| Disturbance of consciousness refers to a state of people’s disorder in themselves andenvironment’s perception, or mental activities that people perceive environment occurringdisorders. Disturbance of consciousness is mainly for the sense of content and (or) arousaldisorder, and it is a common clinical disease. At present, domestic and overseas determineunconsciousness patients’unconsciousness degree depends on some scales made by expertsand the experience of clinicians, with a certain degree of subjectivity and can not be veryaccurately assessment the patient’s consciousness level.Serious disturbance of consciousness including vegetative state (VS) and minimallyconscious state (MCS), VS is more serious than MCS. VS patients have sleep—wake cycle,but complete loss of the awareness capabilities of themselves and the surroundingenvironment, that the separation occurred awakening and awareness. MCS patients have weakawareness capability. The distinction between VS and MCS depends on whether there isevidence that can prove patients have awareness skills, which is one of the challenges inclinical to distinguish VS and MCS.EEG was recorded the brain cells spontaneous, rhythmic electrical activity by electrodes,which can reflect the status of patients’brain activity and its level of consciousness.We collected eight cases original EEG of disturbance of consciousness patients,including four cases of MCS patients and four cases of VS patients. Each patient collectedthree states of EEG. They were quiet state, call-name state and the state of using voice to tipraising hand. Finish the work of collecting patients’clinical information and scoring patientswith coma recovery scale-revised.The main work done by this article is the first of using the method to de-noising whichcombines neighborhood comparison and wavelet transform, and then analysis the de-noisedEEG with linear and nonlinear methods. First, analysis the EEG changes in different states ofthe same patient and compared the EEG amplitude changes between MCS and VS at the samestate. Second, MCS and VS patients’EEG rhythm wave were extracted respectively andcompared the difference between the two. Third, the same patient’s sample entropy changewas compared under different conditions, and compared the sample entropy changes betweenMCS group and VS group under the same state. Fourth, compared the approximate entropychanges at the same patients in different status, and the approximate entropy changes betweenMCS group and VS group at the same status were compared.Experiment results show that MCS patients’EEG amplitude greater than VS patients’, and the EEG signal’s amplitude changed little about the same patient in different states. Thealpha rhythm wave and beta rhythm wave in MCS group are significantly stronger than theVS group’s. At the stimulate states patient’s sample entropy and approximate entropy arehigher than the state when patient quiet, but the changes are not obviously. Whether it is aquiet state, or call-name stimulate state, or the state of using voice to tip raising hand, MCSgroup’s sample entropy and approximate entropy are significantly higher than the VS group’s.Study concluded that EEG and its rhythm wave can intuitively reflect the patient’sconsciousness level. The patient’s EEG activity by external stimulus state was stronger thanits quiet state, which can explain external stimulus maybe have some impacts on the recoveryof unconscious patients. The deeper level of consciousness, the lower value of two nonlinearparameters sample entropy and approximate entropy, indicating that these two parameters candistinguish different levels of consciousness and also can response the consciousness scale ofpatients more objective and quantitative. Nonlinear parameters can provide a strong basis forthe clinician to judge the patient’s consciousness level. |
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