human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND PURPOSE Recent research suggests that an increased level of stroke-affected left hemisphere cortical ( especially frontal ) excitability is associated with better language improvement in aphasic patients .  Anodal transcranial direct current stimulation ( A-tDCS ) , increasing cortical activity , may facilitate perilesional left hemisphere recruitment to subserve language processing and enhance effects of behavioural therapy . The aim of the study ( r and omized , double-blind , sham-controlled ) was to evaluate the effectiveness of repeated A-tDCS over Broca area as a strategy to enhance aphasia recovery during early post-stroke rehabilitation . MATERIAL AND METHODS Thirty-seven participants with moderate or severe aphasia were r and omized to receive 15 consecutive daily sessions of A-tDCS ( 1 mA , 10 min ; experimental group , n = 18 ) or sham stimulation ( 1 mA , 25 s ; control group , n = 19 ) followed by language therapy .  Effects of tDCS were assessed using the Boston Diagnostic Aphasia Examination , performed before and after the rehabilitation , and three months later . RESULTS The results did not confirm a positive impact of repeated A-tDCS , preceding language therapy , on language abilities in our patients . Although both groups improved after the therapy , there were no statistically significant differences between groups in either short-term or long-term tDCS effects . Effect sizes for the experimental group , at post-treatment and the 3-month follow-up , were slightly higher than in controls but insufficient to infer any beneficial influence of the applied intervention . CONCLUSIONS The findings do not support  A-tDCS functional benefits during early rehabilitation of post-stroke aphasia . Further research is needed to explore the effectiveness of this kind of neuromodulation Background . No rehabilitation intervention has effectively improved functional use of the arm and h and in patients with severe upper limb paresis after stroke . Pilot studies suggest the potential for transcranial direct current stimulation and bilateral robotic training to enhance gains . Objective . In a double-blind , r and omized trial the combination of these interventions was tested . Methods . This study r and omized 96 patients with an ischemic supratentorial lesion of 3 to 8 weeks ’ duration with severe impairment of motor control with a Fugl-Meyer score ( FMS ) for the upper limb < 18 into 3 groups . For 6 weeks , group A received anodal stimulation of the lesioned hemisphere , group B received cathodal stimulation of the nonlesioned side for 20 minutes at 2.0 mA , and group C received sham stimulation . The electrodes were placed over the h and area and above the contralateral orbit . Contemporaneously , the subjects practice d 400 repetitions each of 2 different bilateral movements on a robotic assistive device . Results . The groups were matched at onset . The FMS improved in all patients at 6 weeks ( P < .001 ) . No between-group differences were found ; initial versus finish FMS scores were 7.8 ± 3.8 versus 19.1 ± 14.4 in group A , 7.9 ± 3.4 versus 18.8 ± 10.5 in group B , and 8.2 ± 4.4 versus 19.2 ± 15.0 in group C. No significant changes between groups were present at 3 months . Conclusions . Neither anodal nor cathodal transcranial direct current stimulation enhanced the effect of bilateral arm training in this exploratory trial of patients with cortical involvement and severe weakness . Unilateral h and training and upregulation of the nonlesioned hemisphere might also be tried in this population BACKGROUND Transcranial direct current stimulation ( tDCS ) enhances treatment outcomes  post-stroke .  Feasibility and tolerability of high-definition ( HD ) tDCS ( a technique that increases current focality and intensity ) for consecutive weekdays as an adjuvant to behavioral treatment in a clinical population has not been demonstrated . OBJECTIVE To determine HD-tDCS  feasibility outcomes : 1 ) ability to implement study as design ed , 2 ) acceptability of repeated HD-tDCS administration to patients , and 3 ) preliminary efficacy . METHODS Eight patients with chronic post-stroke aphasia participated in a r and omized crossover trial with two arms : conventional sponge-based ( CS ) tDCS and HD-tDCS . Computerized anomia treatment was administered for five consecutive days during each treatment arm . RESULTS Individualized modeling/targeting procedures and an 8-channel HD-tDCS device were developed . CS-tDCS and HD-tDCS were comparable in terms of implementation , acceptability , and outcomes . Naming accuracy and response time improved for both stimulation conditions . Change in accuracy of trained items was numerically higher ( but not statistically significant ) for HD-tDCS compared to CS-tDCS for most patients . CONCLUSIONS Regarding feasibility , HD-tDCS treatment studies can be implemented when design ed similarly to documented CS-tDCS studies . HD-tDCS is likely to be acceptable to patients and clinicians . Preliminary efficacy data suggest that HD-tDCS effects , using only 4 electrodes , are at least comparable to CS-tDCS Non‐invasive transcranial direct current stimulation ( tDCS ) can enhance recovery after stroke . However , fundamental knowledge about how tDCS impacts neural processing in the lesioned human brain is currently lacking . In the present study , it was investigated how tDCS modulates brain function in patients with post‐stroke language impairment ( aphasia ) . In a cross‐over , r and omized trial , patients named pictures of common objects during functional magnetic resonance imaging ( fMRI ) . Concurrently , excitatory ( anodal‐ ) or sham‐tDCS ( 1 mA , 20 min , or 30 s , respectively ) was administered to the left primary motor cortex , a montage with demonstrated potential to improve aphasic language . By choosing stimuli that could reliable be named by the patients , the authors aim ed to derive a pure measure of stimulation effects that was independent of treatment or performance effects and to assess how tDCS interacts with the patients ' residual language network . Univariate fMRI data analysis revealed reduced activity in domain‐general regions mediating high‐level cognitive control  during anodal‐tDCS . Independent component functional network analysis demonstrated selectively increased language network activity and an inter‐correlated shift from higher to lower frequency b and s , indicative of increased within‐network communication . Compared with healthy controls , anodal‐tDCS result ed in overall “ normalization ” of brain function in the patients . These results demonstrate for the first time how tDCS modulates neural processing in stroke patients . Such information is crucial to assure that behavioral treatments targeting specific neural circuits overlap with regions that are modulated by tDCS , thereby maximizing stimulation effects during therapy . Hum Brain Mapp 38:1518–1531 , 2017 . © 2016 Wiley Periodicals , Knowledge of the frequency and remission of aphasia is essential for the rehabilitation of stroke patients and provides insight into the brain organization of language . We studied prospect ively and consecutively an unselected and community‐based sample of 881 patients with acute stroke .  Assessment of aphasia  was done at admission , weekly during the hospital stay , and at a 6‐months follow‐up using the aphasia score of the Sc and inavian Stroke Scale .  Thirty‐eight percent had aphasia at the time of admission ; at discharge 18 % had aphasia .  Sex was not a determinant of aphasia in stroke , and no sex difference in the anterior‐posterior distribution of lesions was found . The remission curve was steep : Stationary language function in 95 % was reached within 2 weeks in those with initial mild aphasia , within 6 weeks in those with moderate , and within 10 weeks in those with severe aphasia . A valid prognosis of aphasia could be made within 1 to 4 weeks after the stroke depending on the initial severity of aphasia . Initial severity of aphasia was the only clinical ly relevant predictor of aphasia outcome . Sex , h and edness , and side of stroke lesion were not independent outcome predictors , and the influence of age was minimal PURPOSE Recent research in patients with chronic aphasia shows an association between excitatory anodal transcranial direct current stimulation ( A-tDCS ) of the stroke-affected left hemisphere coupled with speech and language therapy ( SLT ) and better language performance . The present study aim ed to investigate this association during the early post-stroke rehabilitation period , when adaptive changes are most possible on neurophysiological and behavioral levels . METHODS We r and omized 24 patients with non-fluent aphasia to receive 15 consecutive sessions ( 5 days/week for 3 weeks ) of A-tDCS ( 1 mA , 10 min ; n = 14 ) or sham tDCS ( S-tDCS : 1 mA , 25 sec ; n = 10 ) over Broca 's area followed by 45-min SLT . Naming ability was assessed before the rehabilitation , after its completion , and three months later . RESULTS Both groups significantly improved after the therapy . There were no statistically significant between-group differences in the short-term or long-term tDCS effects on naming accuracy and naming time . The A-tDCS group obtained higher effect sizes in naming time , both post-treatment and at the 3-month follow-up , suggesting potential benefits of the stimulation . CONCLUSIONS The findings provide only weak evidence for A-tDCS-related language gains during early neurorehabilitation of post-stroke aphasia . Further research is needed to explore the effectiveness of this kind of neuromodulation Background and Purpose — Recent research suggests that increased left hemisphere cortical activity , primarily of the left frontal cortex , is associated with improved naming performance in stroke patients with aphasia . Our aim was to determine whether anodal transcranial direct-current stimulation ( tDCS ) , a method thought to increase cortical excitability , would improve naming accuracy in stroke patients with aphasia when applied to the scalp overlying the left frontal cortex . Methods — Ten patients with chronic stroke-induced aphasia received 5 days of anodal tDCS ( 1 mA for 20 minutes ) and 5 days of sham tDCS ( for 20 minutes , order r and omized ) while performing a computerized anomia treatment . tDCS positioning was guided by a priori functional magnetic resonance imaging results for each individual during an overt naming task to ensure that the active electrode was placed over structurally intact cortex . Results — Results revealed significantly improved naming accuracy of treated items ( F[1,9]=5.72 , P<0.040 ) after anodal tDCS compared with sham tDCS . Patients who demonstrated the most improvement were those with perilesional areas closest to the stimulation site . Crucially , this treatment effect persisted at least 1 week after treatment . Conclusions — Our findings suggest that anodal tDCS over the left frontal cortex can lead to enhanced naming accuracy in stroke patients with aphasia and , if proved to be effective in larger studies , may provide a supplementary treatment approach for anomia Background and Purpose — Previous evidence suggests that anodal transcranial direct current stimulation ( A-tDCS ) applied to the left hemisphere can improve aphasic participants ' ability to name common objects . The current study further examined this issue in a more tightly controlled experiment in participants with fluent aphasia . Methods — We examined the effect of A-tDCS on reaction time during overt picture naming in 8 chronic stroke participants . Anode electrode placement targeted perilesional brain regions that showed the greatest activation on a pretreatment functional MRI scan administered during overt picture naming with the reference cathode electrode placed on the contralateral forehead . A-tDCS ( 1 mA ; 20-minute ) was compared with sham tDCS ( S-tDCS ) in a crossover design . Participants received 10 sessions of computerized anomia treatment ; 5 sessions included A-tDCS and 5 included S-tDCS . Results — Coupling A-tDCS with behavioral language treatment reduced reaction time during naming of trained items immediately posttreatment ( Z=1.96 , P=0.025 ) and at subsequent testing 3 weeks later ( Z=2.52 , P=0.006 ) . Conclusions — A-tDCS administered during language treatment decreased processing time during picture naming by fluent aphasic participants . Additional studies combining A-tDCS , an inexpensive method with no reported serious side effects , with behavioral language therapy are recommended Several studies have already shown that transcranial direct current stimulation ( tDCS ) is a useful tool for enhancing recovery in aphasia . However , all tDCS studies have previously investigated the effects using unihemisperic stimulation . No reports to date have examined the role of bihemispheric tDCS on aphasia recovery . Here , eight aphasic persons with apraxia of speech underwent intensive language therapy  in two different conditions : real bihemispheric anodic ipsilesional stimulation over the left Broca 's area and cathodic contralesional stimulation over the right homologue of Broca 's area , and a sham condition . In both conditions , patients underwent concurrent language therapy for their apraxia of speech . The language treatment lasted 10 days ( Monday to Friday , then weekend off , then Monday to Friday ) . There was a 14-day intersession interval between the real and the sham conditions . In all patients , language measures were collected before ( T0 ) , at the end of ( T10 ) and 1 week after the end of ( F/U ) treatment . Results showed that after simultaneous excitatory stimulation to the left frontal hemisphere and inhibitory stimulation to the right frontal hemisphere regions , patients exhibited a significant recovery not only in terms of better accuracy and speed in articulating the treated stimuli but also in other language tasks ( picture description , noun and verb naming , word repetition , word reading ) which persisted in the follow-up session . T 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND PURPOSE Recent research suggests that an increased level of stroke-affected left hemisphere cortical ( especially frontal ) excitability is associated with better language improvement in aphasic patients .  Anodal transcranial direct current stimulation ( A-tDCS ) , increasing cortical activity , may facilitate perilesional left hemisphere recruitment to subserve language processing and enhance effects of behavioural therapy . The aim of the study ( r and omized , double-blind , sham-controlled ) was to evaluate the effectiveness of repeated A-tDCS over Broca area as a strategy to enhance aphasia recovery during early post-stroke rehabilitation . MATERIAL AND METHODS Thirty-seven participants with moderate or severe aphasia were r and omized to receive 15 consecutive daily sessions of A-tDCS ( 1 mA , 10 min ; experimental group , n = 18 ) or sham stimulation ( 1 mA , 25 s ; control group , n = 19 ) followed by language therapy .  Effects of tDCS were assessed using the Boston Diagnostic Aphasia Examination , performed before and after the rehabilitation , and three months later . RESULTS The results did not confirm a positive impact of repeated A-tDCS , preceding language therapy , on language abilities in our patients . Although both groups improved after the therapy , there were no statistically significant differences between groups in either short-term or long-term tDCS effects . Effect sizes for the experimental group , at post-treatment and the 3-month follow-up , were slightly higher than in controls but insufficient to infer any beneficial influence of the applied intervention . CONCLUSIONS The findings do not support  A-tDCS functional benefits during early rehabilitation of post-stroke aphasia . Further research is needed to explore the effectiveness of this kind of neuromodulation Background . No rehabilitation intervention has effectively improved functional use of the arm and h and in patients with severe upper limb paresis after stroke . Pilot studies suggest the potential for transcranial direct current stimulation and bilateral robotic training to enhance gains . Objective . In a double-blind , r and omized trial the combination of these interventions was tested . Methods . This study r and omized 96 patients with an ischemic supratentorial lesion of 3 to 8 weeks ’ duration with severe impairment of motor control with a Fugl-Meyer score ( FMS ) for the upper limb < 18 into 3 groups . For 6 weeks , group A received anodal stimulation of the lesioned hemisphere , group B received cathodal stimulation of the nonlesioned side for 20 minutes at 2.0 mA , and group C received sham stimulation . The electrodes were placed over the h and area and above the contralateral orbit . Contemporaneously , the subjects practice d 400 repetitions each of 2 different bilateral movements on a robotic assistive device . Results . The groups were matched at onset . The FMS improved in all patients at 6 weeks ( P < .001 ) . No between-group differences were found ; initial versus finish FMS scores were 7.8 ± 3.8 versus 19.1 ± 14.4 in group A , 7.9 ± 3.4 versus 18.8 ± 10.5 in group B , and 8.2 ± 4.4 versus 19.2 ± 15.0 in group C. No significant changes between groups were present at 3 months . Conclusions . Neither anodal nor cathodal transcranial direct current stimulation enhanced the effect of bilateral arm training in this exploratory trial of patients with cortical involvement and severe weakness . Unilateral h and training and upregulation of the nonlesioned hemisphere might also be tried in this population BACKGROUND Transcranial direct current stimulation ( tDCS ) enhances treatment outcomes  post-stroke .  Feasibility and tolerability of high-definition ( HD ) tDCS ( a technique that increases current focality and intensity ) for consecutive weekdays as an adjuvant to behavioral treatment in a clinical population has not been demonstrated . OBJECTIVE To determine HD-tDCS  feasibility outcomes : 1 ) ability to implement study as design ed , 2 ) acceptability of repeated HD-tDCS administration to patients , and 3 ) preliminary efficacy . METHODS Eight patients with chronic post-stroke aphasia participated in a r and omized crossover trial with two arms : conventional sponge-based ( CS ) tDCS and HD-tDCS . Computerized anomia treatment was administered for five consecutive days during each treatment arm . RESULTS Individualized modeling/targeting procedures and an 8-channel HD-tDCS device were developed . CS-tDCS and HD-tDCS were comparable in terms of implementation , acceptability , and outcomes . Naming accuracy and response time improved for both stimulation conditions . Change in accuracy of trained items was numerically higher ( but not statistically significant ) for HD-tDCS compared to CS-tDCS for most patients . CONCLUSIONS Regarding feasibility , HD-tDCS treatment studies can be implemented when design ed similarly to documented CS-tDCS studies . HD-tDCS is likely to be acceptable to patients and clinicians . Preliminary efficacy data suggest that HD-tDCS effects , using only 4 electrodes , are at least comparable to CS-tDCS Non‐invasive transcranial direct current stimulation ( tDCS ) can enhance recovery after stroke . However , fundamental knowledge about how tDCS impacts neural processing in the lesioned human brain is currently lacking . In the present study , it was investigated how tDCS modulates brain function in patients with post‐stroke language impairment ( aphasia ) . In a cross‐over , r and omized trial , patients named pictures of common objects during functional magnetic resonance imaging ( fMRI ) . Concurrently , excitatory ( anodal‐ ) or sham‐tDCS ( 1 mA , 20 min , or 30 s , respectively ) was administered to the left primary motor cortex , a montage with demonstrated potential to improve aphasic language . By choosing stimuli that could reliable be named by the patients , the authors aim ed to derive a pure measure of stimulation effects that was independent of treatment or performance effects and to assess how tDCS interacts with the patients ' residual language network . Univariate fMRI data analysis revealed reduced activity in domain‐general regions mediating high‐level cognitive control  during anodal‐tDCS . Independent component functional network analysis demonstrated selectively increased language network activity and an inter‐correlated shift from higher to lower frequency b and s , indicative of increased within‐network communication . Compared with healthy controls , anodal‐tDCS result ed in overall “ normalization ” of brain function in the patients . These results demonstrate for the first time how tDCS modulates neural processing in stroke patients . Such information is crucial to assure that behavioral treatments targeting specific neural circuits overlap with regions that are modulated by tDCS , thereby maximizing stimulation effects during therapy . Hum Brain Mapp 38:1518–1531 , 2017 . © 2016 Wiley Periodicals , Knowledge of the frequency and remission of aphasia is essential for the rehabilitation of stroke patients and provides insight into the brain organization of language . We studied prospect ively and consecutively an unselected and community‐based sample of 881 patients with acute stroke .  Assessment of aphasia  was done at admission , weekly during the hospital stay , and at a 6‐months follow‐up using the aphasia score of the Sc and inavian Stroke Scale .  Thirty‐eight percent had aphasia at the time of admission ; at discharge 18 % had aphasia .  Sex was not a determinant of aphasia in stroke , and no sex difference in the anterior‐posterior distribution of lesions was found . The remission curve was steep : Stationary language function in 95 % was reached within 2 weeks in those with initial mild aphasia , within 6 weeks in those with moderate , and within 10 weeks in those with severe aphasia . A valid prognosis of aphasia could be made within 1 to 4 weeks after the stroke depending on the initial severity of aphasia . Initial severity of aphasia was the only clinical ly relevant predictor of aphasia outcome . Sex , h and edness , and side of stroke lesion were not independent outcome predictors , and the influence of age was minimal PURPOSE Recent research in patients with chronic aphasia shows an association between excitatory anodal transcranial direct current stimulation ( A-tDCS ) of the stroke-affected left hemisphere coupled with speech and language therapy ( SLT ) and better language performance . The present study aim ed to investigate this association during the early post-stroke rehabilitation period , when adaptive changes are most possible on neurophysiological and behavioral levels . METHODS We r and omized 24 patients with non-fluent aphasia to receive 15 consecutive sessions ( 5 days/week for 3 weeks ) of A-tDCS ( 1 mA , 10 min ; n = 14 ) or sham tDCS ( S-tDCS : 1 mA , 25 sec ; n = 10 ) over Broca 's area followed by 45-min SLT . Naming ability was assessed before the rehabilitation , after its completion , and three months later . RESULTS Both groups significantly improved after the therapy . There were no statistically significant between-group differences in the short-term or long-term tDCS effects on naming accuracy and naming time . The A-tDCS group obtained higher effect sizes in naming time , both post-treatment and at the 3-month follow-up , suggesting potential benefits of the stimulation . CONCLUSIONS The findings provide only weak evidence for A-tDCS-related language gains during early neurorehabilitation of post-stroke aphasia . Further research is needed to explore the effectiveness of this kind of neuromodulation Background and Purpose — Recent research suggests that increased left hemisphere cortical activity , primarily of the left frontal cortex , is associated with improved naming performance in stroke patients with aphasia . Our aim was to determine whether anodal transcranial direct-current stimulation ( tDCS ) , a method thought to increase cortical excitability , would improve naming accuracy in stroke patients with aphasia when applied to the scalp overlying the left frontal cortex . Methods — Ten patients with chronic stroke-induced aphasia received 5 days of anodal tDCS ( 1 mA for 20 minutes ) and 5 days of sham tDCS ( for 20 minutes , order r and omized ) while performing a computerized anomia treatment . tDCS positioning was guided by a priori functional magnetic resonance imaging results for each individual during an overt naming task to ensure that the active electrode was placed over structurally intact cortex . Results — Results revealed significantly improved naming accuracy of treated items ( F[1,9]=5.72 , P<0.040 ) after anodal tDCS compared with sham tDCS . Patients who demonstrated the most improvement were those with perilesional areas closest to the stimulation site . Crucially , this treatment effect persisted at least 1 week after treatment . Conclusions — Our findings suggest that anodal tDCS over the left frontal cortex can lead to enhanced naming accuracy in stroke patients with aphasia and , if proved to be effective in larger studies , may provide a supplementary treatment approach for anomia Background and Purpose — Previous evidence suggests that anodal transcranial direct current stimulation ( A-tDCS ) applied to the left hemisphere can improve aphasic participants ' ability to name common objects . The current study further examined this issue in a more tightly controlled experiment in participants with fluent aphasia . Methods — We examined the effect of A-tDCS on reaction time during overt picture naming in 8 chronic stroke participants . Anode electrode placement targeted perilesional brain regions that showed the greatest activation on a pretreatment functional MRI scan administered during overt picture naming with the reference cathode electrode placed on the contralateral forehead . A-tDCS ( 1 mA ; 20-minute ) was compared with sham tDCS ( S-tDCS ) in a crossover design . Participants received 10 sessions of computerized anomia treatment ; 5 sessions included A-tDCS and 5 included S-tDCS . Results — Coupling A-tDCS with behavioral language treatment reduced reaction time during naming of trained items immediately posttreatment ( Z=1.96 , P=0.025 ) and at subsequent testing 3 weeks later ( Z=2.52 , P=0.006 ) . Conclusions — A-tDCS administered during language treatment decreased processing time during picture naming by fluent aphasic participants . Additional studies combining A-tDCS , an inexpensive method with no reported serious side effects , with behavioral language therapy are recommended Several studies have already shown that transcranial direct current stimulation ( tDCS ) is a useful tool for enhancing recovery in aphasia . However , all tDCS studies have previously investigated the effects using unihemisperic stimulation . No reports to date have examined the role of bihemispheric tDCS on aphasia recovery . Here , eight aphasic persons with apraxia of speech underwent intensive language therapy  in two different conditions : real bihemispheric anodic ipsilesional stimulation over the left Broca 's area and cathodic contralesional stimulation over the right homologue of Broca 's area , and a sham condition . In both conditions , patients underwent concurrent language therapy for their apraxia of speech . The language treatment lasted 10 days ( Monday to Friday , then weekend off , then Monday to Friday ) . There was a 14-day intersession interval between the real and the sham conditions . In all patients , language measures were collected before ( T0 ) , at the end of ( T10 ) and 1 week after the end of ( F/U ) treatment . Results showed that after simultaneous excitatory stimulation to the left frontal hemisphere and inhibitory stimulation to the right frontal hemisphere regions , patients exhibited a significant recovery not only in terms of better accuracy and speed in articulating the treated stimuli but also in other language tasks ( picture description , noun and verb naming , word repetition , word reading ) which persisted in the follow-up session . T 
    Output:
    