Poststroke Aphasia Recovery Research Articles

Neuroimaging in aphasia treatment research: Consensus and practical guidelines for data analysis

Functional magnetic resonance imaging is the most widely used imaging technique to study treatment-induced recovery in post-stroke aphasia. The longitudinal design of such studies adds to the challenges researchers face when studying patient populations with brain damage in cross-sectional settings. The present review focuses on issues specifically relevant to neuroimaging data analysis in aphasia treatment research identified in discussions among international researchers at the Neuroimaging in Aphasia Treatment Research Workshop held at Northwestern University (Evanston, Illinois, USA). In particular, we aim to provide the reader with a critical review of unique problems related to the pre-processing, statistical modeling and interpretation of such data sets. Despite the fact that data analysis procedures critically depend on specific design features of a given study, we aim to discuss and communicate a basic set of practical guidelines that should be applicable to a wide range of studies and useful as a reference for researchers pursuing this line of research.

Post‐stroke aphasia prognosis: a review of patient‐related and stroke‐related factors

Recovery of language function in individuals with post-stroke aphasia is associated with a variety of patient and stroke-related indices. Amidst a complex interaction of a multitude of variables, clinicians are faced with the arduous challenge of predicting aphasia recovery patterns and subsequently, long-term outcomes in these individuals. Unfortunately, predictive factors are highly variable making prognosis of aphasia recovery difficult. Therefore, the objective of this review was to assess the influence of patient-related and stroke-related factors on language recovery in individuals with post-stroke aphasia. We completed a literature review to assess and identify evidence-based patient and stroke-related variables shown to be influential in aphasia recovery. A range of patient-related (gender, handedness, age, education, socio-economic status and intelligence) and stroke-related indices (initial severity, lesion site and lesion size) were identified as potential influential factors to post-stroke aphasia recovery. Initial severity of aphasia emerged as the factor most predictive of long-term aphasia recovery. Other influential factors of post-stroke language recovery included lesion site and size. Stroke-related factors, including aphasia severity, lesion site and lesion size, appear most critical to post-stroke aphasia recovery. The findings presented in this review offer clinicians an evidenced-based framework to assist in prediction of post-stroke aphasia recovery patterns and subsequent long-term functional communication outcomes.

Poststroke Aphasia Recovery Assessed With Functional Magnetic Resonance Imaging and a Picture Identification Task

Stroke patients often display deficits in language function, such as correctly naming objects. Our aim was to evaluate the reliability and the patterns of poststroke language recovery using a picture identification task during functional magnetic resonance imaging (fMRI) at 4 T. Four healthy subjects and 4 subjects with left middle cerebral artery stroke with chronic (>1 year) aphasia were enrolled in the study. In each subject, 10 fMRI scans were performed over a 10-week period using a picture-identification task. The active condition involved presenting subject with a panel of 4 figures (eg, drawings of 4 animals) every 6 seconds and asking the subject to indicate which figure matched the written name in the center. The control condition was a same/different judgment task with pairs of geometric figures (squares, octagons, or combination) presented every 6 seconds. Thirty-second active/control blocks were repeated 5 times each, and responses were recorded. The stoke subjects and controls had similar demographic characteristics, including age (46 vs 53 years), personal handedness (Edinburg Handedness Inventory, 89 vs 95), familial handedness (93 vs 95), and years of education (14.3 vs 14.8). For the active condition, the controls performed better than the stroke subjects (97.7% vs 89.1%; P < .001); the 2 groups performed similarly for the control condition (99.5% vs 98.8%; P = .23). On fMRI, the controls exhibited bilateral,L> R positive blood oxygenation level-dependent (BOLD) activations in frontal andtemporal language areas and symmetric retrosplenial and posterior cingulate areas and symmetric negative BOLD activations in bilateral frontotemporal language networks. In contrast, the stroke subjects exhibited positive BOLD activations predominantly in peristroke areas and negative BOLD activations in the unaffected (right) hemisphere. Both groups displayed high activation reliability (asmeasured by the intraclass correlation coefficient [ICC]) in the left frontal and temporal language areas, although in the stroke subjects the ICC in the frontal regions was spread over a much larger peristroke area. This study documents the utility of the picture-identification task for poststroke language recovery evaluation. Our data suggest that adult stroke patients use functional peristroke areas to perform language functions.

The ‘Standard’ for Poststroke Aphasia Recovery

See related article, pages 1485–1488. The past 2 decades may be remembered as the decades of metrics in medicine. All aspects of our work have been measured and charted by relative value units, H-indices, case mix indices, mean lengths of stay, mean patient satisfaction scores, and so on. Some metrics are important, some less so. However, 1 important measure is the degree to which a patient with stroke will be able to improve in the next 90 days. Decisions need to be made about whether to apply for disability, move to assisted living, or whether to wait for improvement to occur. We as stroke neurologists think we know the answers, but we all give different answers based on very little data; we often say it depends on the size of the stroke, the patient’s age and education, the severity and type of the deficit, the quality and duration of therapy, and so on. However, seemingly within a wide range of these variables, Lazar and colleagues1 have found that that there is a single answer that does not depend on any of these variables; by 90 days, patients improve by approximately 70% of the maximum potential recovery (the maximum potential language score minus their initial score) as long as they receive at …

Poststroke and Brain Injury Rehabilitation Treatment Strategies

In the June, July, and August issues of the Journal, we introduced the first three parts of a four-issue special series focused on innovative, physiologic treatments for stroke and traumatic brain injury.1–3 These disorders are leading causes of adult disability in the United States, accounting for tremendous personal, social, and financial costs for survivors, caregivers, and society. In the June issue, Hillis has provided an up-to-date review on how physiologic treatments may optimize poststroke aphasia recovery.4 Choi et al.5 and Buxbaum et al.6 have presented data in the July issue relevant to poststroke spatial neglect treatment. The August issue has focused on pharmaceutical treatment of acquired adynamic speech and disordered consciousness.7,8 In this issue, we consider how rehabilitative strategies can be refined and developed further. In rehabilitation science, it is absolutely critical that we move from basic discovery—new, potentially promising neurorehabilitation interventions—toward large-scale, systematic clinical studies and beyond, to their optimal application. Even within our own field, intermediate-stage studies are criticized because they do not use randomized controlled or meta-analytic methodology. However, phase III research planning is neither appropriate nor desirable when a treatment hypothesis is being refined, and its feasibility and optimal setting are being explored.9 This issue presents two papers on combined treatment strategies for poststroke hemiparesis, an area emerging from observational reports into systematic group studies. Malcolm et al.10 added repetitive transcranial magnetic stimulation to a modified protocol for constraint-induced therapy. Although constraint-induced therapy seems to have resulted in motor improvement, adjuvant repetitive transcranial magnetic stimulation induced changes in motor excitability in treated patients without an associated, clinically evident treatment effect. Their results suggest that the relationship between physiologic parameters and functional improvement needs clarification, as do optimal parameters for designing constraint-induced therapy to produce functional gains across individuals. Levy et al.11 examined a combination of botulinum toxin A injections, evidence-based exercise therapy, and constraint-induced movement therapy in hemiparetic patients with spasticity, and motor function insufficient for constraint-induced movement therapy candidacy by standard criteria. Motor ability improved with toxin and exercise therapy, but in the four patients who became eligible, gains made with subsequent constraint-induced movement therapy unfortunately receded as spasticity returned. A larger-scale investigation of constraint-induced movement therapy in stroke survivors with very low motor functional ability, after administering botulinum toxin A/exercise treatment, may now be indicated. We are grateful for the opportunity to bring Journal readers the four-issue special series on brain injury rehabilitation. We hope these articles stimulate a continuing dialogue in the rehabilitation science community and aid in developing more studies to complete and strengthen our translational continuum.

A proposed regional hierarchy in recovery of post-stroke aphasia

Activation studies in patients with aphasia due to stroke or tumours in the dominant hemisphere have revealed effects of disinhibition in ipsilateral perilesional and in contralateral homotopic cortical regions, referred to as collateral and transcallosal disinhibition. These findings were supported by studies with selective disturbance of cortical areas by repetitive transcranial magnetic stimulation (rTMS) in healthy volunteers and in patients with focal brain lesions. Both, collateral as well as transcallosal disinhibition might be relevant for the compensation of lesions within a functional network. From these data a hierarchical organization of recovery of aphasia after stroke and of compensation of language defects due to brain tumours can be deduced, by which the reactivation of undamaged network areas of the ipsilateral hemisphere usually lead to better outcome than the involvement of homotopic contra-lateral regions. rTMS can be used to identify areas relevant for speech production and might play a role in treatment strategies targeted at modulating the activity of contralateral homotopic areas of the functional network which might interfere with language recovery.

Neural substrates of word recovery in chronic poststroke aphasia: an fMRI study

Neural substrates of word recovery in chronic poststroke aphasia: an fMRI study

Amphetamines for improving stroke recovery: a systematic cochrane review.

The search for pharmacological therapies, which may facilitate the recovery process after a permanent brain injury, has been intensified during the past decade. One of the most extensively studied pharmacological approaches to stimulate recovery after experimental stroke is treatment with amphetamines. Experimental animal studies suggest that treatment with amphetamines improve recovery after focal cerebral ischemia. If the effect were similar in humans, amphetamine treatment could have a major impact on recovery from stroke. This systematic review aims to assess the effects of amphetamine treatment, as compared with placebo, in patients with stroke. We searched the Cochrane Stroke Group Trials Register (last searched November 2002). In addition, we searched the …