Quantitative electroencephalography in predicting on outcome of awakening in long-term unconscious patients after severe traumatic brain injury

Abstract

Objective To explore the quantitative electroencephalography in unconscious patients after severe traumatic brain injury （TBI） to predict awakening.Method All cases were divided into two groups（ the awake group 19 cases and the unfavourable prognosis group 22 cases）.Two weeks after admission the original EEGs were preformed in 41 patients suffering from severe TBI with duration of disturbance of unconsciousness ≥2 weeks.The sampled data did make fast Fourier transform to obtain the power spectrum analysis with the computer software.The power spectrum was divided into 6 bandwidth by frequency： δ（ 1.0～4.0 Hz）、θ（4.1 ～8.0 Hz） 、α1（8.1 ～10.0 Hz） 、α2（10.1 ～13 Hz） 、β1 （13.1 ～17.5 Hz） 、β2（17.6 ～35.0 Hz）.Calculate the absolute power value in each band and δ ＋ θ/β ＋ β value and research the correlation of the both group.The awakening after the sixth months from injury was used as the criterion.Results The score of δ ＋ θ/α ＋ β was 5.432 ± 3.277 in the awake group,yet in the unfavourable prognosis group was 8.724 ± 5.641.Using the two independent sample t test, both groups had significant difference, t =2.237 （ P = 0.030 ）.Using Pearson correlation analysis, r = - 0.622, P = 0.004, both Glasgow coma score and δ ＋ θ/α ＋ β value had negative correlation.Conclusions As an inexpensive,objective and rapid means of the evaluation of brain function,the QEEG can accurately reflect the degree of brain dysfunction and assess the prognosis of patients. Key words: Craniocerebral trauma; Consciousness disorders; Prognosis; Quantitative electroencephalography