An event-related potential objective evaluation study of mental fatigue based on 2-back task / 生物医学工程学杂志

The electroencephalographic characteristics of mental fatigue, which was induced by long-term working memory task of 2-back, were studied by event-related potential (ERP) technology in order to obtain objective evaluation indicators for mental fatigue. Thirty-two healthy male subjects, 22-28 years old, were divided into two groups evenly, one is un-fatigue group and the other is fatigue group. The fatigue group performed a 2-back task for 100 min continuously, while the un-fatigue group just performed a 2-back task at the first and last 10 min respectively, and rested during the middle 80 min. The subjective levels of fatigue, task performance and electroencephalogram were recorded. The impaired thought and attention states, enhanced sleepy and fatigue feeling were found in the fatigue group, meanwhile their reaction time to 2-back task extended, and the accuracy decreased significantly. These results verified the validity of mental fatigue model induced by 2-back task, and then the ERP characteristic parameters were compared and analyzed between fatigue group and un-fatigue group. The results showed that the fatigue group's amplitudes of P300 ( = 2.539, 0.05). These results demonstrate that P300 and ERN can be considered as potential evaluation indictors for mental fatigue induced by long-term working memory task, which will provide basis for the future exploring of countermeasure for mental fatigue.

Deficits in Verbal Working Memory among College Students with Attention-Deficit/Hyperactivity Disorder Traits: An Event-related Potential Study

OBJECTIVE: This study investigated verbal working memory in college students with traits of attention-deficit/hyperactivity disorder (ADHD) using event-related potentials and the 2-back task. METHODS: Based on scores on the Adult ADHD Self-Report Scale and Conners' Adult ADHD Rating Scale, participants were assigned to the normal control (n=28) or ADHD-trait (n=29) group. The 2-back task, which was administered to evaluate working memory, consists of a congruent condition, under which the current stimulus is the same as the one presented two trials earlier, and an incongruent condition, under which the current stimulus is not the same as the one presented two trials earlier. The numbers 1, 2, 3, and 4 were used as stimuli. RESULTS: On the 2-back task, the ADHD-trait group committed significantly more errors in response to congruent stimuli and showed a smaller P300 amplitude than did the control group. CONCLUSION: These results indicate that college students with ADHD traits have deficits in verbal working memory, possibly due to difficulties in memory updating or attentional allocation.