Two-channel electrotactile stimulation for sensory feedback of fingers of prosthesis

Effective Evaluation of Finger Sensation Evoking by Non-Invasive Stimulation for Sensory Function Recovery in Transradial Amputees

“…Electrical stimulation on PHM areas, also known as Transcutaneous Electrical Nerve Stimulation (TENS) [2], is conducted on the skin surface of residual limbs to induce phantom finger sensations for amputees [25], [26]. Feelings of different types and intensities can be evoked by adjusting TENS configurations including stimulus current frequency, amplitude, and pulse width, as well as stimulation position [4], [27], [28]. In another aspect, the selection of optimal stimulation positions remains a major challenge due to individual differences in amputation conditions among amputees [4], [29].…”

“…It has been established that there are responses in amputees' encephalic regions, i.e., motor-sensory cortex, when phantom finger sensations are induced by stimulating the PHM area [22], [23], indicating a mapping relationship between brain and PHM. Recent studies showed that cortical topographic maps based on magnetoencephalography (MEG) or electroencephalography (EEG) are useful in analyzing cortex activities corresponding to evoked sensations, where connections between stimulation, sensation, and cerebral cortex activities for limb amputees might be revealed [28], [32]- [34]. However, investigation of the relationships among stimulation configurations, evoked sensations, and cerebral cortex activities for limb amputees has rarely been conducted to the best of our knowledge.…”

“…2(b), to verify the PHM distribution. A series of bipolar square-wave pulses [25], [26], [28], [35] with a frequency of 50 Hz, a wave width of 200 μs, an interval time of 200 μs, and adjustable amplitude ranging from 1 to 5 mA, as shown in Fig. 3, were applied on the preliminarily selected stimulation positions at the amputee's stump to evoke phantom finger sensations.…”

Electrotactile feedback applications for hand and arm interactions: A systematic review, meta-analysis, and future directions

“…The rationale is that the electrical stimulation is provided to the forearm or the upper arm, by electrodes placed in the circumference of the limb (aka non-somatotopic feedback), where the stimulation of each electrode attempts to represent the tactile sensation of a hand's part (e.g, a finger and/or the palm.). Indeed, the users can differentiate each stimulation and associate it correctly with the corresponding finger [68], without requiring a somatotopic feedback (i.e., the electrodes to be placed near or at the amputation area) [70]. Also, in the hybrid systems (i.e., vibrotactile and electrotactile), the electrotactile feedback can be easily differentiated from the vibrotactile feedback [17].…”

Tactile Feedback in Closed-Loop Control of Myoelectric Hand Grasping: Conveying Information of Multiple Sensors Simultaneously via a Single Feedback Channel

“…A few studies have recognized the need for the more efficient use of the feedback channels and proposed the use of multiple sensor information via a single feedback channel. Multiple sets of information have been transmitted in a sequential manner (Ninu et al, 2014), event triggered (Clemente et al, 2016), or representing only a discrete combination of the information from two sensors (Choi et al, 2016(Choi et al, , 2017. Time sequential (Ninu et al, 2014) or event triggered feedback (Clemente et al, 2016) can be used for tasks or events where the need for each sensing information can be decoupled over the subsequent events, therefore do not address the need described above for simultaneous feedback information.…”