Functional Connectivity and Classification of Actual and Imaginary Motor Movement
Total Page:16
File Type:pdf, Size:1020Kb
International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-9 Issue-2, December, 2019 Functional Connectivity and Classification of Actual and Imaginary Motor Movement Nilima Salankar, Anjali Mishra, Pratikshya Mishra Abstract— Imaginary Motor movement is an utmost In this study author have studied the different patterns of important for the designing of brain computer interface to assist connectivity between the actual ,imaginary motor movement the individual with physically disability. Brain signals associated and no motor movement with eyes open and eyes closed, it with actual motor movement include the signal for muscle would help to design brain computer interface to help to activity whereas in case of imaginary motor movement actual survive the physically challenged people. In this study muscle movement is not present .Authors have investigated the similarity/dissimilarity between the eeg signals generated in both authors has identified the most activated portion of the brain the cases along with the baseline activity. To instruct the brain in the form of lobes frontal, temporal, parietal and occipital. computer interface signals generated by electrodes of EEG must Electroencephalography is a non-invasive technique to resemble with actual motor movement. Selection of electrodes record brain signals; various signal processing techniques placement plays an important role for this purpose. In this study can give insight into the mental state, emotional condition of major four regions of the brain has been covered frontal, the person and motion intents. In literature, experiments for temporal, parietal and occipital region of the scalp and features recognition or detection of imaginary motion are available are extracted from the signals are standard deviations, kurtosis, with different accuracy and relevance. This approach is skew and mean. Support Vector Machine is used for the beneficial to help the paralysed patients to use the computer classification between actual and imaginary motor movement along with differentiation between baseline and imaginary motor application efficiently. EEG Motor Movement/Imagery movement and actual motor movement at 14 different electrodes Dataset was used in [1] available on PhysioNet [2]. 106 positions. Statistical performances of the classifier have been volunteers were instructed to perform several real or evaluated by computing sensitivity, specificity and accuracy. The imaginary movement tasks likes’ fists open and close, feet location involved to achieve maximum accuracy for the movement, etc. while EEG signals were recorded in 64 classification of motor movements (actual and imaginary) and no channel BCI2000 systems. [1] Eighteen intact and four motor movement is at frontal, temporal and parietal region amputated participants volunteered to perform and/or whereas very less involvement has been seen of occipital region. imagine to perform eleven motor imagery tasks with a single INDEX TERMS—EEG, ACTUAL, IMAGINARY hand in [3] like finger and wrist movements, grasping tasks, etc. Eleven subjects participated for three hand and wrist I. INTRODUCTION movements MI experiment – hand opening/ closing, wrist Major difference in case of actual and imaginary motor flexion/ extension and forearm pronation/ supination in [4] movement is activation/no activation of muscular signals while EEG data was acquired using G.Nautilus headset with inside the brain. Actual motor movement comes along with 16 electrodes positioned as per 10/20 system [5]. A dataset the muscular trigger whereas it is completely missing in case of 64 EEG recordings taken in [7] from 25 healthy subjects of imaginary motor movement. For the individual with while performing real and imaginary motor movements of physical disability of hands can’t make actual movement but hands and feet. A study comparing Brain computer interface can be operated by giving the signals through the brain. And approaches, P300 and Motor Imagery, was done to identify for the design of brain computer interface(BCI) application the most efficient BCI based typing application. [9] The for the physically disable individual the correlation between EEG signals were recorded using 14 channels Emotiv EEG actual and imaginary motor movement should be clearly headset. Three actions were considered for navigating studied. So definitely network generated among the brain through the virtual keyboard- moving across horizontal axis, region should be apparently different in case of actual and vertical axis and selecting the button. The dataset IV a and imaginary motor movement. On the basis of network IV b of BCI competition III was used for Motor Imagery generated and supporting relevant features movement and classification in [13] and the results of the algorithms were no movement can be easily understood by the application compared for high dimensional all channel data and just 18 through the brain signals which captured by placing electrode channels in sensory motor cortex area data. electrode position on the scalp. This is useful to operate the Efficient channel selections algorithms help decide which gadgets with brain signals rather than performing actual channels to consider for a particular EEG application, since activity so imagine about moving hand is actually equivalent EEG data is recorded from several locations across the to moving hand for an BCI application. In literature as per brain. [10] Advantage of channel selection is that it reduces broadmann atlas brain has various segments responsible for computational complexity and over fitting, removes noise specified task. In case of physically challenged case, person while improving the classification accuracy. Filter, wrapper can’t operate their hands but still can think about movement. and hybrid methods for channel selection are discussed in [10]. In filter method channels are ranked with information- Revised Manuscript Received on December 15, 2019. based measures like correlation coefficient, mutual Dr. Nilima Salankar, Assistant Professor, Department of School of information, etc. In wrapper method, a classifier is used to Computer Science, University of Petroleum and Energy Studies Dehradun, evaluate the channel subsets. India. (E-mail: [email protected]) Anjali Mishra, Mtech Student in Computer Science, University of Petroleum and Energy Studies Dehradun, India. Pratikshya Mishra, Mtech student in Computer Science, University of Petroleum and Energy Studies Dehradun, India. Retrieval Number: B3257129219/2019©BEIESP Published By: DOI: 10.35940/ijeat.B3257.129219 Blue Eyes Intelligence Engineering 529 & Sciences Publication Functional Connectivity and Classification of Actual and Imaginary Motor Movement Hybrid method is a combination of the two, a rather Multilayer back propagation neural networks is used in [12] ensemble approach. For processing the signals are for classification. After cross correlation in [13] LS-SVM transformed into time-frequency domain, split into the classifier with RBF kernel, Logistic Regression and kernel standard frequency bands of 2-4 Hz (delta), 4-7 Hz (theta), Logistic regression were used for MI classification. 8-15 Hz (alpha), 15-29 Hz (beta) and 30-59 Hz (gamma). Classification results of rough sets method indicated that Then Hilbert transform is used on the resulting bands to find universal parameters couldn’t be decided upon, and each the overall activity in a band. [1]. Features like mean, subject had to be considered differently for parameter variance, min, max and sum of squared samples of signal selection and classification. [1] For subject dependent envelope were extracted for [1] for each sub band in each of training procedures, accuracy obtained in [3] is 88.8% for the sensor or electrode position. Signal envelope differences intact participants and 90.2% for amputated participants, and were calculated and summed up for all the samples, to be for subject independent training the accuracy was 80.8% and considered as another feature. [1]. A sliding window 87.8% respectively. Detecting actual motor activity of both approach is used in [3] to decompose each EEG signal into hands with 80% accuracy and imaginary motor activity with overlapping segments, convert to time-frequency domain just 34% accuracy in [7]. iQSA technique in [8] gives a and extract five categories of time frequency features- log- 82.3% accuracy for 0.5 seconds samples of EEG signal amplitude, amplitude, statistical, spectral, and spectral- recordings, and 73.16% for 3 seconds samples. The entropy based category. Common spatial pattern algorithm proposed model in [11] gives an accuracy of 60.61% for was used for feature extraction in [4] from the whole band Emotiv Epoc headset dataset and 86.50% for wet gel and then from the five filtered bands. Discrete Wavelet electrodes. The average classification accuracy of sensor Transform (DWT) is used for features extraction from EEG signals in [12] is 72.6%, that of SOBI is 90.6%, energy signals in [6] and input feature vectors like mean, standard entropy is 84.4%, and phase synchronization measure is deviation, and peak power gave better classification results. 86.2%. The average accuracy rate for motor area channels in Features extraction based on spectral density was explored [13] for CC-LS-SVM is 97.12%, CC-LR is 88.18%, CC- in [7], after converting the signals into frequency domain KLR is 95.35%. For all channels, CC-LS-SVM gives and applying Fast Fourier Transform. A quaternion-based 97.96% accuracy,