the single participant of this study was a man with left severe hemiplegia resulting from a stroke six years ( 72 months ) earlier . his arm and hand were at stage 1 on chedoke - macmaster stages of movement recovery with no voluntary movement . he was 64 years old and every other rehabilitation intervention in which he participated , including fest ( without bci activation ) , had failed to produce any change in his ability to move his affected upper limb . we created a neuroprosthesis for reaching using a four - channel stimulator ( compex , switzerland ) , which was programmed to perform 
 forward reaching ( making it possible to reach to the right knee as well )  for which the anterior deltoid and triceps brachii were stimulated , with arm retreival produced by stimulating the posterior deltoid and biceps brachii.reaching to the mouth ( which also allowed reaching to the right shoulder )  achieved by aplying stimulation to the anterior deltoid and biceps brachii , while retrieval was produced by stimulation the posterior deltoid and triceps brachii.lateral reaching  produced by stimulating biceps brachii followed by anterior and posterior deltoid and finally by the triceps brachii , while retrieving was achieved by stimulating the biceps brachii muscle , discontinuing deltoid stimulation , and stimulating the triceps brachii to produce arm extension while lowering the arm . forward reaching ( making it possible to reach to the right knee as well )  for which the anterior deltoid and triceps brachii were stimulated , with arm retreival produced by stimulating the posterior deltoid and biceps brachii . reaching to the mouth ( which also allowed reaching to the right shoulder )  achieved by aplying stimulation to the anterior deltoid and biceps brachii , while retrieval was produced by stimulation the posterior deltoid and triceps brachii . lateral reaching  produced by stimulating biceps brachii followed by anterior and posterior deltoid and finally by the triceps brachii , while retrieving was achieved by stimulating the biceps brachii muscle , discontinuing deltoid stimulation , and stimulating the triceps brachii to produce arm extension while lowering the arm . transitioning between movement phases ( i.e. , reach and retrieve ) could be triggered using a ttl - level signal provided by an external switch or a bci . the bci was implemented as a simple  brain - switch  , which was activated whenever the power within the beta range ( 13 hz- 30 hz ) of the participant s eeg decreased below a threshold , indicating the participant s intention to move his arm . this frequency range was selected by identifying spectral components displaying erd using data collected when the participant attempted repeatedly to perform hand ( palmar and lateral grasps , precision pinch , and hand opening ) movements following a ready - go - stop experimental cue . the analysis was performed using a total of 104 attempted movement repetitions and applied to six eeg electrode positions ( f3 , fz , f4 , c3 , cz , c4 of the 10 - 20 electrode placement system ) . the frequency band between 18 hz and 28 hz at the fz location were found to be the most suitable for implementing the bci . eeg recordings for this process were performed using a synamprt eeg amplifier ( compumedics , u.s.a . ) at a sampling rate of 1 khz and filtered between 0.05 hz and 40 hz . erd estimation was performed with custom - made software ( matlab , mathworks , u.s.a . ) . to create the bci , acquisition of eeg activity was performed using a desktop biopotential amplifier ( qp511 , grass telefunken , germany ) and a data acquisition system ( usb-6363 , national instruments , u.s.a . ) using a sampling frequency of 300 hz . the eeg signal from electrode fz was band - pass filtered ( 10-hz - 100 hz ) and amplified ( 20,000x ) prior to its digital acquisition . all processing was implemented using custom - made software ( labview , national instruments , u.s.a . ) . the bci estimated a moving average ( over a 500 ms period ) of the eeg rms value measured every 125 ms . for an activation to take place , the moving average had to decrease below a threshold for a pre - specified duration ( 500 ms to 1,200 ms ) . the experimenters could adjust both parameters at any moment during the operation of the system . this pulse was delivered to the neuroprosthesis for reaching where it triggered a transition in the state of the electrical stimulation ( e.g. , from active reaching to retrieving the arm ) . in addition , an external manual switch could also be used by the experimenters bypassing the bci altogether in cases in which the brain interface failed to identify the intention to move . one of them guided the arm in motion ( assisted by the electrical stimulation ) and could trigger the stimulation manually bypassing the bci completely . the second experimenter demonstrated the movement to perform at every repetition and could also adjust the bci activation parameters ( i.e. , activation threshold and latency ) . the intervention consisted of 40 90-minute sessions ( 30-minute setup and 60-minute active therapy ) delivered three times a week . during each session the participant attempted to reach to different targets ( listed above in the neuroprosthesis implementation ) repeatedly following the experimenters instructions . each movement was performed with a brief pause between phases ( i.e. , the participant would reach , hold the reaching position for a few seconds , and then return his arm to a starting position followed by a few moments of relaxation with no stimulation ) . we measured the effects of the intervention using five assessments , measured at beginning , midpoint and end of the study . the assessments were the toronto rehabilitation institute - hand function test ( trihft ) , the action research arm test ( arat ) , functional independence measure ( fim ) , self - care component of the functional independence measure , and fugl - meyer assessment upper extremity sub - score . the single participant of this study was a man with left severe hemiplegia resulting from a stroke six years ( 72 months ) earlier . his arm and hand were at stage 1 on chedoke - macmaster stages of movement recovery with no voluntary movement . he was 64 years old and every other rehabilitation intervention in which he participated , including fest ( without bci activation ) , had failed to produce any change in his ability to move his affected upper limb . we created a neuroprosthesis for reaching using a four - channel stimulator ( compex , switzerland ) , which was programmed to perform 
 forward reaching ( making it possible to reach to the right knee as well )  for which the anterior deltoid and triceps brachii were stimulated , with arm retreival produced by stimulating the posterior deltoid and biceps brachii.reaching to the mouth ( which also allowed reaching to the right shoulder )  achieved by aplying stimulation to the anterior deltoid and biceps brachii , while retrieval was produced by stimulation the posterior deltoid and triceps brachii.lateral reaching  produced by stimulating biceps brachii followed by anterior and posterior deltoid and finally by the triceps brachii , while retrieving was achieved by stimulating the biceps brachii muscle , discontinuing deltoid stimulation , and stimulating the triceps brachii to produce arm extension while lowering the arm . forward reaching ( making it possible to reach to the right knee as well )  for which the anterior deltoid and triceps brachii were stimulated , with arm retreival produced by stimulating the posterior deltoid and biceps brachii . achieved by aplying stimulation to the anterior deltoid and biceps brachii , while retrieval was produced by stimulation the posterior deltoid and triceps brachii . lateral reaching  produced by stimulating biceps brachii followed by anterior and posterior deltoid and finally by the triceps brachii , while retrieving was achieved by stimulating the biceps brachii muscle , discontinuing deltoid stimulation , and stimulating the triceps brachii to produce arm extension while lowering the arm . transitioning between movement phases ( i.e. , reach and retrieve ) could be triggered using a ttl - level signal provided by an external switch or a bci . the bci was implemented as a simple  brain - switch  , which was activated whenever the power within the beta range ( 13 hz- 30 hz ) of the participant s eeg decreased below a threshold , indicating the participant s intention to move his arm . this frequency range was selected by identifying spectral components displaying erd using data collected when the participant attempted repeatedly to perform hand ( palmar and lateral grasps , precision pinch , and hand opening ) movements following a ready - go - stop experimental cue . the analysis was performed using a total of 104 attempted movement repetitions and applied to six eeg electrode positions ( f3 , fz , f4 , c3 , cz , c4 of the 10 - 20 electrode placement system ) . the frequency band between 18 hz and 28 hz at the fz location were found to be the most suitable for implementing the bci . eeg recordings for this process were performed using a synamprt eeg amplifier ( compumedics , u.s.a . ) at a sampling rate of 1 khz and filtered between 0.05 hz and 40 hz . erd estimation was performed with custom - made software ( matlab , mathworks , u.s.a . ) . to create the bci , acquisition of eeg activity was performed using a desktop biopotential amplifier ( qp511 , grass telefunken , germany ) and a data acquisition system ( usb-6363 , national instruments , u.s.a . ) using a sampling frequency of 300 hz . the eeg signal from electrode fz was band - pass filtered ( 10-hz - 100 hz ) and amplified ( 20,000x ) prior to its digital acquisition . all processing was implemented using custom - made software ( labview , national instruments , u.s.a . ) . the bci estimated a moving average ( over a 500 ms period ) of the eeg rms value measured every 125 ms . for an activation to take place , the moving average had to decrease below a threshold for a pre - specified duration ( 500 ms to 1,200 ms ) . the experimenters could adjust both parameters at any moment during the operation of the system . this pulse was delivered to the neuroprosthesis for reaching where it triggered a transition in the state of the electrical stimulation ( e.g. , from active reaching to retrieving the arm ) . in addition , an external manual switch could also be used by the experimenters bypassing the bci altogether in cases in which the brain interface failed to identify the intention to move . one of them guided the arm in motion ( assisted by the electrical stimulation ) and could trigger the stimulation manually bypassing the bci completely . the second experimenter demonstrated the movement to perform at every repetition and could also adjust the bci activation parameters ( i.e. , activation threshold and latency ) . the intervention consisted of 40 90-minute sessions ( 30-minute setup and 60-minute active therapy ) delivered three times a week . during each session the participant attempted to reach to different targets ( listed above in the neuroprosthesis implementation ) repeatedly following the experimenters instructions . each movement was performed with a brief pause between phases ( i.e. , the participant would reach , hold the reaching position for a few seconds , and then return his arm to a starting position followed by a few moments of relaxation with no stimulation ) . we measured the effects of the intervention using five assessments , measured at beginning , midpoint and end of the study . the assessments were the toronto rehabilitation institute - hand function test ( trihft ) , the action research arm test ( arat ) , functional independence measure ( fim ) , self - care component of the functional independence measure , and fugl - meyer assessment upper extremity sub - score . the recorded values are displayed in table 1 . the fugl - meyer assessment upper extremity sub - score had a clinically significant change ( 6 points ; 13 points at baseline and 19 points at the end of the intervention ) . the fim self - care subscores registered non - significant improvements ( 28 and 35 at baseline and end , respectively ) . all the other assessments remained unchanged ( table 1 ) , likely due to the fact that the trihft and arat require hand function beyond the functional gains observed . in addition , although the fma - ue sub - score and fim self - care subscores were very similar ( or the same ) between the midpoint and discharges assessments , it was evident that the quality of the movement ( e.g. , speed and smootheness ) improved between these two measurements qualitatively , the bci was able to detect the participant s intention to move and consequently trigger the neuroprosthesis when required . our preliminary results suggests that the bci was able to trigger the neuroprosthesis for the majority of reaching movement repetitions ( sometimes with accuracies as high as 90% ) , although a full data analysis is yet to be completed . the most common source of interference that affected the bci was electrical interference originating from activation of facial muscles ( i.e. , reflective of the participants physical effort ) . in conclusion , the results of this study suggest that integration of a simple single - channel bci with fest may help individuals with severe hemiplegia resulting from stroke regain voluntary arm reaching function , even 6 years ( 72 months ) after having a stroke . further testing is required to verify the findings presented here including a large number of participants .
we present here the integration of brain - computer interfacing ( bci ) technology with functional electrical stimulation therapy to restore voluntary function . 
 the system was tested with a single man with chronic ( 6 years ) severe left hemiplegia resulting from a stroke . 
 the bci , implemented as a simple  brain - switch  activated by power decreases in the 18 hz 
 28 hz frequency range of the participant s electroencephalograpic signals , triggered a neuroprosthesis designed to facilitate forward reaching , reaching to the mouth , and lateral reaching movements . 
 after 40 90-minute sessions in which the participant attempted the reaching tasks repeatedly , with the movements assisted by the bci - triggered neuroprosthesis , the participant s arm function showed a clinically significant six point increase in the fugl - meyer asessment upper extermity sub - score . 
 these initial results suggest that the combined use of bci and functional electrical stimulation therapy may restore voluntary reaching function in individuals with chronic severe hemiplegia for whom the rehabilitation alternatives are very limited .