The gap effect in pro-saccades and anti-saccades in psychometric schizotypes.

Schizophrenic patients and their first-degree relatives exhibit deficits in the anti-saccade task. In the present study, anti-saccade task performance was examined in subjects with 'high' and 'low' expressions of the schizotypal personality trait. For that purpose, the SPQ-G, the German adaptation of the Schizotypal Personality Questionnaire (SPQ; Raine, 1991), was filled in by 489 university students. Twenty and 21 participants with 'high' and 'low' SPQ-G scores, respectively, were compared with respect to saccadic eye movements elicited under the overlap and 200 ms gap conditions of the pro- and anti-saccade tasks. Each task block comprised 150 trials, 75 to either side in random order. The order of presentation of the task blocks was counterbalanced across the participants of each group. Saccadic reaction times were slower during the anti- as compared to the pro-saccade task and under the overlap as compared to the gap condition. Direction errors occurred almost exclusively during the anti-saccade task, express saccades mainly under the pro-saccadic gap condition. High-schizotypal participants did not differ significantly from low-schizotypal participants in any of these measures. While these results might suggest normal anti-saccade task performance in schizotypal personality as defined by the SPQ-G, the sampling strategy adopted in the present study is the more plausible explanation for the lack of group differences.

Stress and strain of blue and white collar workers during work and leisure time: results of psychophysiological and behavioral monitoring.

This study of 29 blue and 57 white collar workers (mean age 50 and 51 yr) investigated behavior and the level of subjective stress and objective strain during work and leisure time. Physiological and psychological parameters as well as behavioral activities were assessed simultaneously using a special ambulatory monitoring device capable of storing 23 h records. Total strain was operationalized by heart rate (HR), physical strain by physical activity, emotional strain by non-metabolic HR, and mental strain by HR variability. Analysis of the physiological parameters for the working hours from 8 to 16 h revealed differences between the hours for physical activity, HR, and non-metabolic HR but not for HR variability. Between 12 and 13 h, physical activity was somewhat lower and non-metabolic HR higher, presumedly caused by the lunch break. Physical activity and HR were higher for blue than white collar workers due to the different tasks of the workers. Self-reports of excitement and enjoyment during the working hours showed no main effects in the MANOVA. Comparison between total working time and leisure time revealed lower physical activity and HR but higher non-metabolic HR for leisure time. In the self-reports, however, leisure time was rated less exciting and more pleasant than working time. There was no indication of higher emotional strain for one or the other group, but mental strain at work was somewhat higher for the blue collar workers. In a questionnaire, white collar workers reported having significantly more stress at work and outside work than blue collar workers. Analysis of the behavior during leisure time (physical activity, activity, social contacts) showed only minor differences between the groups.

Occupational stress and strain of female students: results of physiological, behavioral, and psychological monitoring.

This study of 50 female students (mean age 23) investigated the level of acute and chronic subjective stress, objective strain of everyday university life, and behavior (time budget during a normal day). Physiological parameters, behavioral activities, and psychological parameters were assessed simultaneously both while at the university and at home using a special ambulatory monitoring device capable of storing 23-h records. Comparison between typical study (seminar, lecture) and leisure activities (resting, conversation, etc.) revealed lower heart rate variability during university-related activities, indicative of increased mental load. Physical activity was higher during leisure activities, but heart rate was even higher during study time. Students rated leisure activities to be more enjoyable but less exciting or arousing than studies. Two-factorial MANOVAs with the factors "stay' (at the university, at home) and "chronically stressed by studies', a rating made one week before the monitoring (stressed versus non-stressed students), showed significantly higher heart rates for the chronically stressed students, particularly while at the university as opposed to at home. These students also showed decreased heart rate variability as compared to the non-stressed students, indicating greater mental workload. No differences between the groups were found in socioeconomic variables and personality traits (neuroticism, extraversion, achievement motivation). The results are discussed in the context of the stress concept.

Perception of emotions in everyday life: studies with patients and normals.

Five studies with nearly 500 subjects recruited from the university, the work place, and from rehabilitation clinics served to investigate the perception of emotional events in everyday life. Physiological parameters (heart rate, physical activity, additional heart rate) and psychological parameters (excitement, enjoyment) were assessed simultaneously throughout the day using a special ambulatory monitoring device capable of storing 23-h records. Emotional events were identified by an increase of heart rate without an accompanying increase in physical activity (additional heart rate) and under special requirements a feedback signal was given which requested subjects to answer predefined questions. Between these 'true' feedbacks, 'random' feedbacks were interspersed with no indication of emotional arousal. Subjects were unaware that the feedback signal was triggered by their own heart rate. Laboratory experiments with films of different emotional quality showed that the method is suitable for the detection of emotional arousal. Comparisons of true feedbacks (emotional events) with random feedbacks (neutral situations) did not show significant differences for excitement and enjoyment ratings for any of the normal samples and for one of the patient samples. Only a sample of coronary heart disease patients showed small differences in the psychological variables which were significant due to the large sample size. From the results it may be concluded that the perception of physiological changes indicating emotional arousal in everyday life is quite different from the results suggested by laboratory experiments. The findings are discussed within the theoretical framework of 'competition of cues' and 'cognitive schemas' proposed by Pennebaker (1982, The psychology of physical symptoms, New York: Springer).

Physical, mental, emotional, and subjective workload components in train drivers.

This study, using 12 train drivers on a high speed track and 11 drivers on a mountain track, tried to differentiate between the physical, emotional, mental, and subjective workload components imposed on the drivers during work. With the simultaneous recording and on-line analysis of heart rate and physical activity, the emotional component in terms of the so-called additional heart rate was separated from the physical component. Mental workload was calculated by the heart rate variability and by shifts in the T-wave amplitude of the ECG. Speed of the train, mode of driving, and stress of the situation were rated by two observers who accompanied the drivers in the cabin. During speeds up to 100 km/h as compared to standstills no heart rate changes occurred, but with speeds from 100 km/h up to 200 km/h heart rate decreased indicating a monotony effect. However, heart rate variability, and T-wave amplitude indicated higher mental load during driving in most speed categories. Starting the train and coming to a halt showed greater emotional workload as compared to moving. Observer ratings of stress and subjective ratings of stress by the drivers revealed several discrepancies. Discrepancies were also seen between workload as indicated by the physiological parameters, and corresponding stress ratings by the observers or by the drivers.

Differences between patients with asymptomatic and symptomatic myocardial infarction: the relevance of psychological factors.

Several hypotheses describe the phenomenon asymptomatic myocardial infarction (MI) blockade of afferent cardiac nerves, pain inhibition by endogenous opioids, and insufficient severity of myocardial ischaemia. Psychological factors, however, are rarely considered. The present study involved 35 asymptomatic (AMI) and 35 symptomatic patients (SMI) selected from a sample of 199 patients with myocardial infarction. During observation in a rehabilitation clinic, the following were assessed: biochemical variables; ECG at rest, at exercise, and during Holter monitoring; and a special 23 h monitoring of physical activity, ECG changes, and subjective feelings. Psychological assessments with questionnaires were also performed and comprised: personality evaluation; physical complaints; possible predisposing features for the development of MI; expectations regarding the benefit of rehabilitation; circumstances at the time of infarction; and socioeconomic and historical data. The hypothesis that physiological factors might explain the differences between AMI and SMI is not substantiated by our results. However, the hypothesis of the role of psychological factors is supported. As opposed to AMI patients, SMI patients are characterized by frequent complaints of poor health, neuroticism, and introversion. At the time of infarction, SMI patients had more frequent premonitory symptoms of longer duration. Moreover, SMI patients had more frequent previous hospital or nursing home admissions. At the end of the rehabilitation treatment, only 43% of the SMI patients were judged by their physician as fit for work as against 71% of the AMI patients.

Covariation of physiological sleep parameters in coronary patients and their relationships to sleep quality.

Relationships between the time series of five physiological sleep parameters were examined and related to sleep quality. Twenty-eight male coronary patients participated in the investigation. Recordings were carried out with a mobile device consisting of two Medilog 4-24 recorders and one DMI-recorder assessing five biosignals: EEG, EOG, EMG, ECG and body movements. Relationships between the time series of physiological sleep parameters were obtained by partitioning of covariance. The investigation showed that substantial relationships exist between the time series of the EEG, the number of eye movements and heart rate. Moreover, the time series of body movements showed substantial relationships to the time series of the EMG and heart rate. High correlations between the time series of the EEG and heart rate were related to a better sleep quality.

Diurnal variations of ECG parameters during 23-hour monitoring in cardiac patients with ventricular arrhythmias or ischemic episodes.

ECG and physical activity (recorded with motion detectors) were continuously monitored during 23 hours in 31 male cardiac patients (81% with myocardial infarction). According to the occurrence of ventricular arrhythmias (VA) or ischemic episodes (IE), each patient was grouped in one of three diagnostic categories: neither VA nor IE, VA with or without IE, and IE only. Analysis of the ECG parameters was done beat-by-beat and averaged on a 1-min basis. Results were derived from the 2-hour means between 2 p.m. and 12 p.m. MANOVA revealed significant group differences for heart rate variability (greater for the group with VA), R-wave amplitude (higher for the group with IE), and P-wave amplitude (higher for the group with VA). Significant time effects were observed for all variables except QRS- and P-wave durations. As may be expected, physical activity and heart rate were lower at night. Heart rate variability, PQ-interval, PR-segment, QT-interval, ST-segment, and T-wave duration increased during the night. R-wave amplitude also increased but the relative P- and T-wave amplitudes decreased. The corrected QT-interval, QTc, was shorter at night and the ST-segment, J + 60-point, S-wave, and J-point amplitudes were less negative. Group X Time interactions were observed for T-wave amplitude. For this amplitude, the decrease during the night was prominent only for the VA group. The results of this study suggest that the three diagnostic groups can be differentiated by diverse ECG parameters.