腦電圖分析

分類

• 時域（time domain）：分析啲訊號嘅時間點相關資訊，例如係喺做咗幾次同一樣嘅試驗之後，睇吓會唔會（例如）次次試驗嘅第 30 秒都會有個零舍強嘅微電壓（睇埋下面事件相關電位）；會考慮嘅嘢包括
• 功率（power，${\displaystyle P_{\xi }}$）：${\displaystyle P_{\xi }=1/T\sum |{\xi (t)}|^{2}}$
• 平均值（mean，${\displaystyle \mu _{\xi }}$）：${\displaystyle \mu _{\xi }=1/T\sum {\xi (t)}}$
• 變異數（variance，${\displaystyle \sigma _{\xi }^{2}}$）：${\displaystyle \sigma _{\xi }^{2}=1/T\sum (\xi (t)-\mu _{\xi })^{2}}$... 等等，仲可以計呢啲數據 foreach 時段嘅數值[5]
• 頻域（frequency domain）：分析啲訊號嘅頻率相關資訊，例如係將某段時間之間嘅訊號拆開變幾個腦電波，再分析每個腦電波嘅波幅；詳情可以睇下面腦電波傅立葉變換
傅立葉變換最基本條式：${\displaystyle {X}(\omega )=\int _{-\infty }^{\infty }x(t)\ e^{-j\omega t}\,dt,}$${\displaystyle {X}(\omega )}$ 係一個頻率嘅函數，而 ${\displaystyle x(t)}$ 係一個時間嘅函數[6]
• 時頻分析（time-frequency analysis）： 指同時分析時間點同頻率相關嘅資訊，例如係比較唔同時段（時間分析），睇吓唔同時段喺「邊個頻率嘅腦電波振幅最勁」（頻率分析）上會唔會有差異[7]

參考書

• Brazier, M. A. B. (1970), The Electrical Activity of the Nervous System, London: Pitman.

攷

1. Pardey, J.; Roberts, S.; Tarassenko, L. (January 1996). "A review of parametric modelling techniques for EEG analysis". Medical Engineering & Physics. 18 (1): 2–11.
2. Knyazev, G. G. (2012). EEG delta oscillations as a correlate of basic homeostatic and motivational processes. Neuroscience & Biobehavioral Reviews, 36(1), 677-695.
3. Feinberg, I., March, J. D., Floyd, T. C., Jimison, R., Bossom-Demitrack, L., & Katz, P. H. (1985). Homeostatic changes during post-nap sleep maintain baseline levels of delta EEG. Electroencephalography and Clinical Neurophysiology, 61(2), 134-137.
4. Acharya, U. Rajendra; Vinitha Sree, S.; Swapna, G.; Martis, Roshan Joy; Suri, Jasjit S. (June 2013). "Automated EEG analysis of epilepsy: A review". Knowledge-Based Systems. 45: 147–165.
5. Hjorth Bo (1970). Eeg analysis based on time domain properties. Electroencephalograph, Clin Neurophysiol, 29(3):306–310.
6. Adeli, Hojjat; Zhou, Ziqin; Dadmehr, Nahid (February 2003). "Analysis of EEG records in an epileptic patient using wavelet transform". Journal of Neuroscience Methods. 123 (1): 69–87.