A Qualitative Exploration of Stroke Survivors' Experiences of Using a Stroke Helpline.

BACKGROUND: StrokeLine is a stroke-specific helpline used by stroke survivors and their families in Australia to access professional support. There has been little research exploring stroke survivors' experiences of using helplines and their perceived impact on their stroke recovery. AIM: The aim of this study is to explore the reasons prompting stroke survivors to call StrokeLine and their experiences and to describe the perceived impact of calling StrokeLine on their recovery. METHODS: An exploratory descriptive qualitative study was undertaken using thematic analysis of data collected through semi-structured interviews of stroke survivors between December 2020 and May 2022. Participants were recruited using purposive sampling. Interviews were conducted via audio-recorded Zoom conference calling and transcribed verbatim for thematic analysis. RESULTS: A total of eight callers (four men and women women) participated, with the time since stroke ranging from 3.5 months to 5 years. Four major themes were identified, including 17 sub-themes. Key themes included (1) factors prompting use of StrokeLine; (2) experience of using StrokeLine; (3) perceived impact of using StrokeLine; and (4) conceptualising StrokeLine service provision. CONCLUSIONS: Participants perceived their experience of contacting StrokeLine as having a positive impact on their stroke recovery, leaving them feeling empowered and motivated to self-manage their condition. PATIENT OR PUBLIC CONTRIBUTION: Stroke survivors with lived experience influenced the conceptualisation of this study through conversations with consumers and the Stroke Foundation. Eight stroke survivors were involved as participants in the research study.

The barriers and facilitators to satisfaction with botulinum neurotoxin treatment in people with cervical dystonia: a systematic review.

BACKGROUND: Cervical dystonia (CD) is an isolated, focal, idiopathic dystonia affecting the neck and upper back. CD is usually treated by botulinum neurotoxin (BoNT) injections into the dystonic muscles; however, about 20% of people will discontinue BoNT therapy. This systematic review aimed to determine the barriers to satisfaction and facilitators that could improve satisfaction with BoNT therapy for people with CD. METHODS: A database search for journal articles investigating satisfaction with BoNT treatment in CD identified seven qualitative studies and one randomised controlled trial. Results were grouped into "direct" and "indirect" barriers and facilitators. RESULTS: The most reported direct barrier to satisfaction with BoNT was treatment non-response, reported by up to 66% of participants. Other direct barriers included negative side effects, early wearing-off of treatment effect and inexperience of the treating physician. Indirect barriers included limited accessibility to treatment (including cost) and personal choice. Direct facilitators of satisfaction with BoNT included relief of symptoms and flexible re-treatment intervals. Indirect facilitators included easy accessibility to treatment. CONCLUSIONS: Despite BoNT having a discontinuation rate of only 20%, it appears a much greater proportion of people with CD are dissatisfied with this treatment. As BoNT is currently the main treatment offered to people with CD, efforts to improve treatment response rates, reduce side effects and make treatment more flexible and readily available should be adopted to improve the quality of life for people with CD.

Cortical neurophysiology of primary isolated dystonia and non-dystonic adults: A meta-analysis.

Transcranial magnetic stimulation (TMS) is a non-invasive method to assess neurophysiology of the primary motor cortex in humans. Dystonia is a poorly understood neurological movement disorder, often presenting in an idiopathic, isolated form across different parts of the body. The neurophysiological profile of isolated dystonia compared to healthy adults remains unclear. We conducted a systematic review with meta-analysis of neurophysiologic TMS measures in people with isolated dystonia to provide a synthesized understanding of cortical neurophysiology associated with isolated dystonia. We performed a systematic database search and data were extracted independently by the two authors. Separate meta-analyses were performed for TMS measures of: motor threshold, corticomotor excitability, short interval intracortical inhibition, cortical silent period, intracortical facilitation and afferent-induced inhibition. Standardized mean differences were calculated using a random effects model to determine overall effect sizes and confidence intervals. Heterogeneity was explored using dystonia type subgroup analysis. The search resulted in 78 studies meeting inclusion criteria, of these 57 studies reported data in participants with focal hand dystonia, cervical dystonia, blepharospasm or spasmodic dysphonia, and were included in at least one meta-analysis. The cortical silent period, short-interval intracortical inhibition and afferent-induced inhibition was found to be reduced in isolated dystonia compared to controls. Reduced GABAergic-mediated inhibition in the primary motor cortex in idiopathic isolated dystonia's suggest interventions targeted to aberrant cortical disinhibition could provide a novel treatment. Future meta-analyses require neurophysiology studies to use homogeneous cohorts of isolated dystonia participants, publish raw data values, and record electromyographic responses from dystonic musculature where possible.

Neck rotation modulates motor-evoked potential duration of proximal muscle cortical representations in healthy adults.

Transcranial magnetic stimulation (TMS) produces motor-evoked potentials (MEP) used to infer changes in corticomotor excitability. In humans, neck rotation can probe reticulospinal input on corticomotor output. This study investigated the effect of neck rotation on MEP duration in a proximal and distal upper limb muscle and compared responses between rest and preactivation. Single-pulse TMS to motor cortex was used to evoke MEPs at two stimulus intensities in 18 healthy adults (20-40 years). Surface electromyography recorded MEPs from the non-dominant biceps brachii (BB) and first dorsal interosseous (FDI). Participants were seated with the target muscle at rest or 10% preactivated, and head rotated ipsilateral, contralateral, or in neutral position. The primary outcome was MEP tail, defined as the mean difference in MEP duration between active and rest trials. Secondary outcomes were MEP duration and amplitude. MEP tail was modulated by neck rotation in the proximal BB (P = 0.03) but not distal FDI (P > 0.19), with shorter duration during ipsilateral or contralateral rotation relative to neutral. In a neutral neck position, MEP duration was prolonged by muscle preactivation and higher TMS intensities in the FDI and BB (P < 0.03). Neck rotation attenuated the prolongation of MEP duration during preactivation in the BB, but not the FDI. Neck rotation had no effect on MEP amplitude for either muscle (P > 0.05). Modulation of the late portion of the MEP by rotation of the neck could indicate subcortical projections to alpha-motoneuron pools are stronger in proximal than distal upper limb muscles. These findings may have relevance for using MEP duration as a neural biomarker in neurological diseases.

Consensus Paper: Experimental Neurostimulation of the Cerebellum.

The cerebellum is best known for its role in controlling motor behaviors. However, recent work supports the view that it also influences non-motor behaviors. The contribution of the cerebellum towards different brain functions is underscored by its involvement in a diverse and increasing number of neurological and neuropsychiatric conditions including ataxia, dystonia, essential tremor, Parkinson's disease (PD), epilepsy, stroke, multiple sclerosis, autism spectrum disorders, dyslexia, attention deficit hyperactivity disorder (ADHD), and schizophrenia. Although there are no cures for these conditions, cerebellar stimulation is quickly gaining attention for symptomatic alleviation, as cerebellar circuitry has arisen as a promising target for invasive and non-invasive neuromodulation. This consensus paper brings together experts from the fields of neurophysiology, neurology, and neurosurgery to discuss recent efforts in using the cerebellum as a therapeutic intervention. We report on the most advanced techniques for manipulating cerebellar circuits in humans and animal models and define key hurdles and questions for moving forward.

Are ipsilateral motor evoked potentials subject to intracortical inhibition?

Paired-pulse transcranial magnetic stimulation (TMS) can be used to examine intracortical inhibition in primary motor cortex (M1), termed short-interval intracortical inhibition (SICI). To our knowledge, SICI has only been demonstrated in contralateral motor evoked potentials (MEPs). Ipsilateral MEPs (iMEPs) are assumed to reflect excitability of an uncrossed oligosynaptic pathway, and can sometimes be evoked in proximal upper-limb muscles using high-intensity TMS. We examined whether iMEPs in the biceps brachii (BB) would be suppressed by subthreshold conditioning, therefore demonstrating SICI of iMEPs. TMS was delivered to the dominant M1 to evoke conditioned (C) and nonconditioned (NC) iMEPs in the nondominant BB of healthy participants during weak bilateral elbow flexion. The conditioning stimulus intensities tested were 85%, 100%, and 115% of active motor threshold (AMT), at 2 ms and 4 ms interstimulus intervals (ISI). The iMEP ratio (C/NC) was calculated for each condition to assess the amount of inhibition. Inhibition of iMEPs was present at 2 ms ISI with 100% and 115% AMT (bothP< 0.03), mediated by a reduction in persistence and size (allP< 0.05). To our knowledge, this is the first demonstration of SICI of iMEPs. This technique may be useful as a tool to better understand the role of ipsilateral M1 during functional motor tasks.

Neurophysiological and behavioural effects of dual-hemisphere transcranial direct current stimulation on the proximal upper limb.

Dual-hemisphere transcranial direct current stimulation over the primary motor cortex (M1-M1 tDCS) is assumed to modulate neural excitability in a polarity-dependent manner and improve motor performance of the hand. In the proximal upper limb, the neurophysiological and behavioural after-effects of M1-M1 tDCS are not well known. This study investigated the after-effects of M1-M1 tDCS on contralateral, ipsilateral and transcallosal excitability to the proximal upper limb muscle biceps brachii (BB). Circle tracing was used to assess motor performance before and after tDCS as this task requires coordination of proximal and distal musculature. Sixteen healthy right-handed adults participated in the study, each receiving M1-M1 tDCS (1 mA, 15 min) or sham tDCS in separate sessions. The anode was positioned over right M1 and cathode over left M1. M1-M1 tDCS suppressed transcallosal inhibition from the M1 under the cathode (P < 0.045). No other neurophysiologic or behavioural effects were observed (P > 0.6). The study provides important information regarding inconsistent neurophysiological and behavioural changes following tDCS that have implications for future tDCS research on the motor system.

A dissociation between propriospinal facilitation and inhibition after bilateral transcranial direct current stimulation.

Propriospinal premotoneurons (PN) are essential for accurate control of the upper limb. They receive bilateral input from premotor (PM) and primary motor (M1) cortices. In humans, excitability of PNs can be estimated from motor-evoked potentials (MEPs) by pairing a descending volley using transcranial magnetic stimulation (TMS) to summate with an ascending volley from peripheral nerve stimulation at the C3-C4 level of the spinal cord. Transcranial direct current stimulation (tDCS) alters excitability of cortical and subcortical areas. A recent study demonstrated that cathodal tDCS can suppress facilitatory (FAC) and inhibitory (INH) components of PN excitability, presumably via effects on corticoreticulospinal neurons (Bradnam LV, Stinear CM, Lewis GN, Byblow WD. J Neurophysiol 103: 2382-2389, 2010). The present study investigated the effects of bilateral tDCS with healthy subjects. The cathode was placed over left dorsal PM or M1 and the anode over right M1 in separate sessions (PM-M1, M1-M1, or Sham). TMS of right M1 elicited MEPs in left biceps brachii across a range of TMS intensities chosen to examine PN-mediated FAC and INH. Conditioning was applied using median nerve stimulation with an interstimulus interval that coincided with TMS and peripheral volleys summating at the C3-C4 level. All participants showed FAC at TMS intensities near active motor threshold and INH at slightly higher intensities. After tDCS, FAC was reduced for M1-M1 compared with Sham but not after PM-M1 stimulation. Contrary to an earlier study with cathodal tDCS, INH was unchanged across all sessions. The difference between these and earlier findings may relate to dual- vs. single-hemisphere M1 stimulation. M1-M1 tDCS may be a useful adjuvant to techniques that aim to reduce upper limb impairment after stroke.

Unravelling dystonic pain; a mixed methods survey to explore the language of dystonic pain and impact on life.

PURPOSE: Dystonia is a neurological disorder characterised by involuntary muscle contractions. Pain is the primary non-motor symptom, and limited studies have investigated how dystonic pain is experienced. This study aimed to investigate how people with isolated dystonia describe their pain and compare across subgroups of dystonia. METHODS: Anonymous online survey via social media asking participants to describe their pain in their own words, complete the McGill Pain Questionnaire (MPQ), and answer demographic questions. Thematic analysis identified common themes and frequencies were calculated for demographic and MPQ data. RESULTS: One-hundred and sixty-five respondents were included (mean age 51 years, 85% female). Thematic analysis identified four major themes "Physical sensations", "Temporal features", "Destruction", "Impact on life" with several sub-themes. The most chosen MPQ descriptor was "exhausting" followed by "tight," "sharp," "pulling," and "aching". The most common descriptors showed similar prevalence across subgroups of dystonia. CONCLUSION: As no objective tests for pain exist, pain sufferers must use language to describe their pain experience. People with isolated dystonia used sensory words combined with metaphorical language to detail temporal features of pain, as well as destructive internal battles or feelings of external forces acting upon them, and the significant toll pain has on everyday life. Implications for rehabilitationPain is a common and debilitating non-motor symptom for people living with dystonia and should be discussed in a persons treatment plan.Pain sufferers use language to discuss their pain experience with others and report they don't feel well understood by others including health professionals.People with dystonic pain commonly described physical sensations, temporal features, destructive forces, and the impact on life caused by their pain.Findings suggest the experience of pain with dystonia is varied and better pain management options for people with dystonia are needed.

Can patients and clinicians find conservative management protocols of anterior cruciate ligament injuries online? A systematic review.

OBJECTIVE: To systematically search the internet for conservative rehabilitation protocols for people with an anterior cruciate ligament (ACL) injury and critically appraise the websites and exercise protocols. DESIGN: Systematic review of online rehabilitation protocols. SEARCH: We searched four online search-engines (Google, Yahoo, Bing, DuckDuckGo). SELECTION CRITERIA: Rehabilitation protocols on active, English language websites aimed at conservative (non-surgical) management of an ACL injury. DATA SYNTHESIS: We extracted descriptive information and assessed quality of the websites using the Journal of the American Medical Association (JAMA) benchmark criteria, the Health on the Net Code (HONcode) certificate, and the Flesch-Kincaid Reading Ease (FKRE). We assessed completeness of exercise protocol reporting using the Consensus on Exercise Reporting Template (CERT). We performed a descriptive analysis. RESULTS: We found 14 websites that met our selection criteria. The protocols varied between 10 and 26 weeks duration, nine were from the United States, five targeted patients, and 13 used multiple phases with a variety of different criteria for progression. Three protocols scored good quality with the JAMA, two were HonCode certified, and ten had good readability according to the FKRE. Completeness of exercise protocol reporting in all but one protocol was poor according to the CERT. CONCLUSION: Few rehabilitation protocols for conservative management of ACL injuries were available online. Most of the websites showed good readability, but poor quality and credibility with inadequate description of exercise protocols.

User profile of people contacting a stroke helpline (StrokeLine) in Australia: a retrospective cohort study.

BACKGROUND: StrokeLine is a specialised telephone helpline led by health professionals in Australia. AIMS: (i) To describe the profile of StrokeLine callers; (ii) to understand the reasons people engage with the service and (iii) how StrokeLine responded to the caller's needs. METHODS: Routine call data were obtained from the StrokeLine between November 2019 and November 2020. Data were extracted and descriptive analyses performed. De-identified free-text data were obtained separately for November 2019 and June 2020 and analysed using qualitative content analysis. RESULTS: Of the 1429 calls most were from carers, family and friends (38%) or the stroke survivor themselves (34%). Most calls were made by women (64%) and the average age of the stroke survivor was ≥65 years (33%) with the time since the stroke occurred <1 year. The main reason for calling was to manage stroke-related impairments (40%). Providing information, support and advice was the most common action provided by StrokeLine staff (25%). Content analysis of 225 calls revealed most stroke survivors called for emotional support, while carers sought more practical guidance. StrokeLine provided information for referral to relevant services and guidance on what to do next. CONCLUSIONS: Most calls were received from family and carers, as well as stroke survivors. They contacted StrokeLine for information and advice, practical solutions, emotional support, and referral advice to other services.

Comparison between 2000 and 2018 on the reporting of statistical significance and clinical relevance in physiotherapy clinical trials in six major physiotherapy journals: a meta-research design.

DESIGN: Meta-research. OBJECTIVE: To compare the prevalence of reporting p values, effect estimates and clinical relevance in physiotherapy randomised controlled trials (RCTs) published in the years 2000 and 2018. METHODS: We performed a meta-research study of physiotherapy RCTs obtained from six major physiotherapy peer-reviewed journals that were published in the years 2000 and 2018. We searched the databases Embase, Medline and PubMed in May 2019, and extracted data on the study characteristics and whether articles reported on statistical significance, effect estimates and confidence intervals for baseline, between-group, and within-group differences, and clinical relevance. Data were presented using descriptive statistics and inferences were made based on proportions. A 20% difference between 2000 and 2018 was regarded as a meaningful difference. RESULTS: We found 140 RCTs: 39 were published in 2000 and 101 in 2018. Overall, there was a high prevalence (>90%) of reporting p values for the main (between-group) analysis, with no difference between years. Statistical significance testing was frequently used for evaluating baseline differences, increasing from 28% in 2000 to 61.4% in 2018. The prevalence of reporting effect estimates, CIs and the mention of clinical relevance increased from 2000 to 2018 by 26.6%, 34% and 32.8% respectively. Despite an increase in use in 2018, over 40% of RCTs failed to report effect estimates, CIs and clinical relevance of results. CONCLUSION: The prevalence of using p values remains high in physiotherapy research. Although the proportion of reporting effect estimates, CIs and clinical relevance is higher in 2018 compared to 2000, many publications still fail to report and interpret study findings in this way.

Cathodal transcranial direct current stimulation of the primary motor cortex improves selective muscle activation in the ipsilateral arm.

Proximal upper limb muscles are represented bilaterally in primary motor cortex. Goal-directed upper limb movement requires precise control of proximal and distal agonist and antagonist muscles. Failure to suppress antagonist muscles can lead to abnormal movement patterns, such as those commonly experienced in the proximal upper limb after stroke. We examined whether noninvasive brain stimulation of primary motor cortex could be used to improve selective control of the ipsilateral proximal upper limb. Thirteen healthy participants performed isometric left elbow flexion by contracting biceps brachii (BB; agonist) and left forearm pronation (BB antagonist) before and after 20 min of cathodal transcranial direct current stimulation (c-tDCS) or sham tDCS of left M1. During the tasks, motor evoked potentials (MEPs) in left BB were acquired using single-pulse transcranial magnetic stimulation of right M1 150-270 ms before muscle contraction. As expected, left BB MEPs were facilitated before flexion and suppressed before pronation. After c-tDCS, left BB MEP amplitudes were reduced compared with sham stimulation, before pronation but not flexion, indicating that c-tDCS enhanced selective muscle activation of the ipsilateral BB in a task-specific manner. The potential for c-tDCS to improve BB antagonist control correlated with BB MEP amplitude for pronation relative to flexion, expressed as a selectivity ratio. This is the first demonstration that selective muscle activation in the proximal upper limb can be improved after c-tDCS of ipsilateral M1 and that the benefits of c-tDCS for selective muscle activation may be most effective in cases where activation strategies are already suboptimal. These findings may have relevance for the use of tDCS in rehabilitation after stroke.

Can Transcranial Direct Current Stimulation Enhance Poststroke Motor Recovery? Development of a Theoretical Patient-Tailored Model.

New treatments that can facilitate neural repair and reduce persistent impairments have significant value in promoting recovery following stroke. One technique that has gained interest is transcranial direct current stimulation (tDCS) as early research suggested it could enhance plasticity and enable greater behavioral recovery. However, several studies have now identified substantial intersubject variability in response to tDCS and clinical trials revealed insufficient evidence of treatment effectiveness. A possible explanation for the varied and negative findings is that the physiologic model of stroke recovery that researchers have used to guide the application of tDCS-based treatments in stroke is overly simplistic and does not account for stroke heterogeneity or known determinants that affect the tDCS response. Here, we propose that tDCS could have a more clearly beneficial role in enhancing stroke recovery if greater consideration is given to individualizing treatment. By critically reviewing the proposed mechanisms of tDCS, stroke physiology across the recovery continuum, and known determinants of tDCS response, we propose a new, theoretical, patient-tailored approach to delivering tDCS after stroke. The proposed model includes a step-by-step principled selection strategy for identifying optimal neuromodulation targets and outlines key areas for further investigation. Tailoring tDCS treatment to individual neuroanatomy and physiology is likely our best chance at producing robust and meaningful clinical benefit for people with stroke and would therefore accelerate opportunities for clinical translation.

Has Reporting on Physical Therapy Interventions Improved in 2 Decades? An Analysis of 140 Trials Reporting on 225 Interventions.

OBJECTIVES: To investigate the completeness of reporting of physical therapy interventions in randomized controlled trials before and after publication of the Template for Intervention Description and Replication (TIDieR) checklist (a reporting guideline for interventions). DESIGN: Meta-research. METHODS: We searched 6 journals for trials using physical therapy interventions that were published in 2000 and 2018. Two independent assessors scored the TIDieR checklist and extracted descriptive information, including Physiotherapy Evidence Database (PEDro) scale scores. We identified control or treatment interventions, exercise-based interventions, and area of physical therapy. We performed a descriptive analysis and defined a priori a 20% difference between studies published in 2000 and 2018 as meaningful. We assessed correlations between TIDieR and PEDro scale scores for all interventions. RESULTS: In total, 140 articles that met selection criteria evaluated 225 interventions (2000, n = 61; 2018, n = 164). Mean ± SD TIDieR score (2000, 7.52 ± 2.62; 2018, 8.26 ± 2.26) did not show a meaningful difference between years for all interventions (+5%), controls (+6%), treatment interventions (+6%), exercise-based interventions (+9%), or musculoskeletal (+4%) or neurological (+7%) physical therapy. For exercise interventions, number of sessions was reported more (+21%) in 2018 than in 2000. For musculoskeletal trials, 2 items were reported more completely in 2018 than in 2000 (materials, +29%; individual versus group, +22%) and 3 items were reported more completely in neurological trials (mode of delivery, +20%, [item 8.1] when +45%, and assessment of fidelity, +20%). The item "Who delivered the intervention?" was reported less completely (-23%) in 2018 than in 2000 in neurological trials. We found no correlation (r = 0.12) between PEDro scale score and TIDieR score. CONCLUSION: There were few meaningful improvements in how physical therapy interventions were described after publication of the TIDieR reporting guideline. J Orthop Sports Phys Ther 2021;51(10):503-509. doi:10.2519/jospt.2021.10642.

Externally validated model predicting gait independence after stroke showed fair performance and improved after updating.

OBJECTIVE: To externally validate recent prognostic models that predict independent gait following stroke. STUDY DESIGN AND SETTING: A systematic search identified recent models (<10 years) that predicted independent gait in adult stroke patients, using easily obtainable predictors. Predictors from the original models were assigned proxies when required, and model performance was evaluated in the validation cohort (n = 957). Models were updated to determine if performance could be improved. RESULTS: Three prognostic models met our criteria, all with high Risk of Bias. Validation data was only available for the Australian model. This model used National Institute of Health Stroke Scale (NIHSS) and age to predict independent gait, using Motor Assessment Scale (MAS) walking item. For validation, Scandinavian Stroke Scale (SSS) was a proxy for NIHSS, and Functional Independence Measure (FIM) locomotion item was a proxy for MAS. The Area Under the Curve was 0.77 (0.74-0.80) and had good calibration in the validation dataset. Adjustment of the intercept and regression coefficients slightly improved discrimination. By adding paretic leg strength, the model further improved (AUC 0.82). CONCLUSION: External validation of the Australian model with proxies showed fair discrimination and good calibration. Updating the model by adding paretic leg strength further improved model performance.

Investigating the mechanisms of acupuncture on neural excitability in healthy adults.

Acupuncture is gaining interest as a potential treatment modality for various neurological conditions. Yet, the underlying mechanisms and efficacy on brain function are not well understood. Therefore, this study investigated the previously proposed hypothesis that acupuncture suppresses motor cortex excitability using transcranial magnetic stimulation (TMS) in healthy adults. The study was randomised, sham-controlled, and double-blinded. Single and paired-pulse TMS was delivered before, during, immediately after, and 30 min after removal of the needle. Acupuncture to the right Hegu acupoint (LI-4) of the hand was delivered by an experienced acupuncturist using standardised manipulations. A disposable (0.22×30 mm, Hwato) needle was used for verum stimulation (penetrating) and a Park retractable needle for sham (nonpenetrating). The peak-to-peak amplitude of TMS-induced motor-evoked potentials was recorded from two intrinsic hand muscles. Needling sensations were quantified using the Massachusett's acupuncture sensation scale. Participant needling sensations were not different between verum or sham acupuncture (P>0.54). Corticomotor excitability, intracortical inhibition, and intracortical facilitation were not modulated by verum or sham acupuncture during, immediately after, or 30 min after, recorded from a local or distant hand muscle to the needling site (all P>0.075). Contrary to previous studies, manual acupuncture did not affect motor cortex excitability in healthy adults. Because of the increasing popularity of acupuncture therapy, further research using patient populations should be considered.

Revisiting interhemispheric imbalance in chronic stroke: A tDCS study.

OBJECTIVE: Chronic stroke patients with moderate-severe motor impairment may have an increased reliance on contralesional vs ipsilesional motor areas to control the paretic arm. We hypothesised that increasing contralesional excitability with anodal transcranial direct current stimulation (a-tDCS) would benefit motor performance in patients with moderate-severe impairment. METHODS: Ten patients with motor impairment at the chronic stage after stroke received a-tDCS, cathodal (c-tDCS) and sham with the target electrode over contralesional motor cortex (M1). Motor performance was quantified from the circularity and size of planar movements made with the paretic arm. Contralateral and ipsilateral corticospinal excitability was inferred using transcranial magnetic stimulation. Corticospinal tract integrity and basal GABA concentration were assessed with magnetic resonance imaging and spectroscopy. RESULTS: Anodal tDCS increased contralesional corticomotor excitability evident from motor evoked potentials in both wrist extensors (both P<0.043). Cathodal tDCS did not affect corticomotor excitability (P>0.37). The effect of tDCS on motor performance with the paretic limb was negatively associated with ipsilesional GABA concentration after c-tDCS (P=0.001). CONCLUSIONS: Further investigation of noninvasive brain stimulation protocols that facilitate contralesional M1 is warranted. SIGNIFICANCE: The inter-hemispheric imbalance model of stroke recovery may not apply to patients with more severe impairment.