Transcranial Direct Current Stimulation Does Not Improve Language Outcome in Subacute Poststroke Aphasia.

BACKGROUND AND PURPOSE: The aim of the present study is to investigate the effect of transcranial direct current stimulation on word-finding treatment outcome in subacute poststroke aphasia. METHODS: In this multi-center, double-blind, randomized controlled trial with 6-month follow-up, we included 58 patients with subacute aphasia (<3 months poststroke), who were enrolled in a stroke rehabilitation program. Patients participated in 2 separate intervention weeks. Each intervention week included 5 daily sessions of 45-minute word-finding therapy combined with either anodal transcranial direct current stimulation (1 mA, 20 minutes; experimental group) or sham transcranial direct current stimulation (control group) over the left inferior frontal gyrus. The primary outcome measure was the Boston Naming Test. Secondary outcome measures included naming performance for trained/untrained picture items and verbal communication. RESULTS: Both the experimental (n=26) and the control group (n=32) improved on the Boston Naming Test over the intervention period and 6-month follow-up; however, there were no significant differences between groups. Also for the secondary outcome measures, no significant differences were found. CONCLUSIONS: The results of the present study do not support an effect of transcranial direct current stimulation as an adjuvant treatment in subacute poststroke aphasia. CLINICAL TRIAL REGISTRATION: URL: http://www.trialregister.nl/trialreg/admin/rctview.asp. Unique identifier: NTR4364.

Maladaptive Plasticity in Aphasia: Brain Activation Maps Underlying Verb Retrieval Errors.

Anomia, or impaired word retrieval, is the most widespread symptom of aphasia, an acquired language impairment secondary to brain damage. In the last decades, functional neuroimaging techniques have enabled studying the neural basis underlying anomia and its recovery. The present study aimed to explore maladaptive plasticity in persistent verb anomia, in three male participants with chronic nonfluent aphasia. Brain activation maps associated with semantic verb paraphasia occurring within an oral picture-naming task were identified with an event-related fMRI paradigm. These maps were compared with those obtained in our previous study examining adaptive plasticity (i.e., successful verb naming) in the same participants. The results show that activation patterns related to semantic verb paraphasia and successful verb naming comprise a number of common areas, contributing to both maladaptive and adaptive neuroplasticity mechanisms. This finding suggests that the segregation of brain areas provides only a partial view of the neural basis of verb anomia and successful verb naming. Therefore, it indicates the importance of network approaches which may better capture the complexity of maladaptive and adaptive neuroplasticity mechanisms in anomia recovery.

Change in Right Inferior Longitudinal Fasciculus Integrity Is Associated With Naming Recovery in Subacute Poststroke Aphasia.

Background. Despite progress made in understanding functional reorganization patterns underlying recovery in subacute aphasia, the relation between recovery and changes in white matter structure remains unclear. Objective. To investigate changes in dorsal and ventral language white matter tract integrity in relation to naming recovery in subacute poststroke aphasia. Methods. Ten participants with aphasia after left-hemisphere stroke underwent language testing and diffusion tensor imaging twice within 3 months post onset, with a 1-month interval between sessions. Deterministic tractography was used to bilaterally reconstruct the superior longitudinal fasciculus (SLF), inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), middle longitudinal fasciculus (MdLF), and uncinate fasciculus (UF). Per tract, the mean fractional anisotropy (FA) was extracted as a measure of microstructural integrity. Naming accuracy was assessed with the Boston Naming Test (BNT). Correlational analyses were performed to investigate the relationship between changes in FA values and change in BNT score. Results. A strong positive correlation was found between FA change in the right ILF within the ventral stream and change on the BNT (r = 0.91, P < .001). An increase in FA in the right ILF was associated with considerable improvement of naming accuracy (range BNT change score: 12-14), a reduction with limited improvement or slight deterioration. No significant correlations were found between change in naming accuracy and FA change in any of the other right or left ventral and dorsal language tracts. Conclusions. Naming recovery in subacute aphasia is associated with change in the integrity of the right ILF.

Comparison of two configurations of transcranial direct current stimulation for aphasia treatment.

OBJECTIVE: To compare 2 configurations of transcranial direct current stimulation (tDCS) for treatment of aphasia. DESIGN: Randomized cross-over study. SUBJECTS: Patients with chronic post-stroke aphasia (n = 13). METHODS: tDCS was combined with word-finding therapy in 3 single sessions. In session 1, sham-tDCS/pseudo-stimulation was applied. In sessions 2 and 3, 2 active configurations were provided in random order: anodal tDCS over the left inferior frontal gyrus (l-IFG) and anodal tDCS over the left posterior superior temporal gyrus (l-STG). The optimal configuration was determined per individual based on a pre-set improvement in naming trained (> 20%) and untrained picture items (> 10%). RESULTS: Overall, participants improved on trained items (median = 50%; interquartile range = 20-85) and post-treatment performance was highest in the active l-IFG condition (p = 0.040). Of the 13 participants, 6 (46%) showed relevant improvement during active tDCS; either in the l-IFG condition (n = 4; 31%) or in both the l-IFG and l-STG conditions (n = 2; 15%). On the untrained items there was no improvement (median = 0%; interquartile range = 0-0). CONCLUSION: This randomized cross-over single-session protocol to determine an optimal tDCS configuration for treatment of aphasia suggests that only performance on trained items can be used as guidance for configuration, and that it is relevant for half of the patients. For this subgroup, the l-IFG configuration is the optimal choice.

The Role of the BDNF Val66Met Polymorphism in Recovery of Aphasia After Stroke.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is assumed to play a role in mediating neuroplasticity after stroke. Carriers of the function-limiting Val66Met (rs6265) single nucleotide polymorphism (SNP) may have a downregulation in BDNF secretion, which may lead to a poorer prognosis after stroke compared to noncarriers in motor learning and motor function recovery. The present study investigates whether this polymorphism may also affect the recovery of poststroke aphasia (ie, language impairment). OBJECTIVE: To study the influence of the BDNF Val66Met polymorphism on the recovery of poststroke aphasia. METHODS: We included 53 patients with poststroke aphasia, all participating in an inpatient rehabilitation program with speech and language therapy. All patients were genotyped for the Val66Met SNP and subdivided into carriers (at least one Met allele) and noncarriers (no Met allele). Primary outcome measures included the improvement over rehabilitation time on the Amsterdam-Nijmegen Everyday Language Test (ANELT) and the Boston Naming Test (BNT). RESULTS: The outcome measures showed a large variability in the improvement scores on both the ANELT and BNT. There was no significant difference between noncarriers and carriers in the primary outcome measures. CONCLUSION: This study investigated the effect of the BDNF Val66Met polymorphism on clinical recovery of poststroke aphasia. In contrast to earlier studies describing a reducing effect of this polymorphism on motor function recovery after stroke, the present study does not support a reduction in language recovery for carriers compared to noncarriers with poststroke aphasia.

Transcranial direct current stimulation in post-stroke sub-acute aphasia: study protocol for a randomized controlled trial.

BACKGROUND: Transcranial direct current stimulation (tDCS) is a promising new technique to optimize the effect of regular Speech and Language Therapy (SLT) in the context of aphasia rehabilitation. The present study focuses on the effect of tDCS provided during SLT in the sub-acute stage after stroke. The primary aim is to evaluate the potential effect of tDCS on language functioning, specifically on word-finding, as well as generalization effects to verbal communication. The secondary aim is to evaluate its effect on social participation and quality of life, and its cost-effectiveness. METHODS: We strive to include 58 stroke patients with aphasia, enrolled in an inpatient or outpatient stroke rehabilitation program, in a multicenter, double-blind, randomized controlled trial with two parallel groups and 6 months' follow-up. Patients will participate in two separate intervention weeks, with a pause of 2 weeks in between, in the context of their regular aphasia rehabilitation program. The two intervention weeks comprise daily 45-minute sessions of word-finding therapy, combined with either anodal tDCS over the left inferior frontal gyrus (1 mA, 20 minutes; experimental condition) or sham-tDCS over the same region (control condition). The primary outcome measure is word-finding. Secondary outcome measures are verbal communication, social participation, quality of life, and cost-effectiveness of the intervention. DISCUSSION: Our results will contribute to the discussion on whether tDCS should be implemented in regular aphasia rehabilitation programs for the sub-acute post-stroke population in terms of (cost-)effectiveness. TRIAL REGISTRATION: Nederlands Trail Register: NTR4364 . Registered on 21 February 2014.