The Correlation Analysis Between EEG Spectral Power And Cognition In Epilepsy

Objective To investigate the difference of neuropsychological test and background activity between patients with epilepsy and normal adults by means of EEG power spectrum and evaluate the value of EEG power spectrum in the assessment of cognitive impairment in patients with epilepsy.Methods 61 patients with epilepsy meeting the inclusion and exclusion criteria were included in the study,The control group comprised of 24 healthy volunteers matched with respect to age,sex,and education.Neuropsychological test including brief screening scale for cognition(MMSE,Mo CA),short-term memory(clinical memory scale),information processing speed(digital symbols substitution test),working memory(digit span test),language(verbal fluency test)and EEG were performed in all the people.Background activity about 2 min were analysis of different frequency bands(?????1??2??1??2)in different brain regions(prefrontal area,frontal area,temporal area,central-parietal area,occipital regions).Neuropsychological test and EEG power spectrum including absolute power(AP)and relative power(RP)were compared between epilepsy patients and control group.The correlation between the Neuropsychological test scores and EEG power spectrum in epilepsy group were analyzed.According to the memory quotient(MQ),epilepsy group were further divided into MQ-normal group(MQ?90)and MQ-decline group(MQ<90).comparison between epilepsy subgroup in EEG power spectrum were carried out.The correlation between the Neuropsychological test scores and EEG power spectrum in MQ-decline group were analyzed All the data were analyzed by SPSS statistical software.Results 1.The comparison of Neuropsychological test between epilepsy group and control group: compared to the control group,the epilepsy group had statistically significant lower score in Mo CA,memory quotient and the age scale score of sub-test,digital symbols and fall back(P < 0.05),MMSE,word fluency along the back words have no significant difference(P > 0.05).2.The comparison of EEG power spectrum between epilepsy group and control group: compared with control group,with respect to absolute power,the epilepsy group showed statistically significant greater absolute power in the ? and ? ranges at the majority of the brain,and statistically significantly greater absolute power in the?1range at temporal area and central-parietal area while the greater power in the ?2 range at central-parietal area.For relative power,the temporal region showed statistically significant greater relative power in the ? range and lower in the ?1range,the greater relative power in the ? range was also appeared at occipital area(P < 0.05).3.The correlation analysis between Neuropsychological test and EEG power spectrum in epilepsy: digital symbol substitution test was negatively related to relative power in the ? range at occipital area(R=-0.285,P<0.05).4.The comparison of EEG power spectrum between epilepsy subgroup: Compared to the MQ-normal group,the MQ-decline group showed statistically significantly lower relative power in the ? range,while greater relative power in the ?1,?1range at the frontal area were found(P < 0.05),and the relative power at the ?1range was statistically significantly greater while the relative power at the ? range was lower at the temporal and central-parietal area(P < 0.05).the relative power at the ? range was lower at the occipital area(P < 0.05).5.The correlation analysis between Neuropsychological test and EEG power spectrum in MQ-decline group: a significantly negative correlation between verbal fluency and relative power in the ? range at temporal area was found(R =-0.375,P<0.05).6.The comparison of neuropsychological test between epilepsy subgroup with different education level: compared to the 10-12 years group,?9 years group had statistically significant lower score in digital symbol substitution test,word fluency and digit span(P < 0.05).compared to >12 years group,expect image free recall,?9 years group showed lower score in all the neuropsychological test(P < 0.05).and 10-12 years group had lower score in image free recall,verbal fluency(P < 0.05).Conclusion 1.Patient with epilepsy suffer from cognitive impairment including short memory,working memory and information processing speed.Memory impairment in epilepsy including semantic and non-semantic short memory.Epileptic patients with lower education show decline in cognition.Making patients with epilepsy receive normal education may be the important way to improve cognition in patients with epilepsy.2.Compared with the normal,people with epilepsy were characterized with greater ??? absolute power and changes in relative power in ???1range at temporal area and occipital area.3.EEG power spectrum can use as a tool to assess cognition in epilepsy.Relative power in ? range at occipital area is negatively related to information processing speed.4.Compared to MQ-normal group,epilepsy patient with memory decline showed different EEG power spectrum.a significantly negative correlation between verbal fluency and relative power in the ? range at temporal area was found in MQ-decline group.