Effects of an n-back task on indicators of perceived cognitive fatigue and fatigability in healthy adults

Abstract

Fatigue is a multidimensional concept with diverse physical and mental determinants. The aims of the present study are: to know the efficacy of a high attentional demand test to induce acute cognitive fatigue (ACF) and to document its effects on perceived cognitive fatigue (PCF - subjective symptoms) and fatigability (F- resting heart rate and eye blinks). A quasi-experimental repeated measures design with two non-equivalent groups was used (experimental G1, n= 16, age M = 33.50 years, SD = 6.94; control G2 n= 13; age M = 38.77, SD = 5.90). Participants were exposed to a cognitive deficit induction test (n-back test, G1) or exposure to a content-neutral video (SML, G2). ACF indices were assessed using a reverse digit retention test. The findings suggest a decline in cognitive performance post-experimental manipulation comparable to the neutral group, evidenced by a lower number of hits and longer response time for a digit retention test, suggesting the effectiveness of the n-back test as a method to induce acute cognitive fatigue. The post-performance effects of the n-back task were associated with statistically significant changes in all PCF assessments. These changes turned out to be non-significant for physiological aspects of fatigability. Implications for the operational feasibility of employing PCF measurements in the short-term assessment of acute mental fatigue are discussed.