Table 1 Summary of non-invasive BCI-controlled FES studies used for rehabilitation of upper-limb motor function

Daly et al. [34]

1 stroke patient (F, 43 y)

1-channel EEG trigger detected by signal power change using a threshold method to classify rest vs. active states

1-channel FES applied to facilitate finger extension movements

Case study intervention: 9 session of 45 min delivered 3 times per week for 3 weeks

Participant’s ability to produce voluntary finger movements was improved after 9 sessions

Mukaino et al. [93]

1 stroke patient (M, 38 y)

Multi-channel EEG trigger using an LDA classifier detected signal power change of a multi-feature space to classify rest vs. active states

1-channel FES applied to facilitate finger extension movements

Case study crossover control design: (i) BCI-FES or (ii) FES was delivered for 60 min over the course of 2 weeks (10 days in total)

Clinical improvements and muscle tone changes were seen after BCI-FES as well as lateralization of cortical activations and affected corticomuscular coherence

Li et al. [74]

Multi-channel EEG trigger using an SVM classifier was used to detect rest vs. active states

1-channel FES applied to facilitate wrist extension movements

Randomized controlled intervention: (i) BCI-FES or (ii) FES training was delivered three times per week for 8 weeks

Improvements in motor function, activation of bilateral hemispheres, and altered activation of the sensorimotor cortexes was shown after BCI-FES intervention.

Kim et al. [66]

2-channel EEG trigger detected attention-related sensory motor rhythm using a threshold to classify rest vs. active states

1-channel FES was applied to stimulate wrist extensor muscles of the affected upper-limb

Randomized controlled intervention: (i) BCI-FES or (ii) conventional therapy (control) was delivered for 30 min per session over 4 weeks

Improvements in functional mobility and range of motion, suggesting improved motor function, was shown after BCI-FES intervention.

Marquez-Chin et al. [80]

1 stroke patient (M, 64 y)

1-channel EEG trigger detected by signal power change using a threshold to classify rest vs. active states

Multi-channel FES facilitated reaching movements: (i) forward reaching/retrieving (ii) reaching to the mouth, and (iii) lateral reaching

Case study intervention: 40 sessions of 90 min of BCI-FES were delivered 3 times per week

Improvements in clinical scores as well as the changes in arm function were shown after 40 sessions.

Osuagwu et al. [107]

Multi-channel EEG trigger using an LDA classifier detected signal power changes of a feature space to classify rest vs. active states

Multi-channel FES was applied to facilitate hand extension or flexion of both hands during active states

Randomized controlled intervention: (i) BCI-FES or (ii) FES were delivered 3–5 times weekly for 1 h (20 sessions in total)

BCI-FES therapy results in better neurological recovery and improvements in muscle strength compared to FES

Biasiucci et al. [17]

Multi-channel EEG trigger using a Gaussian classifier was used to discriminate rest vs. hand extension states

1-channel FES was applied to facilitate hand extension movements

Randomized controlled intervention: (i) BCI-FES or (ii) FES were delivered two times per week for a period of 5 weeks (10 sessions in total)

Improvements in motor function were accompanied by increase in functional connectivity between motor areas in the affected hemisphere after BCI-FES

Jovanovic et al. [58]

1 stroke patient (M, 57 y)

1-channel EEG trigger detected by signal power change using a threshold to classify rest vs. active states

Multi-channel FES facilitated functional movements: (i) hand opening/closing, and (ii) arm reaching/retrieving (varied between sessions)

Case study intervention: Two 40 one-hour BCI-FES sessions (80 sessions in total) were delivered with 3 sessions per week

Improvements in clinical scores and functional capacity were shown after completion of 80 therapy sessions