Relationship between sleep disturbance,depression and anxiety in the 12 months following a cardiac event

We aimed to assess the prevalence of sleep disturbance in a cardiac patient population over a 12-month period and assess its relationship with treatment adherence, self-efficacy, anxiety and depression. A total of 134 patients consecutively admitted to two Australian hospitals after acute myocardial infarction (31%), or to undergo bypass surgery (29%) or percutaneous coronary intervention (40%) were interviewed at six weeks and four and 12 months. Sleep disturbance was measured using a recode of the Beck Depression Inventory (v.2) item 16. Anxiety and depression were assessed by the Hospital Anxiety and Depression Scale. Sleep disturbance was highly prevalent (69%) at 6 weeks but was not associated with 12-month psychological outcomes. Path analysis revealed that sleep disturbance at 4 months was, however, associated with reduced treatment adherence and self-efficacy, and higher anxiety and depression scores at 12 months. The high prevalence of sleep disturbance in this study and its association with psychological outcomes may have adverse prognostic implications and possibly impede cardiac rehabilitation efforts.     

The mitigating role of leader‒member exchange when perceiving psychological contract violation: a diary survey study among volunteers

Several scholars in the field of volunteering emphasized the pivotal role of psychological contract (PC) violation in explaining maladaptive behavioural reactions—such as counterproductive work behaviour (CWB)—of volunteers. Reactions to violation feelings are, however, interrelated and may intensify over time. Extending this dynamic perspective, we introduce momentary leader–member exchange (LMX) as a buffering social resource in the relationship between violation feelings and (1) CWB and (2) the likelihood to perceive a PC breach. Using weekly diary survey data from 247 volunteers (827 observations), we conducted a moderated multilevel zero-inflated Poisson regression analysis. As hypothesized, experiencing feelings of violation during one week related positively to CWB towards the organization (CWB-O), but not to CWB towards individuals (CWB-I) during the next week. Moreover, experiencing violation feelings during one week increased the likelihood to perceive a PC breach during the subsequent week. Finally, experiencing a high-quality LMX relationship effectively mitigated the positive relationship between violation feelings during one week and (1) CWB-O, and (2) the likelihood to perceive a PC breach during the next week. Our study highlights momentary LMX as an effective redressing mechanism in the relationship between violation feelings and undesirable employee outcomes.     

Timing of early warning stages in a multi stage collision warning system: Drivers’ evaluation depending on situational influences

By means of car2x communication technologies (car2x) driver warnings can be presented to drivers quite early. However, due to their early timing they could be misunderstood by drivers, distract or even disturb them. These problems arise if, at the moment of the warning, the safety–critical situation is not yet perceivable or critical. In order to examine, when drivers want to receive early warnings as a function of the situation criticality, a driving simulator study was conducted using the two early warning stages of a multi stage collision warning system (first stage: informing the driver; second stage: prewarning the driver). The optimum timing to activate these two early warning stages was derived by examining the drivers’ evaluation of these timings concerning their appropriateness and usefulness. As situational variation, drivers traveling at about 100 km/h were confronted with slow moving traffic either driving at 25 km/h or 50 km/h at the end of a rural road.In total, 24 participants were tested in a within-subjects design (12 female, 12 male; M = 26.6 years, SD = 7.2 years). For both stages, drivers preferred an earlier timing when approaching slow moving traffic traveling at 25 km/h (first stage: 447 m, second stage: 249 m ahead of the lead vehicle) compared to 50 km/h (first stage: 338 m, second stage: 186 m ahead of the lead vehicle). The drivers’ usefulness rating also varied with the timing, spanning a range of 8 s for driver-accepted timing variations and showed correspondence to the drivers’ appropriateness ratings. Based on these results and those of a previous study, a timing function for each of the two early warning stages depending on the speed difference between the safety–critical object and the host vehicle is presented. Indirectly, similar adaptations are already implemented in current collision warning systems, which use the time-to-collision to give drivers acute warnings in a later stage, when an immediate reaction of the driver may still prevent a collision. However, this study showed that drivers also favor this kind of adaptation for earlier warning stages (information and prewarning). Thus, adapting the timing according to the drivers’ preferences will contribute to a better acceptance of these collision warning systems.