视觉显示终端心算作业脑力负荷的评价

Mental workload for mental arithmetic on visual display terminal

目的探讨用主观评分法、主任务评定法、心理生理学评定法3种脑力负荷评定方法来评价视觉显示终端(VDT)心算作业时脑力负荷的可行性。方法记录分析了受试者完成3种不同难度心算时的Cooper-Harper量表评分、正确率、做题速度、心率变异性、瞳孔直径、眨眼率等脑力负荷评定指标。结果随着心算算式变数位数的增加,3组心算的Cooper-Harper量表评分分值逐渐增加；心算的正确率逐渐下降；做题的速度逐渐减慢；瞳孔直径逐渐增大；眨眼率逐渐减少。与休息时相比,心算时心率变异性(HRV)的总的频域值(TP)、极低频成分(VLF)、低频成分(LF)、低频的归一化值(LFnorm)、低频/高频比率(LF/HF)值降低,高频的归一化值(HFnorm)、HF/TP、相邻RR间期差的均方根(rMSSD)值增大,但3组心算之间的差异无统计学意义(P＞0．05)。结论随着心算算式变数位数的增加,受试者脑力负荷增加。3种脑力负荷评定方法均能在一定程度上反映不同难度心算任务的脑力负荷信息,联合应用多种指标评定脑力负荷更为可行。

Objective To investigate the pussibility of subjective rate, primary task evaluation and psychophysiology evaluation as methods for mental workload assessment of mental arithmetic on visual display terminal （VDT）. Methods The indexes including Cooper-Harper scale score, correct rate, speed in answering questions, heart rate variability, pupil size and blink rate were recorded during the performance of three different difficult tasks. Results With the variable number of formula increasing, the Cooper-Harper scale score increased, the right rate decreased, the speed decreased, pupil size increased, and blink rate significantly decreased. In comparison with rest, the value of TP, VLF, LF, LFnorm, LF/HF decreased remarkably in the mental arithmetic task, the value of HFnorm, HF/TP, rMSSD increased. However, the difference was not significant among three groups. With the variable number of formula increasing, the participant＇s mental workload increases. Every method of mental workload evaluation can assess the mental workload information for three tasks at various different levels in a way. Multi-indexes may be appropriate for mental load assessment.