Neuroscience insights improve neurorehabilitation of poststroke aphasia

'But I have a cat, I have to talk to her now': a qualitative study on reasons for not participating in guideline-based aphasia therapy from the perspective of patients in German-speaking countries

OBJECTIVES

Clinical guidelines recommend high-frequency speech therapy for people with aphasia. Little is known about the experiences of people with aphasia with high-frequency speech therapy, why they do not receive it, what they expect from it and their general wishes and requirements for therapy. The aim of this qualitative study was to investigate the reasons for refusing high-frequency speech therapy and therapy preferences of patients with aphasia.

DESIGN

An interview study with people with aphasia.

SETTING

Interviewees were recruited via snowball sampling in different settings of healthcare system (eg, speech and language practices, self-help groups, clinics of neurorehabilitation).

PARTICIPANTS

Twenty-one people with aphasia and one relative participated in semi-structured interviews.

RESULTS

We identified five categories of not using high-frequency speech therapy: patient-related factors, health system-related factors, disease-related factors, social-economic factors and organisational factors. Most reasons for non-utilisation are within the domain of the healthcare system and are partly attributable to personnel shortages in care provision and knowledge deficits among healthcare practitioners. Patient therapy preferences notably pertain to the enhancement of speech therapy services, encompassing sessions both inclusive and exclusive of family members as well as the facilitation of information dissemination.

CONCLUSIONS

As expected, there were indications of a lack of staff, poor care in rural areas and the influence of being affected by aphasia for a longer period on utilisation behaviour. These factors in the healthcare system and organisational factors are not unknown to those with practical experience, and some of them must and could be changed quickly. This would require a change from the established face-to-face setting in presence to sufficient digital therapy adjuvants. The results of patient-related factors could be a further reason to reflect on speech therapy and its settings and to view and treat people with aphasia in a more holistic, less language-focused way.

Can human brain connectivity explain verbal working memory?

The ability of humans to store spoken words in verbal working memory and build extensive vocabularies is believed to stem from evolutionary changes in cortical connectivity across primate species. However, the underlying neurobiological mechanisms remain unclear. Why can humans acquire vast vocabularies, while non-human primates cannot? This study addresses this question using brain-constrained neural networks that realize between-species differences in cortical connectivity. It investigates how these structural differences support the formation of neural representations for spoken words and the emergence of verbal working memory, crucial for human vocabulary building. We develop comparative models of frontotemporal and occipital cortices, reflecting human and non-human primate neuroanatomy. Using meanfield and spiking neural networks, we simulate auditory word recognition and examine verbal working memory function. The "human models", characterized by denser inter-area connectivity in core language areas, produced larger cell assemblies than the "monkey models", with specific topographies reflecting semantic properties of the represented words. Crucially, longer-lasting reverberant neural activity was observed in human versus monkey architectures, compatible with robust verbal working memory, a necessary condition for vocabulary building. Our findings offer insights into the structural basis of human-specific symbol learning and verbal working memory, shedding light on humans' unique capacity for large vocabulary acquisition.

Language and gesture neural correlates: A meta-analysis of functional magnetic resonance imaging studies

BACKGROUND

Humans often use co-speech gestures to promote effective communication. Attention has been paid to the cortical areas engaged in the processing of co-speech gestures.

AIMS

To investigate the neural network underpinned in the processing of co-speech gestures and to observe whether there is a relationship between areas involved in language and gesture processing.

METHODS & PROCEDURES

We planned to include studies with neurotypical and/or stroke participants who underwent a bimodal task (i.e., processing of co-speech gestures with relative speech) and a unimodal task (i.e., speech or gesture alone) during a functional magnetic resonance imaging (fMRI) session. After a database search, abstract and full-text screening were conducted. Qualitative and quantitative data were extracted, and a meta-analysis was performed with the software GingerALE 3.0.2, performing contrast analyses of uni- and bimodal tasks.

MAIN CONTRIBUTION

The database search produced 1024 records. After the screening process, 27 studies were included in the review. Data from 15 studies were quantitatively analysed through meta-analysis. Meta-analysis found three clusters with a significant activation of the left middle frontal gyrus and inferior frontal gyrus, and bilateral middle occipital gyrus and inferior temporal gyrus.

CONCLUSIONS

There is a close link at the neural level for the semantic processing of auditory and visual information during communication. These findings encourage the integration of the use of co-speech gestures during aphasia treatment as a strategy to foster the possibility to communicate effectively for people with aphasia.

WHAT THIS PAPER ADDS

What is already known on this subject Gestures are an integral part of human communication, and they may have a relationship at neural level with speech processing. What this paper adds to the existing knowledge During processing of bi- and unimodal communication, areas related to semantic processing and multimodal processing are activated, suggesting that there is a close link between co-speech gestures and spoken language at a neural level. What are the potential or actual clinical implications of this work? Knowledge of the functions related to gesture and speech processing neural networks will allow for the adoption of model-based neurorehabilitation programs to foster recovery from aphasia by strengthening the specific functions of these brain networks.

Turning the Spotlight to Cholinergic Pharmacotherapy of the Human Language System

Even though language is essential in human communication, research on pharmacological therapies for language deficits in highly prevalent neurodegenerative and vascular brain diseases has received little attention. Emerging scientific evidence suggests that disruption of the cholinergic system may play an essential role in language deficits associated with Alzheimer's disease and vascular cognitive impairment, including post-stroke aphasia. Therefore, current models of cognitive processing are beginning to appraise the implications of the brain modulator acetylcholine in human language functions. Future work should be directed further to analyze the interplay between the cholinergic system and language, focusing on identifying brain regions receiving cholinergic innervation susceptible to modulation with pharmacotherapy to improve affected language domains. The evaluation of language deficits in pharmacological cholinergic trials for Alzheimer's disease and vascular cognitive impairment has thus far been limited to coarse-grained methods. More precise, fine-grained language testing is needed to refine patient selection for pharmacotherapy to detect subtle deficits in the initial phases of cognitive decline. Additionally, noninvasive biomarkers can help identify cholinergic depletion. However, despite the investigation of cholinergic treatment for language deficits in Alzheimer's disease and vascular cognitive impairment, data on its effectiveness are insufficient and controversial. In the case of post-stroke aphasia, cholinergic agents are showing promise, particularly when combined with speech-language therapy to promote trained-dependent neural plasticity. Future research should explore the potential benefits of cholinergic pharmacotherapy in language deficits and investigate optimal strategies for combining these agents with other therapeutic approaches.

Supporting Post-Stroke Language and Cognition with Pharmacotherapy: Tools for Each Phase of Care

PURPOSE OF REVIEW

There is enormous enthusiasm for the possibility of pharmacotherapies to treat language deficits that can arise after stroke. Speech language therapy remains the most frequently utilized and most strongly evidenced treatment, but the numerous barriers to patients receiving the therapy necessary to recover have motivated the creation of a relatively modest, yet highly cited, body of evidence to support the use of pharmacotherapy to treat post-stroke aphasia directly or to augment traditional post-stroke aphasia treatment. In this review, we survey the use of pharmacotherapy to preserve and support language and cognition in the context of stroke across phases of care, discuss key ongoing clinical trials, and identify targets that may become emerging interventions in the future.

RECENT FINDINGS

Recent trials have shifted focus from short periods of drug therapy supporting therapy in the chronic phase to longer terms approaching pharmacological maintenance beginning more acutely. Recent innovations in hyperacute stroke care, such as tenecteplase, and acute initiation of neuroprotective agents and serotonin reuptake inhibitors are important areas of ongoing research that complement the ongoing search for effective adjuvants to later therapy. Currently there are no drugs approved in the United States for the treatment of aphasia. Nevertheless, pharmacological intervention may provide a benefit to all phases of stroke care.

Pharmacotherapy for post-stroke aphasia: what are the options?

INTRODUCTION

Aphasia is a common, long-lasting aftermath of stroke lesions. There is an increased integration of pharmacotherapy as an adjunctive strategy to speech and language therapy (SLT) for post-stroke aphasia (PSA). Nevertheless, more research in pharmacotherapy for acute and chronic PSA is necessary, including the election of drugs that target different neurotransmitter systems and deficits in specific language domains.

AREAS COVERED

This article updates the role of pharmacotherapy for PSA, focusing the spotlight on some already investigated drugs and candidate agents deserving of future research. Refining the precision of drug election would require using multimodal biomarkers to develop personalized treatment approaches. There is a solid need to devise feasible randomized controlled trials adapted to the particularities of the PSA population. The emergent role of multimodal interventions combining one or two drugs with noninvasive brain stimulation to augment SLT is emphasized.

EXPERT OPINION

Pharmacotherapy can improve language deficits not fully alleviated by SLT. In addition, the 'drug-only' approach can also be adopted when administering SLT is not possible. The primary goal of pharmacotherapy is reducing the overall aphasia severity, although targeting language-specific deficits (i.e. naming, spoken output) also contributes to improving functional communication. Unfortunately, there is still little information for recommending a drug for specific language deficits.

Psychometric Testing of the CEECCA Questionnaire to Assess Ability to Communicate among Individuals with Aphasia

(1) Background: The CEECCA questionnaire assesses the ability to communicate among individuals with aphasia. It was designed using the NANDA-I and NOC standardised nursing languages (SNLs), reaching high content validity index and representativeness index values. The questionnaire was pilot-tested, demonstrating its feasibility for use by nurses in any healthcare setting. This study aims to identify the psychometric properties of this instrument. (2) Methods: 47 individuals with aphasia were recruited from primary and specialist care facilities. The instrument was tested for construct validity and criterion validity, reliability, internal consistency, and responsiveness. The NANDA-I and NOC SNLs and the Boston test were used for criterion validity testing. (3) Results: five language dimensions explained 78.6% of the total variance. Convergent criterion validity tests showed concordances of up to 94% (Cohen's κ: 0.9; p < 0.001) using the Boston test, concordances of up to 81% using DCs of NANDA-I diagnoses (Cohen's κ: 0.6; p < 0.001), and concordances of up to 96% (Cohen's κ: 0.9; p < 0.001) using NOC indicators. The internal consistency (Cronbach's alpha) was 0.98. Reliability tests revealed test-retest concordances of 76-100% (p < 0.001). (4) Conclusions: the CEECCA is an easy-to-use, valid, and reliable instrument to assess the ability to communicate among individuals with aphasia.

Motor imagery training to improve language processing: What are the arguments?

Studies showed that motor expertise was found to induce improvement in language processing. Grounded and situated approaches attributed this effect to an underlying automatic simulation of the motor experience elicited by action words, similar to motor imagery (MI), and suggest shared representations of action conceptualization. Interestingly, recent results also suggest that the mental simulation of action by MI training induces motor-system modifications and improves motor performance. Consequently, we hypothesize that, since MI training can induce motor-system modifications, it could be used to reinforce the functional connections between motor and language system, and could thus lead to improved language performance. Here, we explore these potential interactions by reviewing recent fundamental and clinical literature in the action-language and MI domains. We suggested that exploiting the link between action language and MI could open new avenues for complementary language improvement programs. We summarize the current literature to evaluate the rationale behind this novel training and to explore the mechanisms underlying MI and its impact on language performance.

EEG in Neurorehabilitation: A Bibliometric Analysis and Content Review

BACKGROUND

There is increasing interest in the role of EEG in neurorehabilitation. We primarily aimed to identify the knowledge base through highly influential studies. Our secondary aims were to imprint the relevant thematic hotspots, research trends, and social networks within the scientific community.

METHODS

We performed an electronic search in Scopus, looking for studies reporting on rehabilitation in patients with neurological disabilities. We used the most influential papers to outline the knowledge base and carried out a word co-occurrence analysis to identify the research hotspots. We also used depicted collaboration networks between universities, authors, and countries after analyzing the cocitations. The results were presented in summary tables, plots, and maps. Finally, a content review based on the top-20 most cited articles completed our study.

RESULTS

Our current bibliometric study was based on 874 records from 420 sources. There was vivid research interest in EEG use for neurorehabilitation, with an annual growth rate as high as 14.3%. The most influential paper was the study titled "Brain-computer interfaces, a review" by L.F. Nicolas-Alfonso and J. Gomez-Gill, with 997 citations, followed by "Brain-computer interfaces in neurological rehabilitation" by J. Daly and J.R. Wolpaw (708 citations). The US, Italy, and Germany were among the most productive countries. The research hotspots shifted with time from the use of functional magnetic imaging to EEG-based brain-machine interface, motor imagery, and deep learning.

CONCLUSIONS

EEG constitutes the most significant input in brain-computer interfaces (BCIs) and can be successfully used in the neurorehabilitation of patients with stroke symptoms, amyotrophic lateral sclerosis, and traumatic brain and spinal injuries. EEG-based BCI facilitates the training, communication, and control of wheelchair and exoskeletons. However, research is limited to specific scientific groups from developed countries. Evidence is expected to change with the broader availability of BCI and improvement in EEG-filtering algorithms.

Common Neuroanatomical Substrate of Cholinergic Pathways and Language-Related Brain Regions as an Explanatory Framework for Evaluating the Efficacy of Cholinergic Pharmacotherapy in Post-Stroke Aphasia: A Review

Despite the relative scarcity of studies focusing on pharmacotherapy in aphasia, there is evidence in the literature indicating that remediation of language disorders via pharmaceutical agents could be a promising aphasia treatment option. Among the various agents used to treat chronic aphasic deficits, cholinergic drugs have provided meaningful results. In the current review, we focused on published reports investigating the impact of acetylcholine on language and other cognitive disturbances. It has been suggested that acetylcholine plays an important role in neuroplasticity and is related to several aspects of cognition, such as memory and attention. Moreover, cholinergic input is diffused to a wide network of cortical areas, which have been associated with language sub-processes. This could be a possible explanation for the positive reported outcomes of cholinergic drugs in aphasia recovery, and specifically in distinct language processes, such as naming and comprehension, as well as overall communication competence. However, evidence with regard to functional alterations in specific brain areas after pharmacotherapy is rather limited. Finally, despite the positive results derived from the relevant studies, cholinergic pharmacotherapy treatment in post-stroke aphasia has not been widely implemented. The present review aims to provide an overview of the existing literature in the common neuroanatomical substrate of cholinergic pathways and language related brain areas as a framework for interpreting the efficacy of cholinergic pharmacotherapy interventions in post-stroke aphasia, following an integrated approach by converging evidence from neuroanatomy, neurophysiology, and neuropsychology.

No evidence of impediment by three common classes of prescription drugs to post-stroke aphasia recovery in a retrospective longitudinal sample

A number of pharmaceuticals have been identified as potential adjuvants to speech language therapy following stroke, but it is also important to consider which pharmaceuticals may result in a less robust recovery. Here we examine whether post-stroke language recovery was meaningfully impeded by cholinergic, GABAergic, or dopaminergic medications patients received. Eighty participants with left hemisphere stroke were examined retrospectively to see whether the use of one of these three classes of medication prior to admission for acute stroke, during their inpatient stay, or at discharge was associated with differences in recovery on three common measures of language. While prescription of any of the candidate drugs was relatively uncommon, groups were very well matched for many common factors that impact performance. When age, education, and acute lesion volume were controlled, there were no significant differences in performance among those taking cholinergic, GABAergic, or dopaminergic medications and those who were not. Those who experienced a "good recovery" of language (≥10% improvement on any one language measure over time) had similar exposure to these drugs to those with a poor recovery. This work represents a first look at these drug classes with regard to their effects on the recovery of language after stroke and should not be interpreted as resolving all potential for concern, but these results do offer modest reassurance that these common classes of pharmacotherapy, when given for short periods in this population, do not appear to have marked deleterious effects on post-stroke recovery of language.

Kinesthetic motor-imagery training improves performance on lexical-semantic access

The objective of this study was to evaluate the effect of Motor Imagery (MI) training on language comprehension. In line with literature suggesting an intimate relationship between the language and the motor system, we proposed that a MI-training could improve language comprehension by facilitating lexico-semantic access. In two experiments, participants were assigned to a kinesthetic motor-imagery training (KMI) group, in which they had to imagine making upper-limb movements, or to a static visual imagery training (SVI) group, in which they had to mentally visualize pictures of landscapes. Differential impacts of both training protocols on two different language comprehension tasks (i.e., semantic categorization and sentence-picture matching task) were investigated. Experiment 1 showed that KMI training can induce better performance (shorter reaction times) than SVI training for the two language comprehension tasks, thus suggesting that a KMI-based motor activation can facilitate lexico-semantic access after only one training session. Experiment 2 aimed at replicating these results using a pre/post-training language assessment and a longer training period (four training sessions spread over four days). Although the improvement magnitude between pre- and post-training sessions was greater in the KMI group than in the SVI one on the semantic categorization task, the sentence-picture matching task tended to provide an opposite pattern of results. Overall, this series of experiments highlights for the first time that motor imagery can contribute to the improvement of lexical-semantic processing and could open new avenues on rehabilitation methods for language deficits.

Noninvasive stimulation of the unlesioned hemisphere and phonological treatment in a case of chronic anomia post-stroke

Chronic lexical anomia after left hemisphere (LH) stroke improves under personalized phonological treatment (PT). Cortical linking between language and hand motor areas (hand_M1) questioned whether PT-related improvement relies on the unlesioned hemisphere (UH) plasticity when LH is dysfunctional. Our 70-yo-woman case study showed that 10 sessions of excitatory stimulation of UH_hand-M1 combined with PT hastened oral picture naming improvement as compared to sham+PT and changes were maintained together with changes of untrained items andcorticomotor excitability increase. This supports a role of stimulation-induced plasticity of UH_hand M1 in language recovery, at least in the improvement of lexical anomia in chronic stroke.

Better language through chemistry: Augmenting speech-language therapy with pharmacotherapy in the treatment of aphasia

Speech and language therapy is the standard treatment of aphasia. However, many individuals have barriers in seeking this measure of extensive rehabilitation treatment. Investigating ways to augment therapy is key to improving poststroke language outcomes for all patients with aphasia, and pharmacotherapies provide one such potential solution. Although no medications are currently approved for the treatment of aphasia by the United States Food and Drug Administration, numerous candidate mechanisms for pharmaceutical manipulation continue to be identified based on our evolving understanding of the neurometabolic experience of stroke recovery across molecular, cellular, and functional levels of inquiry. This chapter will review evidence for catecholaminergic, glutamatergic, cholinergic, and serotonergic drug therapies and discuss future directions for both candidate drug selection and pharmacotherapy practice in people with aphasia.

Substrates of speech treatment-induced neuroplasticity in adults and children with motor speech disorders: A systematic scoping review of neuroimaging evidence

Purpose: Neuroimaging may provide clinical evidence for speech treatment-induced neuroplasticity. This review aimed to report the current scope of evidence relating to brain changes identified using neuroimaging techniques, following effective speech intervention in adults and children with motor speech disorders (MSD).Method: Studies were retrieved from five electronic databases (PubMed, CINAHL, EMBASE (Medline), SCOPUS, and Web of Science) and a general internet search.Result: Seven studies met the inclusion criteria. Using structural or functional neuroimaging techniques, five studies reported on the effects of the Lee Silverman Voice Treatment for dysarthria in adults and children, one study on the outcome of rhythmic-melodic voice training in adults with apraxia of speech, and one study on the effects of Prompts for Restructuring Oral Muscular Phonetic Targets therapy in children with idiopathic apraxia of speech. Identified brain changes included: enhanced white matter tract integrity; normalisation of baseline cortical activity; right-hemisphere shifts in re-organisation; perilesional activations; and cortical thinning.Conclusion: The current review identified preliminary evidence for treatment-dependent brain changes in adults and children with MSD. Although important to interpret within the context of Phase I research, the identification of therapeutic effects across seven heterogeneous studies suggests that treatment-induced improvements in speech performance are underpinned by demonstrable alterations in brain structure and/or function. Future research is required to better define these mechanisms of neuronal re-organisation in individuals receiving treatment for MSD, including their prognostic potential.

Long-Term Stability of Short-Term Intensive Language-Action Therapy in Chronic Aphasia: A 1-2 year Follow-Up Study

Background. Intensive aphasia therapy can improve language functions in chronic aphasia over a short therapy interval of 2-4 weeks. For one intensive method, intensive language-action therapy, beneficial effects are well documented by a range of randomized controlled trials. However, it is unclear to date whether therapy-related improvements are maintained over years. Objective. The current study aimed at investigating long-term stability of ILAT treatment effects over circa 1-2 years (8-30 months). Methods. 38 patients with chronic aphasia participated in ILAT and were re-assessed at a follow-up assessment 8-30 months after treatment, which had been delivered 6-12.5 hours per week for 2-4 weeks. Results. A standardized clinical aphasia battery, the Aachen Aphasia Test, revealed significant improvements with ILAT that were maintained for up to 2.5 years. Improvements were relatively better preserved in comparatively young patients (<60 years). Measures of communicative efficacy confirmed improvements during intensive therapy but showed inconsistent long-term stability effects. Conclusions. The present data indicate that gains resulting from intensive speech-language therapy with ILAT are maintained up to 2.5 years after the end of treatment. We discuss this novel finding in light of a possible move from sparse to intensive therapy regimes in clinical practice.

The effects of intensity on a phonological treatment for anomia in post-stroke aphasia

INTRODUCTION

The evidence regarding optimal treatment intensity is mixed, and differing definitions have further confounded existing findings. The primary objective of this study was to compare the efficacy of Phonological Components Analysis (PCA) treatment for anomia delivered at intense and non-intense schedules, using a well-controlled design. The number of teaching episodes and active ingredients of therapy are important considerations when defining intensity. We hypothesized that an active ingredient of PCA is the self-generation of phonological components during therapy sessions. Our secondary aim was to examine whether component generation predicted treatment outcome.

METHODS

Sixteen adults (M = 52.63 years old, SD = 11.40) with chronic post-stroke aphasia (M = 4.52 years post-onset, SD = 5.55) were randomly assigned to intensive (IT) or standard (ST) PCA treatment conditions. Cumulative treatment intensity in both conditions was equivalent: ST participants received PCA 1 hour/day, 3 days/week for 10 weeks, whereas IT participants received PCA 3 hours/day, 4 days/week for 2.5 weeks. The primary outcome was naming accuracy on a set of treated and (matched) untreated words, measured pre- and post-treatment, and at four- and eight-week follow-ups.

RESULTS

IT and ST conditions were similarly efficacious. However, secondary analyses suggest an advantage for the IT condition in naming of the treated words immediately post-treatment, but not at follow-ups. The self-generation of phonological components emerged as a significant positive predictor of naming accuracy for both the treated and untreated words. However, this relationship did not reach significance once baseline anomia severity was accounted for.

CONCLUSIONS

Although replication in a larger sample is warranted, results suggest that PCA treatment is similarly efficacious when delivered at different intensities. Other factors related to the quality of treatment (i.e., active ingredients such as cue-generation) may play an important role in determining treatment efficacy and must also be considered when comparing treatment intensities.

Simulating lesion-dependent functional recovery mechanisms

Functional recovery after brain damage varies widely and depends on many factors, including lesion site and extent. When a neuronal system is damaged, recovery may occur by engaging residual (e.g., perilesional) components. When damage is extensive, recovery depends on the availability of other intact neural structures that can reproduce the same functional output (i.e., degeneracy). A system's response to damage may occur rapidly, require learning or both. Here, we simulate functional recovery from four different types of lesions, using a generative model of word repetition that comprised a default premorbid system and a less used alternative system. The synthetic lesions (i) completely disengaged the premorbid system, leaving the alternative system intact, (ii) partially damaged both premorbid and alternative systems, and (iii) limited the experience-dependent plasticity of both. The results, across 1000 trials, demonstrate that (i) a complete disconnection of the premorbid system naturally invoked the engagement of the other, (ii) incomplete damage to both systems had a much more devastating long-term effect on model performance and (iii) the effect of reducing learning capacity within each system. These findings contribute to formal frameworks for interpreting the effect of different types of lesions.

Diagnosing and managing post-stroke aphasia

Introduction: Aphasia is a debilitating language disorder and even mild forms of aphasia can negatively affect functional outcomes, mood, quality of life, social participation, and the ability to return to work. Language deficits after post-stroke aphasia are heterogeneous. Areas covered: The first part of this manuscript reviews the traditional syndrome-based classification approach as well as recent advances in aphasia classification that incorporate automatic speech recognition for aphasia classification. The second part of this manuscript reviews the behavioral approaches to aphasia treatment and recent advances such as noninvasive brain stimulation techniques and pharmacotherapy options to augment the effectiveness of behavioral therapy. Expert opinion: Aphasia diagnosis has largely evolved beyond the traditional approach of classifying patients into specific syndromes and instead focuses on individualized patient profiles. In the future, there is a great need for more large scale randomized, double-blind, placebo-controlled clinical trials of behavioral treatments, noninvasive brain stimulation, and medications to boost aphasia recovery.

Adjunctive Approaches to Aphasia Rehabilitation: A Review on Efficacy and Safety

Aphasia is one of the most socially disabling post-stroke deficits. Although traditional therapies have been shown to induce adequate clinical improvement, aphasic symptoms often persist. Therefore, unconventional rehabilitation techniques which act as a substitute or as an adjunct to traditional approaches are urgently needed. The present review provides an overview of the efficacy and safety of the principal approaches which have been proposed over the last twenty years. First, we examined the effectiveness of the pharmacological approach, principally used as an adjunct to language therapy, reporting the mechanism of action of each single drug for the recovery of aphasia. Results are conflicting but promising. Secondly, we discussed the application of Virtual Reality (VR) which has been proven to be useful since it potentiates the ecological validity of the language therapy by using virtual contexts which simulate real-life everyday contexts. Finally, we focused on the use of Transcranial Direct Current Stimulation (tDCS), both discussing its applications at the cortical level and highlighting a new perspective, which considers the possibility to extend the use of tDCS over the motor regions. Although the review reveals an extraordinary variability among the different studies, substantial agreement has been reached on some general principles, such as the necessity to consider tDCS only as an adjunct to traditional language therapy.

Multisensory cueing facilitates naming in aphasia

BACKGROUND

Impaired naming is a ubiquitous symptom in all types of aphasia, which often adversely impacts independence, quality of life, and recovery of affected individuals. Previous research has demonstrated that naming can be facilitated by phonological and semantic cueing strategies that are largely incorporated into the treatment of anomic disturbances. Beneficial effects of cueing, whereby naming becomes faster and more accurate, are often attributed to the priming mechanisms occurring within the distributed language network.

OBJECTIVE

We proposed and explored two novel cueing techniques: (1) Silent Visuomotor Cues (SVC), which provided articulatory information of target words presented in the form of silent videos, and (2) Semantic Auditory Cues (SAC), which consisted of acoustic information semantically relevant to target words (ringing for "telephone"). Grounded in neurophysiological evidence, we hypothesized that both SVC and SAC might aid communicative effectiveness possibly by triggering activity in perceptual and semantic language regions, respectively.

METHODS

Ten participants with chronic non-fluent aphasia were recruited for a longitudinal clinical intervention. Participants were split into dyads (i.e., five pairs of two participants) and required to engage in a turn-based peer-to-peer language game using the Rehabilitation Gaming System for aphasia (RGSa). The objective of the RGSa sessions was to practice communicative acts, such as making a request. We administered SVCs and SACs in a pseudorandomized manner at the moment when the active player selected the object to be requested from the interlocutor. For the analysis, we compared the times from selection to the reception of the desired object between cued and non-cued trials.

RESULTS

Naming accuracy, as measured by a standard clinical scale, significantly improved for all stimuli at each evaluation point, including the follow-up. Moreover, the results yielded beneficial effects of both SVC and SAC cues on word naming, especially at the early intervention sessions when the exposure to the target lexicon was infrequent.

CONCLUSIONS

This study supports the efficacy of the proposed cueing strategies which could be integrated into the clinic or mobile technology to aid naming even at the chronic stages of aphasia. These findings are consistent with sensorimotor accounts of language processing, suggesting a coupling between language, motor, and semantic brain regions.

TRIAL REGISTRATION

NCT02928822 . Registered 30 May 2016.

Pharmacotherapy of Traumatic Childhood Aphasia: Beneficial Effects of Donepezil Alone and Combined With Intensive Naming Therapy

At present, language therapy is the only available treatment for childhood aphasia (CA). Studying new interventions to augment and hasten the benefits provided by language therapy in children is strongly needed. CA frequently emerges as a consequence of traumatic brain injury and, as in the case of adults, it may be associated with dysfunctional activity of neurotransmitter systems. The use of cognitive-enhancing drugs, alone or combined with aphasia therapy, promotes improvement of language deficits in aphasic adults. In this study we report the case of a 9-year-old right-handed girl, subject P, who had chronic anomic aphasia associated with traumatic lesions in the left temporal-parietal cortex. We performed a single-subject, open-label study encompassing administration of the cholinergic agent donepezil (DP) alone during 12 weeks, followed by a combination of DP and intensive naming therapy (INT) for 2 weeks and thereafter by a continued treatment of DP alone during 12 weeks, a 4-week washout period, and another 2 weeks of INT. Four comprehensive language and neuropsychological evaluations were performed at different timepoints along the study, and multiple naming evaluations were performed after each INT in order to assess performance in treated and untreated words. Structural magnetic resonance imaging (MRI) was performed at baseline. MRI revealed two focal lesions in the left hemisphere, one large involving the posterior inferior and middle temporal gyri and another comprising the angular gyrus. Overall, baseline evaluation disclosed marked impairment in naming with mild-to-moderate compromise of spontaneous speech, repetition, and auditory comprehension. Executive and attention functions were also affected, but memory, visuoconstructive, and visuoperceptive functions were preserved. Treatment with DP alone significantly improved spontaneous speech, auditory comprehension, repetition, and picture naming, in addition to processing speed, selective, and sustained attention. Combined DP-INT further improved naming. After washout of both interventions, most of these beneficial changes remained. Importantly, DP produced no side effects and subject P attained the necessary level of language competence to return to regular schooling. In conclusion, the use of DP alone and in combination with INT improved language function and related cognitive posttraumatic deficits in a child with acquired aphasia. Further studies in larger samples are warranted.

Effects of exercise interventions for specific cognitive domains in old adults with mild cognitive impairment: A meta-analysis and subgroup analysis of randomized controlled trials

OBJECTIVE

To conduct a meta-analysis and subgroup analysis investigating the effects of exercise on mild cognitive impairment (MCI) patients across specific cognitive domain outcomes. We also analyzed and identified the level of influence of exercise interventions on specific cognitive domains.

METHODS

MEDLINE, EMBASE, Cochrane Library, Web of Science, CNKI, the Wan Fang Database, and CBM were searched from inception to April 2018. Randomized controlled trials of exercise interventions in MCI patients older than 55 years, with an outcome measure of cognitive function were included.

RESULTS

Eleven studies with sufficient data met the inclusion criteria for the meta-analysis. Exercise interventions significantly improved general function (g mini-mental state examination Montreal cognitive assessment = 0.32, 95% the 95% confidence interval (CI) 0.1 to 0.54, P = .005 and g Alzheimer disease assessment scale-cognition = -0.45, 95% CI -0.82 to -0.08, P = .02); executive functions (g digit span forward test, digit span backward test, digit span forward test -B, stroop test-A, stroop test-B = 0.66, 95% CI 0.17 to 1.15, P = .008); memory (g Wechsler memory scale immediate recall and Wechsler memory scale delayed recall = 0.37, 95% CI 0.15 to 0.60, P = .001); language ability (g category verbal fluency test and letter verbal fluency test = 0.55, 95% CI 0.22 to 0.89, P = .001); and visuospatial ability (g block design score = 0.38, 95% CI 0.03 to 0.72, P = .03). However, the improvement exercise conferred on the trail-making test part B-A was not statistically significant (g trail-making test part B-A  = -0.25, 95% CI -0.88 to 0.39, P = .45). The preliminary ranking of the effect on the overall effect was as follows: Z language ability > Z executive functions >   memory > Z visuospatial ability.

CONCLUSION

Exercise improves performance in the 5 cognitive domains. Across cognitive domains, language ability was the domain most affected by exercise. Besides, the kind of ranking (Z value) provides a new perspective for community health care workers to prescribe targeted exercise interventions for MCI patients.PROSPERO registration number: CRD42018093902.

Long-term chemogenetic activation of M1 glutamatergic neurons attenuates the behavioral and cognitive deficits caused by intracerebral hemorrhage

Acute spontaneous intracerebral hemorrhage (ICH) is a life-threatening disease. It is often accompanied by severe neurological sequelae largely caused by the loss of integrity of the neural circuits. However, these neurological sequelae have few strong medical interventions. Designer receptors exclusively activated by designer drugs (DREADDs) are important chemogenetic tools capable of precisely modulating the activity of neural circuits. They have been suggested to have therapeutic effects on multiple neurological diseases. Despite this, no empirical research has explored the effects of DREADDs on functional recovery after ICH. We aimed to explore whether the long-term excitation of glutamatergic neurons in primary motor cortex (M1) by DREADD could promote functional recovery after ICH. We used CaMKII-driven Gq/Gi-DREADDs to activate/inhibit M1 glutamatergic neurons for 21 consecutive days, and examined their effects on behavioral and cognitive deficits caused by ICH in a mouse model of ICH targeting striatum. Long-term chemogenetic activation of the M1 glutamatergic neurons increased the spatial memory and sensorimotor ability of mice suffering from ICH. It also attenuated the mitochondrial dysfunctions of striatal neurons by raising the ATP levels and mitochondrial membrane potential while decreasing the 8-OHdG levels. These results strongly suggest that selective stimulation of the M1 glutamatergic neurons contributes to functional recovery after ICH presumably through alleviation of mitochondrial dysfunctions.

Dual-task performance of speech and motor skill: verb generation facilitates grasping behaviour

Pronouncing nouns or verbs while grasping distinctly alters movement. Changes in hand speed and final position occur according to the meaning of the words spoken. These results are typically found when executing a single movement paired with a single word. For example, pronouncing the word 'fast' increased the speed of the hand when reaching to grasp. Our objective was to compare how verb and noun fluency tasks interact with grasping behaviour in a grasp-to-construct task. Because previous imaging research shows that verb and noun production activates distinct neural areas, we reasoned that grasping outcomes would differ according to the category of word produced by participants. Specifically, we hypothesized that verb pronunciation would distinctly affect grasping behaviour compared to producing nouns. We recruited 38 young adults who performed a grasp-to-construct task and two different verbal fluency tasks. Participants completed each task (grasp, verb fluency, and noun fluency) separately as control conditions, and the grasping and each speaking task simultaneously for dual-task conditions. We found that during the dual-task condition, when generating nouns and grasping, participants made significantly more grasping errors (inaccurate grasps) compared to the control and verb dual-task conditions. Moreover, our results revealed a relationship between the number of verbs generated and grasping performance. Participants who generated more verbs were faster and more accurate during the motor component of the dual-task condition. This relationship was not observed when nouns were produced, indicating a unique relationship between verb production and functional grasping. The result is a facilitation effect, diminishing the negative outcome on motor control associated with increased cognitive load (as observed during noun pronunciation).

'What's cooking?' A comparison of an activity-oriented and a table-top programme of therapy on the language performance of people with aphasia

BACKGROUND

Many people with aphasia have word-finding difficulties, with some showing particular difficulties with verbs. Picture-naming therapy is often used to improve naming, but gains are usually limited to therapy items and do not transfer to conversation. Therapy where words are produced in sentences and in real-life activities may be more effective.

AIMS

The current pilot study investigated whether an activity-oriented therapy approach would be accepted and viable if implemented in a community setting, and whether communicating whilst cooking was more beneficial than using paper-based activities. If successful, it would be expected that verb production would improve in structured and unstructured tasks in both naming and narrative tasks.

METHODS & PROCEDURES

The study employed a case-series repeated-measures design, with testing of treated and control items. Seven adults with anomia participated, although only five completed the full programme. Participants were divided into two groups and each group completed both treatments, but in different orders. Each treatment was employed for six 2-h sessions over a 3-week period.

OUTCOMES & RESULTS

Naming of both treated and untreated verbs showed a statistically significant improvement following both treatments and this continued into the maintenance phase. There was a numerical but not statistically significant gain in the variety of verbs used in spoken narratives. Participants predominantly chose positive terms to describe their experience of the programme, but did not prefer one therapy over the other.

CONCLUSIONS & IMPLICATIONS

Preliminary findings suggest that an activity-oriented therapy approach, whether it involves carrying out tasks or paper-based activities, can result in clinically meaningful improvements for people with chronic aphasia. Further research using a randomized control trial is required to determine whether cooking therapy alone is effective.

Combining rTMS With Intensive Language-Action Therapy in Chronic Aphasia: A Randomized Controlled Trial

Neuromodulation technologies, such as transcranial magnetic stimulation (TMS), are promising tools for neurorehabilitation, aphasia therapy included, but not yet in common clinical use. Combined with behavioral techniques, in particular treatment-efficient Intensive Language-Action Therapy (ILAT, previously CIAT or CILT), TMS could substantially amplify the beneficial effect of such behavioral therapy alone (Thiel et al., 2013; Martin et al., 2014; Mendoza et al., 2016; Kapoor, 2017). In this randomized study of 17 subjects with post-stroke aphasia in the chronic stage, we studied the combined effect of ILAT and 1-Hz placebo-controlled navigated repetitive TMS (rTMS) to the right-hemispheric inferior frontal cortex—that is, to the anterior part of the non-dominant hemisphere's homolog Broca's area (pars triangularis). Patients were randomized to groups A and B. Patients in group A received a 2-week period of rTMS during naming training where they named pictures displayed on the screen once every 10 s, followed by 2 weeks of rTMS and naming combined with ILAT. Patients in group B received the same behavioral therapy but TMS was replaced by sham stimulation. The primary outcome measures for changes in language performance were the Western Aphasia Battery's aphasia quotient AQ; the secondary outcome measures were the Boston naming test (BNT) and the Action naming test (Action BNT, ANT). All subjects completed the study. At baseline, no statistically significant group differences were discovered for age, post-stroke time or diagnosis. ILAT was associated with significant improvement across groups, as documented by both primary and secondary outcome measures. No significant effect of rTMS could be documented. Our results agree with previous results proving ILAT's ability to improve language in patients with chronic aphasia. In contrast with earlier claims, however, a beneficial effect of rTMS in chronic post-stroke aphasia rehabilitation was not detected in this study.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03629665

Neurological Aspects of Foreign Accent Syndrome in Stroke Patients

Foreign Accent Syndrome (FAS) is an intriguing motor speech disorder which has captured the interest of the scientific community and media for decades. At the moment, there is no comprehensive model which can account for the pathophysiology of this disorder. This paper presents a review of 112 FAS cases published between 1907 and October 2016: these were analyzed with respect to demographic characteristics, lesion location, associated neurocognitive symptoms, and comorbid speech and language disorders. The analysis revealed that organic-neurogenic FAS is more frequent in women than in men. In organic-neurogenic FAS over half of the patients acquired the foreign accent after a stroke. Their lesions are typically located in the left supratentorial regions of the brain, and generally involve the primary motor cortex and premotor cortex (BA 4 and 6), and/or the basal ganglia. Although neurocognitive data are not consistently reported, vascular FAS patients regularly suffer frontal executive dysfunctions. On the basis of a careful comparison of the cognitive and theoretical accounts of FAS, AoS and ataxic dysarthria, it is concluded that FAS should be regarded a dual component motor speech disorder in which both planning and motor execution of speech may be affected.

The effects of silent visuomotor cueing on word retrieval in Broca's aphasies: A pilot study

About a quarter of stroke patients worldwide suffer serious language disorders such as aphasias. Most common symptoms of Broca's aphasia are word naming disorders which highly impact verbal communication and the quality of life of aphasic patients. In order to recover disturbances in word retrieval, several cueing methods (i.e. phonemic and semantic) have been established to improve lexical access establishing effective language rehabilitation techniques. Based on recent evidence from action-perception theories, which postulate that neural circuits for speech perception and articulation are tightly coupled, in the present work, we propose and investigate an alternative type of cueing using silent articulation-related visual stimuli. We hypothesize that providing patients with primes in the form of silent videos showing lip motions representative of correct pronunciation of target words, will result in faster word retrieval than when no such cue is provided. To test our prediction, we realize a longitudinal clinical virtual reality-based trial with four post-stroke Broca's patients and compare the interaction times between the two conditions over the eight weeks of the therapy. Our results suggest that silent visuomotor cues indeed facilitate word retrieval and verbal execution, and might be beneficial in lexical relearning in chronic Broca's patients.

Efficacy of intensive aphasia therapy in patients with chronic stroke: a randomised controlled trial

OBJECTIVE

Recent evidence has fuelled the debate on the role of massed practice in the rehabilitation of chronic post-stroke aphasia. Here, we further determined the optimal daily dosage and total duration of intensive speech-language therapy.

METHODS

Individuals with chronic aphasia more than 1 year post-stroke received Intensive Language-Action Therapy in a randomised, parallel-group, blinded-assessment, controlled trial. Participants were randomly assigned to one of two outpatient groups who engaged in either highly-intensive practice (Group I: 4 hours daily) or moderately-intensive practice (Group II: 2 hours daily). Both groups went through an initial waiting period and two successive training intervals. Each phase lasted 2 weeks. Co-primary endpoints were defined after each training interval.

RESULTS

Thirty patients-15 per group-completed the study. A primary outcome measure (Aachen Aphasia Test) revealed no gains in language performance after the waiting period, but indicated significant progress after each training interval (gradual 2-week t-score change [CI]: 1.7 [±0.4]; 0.6 [±0.5]), independent of the intensity level applied (4-week change in Group I: 2.4 [±1.2]; in Group II: 2.2 [±0.8]). A secondary outcome measure (Action Communication Test) confirmed these findings in the waiting period and in the first training interval. In the second training interval, however, only patients with moderately-intensive practice continued to make progress (Time-by-Group interaction: P=0.009, η²=0.13).

CONCLUSIONS

Our results suggest no added value from more than 2 hours of daily speech-language therapy within 4 weeks. Instead, these results demonstrate that even a small 2-week increase in treatment duration contributes substantially to recovery from chronic post-stroke aphasia.

Effects of a Tablet-Based Home Practice Program With Telepractice on Treatment Outcomes in Chronic Aphasia

Purpose

The aim of this study was to determine if a tablet-based home practice program with weekly telepractice support could enable long-term maintenance of recent treatment gains and foster new language gains in poststroke aphasia.

Method

In a pre-post group study of home practice outcomes, 21 individuals with chronic aphasia were examined before and after a 6-month home practice phase and again at follow-up 4 months later. The main outcome measure studied was change in naming previously treated or untreated, practiced or unpracticed pictures of objects and actions. Individualized home practice programs were created in iBooks Author with semantic, phonemic, and orthographic cueing in pictures, words, and videos in order to facilitate naming of previously treated or untreated pictures.

Results

Home practice was effective for all participants with severity moderating treatment effects, such that individuals with the most severe aphasia made and maintained fewer gains. There was a negative relationship between the amount of training required for iPad proficiency and improvements on practiced and unpracticed pictures and a positive relationship between practice compliance and same improvements.

Conclusion

Unsupervised home practice with weekly video teleconferencing support is effective. This study demonstrates that even individuals with chronic severe aphasia, including those with no prior smart device or even computer experience, can attain independent proficiency to continue practicing and improving their language skills beyond therapy discharge. This could represent a low-cost therapy option for individuals without insurance coverage and/or those for whom mobility is an obstacle to obtaining traditional aphasia therapy.

Treatments to Promote Neural Repair after Stroke

Stroke remains a major cause of human disability worldwide. In parallel with advances in acute stroke interventions, new therapies are under development that target restorative processes. Such therapies have a treatment time window measured in days, weeks, or longer and so have the advantage that they may be accessible by a majority of patients. Several categories of restorative therapy have been studied and are reviewed herein, including drugs, growth factors, monoclonal antibodies, activity-related therapies including telerehabilitation, and a host of devices such as those related to brain stimulation or robotics. Many patients with stroke do not receive acute stroke therapies or receive them and do not derive benefit, often surviving for years thereafter. Therapies based on neural repair hold the promise of providing additional treatment options to a majority of patients with stroke.

Intensive Communicative Therapy Reduces Symptoms of Depression in Chronic Nonfluent Aphasia

Background. Patients with brain lesions and resultant chronic aphasia frequently suffer from depression. However, no effective interventions are available to target neuropsychiatric symptoms in patients with aphasia who have severe language and communication deficits. Objective. The present study aimed to investigate the efficacy of 2 different methods of speech and language therapy in reducing symptoms of depression in aphasia on the Beck Depression Inventory (BDI) using secondary analysis (BILAT-1 trial). Methods. In a crossover randomized controlled trial, 18 participants with chronic nonfluent aphasia following left-hemispheric brain lesions were assigned to 2 consecutive treatments: (1) intensive language-action therapy (ILAT), emphasizing communicative language use in social interaction, and (2) intensive naming therapy (INT), an utterance-centered standard method. Patients were randomly assigned to 2 groups, receiving both treatments in counterbalanced order. Both interventions were applied for 3.5 hours daily over a period of 6 consecutive working days. Outcome measures included depression scores on the BDI and a clinical language test (Aachen Aphasia Test). Results. Patients showed a significant decrease in symptoms of depression after ILAT but not after INT, which paralleled changes on clinical language tests. Treatment-induced decreases in depression scores persisted when controlling for individual changes in language performance. Conclusions. Intensive training of behaviorally relevant verbal communication in social interaction might help reduce symptoms of depression in patients with chronic nonfluent aphasia.

Neuroimaging of stroke recovery from aphasia - Insights into plasticity of the human language network

The role of left and right hemisphere brain regions in language recovery after stroke-induced aphasia remains controversial. Here, we summarize how neuroimaging studies increase the current understanding of functional interactions, reorganization and plasticity in the language network. We first discuss the temporal dynamics across the time course of language recovery, with a main focus on longitudinal studies from the acute to the chronic phase after stroke. These studies show that the functional contribution of perilesional and spared left hemisphere as well as contralesional right hemisphere regions to language recovery changes over time. The second section introduces critical variables and recent advances on early prediction of subsequent outcome. In the third section, we outline how multi-method approaches that combine neuroimaging techniques with non-invasive brain stimulation elucidate mechanisms of plasticity and reorganization in the language network. These approaches provide novel insights into general mechanisms of plasticity in the language network and might ultimately support recovery processes during speech and language therapy. Finally, the neurobiological correlates of therapy-induced plasticity are discussed. We argue that future studies should integrate individualized approaches that might vary the combination of language therapy with specific non-invasive brain stimulation protocols across the time course of recovery. The way forward will include the combination of such approaches with large data sets obtained from multicentre studies.

Language Learning Variability within the Dorsal and Ventral Streams as a Cue for Compensatory Mechanisms in Aphasia Recovery

Dorsal and ventral pathways connecting perisylvian language areas have been shown to be functionally and anatomically segregated. Whereas the dorsal pathway integrates the sensory-motor information required for verbal repetition, the ventral pathway has classically been associated with semantic processes. The great individual differences characterizing language learning through life partly correlate with brain structure and function within these dorsal and ventral language networks. Variability and plasticity within these networks also underlie inter-individual differences in the recovery of linguistic abilities in aphasia. Despite the division of labor of the dorsal and ventral streams, studies in healthy individuals have shown how the interaction of them and the redundancy in the areas they connect allow for compensatory strategies in functions that are usually segregated. In this mini-review we highlight the need to examine compensatory mechanisms between streams in healthy individuals as a helpful guide to choosing the most appropriate rehabilitation strategies, using spared functions and targeting preserved compensatory networks for brain plasticity.

Neuroimaging Correlates of Post-Stroke Aphasia Rehabilitation in a Pilot Randomized Trial of Constraint-Induced Aphasia Therapy

Background

Recovery from post-stroke aphasia is a long and complex process with an uncertain outcome. Various interventions have been proposed to augment the recovery, including constraint-induced aphasia therapy (CIAT). CIAT has been applied to patients suffering from post-stroke aphasia in several unblinded studies to show mild-to-moderate linguistic gains. The aim of the present study was to evaluate the neuroimaging correlates of CIAT in patients with chronic aphasia related to left middle cerebral artery stroke.

Material/Methods

Out of 24 patients recruited in a pilot randomized blinded trial of CIAT, 19 patients received fMRI of language. Eleven of them received CIAT (trained) and eight served as a control group (untrained). Each patient participated in three fMRI sessions (before training, after training, and 3 months later) that included semantic decision and verb generation fMRI tasks, and a battery of language tests. Matching healthy control participants were also included (N=38; matching based on age, handedness, and sex).

Results

Language testing showed significantly improved performance on Boston Naming Test (BNT; p<0.001) in both stroke groups over time and fMRI showed differences in the distribution of the areas involved in language production between groups that were not present at baseline. Further, regression analysis with BNT indicated changes in brain regions correlated with behavioral performance (temporal gyrus, postcentral gyrus, precentral gyrus, thalamus, left middle and superior frontal gyri).

Conclusions

Overall, our results suggest the possibility of language-related cortical plasticity following stroke-induced aphasia with no specific effect from CIAT training.

Plasticity in the Working Memory System: Life Span Changes and Response to Injury

Working memory acts as a key bridge between perception, long-term memory, and action. The brain regions, connections, and neurotransmitters that underlie working memory undergo dramatic plastic changes during the life span, and in response to injury. Early life reliance on deep gray matter structures fades during adolescence as increasing reliance on prefrontal and parietal cortex accompanies the development of executive aspects of working memory. The rise and fall of working memory capacity and executive functions parallels the development and loss of neurotransmitter function in frontal cortical areas. Of the affected neurotransmitters, dopamine and acetylcholine modulate excitatory-inhibitory circuits that underlie working memory, are important for plasticity in the system, and are affected following preterm birth and adult brain injury. Pharmacological interventions to promote recovery of working memory abilities have had limited success, but hold promise if used in combination with behavioral training and brain stimulation. The intense study of working memory in a range of species, ages and following injuries has led to better understanding of the intrinsic plasticity mechanisms in the working memory system. The challenge now is to guide these mechanisms to better improve or restore working memory function.

Where are aphasia theory and management "headed"?

The sequelae of post-stroke aphasia are considerable, necessitating an understanding of the functional neuroanatomy of language, cognitive processes underlying various language tasks, and the mechanisms of recovery after stroke. This knowledge is vital in providing optimal care of individuals with aphasia and counseling to their families and caregivers. The standard of care in the rehabilitation of aphasia dictates that treatment be evidence-based and person-centered. Promising techniques, such as cortical stimulation as an adjunct to behavioral therapy, are just beginning to be explored. These topics are discussed in this review.

[Functional neuroimaging of the brain structures associated with language in healthy individuals and patients with post-stroke aphasia]

The introduction of non-invasive functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI), in the practice of scientific and clinical research can increase our knowledge about the organization of cognitive processes, including language, in normal and reorganization of these cognitive functions in post-stroke aphasia. The article discusses the results of fMRI studies of functional organization of the cortex of a healthy adult's brain in the processing of various voice information as well as the main types of speech reorganization after post-stroke aphasia in different stroke periods. The concepts of 'effective' and 'ineffective' brain plasticity in post-stroke aphasia were considered. It was concluded that there was an urgent need for further comprehensive studies, including neuropsychological testing and several complementary methods of functional neuroimaging, to develop a phased treatment plan and neurorehabilitation of patients with post-stroke aphasia.

Cholinergic Potentiation and Audiovisual Repetition-Imitation Therapy Improve Speech Production and Communication Deficits in a Person with Crossed Aphasia by Inducing Structural Plasticity in White Matter Tracts

Donepezil (DP), a cognitive-enhancing drug targeting the cholinergic system, combined with massed sentence repetition training augmented and speeded up recovery of speech production deficits in patients with chronic conduction aphasia and extensive left hemisphere infarctions (Berthier et al., 2014). Nevertheless, a still unsettled question is whether such improvements correlate with restorative structural changes in gray matter and white matter pathways mediating speech production. In the present study, we used pharmacological magnetic resonance imaging to study treatment-induced brain changes in gray matter and white matter tracts in a right-handed male with chronic conduction aphasia and a right subcortical lesion (crossed aphasia). A single-patient, open-label multiple-baseline design incorporating two different treatments and two post-treatment evaluations was used. The patient received an initial dose of DP (5 mg/day) which was maintained during 4 weeks and then titrated up to 10 mg/day and administered alone (without aphasia therapy) during 8 weeks (Endpoint 1). Thereafter, the drug was combined with an audiovisual repetition-imitation therapy (Look-Listen-Repeat, LLR) during 3 months (Endpoint 2). Language evaluations, diffusion weighted imaging (DWI), and voxel-based morphometry (VBM) were performed at baseline and at both endpoints in JAM and once in 21 healthy control males. Treatment with DP alone and combined with LLR therapy induced marked improvement in aphasia and communication deficits as well as in selected measures of connected speech production, and phrase repetition. The obtained gains in speech production remained well-above baseline scores even 4 months after ending combined therapy. Longitudinal DWI showed structural plasticity in the right frontal aslant tract and direct segment of the arcuate fasciculus with both interventions. VBM revealed no structural changes in other white matter tracts nor in cortical areas linked by these tracts. In conclusion, cholinergic potentiation alone and combined with a model-based aphasia therapy improved language deficits by promoting structural plastic changes in right white matter tracts.