不同信息类型工作记忆任务中基于脑电的脑力负荷评估

Evaluation of Mental Workload in Working Memory Tasks with Different Information Types Based on EEG

目的探索脑电线性与非线性特征进行跨任务脑力负荷评估的有效性。方法基于N-Back范式分别设计不同信息类型和不同脑力负荷的工作记忆任务,任务执行过程中同步采集18名受试脑电信号,提取信号线性与非线性特征,采用统计分析方法筛选各任务下能够有效反映脑力负荷大小的指标。结果四种任务下,随着任务负荷的增大,额叶Theta能量、Theta/Alpha能量比值及顶叶尺度10以上的脑电信号样本熵均先增大后轻微减小,中央-顶叶Alpha能量则先减小后增大;额叶Theta能量、中央-顶叶Alpha能量及顶叶尺度10以上的脑电信号样本熵特征在字符与客体任务间、两种空间任务间无显著差异,额叶Theta/Alpha能量比值在四种任务间均无显著差异。结论研究结果可为不同信息类型工作记忆任务下的脑力负荷评估提供依据。

Objective Exploring the effectiveness of using EEG linear and nonlinear features for accessing mental workload in different tasks.Methods Working memory tasks with different information types and various mental loads were designed based on N-Back paradigm.EEG signals from 18 normal adults were acquired when tasks were being performed.Linear and nonlinear features of EEGs were then extracted.Indices that can effectively reflect mental workload levels were selected by using multivariate analysis of variance statistical approach.Results With the increment of task load,power of frontal Theta,Theta/Alpha ratio,and sample entropies(scales>10)in parietal regions increased significantly first and decreased slightly then,while the power of central-parietal Alpha decreased significantly first and increased slightly then.No difference in power of frontal Theta,central-parietal Alpha,and sample entropies(scales>10)of parietal regions were found between verbal and object tasks,as well as between two spatial tasks.No difference of frontal Theta/Alpha ratio was found in all the four tasks.Conclusion The results can provide evidence for the mental workload evaluation in tasks with different information types.