Analysis of executive function characteristics and its influencing factors in temporal lobe epilepsy patients

Abstract

Objective To investigate the characteristics of temporal lobe epilepsy (TLE) executive function and its correlation with neuropsychological tests. Methods A total of 25 patients with TLE [including 8 patients with left TLE (LTLE) and 17 patients with right TLE (RTLE)] and 15 healthy controls with matched sex, age and education level admitted to Tianjin Medical University General Hospital and China Resources & WISCO General Hospital from June 2017 to December 2018 were enrolled. Neuropsychological tests [including Mini-Mental State Examination (MMSE), Hamilton Anxiety Rating Scale (HAMA), Beck Depression Inventory (BDI)] and executive function tests [including digital working memory, verbal working memory, Stroop Color-Word Test (SCWT), Trail Making Test-A and B (TMT-A and TMT-B), and Verbal Fluency Test (VFT)] were performed. Pearson correlation analysis and partial correlation analysis were used to explore the correlation between executive function and various factors, and multiple linear stepwise regression analysis was used to verify the linear quantitative relationship between executive function and various factors. Results MMSE score (P = 0.003), digital working memory score (P = 0.000), verbal working memory score (P = 0.000), color response time (P = 0.001), word response time (P = 0.001), color word response time (P = 0.001), TMT-A time (P = 0.010), TMT-B time (P = 0.009) and the number of VFT (P = 0.000) of LTLE group, RTLE group and control group were significantly different. MMSE score (P = 0.013, 0.029), digital working memory score (P = 0.000, 0.000), verbal working memory score (P = 0.000, 0.000) and the number of VFT (P = 0.000, 0.000) in LTLE group and RTLE group were lower than those in control group. Color response time (P = 0.047, 0.000), word response time (P = 0.002, 0.006) and color word response time (P = 0.024, 0.001) were longer than those in control group, but TMT-A time (P = 0.004) and TMT-B time (P = 0.002) in RTLE group were longer than those in control group. There were no significant differences in executive function scores between LTLE group and RTLE group (P > 0.05, for all). Correlation analysis showed that digital working memory score, color response time, vocabulary response time and attention transfer time were positively correlated with MMSE score, HAMA score, BDI score, age, education level, seizure frequency, type of antiepileptic drugs (P < 0.05 or P < 0.01). TMT-A time and TMT-B time were positively correlated with MMSE score, HAMA score, age, education level, seizure frequency, type of anti-epileptic drugs (P < 0.05 or P < 0.01). There was a positive correlation between color word response time and word fluency with HAMA score, age and education level (P < 0.05 or P < 0.01). Multiple linear stepwise regression analysis showed that there was a linear regression relationship between digital working memory score and seizure frequency (standardized partial regression coefficient = 0.998, P = 0.001) and type of antiepileptic drugs (standardized partial regression coefficient = -1.634, P = 0.006). There was a linear regression relationship between verbal working memory score and HAMA score (standardized partial regression coefficient = -0.089, P = 0.035), a linear regression relationship between color response time and education level (standardized partial regression coefficient = -0.097, P = 0.002), a linear regression relationship between vocabulary response time (standardized partial regression coefficient = -0.121, P = 0.004), color word response time (standardized partial regression coefficient = -0.243, P = 0.002), TMT-A time (standardized partial regression coefficient = -5.984, P = 0.002), TMT-B time (standardized partial regression coefficient = -17.376, P = 0.000), attention transfer time (standardized partial regression coefficient = -12.413, P = 0.000) and MMSE score had linear regression relationship. Vocabulary fluency and age (standardized partial regression coefficient = 0.327, P = 0.032), education level (standardized partial regression coefficient = 1.976, P = 0.001), HAMA score (standardized partial regression coefficient = -0.431, P = 0.008) had a linear regression relationship. Conclusions Executive function (working memory, inhibitory control and cognitive flexibility) was impaired in patients with TLE, but there was no significant difference in executive function between RTLE and LTLE. The older the age and the lower the education level, the more severe the overall cognitive dysfunction, the more significant decline in executive function.

Keywords

• epilepsy temporal lobe
• cognition disorders
• neuropsychological tests