Feasibility of a Hybrid Brain-Computer Interface for Advanced Functional Electrical Therapy

Figure 3

The workflow of the two-stage hybrid BCI operation. LED_n (𝑛=1–3) stands for LED beside the cup, CD case, and playing cube, respectively. LED_𝑛=𝑦 is chosen by the subject for visual focusing. If 𝑥=𝑦 at the beginning of stage II (all LEDs off), then the correct SSVEP was detected. FES_𝑛 are the FES patterns for induction of palmar, lateral, and precision grasp, respectively. FES_𝑛=𝑥 is the stimulation pattern adequate for grasping of the object beside LED_𝑛=𝑥. The counters 𝑐₁, 𝑐₂, 𝑐₃, 𝑐₄, 𝑐_𝑒, and 𝑐_𝑟 compute the number of consecutive windows (iterations). The 𝑐₁, 𝑐₂, and 𝑐₃ measure the DT_𝑠 for BP₁, BP₂, and BP₃, respectively. The 𝑐₄ measures the DT_erd. The 𝑐_𝑒 counts the duration of 5-second interval after the LEDs are off when the subject can activate FES. The 𝑐_𝑟 measures the 3-second refractory period after FES_𝑛=𝑥 trigger.