Studys On Predictive Value Of Amplitude-integrated Electroencephalography For Prognosis Of Conscious Disorders With Supratentorial Lesions, Infratentorial Lesions, And Diffuse Lesions

ObjectiveTo obsereve the predictive value of amplitude-integrated electroencephalography(aEEG) on prognosis of conscious disorders,to explore the accuracy,feasibility of aEEG monitoring in patients with supratentorial vascular lesion, infratentorial vascular lesion and diffuse lesion.In order to evaluate the clinical value of aEEG monitoring in patients with different lesions.Methods164 patients were admitted in neurological intensive care nuit(NICU) in Nan Fang Hospital from December 2007 to December 2009.We monitor cerebral function of all patients including neurological examination and aEEG.NicoletOne Monitor was used to record aEEG singnal and raw EEGThe single channel aEEG is ususlly recorded from one pair of parietally placed electrodes(corresponding to P3 and P4 according to the international EEG 10-20 classification). The raw EEG signal is first amplified, then narrowly filtered to attenuate electrical activity of less than 2 Hz and more than 15 Hz, minimizing artifacts from sources such as sweating, muscle activity, and environmental electrical interference. Additional processing includes semilogarithmic amplitude presentation,rectification and smoothing. The aEEG tracing is viewed on a highly compressed time scale, historically at a rate of 6 cm/h.Thus, a full minute of EEG is represented by only a single millimeter of aEEG display.Due to the screen scale used to mesure the upper and lower border of aEEG trace.aEEG trace will be divided into several gradings.Cases admitted criteria:①Fist evaluation performed in 3 days after onset.②Conscious disorders:somnolence,stupor and coma.③Lesions included supratentorial vascular lesion, infratentorial vascular lesion and diffuse lesion.(Diffuse lesion included encephalitis with diffuse edma, Status epilepticus, hypoxic-ischemic encephalopathy(HIE) and metabolic encephalopathy).④All patients were treated with medical conservative treatment.Cases excluded criteria:①Certain diseases and factors affecting cerebral function should be excluded(eg.shock,endocrine secretion diseases, hypothermy).②To be used with antiepileptic drugs or sedatives.③Obvious interfering artifact.④Patient died from other diseases but not central nervous diseases.164 cases of patients met the criteria,and were brought into statistical analysis.Of all,patients with supratentorial vascular lesion were 82 cases,patients with infratentorial vascular lesion were 43 cases,and patients with diffuse lesion were 39 cases.The results of aEEG were categorized into 3 grades:①Normal aEEG: amplitude of aEEG is normal;②mildly abnormal aEEG:amplitude of aEEG is mildly abnormal or amplitude is normal with epilepsy;③severely abnormal aEEG:amplitude of aEEG is mildly abnormal with epilepsy,or amplitude is severely abnormal with or not with epilepsy.Glasgow coma scale(GCS) will be preformed in all patients before aEEG monitoring.Early prognosis included two groups consist of survival and death(containg brain death) according to progression of diseases.3 months prognosis after onset included good outcome and poor outcome.Cerebral performance categories scale(CPCs):CPC 1:Good cerebral performance:conscious, alert,able to work,might have mild neuralgic or psychological,deficit.CPC 2:Moderate cerebral disability:conscious,sufficient cerebral function for independent activities of daily life.Able to work in sheltered environment.CPC 3:Sever cerebral disability:conscious,dependent on others for daily support because of impaired brain function.Ranges from ambulatory state to severe dementia or paralysis.CPC 4:Coma or vegetative state:any degree of coma without the presence of all brain death criteria.Unawareness,even if appears awake(vegetative state) without interaction with environment;may have spontaneous eye opening and sleep/awake cycles.Cerebral unresponsiveness.CPC 5:Brain death:apnea,areflexia,EEG silence, etc.3 months prognosis:we regarded CPC 1 to CPC 2 as good outcome while CPC 3 to CPC 5 as poor outcome.Follow-up method:49 patients were death,115 patients were followed by phone.6 cases lost to follow-up in 3 months later.SPSS 13.0 was used as statistic software. Continuous data were compared using the t text.Discrete data are given as counts.Proportions between groups were compared using the x2 test or Fisher exact text.x2 text and Fisher exact text were used to analyse the relationship between aEEG groups and prognosis.We regrad GCS score 9～14 as the first grade predicting good outcome,and GCS score 3-8 as the second grade predicting poor outcome. Univariate logistic regression was used to evaluate the prognostic value of aEEG and GCS score.Concordance of aEEG grade and GCS score that prediting outcomes of patients was explored withκcoefficient test.P<0.05 was considered statistically significant. ResultsClinical information of all patients:164 patients admitted in NICU were analyzed.Patients of infratentorial vascular leison were 82 cases,infratentorial vascular leison were 43 cases and diffuse leison were 39 cases.6 cases lost to follow-up after 3 months,158 patients were analyzed in 3 months later.After data Statistics,patients of infratentorial vascular leison were 75 cases,infratentorial vascular leison were 41 cases and diffuse leison were 35 cases.The t text and the x2 text indicated no significant difference between good outcome and poor outcome in baseline demographic data.Supratentorial vascular leison:(1)For 82 cases of supratentorial vascular lesion, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was statistically significant(x2=49.731, P=0.000). We regarded poor outcome as dependent,aEEG grade or GCS grade as covariates respectively. Univariate logistic regression showed that aEEG grade and GCS grade were predictive factor of death. Sensitivity and specificity of abnormal aEEG(including mildly abnormal aEEG and severely abnormal aEEG) predicting death was 85.2%,89.1% respectively.Concordance of aEEG grade and GCS score that predicting outcomes was common(K=0.666, P=0.000). Spearman correlation suggested there was positively correlation between aEEG and degree of consiousness(P=0.000, rs=0.645).(2)75 cases of supratentorial vascular lesion were analysed in 3 months later, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was statistically significant(x2=15.673, P=0.000).Univariate logistic regression showed that aEEG grade and GCS grade were predictive factor of poor outcome. Sensitivity and specificity of abnormal aEEG(including mildly abnormal aEEG and severely abnormal aEEG) predicting poor outcome was 53.1%,92.3% respectively.Concordance of aEEG grade and GCS score that predicting outcomes was good(κ=0.723, P=0.000).Infratentorial vascular leison:(1)For 43 cases of infratentorial vascular lesion, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was not statistically significant(x2=3.766, P=0.152). We regarded poor outcome as dependent,aEEG grade or GCS grade as covariates respectively. Univariate logistic regression showed that GCS grade was predictive factor of death (OR=14.167,95%CI,2.635 to 76.176). There was no concordance of aEEG grade and GCS score that predicting outcomes.(P=0.004). Spearman correlation suggested that there was no correlation between aEEG and degree of consiousness (P=0.077).(2)41 cases of infratentorial vascular lesion were analysed in 3 months later, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was not statistically significant(x2=1.113 P=0.573).Univariate logistic regression showed that aEEG grade and GCS grade were not predictive factor of poor outcome.There was no concordance of aEEG grade and GCS score that predicting outcomes (P=0.004).Diffuse leison:(1)For 39 cases of diffuse lesion, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was statistically significant(x2=10.859, P=0.004). We regarded poor outcome as dependent,aEEG grade or GCS grade as covariates respectively. Univariate logistic regression showed that aEEG grade was predictive factor of death. Sensitivity and specificity of abnormal aEEG(including mildly abnormal aEEG and severely abnormal aEEG) predicting death was 100.0%,50.0% respectively.Concordance of aEEG grade and GCS score that predicting outcomes was common(κ=0.528, P=0.001). Spearman correlation suggested there was positively correlation between aEEG and degree of consiousness (P=0.000, rs=0.621).(2)35 cases of diffuse lesion were analysed in 3 months later, difference of outcome between the patients with abnormal aEEG and the patients with normal aEEG was statistically significant(x2=8.090, P=0.018).Univariate logistic regression showed that aEEG grade and GCS grade were predictive factor of poor outcome. Sensitivity and specificity of abnormal aEEG(including mildly abnormal aEEG and severely abnormal aEEG) predicting poor outcome was 76.2%,71.4% respectively.Concordance of aEEG grade and GCS score that predicting outcomes was common(κ=0.650, P=0.000).When compared the predictive value of prognosis in supratentorial vascular leison and diffuse leison.In supratentorial leison,the predictive value of poor outcome was 35.4%.In diffuse leison,the predictive value of poor outcome was 56.4%,there was significant difference between these two groups. Concordance of infratentorial leison and diffuse leison was bad(K=0.195, P=0.028). Early prognosis study found that the right predictive value of aEEG to death was 85.2% in supratentorial leison,and the rate was 0.0% in diffuse leison.3 months prognosis found that the right predictive value of aEEG to death was 55.3% in supratentorial leison,and the rate was 76.2% in diffuse leison.Conclusions1. It is significant to use aEEG as a tool to predict patients'prognosis of supratentorial vascular lesion.Abnormality of aEEG was more serous,the rate of death or poor outcome was higher.Specificity of abnormal aEEG predicting death or 3 months prognoisis was 89.1%,92.3% respectively.And aEEG has an equal accuracy when compared with clinical neurological examination.2. For supratentorial vascular leison and diffuse leison,the aEEG classification is positively correlated with the degree of consciousness.Abnormality of aEEG was more serious,level of coma was deeper.While there was no correlated between aEEG grade and degree of consciousness in the infratentorial vascular leison.3. It is not significant to use aEEG as a tool to predict patients'prognosis of infratentorial vascular lesion.Clinical neurological examination and other method should be uesd for next assessment.4. For diffuse lesion,it is significant to use aEEG as a tool to predict prognosis of patients.Abnormality of aEEG was more serious,prognosis was poorer. Specificity of abnormal aEEG predicting death or 3 months prognoisis was 50.0%,71.4% respectively.And aEEG has an equal accuracy when compared with clinical neurological examination.5. When using aEEG grade as a tool to predcit prognosis,there were difference between supratentorial vascular leison and diffuse leison.Early prognosis study found that,the predictive value was higher in infratentoiral leison. While,3 months prognosis study found that,the predctive value was higher in diffuse leison.