tailieunhanh - Báo cáo hóa học: " Single-trial classification of motor imagery differing in task complexity: a functional near-infrared spectroscopy study"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Single-trial classification of motor imagery differing in task complexity: a functional near-infrared spectroscopy study | Holper and Wolf Journal of NeuroEngineering and Rehabilitation 2011 8 34 http content 8 1 34 Iril JOURNAL OF NEUROENGINEERING NCR AND REHABILITATION RESEARCH Open Access Single-trial classification of motor imagery differing in task complexity a functional near-infrared spectroscopy study Lisa Holper1 2 and Martin Wolf1 Abstract Background For brain computer interfaces BCIs which may be valuable in neurorehabilitation brain signals derived from mental activation can be monitored by non-invasive methods such as functional near-infrared spectroscopy fNIRS . Single-trial classification is important for this purpose and this was the aim of the presented study. In particular we aimed to investigate a combined approach 1 offline single-trial classification of brain signals derived from a novel wireless fNIRS instrument 2 to use motor imagery MI as mental task thereby discriminating between MI signals in response to different tasks complexities . simple and complex MI tasks. Methods 12 subjects were asked to imagine either a simple finger-tapping task using their right thumb or a complex sequential finger-tapping task using all fingers of their right hand. fNIRS was recorded over secondary motor areas of the contralateral hemisphere. Using Fisher s linear discriminant analysis FLDA and cross validation we selected for each subject a best-performing feature combination consisting of 1 one out of three channel 2 an analysis time interval ranging from 5-15 s after stimulation onset and 3 up to four A O2Hb signal features A O2Hb mean signal amplitudes variance skewness and kurtosis . Results The results of our single-trial classification showed that using the simple combination set of channels time intervals and up to four A O2Hb signal features comprising A O2Hb mean signal amplitudes variance skewness and kurtosis it was possible to discriminate single-trials of MI tasks differing in complexity . simple versus complex tasks inter-task paired .