Correlation between cognitive impairment and power of quantitative electroencephalogram in patients with temporal lobe epilepsy / 中华神经科杂志

ABSTRACT

Objective To assess cognitive impairment and its correlation with power of quantitative electroencephalogram (qEEG) in patients with temporal lobe epilepsy (TLE).Methods Fifty-five patients with TLE seen consecutively in Suqian First Hospital and 40 healthy controls (HC) were assessed by Mini-Mental State Examination (MMSE),Brief Cognitive Battery (BCB) and qEEG.The global interhemispheric and intrahemispheric difference values for power spectral ratios (Dv-PSR) were calculated.Cognitive functions and Dv-PSR of the TLE patients and the HC were compared,and correlation between cognitive impairment and power of qEEG was assessed using Spearman correlation analysis.The significance level was set at P≤0.05.Results Statistical analysis showed that MMSE scores did not have statistically significant difference between the TLE patients and the HC (26.9±2.4 vs 27.3±2.6,t=0.502,P=0.549).However,BCB examination showed that immediate memory,incidental memory,delayed recall,learning test,verbal fluency and recognition differed significantly between the TLE and the HC groups (7.34± 1.33 vs 8.92±1.37,6.05±1.12 vs 7.93±1.20,6.77±1.08 vs 8.19±1.14,11.87±4.47 vs 16.8±4.56,8.52±1.74 vs 9.75 ± 1.36,8.74 ± 1.19 vs 9.87 ± 1.18,respectively;t=2.916,Z=3.204,t=2.549,Z=3.937,t=1.341,t=2.791,P＜ 0.05).Interhemispheric Dv-PSR in frontal,central,temporal and parietal area was higher in the TLE group than in the HC group (0.478±0.043 vs 0.252±0.028,0.441±0.051 vs 0.306±0.039,0.394±0.027 vs 0.247± 0.018,0.511±0.036 vs 0.224±0.021,respectively;t=3.711,2.403,3.144,4.327,P＜0.05),and intrahemispheric Dv-PSR in frontal,central,parietal and occipital area (minus temporal area respectively) was also higher in the TLE group than in the HC group (0.521±0.024 vs 0.221±0.017,0.249±0.012 vs 0.167±0.008,0.187± 0.013 vs 0.104 ± 0.007,0.313 ± 0.021 vs 0.127 ± 0.009,respectively;t=4.208,3.192,2.611,3.737,P＜0.05).Spearman analysis showed positive correlations between intrahemispheric,interhemispheric Dv-PSR and several cognitive domains impairment assessed by BCB (P＜0.05).Conclusion There was mild cognitive impairment in TLE patients,which was significantly associated with Dv-PSR assessed by qEEG,suggesting that Dv-PSR measurement may be used as a marker for cognitive impairment in epilepsy.