Chronic Aphasic Patients Research Articles

Increased interhemispheric functional connectivity after right anodal tDCS in chronic non-fluent aphasia: preliminary findings.

Anodal transcranial Direct Current Stimulation (tDCS) is a non-invasive, low-cost and environment-friendly brain neuromodulation technique that increases cortical excitability. In post-stroke aphasia, the role of the right hemisphere in language recovery remains debated. In this preliminary study, we aimed to investigate the efficacy of excitatory tDCS on the right hemisphere in chronic aphasic patients. We applied anodal tDCS to the right homologous region of Broca's area in four chronic aphasic patients while performing a one-month naming rehabilitation treatment. Longitudinal data on language assessment and naming performance were collected. Resting-state fMRI images were acquired before and after treatment to measure changes in functional connectivity. Results showed enhanced positive functional connectivity of the right Broca homologous with the left middle frontal and middle temporal gyri. Every patient showed improvements in language functions, but no major changes in naming performance. These preliminary findings suggest that tDCS applied over the unaffected hemisphere may result in longitudinal inter-hemispheric functional neuroplastic changes that could specifically improve language recovery and could potentially be included in therapeutic neurorehabilitative plans.

The Relationship Between Memory, Type, and Severity of Aphasia With Confrontation Naming in Post-stroke Patients With Chronic Aphasia

Objectives: The brain’s widespread neural functions lead to aphasia in which the patients experience difficulties in cognitive and language functions. Memory, type, and severity of aphasia are associated with language and the naming process. In the current study, we investigated the relationship between memory, type, and severity of aphasia using the confrontation naming test in post-stroke patients with chronic aphasia. Methods: This research was a descriptive-analytic cross-sectional study. We selected 45 chronic aphasia patients aged 35-70 years. The participants with a mild to moderate score in Mini-Mental State Examination (MMSE) were assessed with the Persian naming test, Wechsler Memory Scale, and Persian Western Aphasia Battery. Results: There was a significant difference between memory with correct answers without a cue, correct answers with a semantic cue, and the total correct answers from confrontation naming (P<0.001, r=0.62; P=0.01, r=0.37; and P<0.001, r=0.71; respectively). Furthermore, the results indicated a significant difference between the type of aphasia with subtests of confrontation naming involving correct answers with semantic cues and total correct answers (P=0.02). Also, the results showed a significant difference between the severity of aphasia with correct answers without a cue, correct answers with a semantic cue, and the total correct answers from confrontation naming (P<0.001, r=0.77; P=0.03, r=0.31; and P<0.001, r=0.67; respectively). In comparing semantic and phonetic cues, memory, type, and severity of aphasia indicated significant association only with semantic cues. Discussion: There is an association between memory, type, and severity of aphasia with confrontation naming in patients with aphasia. The data have highlighted the importance of factors that need to be considered to formulate a comprehensive treatment plan to achieve further improvement in naming skills.

Efficacy of Melodic Intonation Therapy in Patients with Chronic Broca’s Aphasia: Speech Language Pathology Perspective

Aphasia is a linguistic problem that occurs after brain damage. It's a broad term that encompasses everything from modest word retrieval challenges to a complete inability to produce and interpret language. Fluent and non-fluent aphasia are two types of aphasia. Non-fluent aphasia is characterized by sluggish, effortful speaking and is caused by a stroke in the left frontotemporal areas. These patients' language production is mainly limited to one- or two-word utterances. Non-fluent aphasic patients can sing fluently despite their significant language production handicap, which has led to the use of singing and music in aphasia rehabilitation. Objective: To examine the effectiveness of Melodic Intonation Therapy (MIT) in patients with chronic Broca's aphasia. Methods: A descriptive study was conducted from March 1 to September 30, 2021, at NUR International University to investigate the efficacy of MIT in patients with persistent Broca's aphasia. For this purpose data was collected from almost 50 speech therapists working with chronic Broca's aphasic patients through a self-designed questionnaire. The questionnaire was used as a data collecting instrument that was designed by expert opinion and literature review. Results: Results indicated that MIT is effective in patients with chronic Broca's aphasia. On asking the respondent about the efficacy of MIT almost 88% responded that MIT is effective, 8% were not sure about the efficacy of MIT and 4% responded MIT is not effective in chronic aphasic patients. On asking the respondent about the development of expressive language 64 % responded that expressive Language is improved while 36 % were not sure about the development of expressive language development. On asking the respondent whether MIT reduces psychological stress on individuals regarding the necessity to speak correctly, 88 % responded with yes while 12 % responded with No that MIT reduces psychological stress. Conclusions: It is concluded from this study that MIT is effective in patients with chronic Broca’s aphasia.

The Role of the Right Hemisphere White Matter Tracts in Chronic Aphasic Patients After Damage of the Language Tracts in the Left Hemisphere.

The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.

Abstract 67: Contributions of the Unaffected Hemisphere to Outcome Predictions of Acute Aphasia

Making accurate predictions about a stroke patient’s language/speech-motor outcome and recovery potential is a challenge. We previously showed that a combined variable of lesion site and size, the Arcuate Fasciculus lesion load (AF-LL), correlated highly with measures of speech fluency in chronic aphasic patients. However, in bi-hemispherically organized systems (such as the speech-motor system), there might also be contributions from the unaffected hemisphere to outcome that have to be determined. Methods: Over a period of several years, ischemic stroke patients presenting with acute aphasia were evaluated using a bedside version of the Western Aphasia Battery complemented by picture naming tests, automatic speech measures, and a custom-made word/phrase spoken and sung test. A total of 110 acute patients were assessed acutely of which 60 followed up at 3 months for outcome assessments. Lesion maps drawn on diffusion-weighted images were used to calculate lesion loads of a probabilistic Arcuate Fasciculus (AF) tract. The homotop version of the AF of the right hemisphere was used to extract regional fractional anisotropy (FA) values. FA values serve as a measure of white matter fiber alignment and integrity. Several prediction models were constructed testing whether or not adding either lesion load measures, or right hemisphere structural measures (tract FA values) and right hemisphere functional measures (singing-speaking dissociation) to acute bedside aphasia assessments would improve outcome predictions. Results: The overall bedside WAB score in the acute stroke period was the best single predictor of overall WAB score outcome at 3 months explaining about 50% of the in-sample and 45% of the out-of-sample variance. This prediction was improved when a AF-lesion-load measures were added to the model (R2=0.62 for out-of-sample predictions). When right hemisphere structural (tract FA values) and functional information (singing-speaking difference) was added, out-of-sample prediction in language outcome at 3 months improved to 83%. Conclusion: A combination of a bedside aphasia test, lesion load of the left hemisphere, as well as structural and functional measures of the unaffected hemisphere predict language outcome.

A Common Serial Order Mechanism for Verbal Working Memory and Language Production: Evidence from Aphasia

A Common Serial Order Mechanism for Verbal Working Memory and Language Production: Evidence from Aphasia

Developing an Arabic Screening Test for Adult-Onset Chronic Aphasia

Aim: To develop a time-efficient Arabic test battery for adult-onset chronic aphasia that provides information about the type and the severity of the disorder. Patient and Methods: A total of 90 participants were recruited and divided into 3 groups. The groups consisted of 30 adult-onset post-stroke chronic aphasic patients, 30 adult non-aphasic adults with central neurological disorders, and a group of 30 non-brain-damaged healthy adults. All participants were assessed using the Mansoura Arabic Screening Aphasia Test (MASAT), which consists of 4 main sections: (1) language expression abilities including repetition and naming items, (2) language comprehension questions, (3) fluency, and (4) reading, writing and calculation items. The content validity, internal consistency, clinical validity, and convergent validity of the MASAT were evaluated. Results: The MASAT demonstrated statistically high reliability and validity. The high α-values in all subtotal scores among the 3 groups were judged to denote excellent intercorrelation among the screening test items. Conclusion: The MASAT is a valid and a reliable brief assessment tool that can be completed on the first clinic appointment that detects the type and severity of Arabic-speaking aphasic patients.

Abstract WP146: Predictors of Recovery From Acute Aphasia

Introduction: Making accurate predictions about a stroke patient’s language/speech-motor outcome and recovery potential is a challenge. We previously showed that a combined variable of lesion site and size pertinent to relevant white matter language structures, the Arcuate Fasciculus lesion load (AF-LL), correlated highly with measures of speech fluency in chronic aphasic patients (Marchina et al., 2011; Wang et al., 2013). However, studies in motor recovery and other domains have shown that behavioral measures in the acute stroke phase might be equal or better predictors of recovery compared to lesion measures. Whether or not any of these measures follow a proportional recovery rule, has not been established. Hypothesis: To evaluate whether acute aphasia measures (overall WAB score) and/or acute lesion measures (e.g., AF-Lesion Load) predict recovery from aphasia. Methods: Over a period of several years, patients presenting with acute aphasia were evaluated using a bedside version of the Western Aphasia Battery complemented by picture naming tests, automatic speech measures, and custom-made word/phrase spoken and sung test. A total of 100 acute patients were assessed of which 56 followed up at 3 months. Lesion maps drawn on diffusion-weighted images were used to calculate lesion loads of a probabilistic Arcuate Fasciculus (AF) tract derived from matched elderly healthy control subjects. Analyses included correlations between recovery potential and actual recovery and other predictors of 3 months outcome. AF-LL was regressed with the overall WAB score, measures of speech fluency and naming ability (using the Boston Naming Test). Results: The overall bedside WAB score in the acute stroke period was the best predictor of the overall WAB score at 3 months (R2=0.60). This predictor was slightly improved when a measure of speaking-singing dissociation was added to the model. Lesion-load of the AF was also a good predictor of WAB score at 3 months (R2=0.48), but did not improve outcome predictions of the WAB score by itself. Overall acute aphasic patients followed a proportional recovery rule, but only recovered about 56% of what was theoretically possible. Conclusion: Language and Speech-Motor Outcome after stroke can be predicted best by a bedside WAB score.

Evidence for language-specificity of a BCI-based language training

Evidence for language-specificity of a BCI-based language training

Less is more: neural mechanisms underlying anomia treatment in chronic aphasic patients.

See Thompson and Woollams (doi:10.1093/brain/awx264) for a scientific commentary on this article. Previous research with aphasic patients has shown that picture naming can be facilitated by concurrent phonemic cueing [e.g. initial phoneme(s) of the word that the patient is trying to retrieve], both as an immediate word retrieval technique, and when practiced repeatedly over time as a long-term anomia treatment. Here, to investigate the neural mechanisms supporting word retrieval, we adopted—for the first time—a functional magnetic resonance imaging task using the same naming procedure as it occurs during the anomia treatment process. Before and directly after a 6-week anomia treatment programme, 18 chronic aphasic stroke patients completed our functional magnetic resonance imaging protocol—a picture naming task aided by three different types of phonemic cues (whole words, initial phonemes, final phonemes) and a noise-control condition. Patients completed a naming task based on the training materials, and a more general comprehensive battery of language tests both before and after the anomia treatment, to determine the effectiveness and specificity of the therapy. Our results demonstrate that the anomia treatment was effective and specific to speech production, significantly improving both patients’ naming accuracy and reaction time immediately post-treatment (unstandardized effect size: 29% and 17%, respectively; Cohen’s d: 3.45 and 1.83). Longer term gains in naming were maintained 3 months later. Functional imaging results showed that both immediate and long-term facilitation of naming involved a largely overlapping bilateral frontal network including the right anterior insula, inferior frontal and dorsal anterior cingulate cortices, and the left premotor cortex. These areas were associated with a neural priming effect (i.e. reduced blood oxygen level-dependent signal) during both immediate (phonemically-cued versus control-cue conditions), and long-term facilitation of naming (i.e. treated versus untreated items). Of note is that different brain regions were sensitive to different phonemic cue types. Processing of whole word cues was associated with increased activity in the right angular gyrus; whereas partial word cues (initial and final phonemes) recruited the left supplementary motor area, and right anterior insula, inferior frontal cortex, and basal ganglia. The recruitment of multiple and bilateral areas may help explain why phonemic cueing is such a successful behavioural facilitation tool for anomia treatment. Our results have important implications for optimizing current anomia treatment approaches, developing new treatments, and improving speech outcome for aphasic patients.

FV 13 Electrophysiological correlates of language recovery – an MEG study of neuroplasticity in chronic post stroke aphasia

Background Previous studies have demonstrated that efficient language and communication therapy in chronic post stroke aphasia leads to significant clinical language improvements ( Pulvermuller et al., 2001 ) and promotes neuroplasticity. Brain areas frequently associated with functional restitution of language comprise perilesional sites in the left hemisphere ( MacGregor et al., 2015 ) as well as right-hemispheric regions, homotopic to those lesioned in the left ( Mohr et al., 2014 ). To date, however, the neuronal mechanisms underlying therapy-induced language changes and functional restitution are still largely unclear. In the present study, hemispheric contributions to neuroplasticity and neurophysiological changes were investigated in chronic aphasia patients by using magnetoencephalography. Methods Patients underwent intensive language action therapy for three hours per day on 10 consecutive week-days. Before and immediately after treatment, language and communication skills were assessed and patients’ brain responses were recorded during automatic language processing, employing a lexical magnetic mismatch negativity (MMNm) paradigm, in which words and meaningless pseudowords were presented auditorily. Results After the two-week therapy interval, patients showed significant clinical improvements of language skills, as assessed by the Boston Diagnostic Aphasia Examination. Spatio-temporal dynamics of neuronal changes revealed a significant increase in word-specific neuro-magnetic MMNm activation around 200 ms after stimulus identification points. This neuromagnetic enhancement of the MMNm brain response occurred specifically for words and was most prominent over perilesional areas in the left hemisphere. Importantly, therapy-induced changes in neuromagnetic activation to words significantly correlated with clinical test performance. Discussion and conclusion The results suggest that language recovery in chronic post stroke aphasia is associated with neuroplastic changes in both cerebral hemispheres. During automatic language processing, particularly perilesional regions in the left-hemisphere seem to contribute to functional restitution in patients with chronic aphasia.

P 67 Electrophysiological correlates of language improvements after intensive language therapy in patients with chronic post-stroke aphasia

Background Aphasia affects approximately one third of all stroke patients and may lead to chronic disability. Effective neurorehabilitation programs focusing on improving speech and language in patients with post-stroke aphasia are essential. A better understanding of the neurobiological processes accompanying language deficits and rehabilitation may bear fruit in the advancement of neurorehabilitation programs. Methods Clinical language performance and neurophysiological correlates of language processing were measured before and after intensive language therapy in patients with chronic (time post-stroke > 1 year) post-stroke aphasia. The mismatch negativity (MMN), a language-related event-related potential (ERP) known to reflect automatic lexico-semantic and grammar processing, was recorded in a distracted oddball paradigm to short spoken sentences. Critical “deviant” sentence stimuli where either well-formed and meaningful, or grammatically incorrect, or meaningless. Results The Aachen Aphasia Test (AAT) demonstrated significant clinical language improvements, which were accompanied by enhancement of the MMN responses, after 4 weeks of speech-language therapy (SLT) delivered with high intensity (10.5 h per week). In particular, MMN amplitudes to grammatically correct and meaningful sentences and to sentences containing a meaningless pseudoword significantly increased after therapy. However, no therapy-related changes in MMN were found for grammatically incorrect sentences that violated pronoun-verb agreement. Discussion/conclusions MMN increases to well-formed meaningful and to meaningless strings and the absence thereof for ungrammatical sentences suggest neuroplastic changes consistent with recent cognitive linguistic theories. The results confirm previous reports that intensive SLT leads to improvements of language and communication skills in chronic aphasia patients and now demonstrate that this clinical improvement is associated with enhanced automatic brain indexes of language processing above single-word level. Furthermore, the data suggest that the language-elicited MMN may be a useful tool to map functional language recovery in post-stroke aphasia patients.

The regional neuronal activity in left posterior middle temporal gyrus is correlated with the severity of chronic aphasia.

BackgroundAphasia is one of the most disabling cognitive deficits affecting >2 million people in the USA. The neuroimaging characteristics of chronic aphasic patients (>6 months post onset) remain largely unknown.ObjectiveThe objective of this study was to investigate the regional signal changes of spontaneous neuronal activity of brain and the inter-regional connectivity in chronic aphasia.Materials and methodsResting-state blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) was used to obtain fMRI data from 17 chronic aphasic patients and 20 healthy control subjects in a Siemens Verio 3.0T MR Scanner. The amplitude of low-frequency fluctuation (ALFF) was determined, which directly reflects the regional neuronal activity. The functional connectivity (FC) of fMRI was assessed using a seed voxel linear correlation approach. The severity of aphasia was evaluated by aphasia quotient (AQ) scores obtained from Western Aphasia Battery test.ResultsCompared with normal subjects, aphasic patients showed decreased ALFF values in the regions of left posterior middle temporal gyrus (PMTG), left medial prefrontal gyrus, and right cerebellum. The ALFF values in left PMTG showed strong positive correlation with the AQ score (coefficient r=0.79, P<0.05). There was a positive FC in chronic aphasia between left PMTG and left inferior temporal gyrus (BA20), fusiform gyrus (BA37), and inferior frontal gyrus (BA47\\45\\44).ConclusionLeft PMTG might play an important role in language dysfunction of chronic aphasia, and ALFF value might be a promising indicator to evaluate the severity of aphasia.

Therapy-Induced Neuroplasticity of Language in Chronic Post Stroke Aphasia: A Mismatch Negativity Study of (A)Grammatical and Meaningful/less Mini-Constructions.

Clinical language performance and neurophysiological correlates of language processing were measured before and after intensive language therapy in patients with chronic (time post stroke >1 year) post stroke aphasia (PSA). As event-related potential (ERP) measure, the mismatch negativity (MMN) was recorded in a distracted oddball paradigm to short spoken sentences. Critical ‘deviant’ sentence stimuli where either well-formed and meaningful, or syntactically, or lexico-semantically incorrect. After 4 weeks of speech-language therapy (SLT) delivered with high intensity (10.5 h per week), clinical language assessment with the Aachen Aphasia Test battery demonstrated significant linguistic improvements, which were accompanied by enhanced MMN responses. More specifically, MMN amplitudes to grammatically correct and meaningful mini-constructions and to ‘jabberwocky’ sentences containing a pseudoword significantly increased after therapy. However, no therapy-related changes in MMN responses to syntactically incorrect strings including agreement violations were observed. While MMN increases to well-formed meaningful strings can be explained both at the word and construction levels, the neuroplastic change seen for ‘jabberwocky’ sentences suggests an explanation in terms of constructions. The results confirm previous reports that intensive SLT leads to improvements of linguistic skills in chronic aphasia patients and now demonstrate that this clinical improvement is associated with enhanced automatic brain indexes of construction processing, although no comparable change is present for ungrammatical strings. Furthermore, the data confirm that the language-induced MMN is a useful tool to map functional language recovery in PSA.

Separate Serial Order Short-term Memory Systems: A Case Series Approach

Separate Serial Order Short-term Memory Systems: A Case Series Approach

Patterns of neural activity predict picture-naming performance of a patient with chronic aphasia

Naming objects represents a substantial challenge for patients with chronic aphasia. This could be in part because the reorganized compensatory language networks of persons with aphasia may be less stable than the intact language systems of healthy individuals. Here, we hypothesized that the degree of stability would be instantiated by spatially differential neural patterns rather than either increased or diminished amplitudes of neural activity within a putative compensatory language system. We recruited a chronic aphasic patient (KL; 66 year-old male) who exhibited a semantic deficit (e.g., often said “milk” for “cow” and “pillow” for “blanket”). Over the course of four behavioral sessions involving a naming task performed in a mock scanner, we identified visual objects that yielded an approximately 50% success rate. We then conducted two fMRI sessions in which the patient performed a naming task for multiple exemplars of those objects. Multivoxel pattern analysis (MVPA) searchlight revealed differential activity patterns associated with correct and incorrect trials throughout intact brain regions. The most robust and largest cluster was found in the right occipito-temporal cortex encompassing fusiform cortex, lateral occipital cortex (LOC), and middle occipital cortex, which may account for the patient's propensity for semantic naming errors. None of these areas were found by a conventional univariate analysis. By using an alternative approach, we extend current evidence for compensatory naming processes that operate through spatially differential patterns within the reorganized language system.

Hemispheric contributions to language reorganisation: An MEG study of neuroplasticity in chronic post stroke aphasia

Previous studies have demonstrated that efficient neurorehabilitation in post stroke aphasia leads to clinical language improvements and promotes neuroplasticity. Brain areas frequently implicated in functional restitution of language after stroke comprise perilesional sites in the left hemisphere and homotopic regions in the right hemisphere. However, the neuronal mechanisms underlying therapy-induced language restitution are still largely unclear. In this study, magnetoencephalography was used to investigate neurophysiological changes in a group of chronic aphasia patients who underwent intensive language action therapy (ILAT), also known as constraint-induced aphasia therapy (CIAT). Before and immediately after ILAT, patients’ language and communication skills were assessed and their brain responses were recorded during a lexical magnetic mismatch negativity (MMNm) paradigm, presenting familiar spoken words and meaningless pseudowords. After the two-week therapy interval, patients showed significant clinical improvements of language and communication skills. Spatio-temporal dynamics of neuronal changes revealed a significant increase in word-specific neuro-magnetic MMNm activation around 200ms after stimulus identification points. This enhanced brain response occurred specifically for words and was most pronounced over perilesional areas in the left hemisphere. Therapy-related changes in neuromagnetic activation for words in both hemispheres significantly correlated with performance on a clinical language test. The findings indicate that functional recovery of language in chronic post stroke aphasia is associated with neuroplastic changes in both cerebral hemispheres, with stronger left-hemispheric contribution during automatic stages of language processing.

New hope for ameliorating stroke-induced deficits?

This scientific commentary refers to ‘Electrical stimulation of the motor cortex enhances treatment outcome in post-stroke aphasia’ by Meinzer et al . (doi:10.1093/brain/aww002). The overall decline in stroke mortality observed over the past decades is due to both a reduction in stroke incidence, primarily resulting from cardiovascular risk factor interventions, and substantial progress in the acute treatment of stroke (e.g. recanalization due to thrombolysis and thrombectomy, decompressive therapy) as well as patient care (stroke units) (Mozaffarian et al. , 2016). These improvements (in particular among people older than 65 years) are mirrored, however, by an increasing number of stroke survivors, who are left with persistent neurological deficits. Despite intensive rehabilitation, at least in countries with well developed healthcare systems, many stroke survivors are left with motor, language, spatial or other neuropsychological sequelae, all of which result in reduced functional independence. Consequently, stroke is the leading cause of acquired long-term disability and globally produces immense health, social and economic burdens (Mozaffarian et al. , 2016). While physiotherapy, language therapy and occupational therapy are widely accepted elements of rehabilitation medicine that aim to restore functioning and quality of life in those with physical disabilities or cognitive impairments, novel approaches to rehabilitation are urgently needed. Such therapies may comprise behavioural, pharmacological or technical approaches, the latter including the use of robotic devices as well as non-invasive neuromodulatory techniques [i.e. transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS)]. In this issue of Brain , Meinzer and colleagues raise new hope for the treatment of post-stroke aphasia by showing that electrical stimulation of the motor cortex [sic!] enhances treatment outcomes (Meinzer et al. , 2016). Meinzer and colleagues performed a registered, randomized, sham-controlled, parallel-group, double-blind clinical trial of 26 chronic aphasic patients with anomia [>12 months after stroke …

Transcranial direct current stimulation to improve naming abilities of persons with chronic aphasia: A preliminary study using individualized based protocol

Abstract Background and purpose Transcranial direct current stimulation (tDCS) is a noninvasive tool to facilitate brain plasticity and enhance language recovery after stroke. Our study aims to develop an efficient protocol for individualizing tDCS to treat naming deficits within chronic aphasia patients. Method Seven patients with chronic aphasia participated in this preliminary study. All participants performed a baseline naming assessment. Next, the best stimulation area (either Broca or Wernicke), best side (either left or right hemisphere), and best type of stimulation (either anodal or cathodal) were assessed with tDCS during four individualized pre-intervention sessions. The location and type of stimulation that produced the greatest improvement for each patient were used in subsequent treatments. Treatment included six stimulation sessions (2 mA, 10 min), three treatments per week, two weeks in a raw. Naming abilities were assessed immediately after treatment, as well as one month and three months after treatment. Sham (placebo like) tDCS was administered to all participants three months post treatment. Results Treatment led to significant improvement in percentage of correct responses compared to baseline, whereas sham led to no equivalent improvement. Improvement was still present three months after treatment. Conclusions An individually-tailored protocol of 2 mA, 10 min tDCS was found to improve naming abilities of individuals with chronic aphasia. If proved to be effective in larger studies, our findings may have important clinical implications for the use of tDCS in enhancing language abilities after stroke.

The dichotomous view on IFG lesion and non-fluent aphasia.

A lesion in inferior frontal gyrus (IFG) is traditionally considered to be crucial for the occurrence of non-fluent aphasia. However, recent studies question the axiomatic causality between a lesion in this area and the expected non-fluent aphasic syndrome. The aim of the present study is to investigate the relationship between IFG lesions and non-fluent aphasia. To address this question, we present radiological and neuropsychological data of 49 chronic aphasic patients. Lesions were identified based on CT and/or MRI scans. Aphasia was assessed using the Boston Diagnostic Aphasia Examination-short form. Analysis indicated a statistically significant association between IFG lesion and non-fluent aphasic disturbances. Nevertheless, a large proportion of our patients did not confirm the traditional prediction, namely that non-fluent patients' lesions would include the inferior frontal gyrus and the opposite would be true for fluent patients. Our results stress the importance of taking into account the size of particular estimates when conducting group analyses. We also argue in favor of examining individual data in clinical practice, and further suggest that the traditional lesion to syndrome correspondence seems to be oversimplified and should be thoroughly revisited.