants were included if they had undergone 2 or more standardized language assessments acquired at time points at least 6 months apart, with the 1st assessment at least 6 months postinjury. A linear mixed-effects model was used to determine the impact of treatment and a variety of demographic and health factors on language change. Results Over time, half of the participants improved (51%), whereas approximately a quarter (26%) decreased, and a quarter (23%) remained stable. A greater number of aphasia treatment hours significantly predicted language improvement ( p = .03), whereas older stroke age was associated with long-term decline ( p = .04). Two interactions were found to be significant in predicting improvement in individuals with diabetes: Increased exercise and younger age at stroke were significant in predicting outcomes ( p < .05). Conclusions Factors that significantly influence language recovery in chronic aphasia include stroke age and receiving aphasia treatment. For those with diabetes, increased exercise was shown to improve outcomes. Results from this study offer clinicians greater insight into the influence of patient factors on long-term recovery from stroke aphasia while suggesting a potential adjunct to language therapy: exercise. Supplemental Material https://doi.org/10.23641/asha.7849304.

Macro-connectomics and microstructure predict dynamic plasticity patterns in the non-human primate brain

The brain displays a remarkable ability to adapt following injury by altering its connections through neural plasticity. Many of the biological mechanisms that underlie plasticity are known, but there is little knowledge as to when, or where in the brain plasticity will occur following injury. This knowledge could guide plasticity-promoting interventions and create a more accurate roadmap of the recovery process following injury. We causally investigated the time-course of plasticity after hippocampal lesions using multi-modal MRI in monkeys. We show that post-injury plasticity is highly dynamic, but also largely predictable on the basis of the functional connectivity of the lesioned region, gradients of cell densities across the cortex and the pre-lesion network structure of the brain. The ability to predict which brain areas will plastically adapt their functional connectivity following injury may allow us to decipher why some brain lesions lead to permanent loss of cognitive function, while others do not.

The brain has the ability to adapt after injury, a process known as plasticity. When one area sustains damage, for example following a car accident or stroke, other areas change their activity and structure to compensate. Understanding how this happens is critical to helping people recover from brain injuries. Certain factors may affect how well the brain can repair itself. These include how much the damaged area interacts with other areas, and which cell types different areas of the brain contain.

Froudist-Walsh et al. set out to determine how these factors influence recovery from brain injury in monkeys, whose brains are similar to our own. The monkeys had damage to a structure called the hippocampus. This part of the brain has a key role in memory, which is often impaired in patients with brain injuries. The hippocampus cannot repair itself because the brain has only a limited capacity to grow new neurons. Instead, the brain attempts to compensate for disruption to the hippocampus via changes in other, undamaged areas.

Using brain imaging, Froudist-Walsh et al. show that the types of changes that occur depend on how much time has passed since the injury. In the first three months, many areas of the brain change how much they coordinate their activity with other areas. Highly connected areas reduce their communication with other areas the most. In the long-term, the responses of brain areas depend more on which cell types they contain. Areas with more support cells known as “glia” – which supply nutrients and energy to neurons – are better able to adapt their connectivity up to a year after the injury.

These findings may ultimately benefit people who have suffered brain injuries after accidents or stroke. They suggest that stimulating intact brain areas may be helpful in the months immediately after an injury. By contrast, long-term therapy may need to focus more on structural repair. Future studies must build on these results to discover the best ways to induce successful recovery from brain injury.

Right hemisphere structural adaptation and changing language skills years after left hemisphere stroke

Stroke survivors with acquired language deficits are commonly thought to reach a ‘plateau’ within a year of stroke onset, after which their residual language skills will remain stable. Nevertheless, there have been reports of patients who appear to recover over years. Here, we analysed longitudinal change in 28 left-hemisphere stroke patients, each more than a year post-stroke when first assessed—testing each patient’s spoken object naming skills and acquiring structural brain scans twice. Some of the patients appeared to improve over time while others declined; both directions of change were associated with, and predictable given, structural adaptation in the intact right hemisphere of the brain. Contrary to the prevailing view that these patients’ language skills are stable, these results imply that real change continues over years. The strongest brain–behaviour associations (the ‘peak clusters’) were in the anterior temporal lobe and the precentral gyrus. Using functional magnetic resonance imaging, we confirmed that both regions are actively involved when neurologically normal control subjects name visually presented objects, but neither appeared to be involved when the same participants used a finger press to make semantic association decisions on the same stimuli. This suggests that these regions serve word-retrieval or articulatory functions in the undamaged brain. We teased these interpretations apart by reference to change in other tasks. Consistent with the claim that the real change is occurring here, change in spoken object naming was correlated with change in two other similar tasks, spoken action naming and written object naming, each of which was independently associated with structural adaptation in similar (overlapping) right hemisphere regions. Change in written object naming, which requires word-retrieval but not articulation, was also significantly more correlated with both (i) change in spoken object naming; and (ii) structural adaptation in the two peak clusters, than was change in another task—auditory word repetition—which requires articulation but not word retrieval. This suggests that the changes in spoken object naming reflected variation at the level of word-retrieval processes. Surprisingly, given their qualitatively similar activation profiles, hypertrophy in the anterior temporal region was associated with improving behaviour, while hypertrophy in the precentral gyrus was associated with declining behaviour. We predict that either or both of these regions might be fruitful targets for neural stimulation studies (suppressing the precentral region and/or enhancing the anterior temporal region), aiming to encourage recovery or arrest decline even years after stroke occurs.

Long-term Recovery in Stroke Accompanied by Aphasia: A Reconsideration

BACKGROUND

This work focuses on the twenty-six individuals who provided data to AphasiaBank on at least two occasions, with initial testing between 6 months and 5.8 years post-onset of aphasia. The data are archival in nature and were collected from the extensive database of aphasic discourse in AphasiaBank.

AIMS

The aim is to furnish data on the nature of long-term changes in both the impairment of aphasia as measured by the Western Aphasia Battery-Revised (WAB-R) and its expression in spoken discourse.

METHODS AND PROCEDURES

AphasiaBank's demographic database was searched to discover all individuals who were tested twice at an interval of at least a year with either: 1) the AphasiaBank protocol; or 2) the AphasiaBank protocol at first testing, and the Famous People Protocol (FPP) at second testing. The Famous People Protocol is a measure developed to assess the communication strategies of individuals whose spoken language limitations preclude full participation in the AphasiaBank protocol. The 26 people with aphasia (PWA) who were identified had completed formal speech therapy before being seen for AphasiaBank. However, all were participants in aphasia centers where at least three hours of planned activities were available, in most cases, twice weekly. WAB-R Aphasia Quotient scores (AQ) were examined, and in those cases where AQ scores improved, changes were assessed on a number of measures from the AphasiaBank discourse protocol.

OUTCOMES AND RESULTS

Sixteen individuals demonstrated improved WAB-R AQ scores, defined as positive AQ change scores greater than the WAB-R AQ standard error of the mean (WAB-SEM); seven maintained their original WAB quotients, defined as AQ change scores that were not greater than the WAB-SEM; and the final three showed negative WAB-R change scores, defined as a negative WAB-R AQ change score greater than the WAB-SEM. Concurrent changes on several AphasiaBank tasks were also found, suggesting that the WAB-R improvements were noted in more natural discourse as well.

CONCLUSIONS

These data are surprising, since conventional wisdom suggests that spontaneous improvement in language is unlikely to occur beyond one year. Long-term improvement or maintenance of early test scores, such as that shown here, has seldom been demonstrated in the absence of formal treatment. Speculations about why these PWA improved, maintained or declined in their scores are considered.

The Prognosis and Recovery of Aphasia Related to Stroke Lesion

Objective

To investigate the effects of specific brain lesions on prognosis and recovery of post-stroke aphasia, and to assess the characteristic pattern of recovery.

Methods

Total of 15 subjects with first-ever, left hemisphere stroke, who were right handed, and who completed language assessment using the Korean version of the Western Aphasia Battery (K-WAB) at least twice during the subacute and chronic stages of stroke, were included. The brain lesions of the participants were evaluated using MRI-cron, SPM8, and Talairach Daemon software.

Results

Subtraction of the lesion overlap map of the participants who showed more than 30% improvement in the aphasia quotient (AQ) by the time of their chronic stage (n=9) from the lesion overlap map of those who did not show more than 30% improvement in the AQ (n=6) revealed a strong relationship with Broca's area, inferior prefrontal gyrus, premotor cortex, and a less strong relationship with Wernicke's area and superior and middle temporal gyri. The culprit lesion related to poor prognosis, after grouping the subjects according to their AQ score in the chronic stage (a cut score of 50), revealed a strong relationship with Broca's area, superior temporal gyrus, and a less strong relationship with Wernicke's area, prefrontal cortex, and inferior frontal gyrus.

Conclusion

Brain lesions in the Broca's area, inferior prefrontal gyrus, and premotor cortex may be related to slow recovery of aphasia in patients with left hemisphere stroke. Furthermore, involvement of Broca's area and superior temporal gyrus may be associated with poor prognosis of post-stroke aphasia.

Neuromagnetic beta and gamma oscillations in the somatosensory cortex after music training in healthy older adults and a chronic stroke patient

OBJECTIVE

Extensive rehabilitation training can lead to functional improvement even years after a stroke. Although neuronal plasticity is considered as a main origin of such ameliorations, specific subtending mechanisms need further investigation. Our aim was to obtain objective neuromagnetic measures sensitive to brain reorganizations induced by a music-supported training.

METHODS

We applied 20-Hz vibrotactile stimuli to the index finger and the ring finger, recorded somatosensory steady-state responses with magnetoencephalography, and analyzed the cortical sources displaying oscillations synchronized with the external stimuli in two groups of healthy older adults before and after musical training or without training. In addition, we applied the same analysis for an anecdotic report of a single chronic stroke patient with hemiparetic arm and hand problems, who received music-supported therapy (MST).

RESULTS

Healthy older adults showed significant finger separation within the primary somatotopic map. Beta dipole sources were more anterior located compared to gamma sources. An anterior shift of sources and increases in synchrony between the stimuli and beta and gamma oscillations were observed selectively after music training. In the stroke patient a normalization of somatotopic organization was observed after MST, with digit separation recovered after training and stimulus induced gamma synchrony increased.

CONCLUSIONS

The proposed stimulation paradigm captures the integrity of primary somatosensory hand representation. Source position and synchronization between the stimuli and gamma activity are indices, sensitive to music-supported training. Responsiveness was also observed in a chronic stroke patient, encouraging for the music-supported therapy. Notably, changes in somatosensory responses were observed, even though the therapy did not involve specific sensory discrimination training.

SIGNIFICANCE

The proposed protocol can be used for monitoring changes in neuronal organization during training and will improve the understanding of the brain mechanisms underlying rehabilitation.

Predicting outcome and recovery after stroke with lesions extracted from MRI images

Here, we present and validate a method that lets us predict the severity of cognitive impairments after stroke, and the likely course of recovery over time. Our approach employs (a) a database that records the behavioural scores from a large population of patients who have, collectively, incurred a comprehensive range of focal brain lesions, (b) an automated procedure to convert structural brain scans from those patients into three-dimensional images of their lesions, and (c) a system to learn the relationship between patients' lesions, demographics and behavioural capacities at different times post-stroke. Validation against data collected from 270 stroke patients suggests that our first set of variables yielded predictions that match or exceed the predictive power reported in any comparable work in the available literature. Predictions are likely to improve when other determinants of recovery are included in the system. Many behavioural outcomes after stroke could be predicted using the proposed approach.

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We use lesion information to predict speech production skills in 270 stroke patients.

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We validate our approach with both cross-sectional and longitudinal patient data.

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Better predictions employ more relevant and detailed lesion site information.

Reading without the left ventral occipito-temporal cortex

The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who acquired dyslexia following extensive LvOT damage. The patient followed a reading trajectory typical of that associated with pure alexia, re-gaining the ability to read aloud many words with declining performance as the length of words increased. Using functional MRI and dynamic causal modelling (DCM), we found that, when short (three to five letter) familiar words were read successfully, visual inputs to the patient’s occipital cortex were connected to left motor and premotor regions via activity in a central part of the left superior temporal sulcus (STS). The patient analysis therefore implied a left hemisphere “reading-without-LvOT” pathway that involved STS. We then investigated whether the same reading-without-LvOT pathway could be identified in 29 skilled readers and whether there was inter-subject variability in the degree to which skilled reading engaged LvOT. We found that functional connectivity in the reading-without-LvOT pathway was strongest in individuals who had the weakest functional connectivity in the LvOT pathway. This observation validates the findings of our patient’s case study. Our findings highlight the contribution of a left hemisphere reading pathway that is activated during the rapid identification of short familiar written words, particularly when LvOT is not involved. Preservation and use of this pathway may explain how patients are still able to read short words accurately when LvOT has been damaged.

Recovery of aphasia after stroke: a 1-year follow-up study

Semantics, phonology, and syntax are essential elements of aphasia diagnosis and treatment. Until now, these linguistic components have not been specifically addressed in follow-up studies of aphasia recovery after stroke. The aim of this observational prospective follow-up study was to investigate semantic, phonological, and syntactic recovery in aphasic stroke patients. In addition, we investigated the recovery of verbal communication and of aphasia severity. We assessed 147 aphasic patients at 1, 2, and 6 weeks, 3 and 6 months, and 1 year after stroke with the ScreeLing, a screening test for detecting deficits on the three main linguistic components, the aphasia severity rating scale (ASRS), a measure of verbal communication, and the Token test, a measure of aphasia severity. We investigated the differences in scores between the six time points with mixed models. Semantics and syntax improved up to 6 weeks (p < 0.001) after stroke, and phonology up to 3 months (p ≤ 0.001). ASRS improved up to 6 months (p < 0.05) and the Token test up to 3 months (p < 0.001). We conclude that in aphasia after stroke, various linguistic components have a different recovery pattern, with phonology showing the longest period of recovery that paralleled aphasia severity, as measured with the Token test. The improvement of verbal communication continues after the stabilization of the recovery of the linguistic components.