Study On Clustering Analysis Of Electroencephalogram Data

EEG data is recorded cerebral electrical activity data that has been acquired through objective experiments.It reflects the cerebral change of electrical activity at different state. Clusteirng analysis used for EEG study is an effective method and as a result it provides useful and valuable results in EEG study.Objective: In this thesis, clustering analysis to EEG data of subjects who have taken in certain alcohol in different period has been performed according to EEG power and relative power.According to the clusters here have got, the differences of clusters when alcohol volume changes have been found.Thereby we can infer the relationship between clusters of 21 derivation electrodes and alcohol volume.Methods: We have performed clustering analysis for 21 derivation electrodes'EEG data collected from six healthy subjects.Clustering analysis has mainly performed clustering for EEG data corresponding six events of closing eyes and taking in 7.2ml alcohol in every 20 minutes for five times.The methods of analysis for EEG data are system clustering analysis and K-means clustering anlalysis. Processing and statistic analysis of EEG data has performed using EEG analysis toolbox and program of clustering analysis.Results: Result of clustering to 21 channels under relative power of six events confirms that four normal clusters have gotten by frontal poles, front and center, occiput and temporal area. Among thirty-six clustering results, frontal poles have been clustered in a cluster in eighteen clusters and have been departed into several clusters in there clusters and the rest have been clustered with other electrodes. The frontal poles have been clustered in a cluster separately when subject close eyes in the beginning. But they have been clustered with the nearby electrodes when subjects take in alcohol. With the volume increases, they have been departed again. Such phenomenon takes place again and again during the six events. About the occiput, except a subject's right and left occiput come into being a cluster, all the other subjects'most occiput electrodes have been clustered in a cluster,and only a few have been clustered with other electrodes and even become the only member in a cluster. There are fourteen clusters have been clustered with the occiput electrodes and most of the rest have been clustered with front and temporal electrodes. The temporal electrodes changes randomly in events and even become the single member in a cluster. Reslut of clustering to EEG power in six events indices that when take in 36ml alcohol, frontal pole and the front except central points has decreased 15.74% and 10.76% separately.Front and central emporals has decreased 5.25% and left posterior temporal increased 18.34%.The parietal and occipital except left posterior temporal and central points has increased 16.50% and 14% separately.The parietal and occipital has increased 16.50% and 14% separately. Clustering to Oz and FPz confirms that the change tendency of power and frequency distribution is gradual.Conclusions: EEG activity has prominent reaction to absorbing alcohol.The regular four clusters when close eyes has been disrupted when subjects take in alcohol.After taking in alcohol, the frontal pole, forehead and center are in a cluster and with the volume increasing frontal poles are in a cluster again.That repeats in six events in turn randomly. The center has usually been clustered with electrodes nearby. The occipital electrodes are in a cluster separately in alcohol events. Tempora changes randomly when take in alcohol and even come into being single electrode. The power of EEG wave increases in the beginning and decreases later during taking in alcohol events.The power of front and central decreases and the back hemisphere increases when take in 1000ml beer. Clustering to two typical channels indices that the change tendency is gradual with alcohol take-in.