Lal's research while affiliated with University of Technology Sydney and other places

Driver fatigue is a major cause of road accidents and has implications for road safety. This review discusses the concepts of fatigue and provides a summary on psychophysiological associations with driver fatigue. A variety of psychophysiological parameters have been used in previous research as indicators of fatigue, with electroencephalography perhaps being the most promising. Most research found changes in theta and delta activity to be strongly linked to transition to fatigue. Therefore, monitoring electroencephalography during driver fatigue may be a promising variable for use in fatigue countermeasure devices. The review also identified anxiety and mood states as factors that may possibly affect driver fatigue. Furthermore, personality and temperament may also influence fatigue. Given the above, understanding the psychology of fatigue may lead to better fatigue management. The findings from this review are discussed in the light of directions for future studies and for the development of fatigue countermeasures.

The aim of the study was to investigate psychophysiological relationships in the transition from alert to drowsiness in a random sample of subjects. Subjects had to comply with defined inclusion criteria. Subjects were sleep deprived and food, caffeine and alcohol intake was controlled prior to the study. The study was carried out in a temperature-controlled environment at a consistent time of the day. The study involved driving a car simulator for approximately 2 h; physiological parameters were recorded simultaneously. These included the International 10-20 system EEG (19 channels), electro-occulogram, electrocardiogram and electromyography. Blood pressure was monitored before and after the driving task. Psychological and fatigue questionnaires were also administered. Psychological measures assessed anxiety, mood, and personal control. A video image of the face served as an independent variable for drowsiness assessment. EEG data was compared for an alert, early fatigue and fully fatigued state using ANOVA, and significant differences were found in the delta, theta, alpha and beta bands. The Scheffe test was then used to determine where the differences existed in the comparison of the three brain states. For all frequency bands the changes in the fatigue states were significantly different to the alert state (P < 0.01). The greatest difference was noted for delta, alpha and theta bands. Heart rate was 5 b.p.m, lower after the study with no significant change in blood pressure. The subjects were slightly-moderately fatigued before and moderately-extremely fatigued after the driving session. The psychological questionnaires revealed a normative sample. The results from our study seem promising especially with heart rate and EEG changes associated with the transition from alert to fatigue states. The results will be utilized in the development of a fatigue countermeasure device.