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Selective sensation based brain-computer interface via mechanical vibrotactile stimulation.

Yao L, Meng J, Zhang D, Sheng X, Zhu X - PLoS ONE (2013)

Bottom Line: The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS.The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%.The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, China.

ABSTRACT
In this work, mechanical vibrotactile stimulation was applied to subjects' left and right wrist skins with equal intensity, and a selective sensation perception task was performed to achieve two types of selections similar to motor imagery Brain-Computer Interface. The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS. The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%. Comparative experiments with motor imagery (with and without presence of stimulation) were also carried out, which further showed the feasibility of selective sensation as an alternative BCI task complementary to motor imagery. Specifically there was significant improvement ([Formula: see text]) from near 65% in motor imagery (with and without presence of stimulation) to above 80% in selective sensation on some subjects. The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system.

Show MeSH
Trial structure of session 1 and session 2.The only difference between the two session was the subject’s task. One was motor imagery, the other was selective sensation.
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pone-0064784-g002: Trial structure of session 1 and session 2.The only difference between the two session was the subject’s task. One was motor imagery, the other was selective sensation.

Mentions: During the EEG recording, the subjects sat in a comfortable armchair in the electrical shielded room. With both forearms and hands resting in the armrest, and the subjects should limit the eye blinks and stay still to avoid any facial or arm muscular movements. The subjects’ task was to perform motor imagery or selective sensation. In the first two sessions, the stimulation was applied to subjects’ wrist skin of both sides during the mental task. Every session contained four runs of 40 trials each, resulting 80 trials for each mental task. A total of 320 trials were performed by the subjects in the first two sessions, lasting for about an hour, and the subject got rested after each run. In the first session, the subject was required to perform motor imagery task of left and right hand, and during that time the vibrations were stimulated at the wrist skins. The procedure of single trial structure was given as follows. At the beginning of each trial, a fixation cross appeared in center of the screen. At the 1st second, a vibration burst with the same intensity stimulated both hands to attract the subject’s attention and be mentally ready for the subsequent task, with vibration time lasted for 200 ms. Then at the 3rd second, a red cue bar pointing either left or right was presented, which superimposed on the fixation cross and lasted for 1.5s. The subjects should perform the mental task after appearance of the cue bar. The mental task continued until to the 8th second, when the fixation cross disappeared. At the 4.5th second, the vibration applied to both hands with the same intensity, till to the end of the motor imagery. In the second session, the trial structure was the same, but the subjects’ task changed. At this session the subject performed selective sensation of left and right vibration afferent inflow according to the cue indication. During the first run of all the two sessions, there was no feedback. During all the subsequent three runs of each session, there would be vibration feedback, according to the on-line classification algorithm implemented within the experiment system. The feedback stimulus was applied according to the decoded task type either left or right, lasting for about 500 ms. After the feedback, there was a relaxation time period lasting for about 1s, during which the subjects should get relaxed and could blink his or her eyes. Then a random time period of about 0 to 2s was inserted after the relaxation period to further avoid subject’s adaptation, after that the next trial began. The whole trial structures were shown in Fig. 2.


Selective sensation based brain-computer interface via mechanical vibrotactile stimulation.

Yao L, Meng J, Zhang D, Sheng X, Zhu X - PLoS ONE (2013)

Trial structure of session 1 and session 2.The only difference between the two session was the subject’s task. One was motor imagery, the other was selective sensation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675213&req=5

pone-0064784-g002: Trial structure of session 1 and session 2.The only difference between the two session was the subject’s task. One was motor imagery, the other was selective sensation.
Mentions: During the EEG recording, the subjects sat in a comfortable armchair in the electrical shielded room. With both forearms and hands resting in the armrest, and the subjects should limit the eye blinks and stay still to avoid any facial or arm muscular movements. The subjects’ task was to perform motor imagery or selective sensation. In the first two sessions, the stimulation was applied to subjects’ wrist skin of both sides during the mental task. Every session contained four runs of 40 trials each, resulting 80 trials for each mental task. A total of 320 trials were performed by the subjects in the first two sessions, lasting for about an hour, and the subject got rested after each run. In the first session, the subject was required to perform motor imagery task of left and right hand, and during that time the vibrations were stimulated at the wrist skins. The procedure of single trial structure was given as follows. At the beginning of each trial, a fixation cross appeared in center of the screen. At the 1st second, a vibration burst with the same intensity stimulated both hands to attract the subject’s attention and be mentally ready for the subsequent task, with vibration time lasted for 200 ms. Then at the 3rd second, a red cue bar pointing either left or right was presented, which superimposed on the fixation cross and lasted for 1.5s. The subjects should perform the mental task after appearance of the cue bar. The mental task continued until to the 8th second, when the fixation cross disappeared. At the 4.5th second, the vibration applied to both hands with the same intensity, till to the end of the motor imagery. In the second session, the trial structure was the same, but the subjects’ task changed. At this session the subject performed selective sensation of left and right vibration afferent inflow according to the cue indication. During the first run of all the two sessions, there was no feedback. During all the subsequent three runs of each session, there would be vibration feedback, according to the on-line classification algorithm implemented within the experiment system. The feedback stimulus was applied according to the decoded task type either left or right, lasting for about 500 ms. After the feedback, there was a relaxation time period lasting for about 1s, during which the subjects should get relaxed and could blink his or her eyes. Then a random time period of about 0 to 2s was inserted after the relaxation period to further avoid subject’s adaptation, after that the next trial began. The whole trial structures were shown in Fig. 2.

Bottom Line: The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS.The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%.The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, China.

ABSTRACT
In this work, mechanical vibrotactile stimulation was applied to subjects' left and right wrist skins with equal intensity, and a selective sensation perception task was performed to achieve two types of selections similar to motor imagery Brain-Computer Interface. The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS. The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%. Comparative experiments with motor imagery (with and without presence of stimulation) were also carried out, which further showed the feasibility of selective sensation as an alternative BCI task complementary to motor imagery. Specifically there was significant improvement ([Formula: see text]) from near 65% in motor imagery (with and without presence of stimulation) to above 80% in selective sensation on some subjects. The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system.

Show MeSH