The Preservation of Cued Recall in the Acute Mentally Fatigued State: A Randomised Crossover Study

Abstract

Purpose: The objective of this study is to investigate the impact of acute mental fatigue on the recall of clinical information in the non-sleep-deprived state. Acute mental fatigue in the non-sleep-deprived subject is rarely studied in the medical workforce. Patient handover has been highlighted as an area of high risk especially in fatigued subjects. This study evaluates the deterioration in recall of clinical information over 2 h with cognitively demanding work in non-sleep-deprived subjects.

Method: A randomised crossover study involving twenty medical students assessed free (presentation) and cued (MCQ) recall of clinical case histories at 0 and 2 h under low and high cognitive load using the N-Back task. Acute mental fatigue was assessed through the Visual Analogue Scale, Stanford Scale and NASA-TLX Mental Workload Rating Scale.

Results: Free recall is significantly impaired by increased cognitive load (p < 0.05) with subjects demonstrating perceived mental fatigue during the high cognitive load assessment. There was no significant difference in the amount of information retrieved by cued recall under high and low cognitive load conditions (p = 1).

Discussion: This study demonstrates the loss of clinical information over a short time period involving a mentally fatiguing, high cognitive load task. Free recall for the handover of clinical information is unreliable. Memory cues maintain recall of clinical information. This study provides evidence towards the requirement for standardisation of a structured patient handover. The use of memory cues (involving recognition memory and cued recall methodology) would be beneficial in a handover checklist to aid recall of clinical information and supports evidence for their adoption into clinical practice.

Fig. 1

a Consort diagram. A crossover design study involving 20 participants. Participants were randomised to 1 of 4 Groups at session 1 (S1) that had been allocated to high (HCL) or low (LCL) cognitive loads. MCQ’s at pre and post cognitive loading were reversed at session 2 (S2). At the end of the study, 1 candidate was excluded from Group 3 and Group 4. b Study protocol. Participants completed baseline questionnaires prior to reading 5 Case Histories for a 20 min time period. Free and Cued recalls were observed consecutively for clinical and non-clinical information at ‘Assessment 1’. Easy or hard 90 min cognitive loading was performed according to allocation. Once completed, participants repeated a Free and Cued Recall assessment task in an identical order to previous at ‘Assessment 2’. The timings indicated on the left of the diagram represent the average time for participants to complete one session

Fig. 2

a Stanford sleepiness scale. The Figure displays subjective levels of sleepiness at baseline, intervention with the N-Back task (High or Low Load) and after Assessment., with error bars displaying standard error. b Visual analogue scale. Subjective rating of level of mentally slow (0) to Quick Witted (100). Error bars = standard error. c Graphic representation of NASA-TLX questionnaire. Error bars = standard Error

Fig. 3

The pairplot displays the difference in information recalled per subject under high and low cognitive load. Value for each condition was the difference in amount of information recalled pre and post N-Back task

Fig. 4

Implementation of cue-based recall in a current unpublished study. Participants are provided with memory cues based on aspects of information desired at handover dependent on input of diagnosis. a Information displayed prior to entering diagnosis. b The display changes on the input of the diagnosis, with information specific to condition displayed. The participant does not have to input all of the information displayed, the principle is to create a cue so that all of the information is considered

Fig. 5

‘Change in Confidence’ after the N-Back task (top = High Load, Bottom = Low Load). A subgroup of six subjects display a possible susceptibility to reduced confidence when under cognitive demand. Six of the lowest nine ranked subjects display reduced confidence after high or low cognitive loading