Operations in space are anything but restful for astronauts, as there are both physical and psychological stressors. One known stressor is the lack of sufficient sleep in space which can...Show moreOperations in space are anything but restful for astronauts, as there are both physical and psychological stressors. One known stressor is the lack of sufficient sleep in space which can drastically impact astronauts’ performance. Successful docking is highly important during space missions since small mistakes can lead to disastrous consequences. The docking process can be trained with the 6df task, a simulation in which six degrees of freedom must be controlled. This experimental study aimed to investigate the effect of susceptibility to sleep deprivation (SSD) on 6df docking performance impairment due to sleep deprivation (SD). A total of 62 participants (28 female; 18-39 years, Mage = 24.84; SDage = 4.69) completed a balanced-repeated-measures-cross-over-total-SD design. Test variables were calculated by subjects’ performance differences between “well-rested-“ and “SD measurements”. The dependent variable docking performance impairment due to SD was operationalised by 6df outcomes(“top-level achieved” and “mean docking accuracy”). SSD was defined as 1/reaction time (RT) from the Psychomotor Vigilance Test. A background analysis showed that participants’ RT slows significantly when SD (p < .001). Multinomial regressions (“top-level achieved”) showed no significant relations between SSD and docking performance impairment, whereas multiple regressions (“mean docking accuracy”) showed significant relations (p < .001). Post-hoc analysis showed that testing order is noteworthy because participants assessed in the order “well-rested-“ followed by “SD measurements” have lower docking performance impairment due to SD than the group with reversed order. Further, a posthoc analysis showed when participants split in “least SSD” and “most SSD”, the effect of SSD on 6df docking performance impairment due to SD was affected by testing order. The importance of testing order suggests the presence of a learning effect, meaning that docking performance impairment due to SD could be reduced by exhaustive training in well-rested conditions. In conclusion, this study can help construct guidelines for determining whether an individual can still perform the operationally relevant task safely under SD. This could also be interesting for other professions such as submarines, pilots, and surgeons, in which six degrees of freedom have to be controlled under SD.Show less
Objective: To explore the relationship between peak melatonin levels and depression scores in patients with rheumatoid arthritis and whether this relationship is mediated by pain, fatigue or...Show moreObjective: To explore the relationship between peak melatonin levels and depression scores in patients with rheumatoid arthritis and whether this relationship is mediated by pain, fatigue or disease activity. Methods: This study was of a cross-sectional, analytical and retrospective design using baseline data of an intervention study. Participants with rheumatoid arthritis were recruited and a total of 30 participants (7 males (23%) and 23 females (77%)) between the ages of 26 and 74 years (M=55.2 and SD=10.74) were analysed in this study. The measures of the study included peak melatonin levels, the IRGL (pain), HADS (depression), DAS-28 (disease activity) and CIS-8 (fatigue). Spearman’s correlations were used to analyse the relationships between all the variables and PROCESS.spss was used to conduct mediation analyses. Results: There was a significant negative relationship between peak melatonin levels and depression scores (p=.039), a significant positive relationship was found between depression and fatigue (p<.001) and a significant positive relationship was found between pain and disease activity (p=.018). The mediation analyses did not reveal any potential mediators. Conclusion: Melatonin is linked to depression; however, this link cannot be explained by the mediators listed in this study and further examination of this link is needed. While there were no potential mediators between melatonin and depression, the relationships found between depression and fatigue as well as between pain and disease activity could be explained by the overlap in the items in the various measurements.Show less
Executive functions (EF) are often impaired in patients with a psychiatric disorder, even after treatment. The neuropsychological assessment Cambridge Neuropsychological Test Automated Battery ...Show moreExecutive functions (EF) are often impaired in patients with a psychiatric disorder, even after treatment. The neuropsychological assessment Cambridge Neuropsychological Test Automated Battery (CANTAB) measures cognitive function, including EF, which is located in the prefrontal cortex. EF performance is associated with prefrontal lobe function and deficits lead to difficulties in everyday functioning. Psychiatry is, in addition to current psychological measures, in search of biological underlying mechanisms. However, the clinical practice lacks biomarkers for investigating psychopathology. Electroencephalography (EEG) has promising utility to measure electrical brain activity, thereby having potential as a biomarker in clinical practice to ease describing, diagnosing and detecting neuropsychological functions. The objective of this study was to estimate a partialcorrelations network of three EF domains and EEG oscillations. A sample of 216 patients with a psychiatric DSM-5 diagnosis conducted a CANTAB assessment and an EEG-scan. In a network analysis, the EF subdomains were correlated to closed-eye resting state EEG oscillations. It was found that alpha oscillations positively correlate (r = .12) with performance on spatial planning tasks (One Touch Stockings of Cambridge: OTS), whereas theta oscillations negatively correlate (r = -.17) with performance on this task. Accordingly, alpha oscillations are suitable for the detection of high prefrontal lobe function performance, , whereas theta oscillations indicate a lower prefrontal lobe function. Therefore, EEG could have practical implications as a biomarker of EF performance.Show less
Beta blocker administration is one of the most common treatment methods for the vascular tumours infantile haemangiomas (IHs). Previous research has attributed possible side-effects to beta...Show moreBeta blocker administration is one of the most common treatment methods for the vascular tumours infantile haemangiomas (IHs). Previous research has attributed possible side-effects to beta blockers, which include sleep disturbances and memory decline. Furthermore, research has found a link between sleep disturbances and memory decline. Thus, the present study aimed to test for possible long-term side-effects of beta blockers atenolol and propranolol. The study focused on children between ages 7-11 with IHs who were treated with beta blockers within their first year of life. The relationship between sleep disturbances and working memory among these children was analyzed. Furthermore, the differences between the study sample and population norms were analyzed regarding sleep disturbances and working memory performance. Lastly, differences between atenolol and propranolol on these measures were explored. The main findings showed a significant correlation between a high likelihood of sleep disturbances and a low working memory performance. In addition, the beta blocker sample showed a higher likelihood of sleep disturbances when compared to population norms. However, no lower working memory performance was detected in this comparison. Furthermore, no significant differences were found between propranolol and atenolol on neither sleep disturbances nor working memory performance. The main conclusion of this study points towards the possible negative relationship of beta blocker treatment with long-term sleep disturbances, which have a negative correlation with working memory performance. Possible directions for future research are discussed.Show less
This thesis aims at transferring the Job Demands-Resources model (JD-R) to the university context, in order to examine processes of health, motivation and performance of higher education students....Show moreThis thesis aims at transferring the Job Demands-Resources model (JD-R) to the university context, in order to examine processes of health, motivation and performance of higher education students. Additionally, the role of mindfulness is looked at. Academic resources (autonomy, role clarity, feedback, relationship with supervisors and relationship with fellow students) and academic demands (role conflict, pace and amount of work and mental workload), student engagement, exhaustion and mindfulness were assessed, as well as performance with a time lag. The study follows a nonexperimental and cross-sectional design with a longitudinal element. Sixty-four students completed a first online questionnaire, 16 a second. Scales from the following questionnaires were utilized: Questionnaire on the Experience and Evaluation of Work (QEEW), Utrecht Work Engagement Scale – student version (UWES-SS), Burn-out Assessment Tool (BAT), Mindfulness Attention and Awareness Scale (MAAS-Short). Performance was operationalised as the number of ECTS-points obtained. Correlations, linear and multiple regression analyses, F-tests (ANOVA) and t-tests for coefficients were conducted with a significance level of p<.05 and a confidence interval of 95%. Role clarity predicted engagement (ß = .347, p = .013, Adjusted R2 = .215), pace and amount of work exhaustion (ß = .364, p = .003, Adjusted R2 = .119) (H1). Both role clarity (ß = .489, p = .001, Adjusted R2 = .201) (H2) and mindfulness (ß = .333, p = .005, Adjusted R2 = .335) (H5) moderated the effect of pace and amount of work on exhaustion. More mindfulness was related to higher role clarity (ß = .25, p = .034, Adjusted R2 = .047), feedback (ß = .371, p = .002, Adjusted R2 = .124), and relationship with supervisors (ß = .318, p = .018, Adjusted R2 = .087) (H3). Mindfulness positively related to engagement (ß = .315, p = .011, Adjusted R2 = .085) and negatively to exhaustion (ß = -.283, p = .024, Adjusted R2 = .065) (H4). Due to low participation rates, only correlations with performance were calculated. Relationship with fellow students correlated with performance (r(15) = .567, p = .027) (H6). The present study shows that the JD-R model is applicable to the university context. Mindfulness has direct and indirect beneficial effects on motivation and well-being of students. In order to promote study engagement and reduce exhaustion, universities should enhance role clarity and mindfulness of students, while seeking to lower pace and amount of work.Show less
Challenging behavior, shown by people with severe dementia, can be experiences as stressful for the nursing staff, family caregivers, volunteers and it also has a negative impact on the quality of...Show moreChallenging behavior, shown by people with severe dementia, can be experiences as stressful for the nursing staff, family caregivers, volunteers and it also has a negative impact on the quality of life of the person with dementia. The Namaste Care Family (NCF) program is a person-centered, multisensory intervention which makes use of palliative care methodologies and emphasizes the involvement of family carers and volunteers. The aim of this study is to examine the effects of the NCF program on challenging behavior in people with severe dementia (N = 231). This longitudinal study is part of a large cluster-randomized controlled trial that examines the effects of the NCF program. In this study, 19 nursing homes from across the Netherlands participated of which 10 nursing homes implemented the NCF program (n = 116) and 9 nursing homes served as control group (n = 115). The implementation of the NCF program started after the baseline assessment in the nursing homes. The follow-up assessments were after 1 month, 3, 6 and 12 months. Challenging behaviors were measured using the Neuropsychiatric Inventory Questionnaire. Mixed models were used to analyze the overall effect of the intervention on 12 symptoms of challenging behavior and three clusters. The False Discovery Rate was used to correct for multiple testing. The intervention group showed more depressive symptoms in the follow-up assessments than the control group on average. The depressive symptoms showed a significant difference if controlled for confounders of 0.33, p = 0.001, with a 95% Confidence Interval of [0.16, 0.50]. The NCF program had no significant effect on 10 of the 12 symptoms. The results for the three clusters were also not significant. To conclude, challenging behavior did not reduce as a result of the NCF program. Depressive symptoms were shown more in the intervention group after receiving NCF. Therefore, it is important to do more research into the NCF program to clarify if and which components of the Namaste sessions have a possible positive or negative effect on symptoms of challenging behavior in order to specify the NCF program.Show less
Conditioning response theory and expectancy theory are primary explanatory models of placebo effect formation within deceptive placebo (DP) paradigm and considered either independent from each...Show moreConditioning response theory and expectancy theory are primary explanatory models of placebo effect formation within deceptive placebo (DP) paradigm and considered either independent from each other (Voudouris, 1990) or related in a form of mediation (Wager, 2005). Additionally, recent development of open-label placebo (OLP) framework has made it possible to apply placebos in clinical practice in a more ethical way while also raising the question as to what enables to observe the placebo effect in this paradigm since the deception is not used. The latter questions the hypothesis of expectancy mediation that holds that placebo occurs when a subject expects it to. Therefore, this study will investigate the role of expectancies in a conditioned placebo response within OLP and DP paradigms. In this study it was hypothesized that 1) conditioning would result in positive placebo effect in both experimental groups, 2) mediating role of expectancies in conditioning shaped placebo effects was hypothesized to be observed when OLP and DP groups scores are combined and 3) mediation of expectancies should be observed in DP group but not in OLP group. To address these hypotheses, an interventional single blinded randomized controlled trial design was used with group differences as between subject factor and activation or deactivation of sham device as within subject factor. Thermal heat pain was used for pain induction. To elicit placebo effects, conditioning procedure together with relevant verbal suggestions about the sham device were delivered. Together, 88 participants were tested with no baseline differences in age, gender, warmth and pain thresholds, and applied temperatures. Conditioning successfully predicted placebo outcome measures. Mediation analysis revealed that expectancies partially mediated conditioning-placebo effect relationship in DP, but not in OLP groups. The findings signify the different mechanisms in DP and OLP framework and points to possible future research directions. Ultimately, full understanding of placebo effects would allow for better treatment of people with chronic conditions, such as chronic pain.Show less
Within placebo research, a discussion has arisen on whether hiding the true nature of this inert treatment is deceptive. Therefore, the administration of an ‘open-label placebo’ (OLP) was...Show moreWithin placebo research, a discussion has arisen on whether hiding the true nature of this inert treatment is deceptive. Therefore, the administration of an ‘open-label placebo’ (OLP) was introduced, a more ethical way to administer the inert treatments by disclosing the intentions of the placebo. Research focusing on the underlying mechanisms of the placebo effect, i.e. the inclusion of classical conditioning, enhancing expectations with verbal suggestions and personality factors such as optimism has yet to focus on the role of these mechanisms in OLP groups. The present study investigated whether there is a difference between OLP and deceptive placebo (DP) effects in experimentally induced heat pain in healthy individuals. Additionally, the role of pain expectations and optimism was studied for both groups. Sixty participants received pain induced by thermal stimuli and were randomized into two groups. For the OLP group, the analgesic placebo device was described as inert and conditioning happened by reducing the stimulus intensity. For the DP group, the placebo device was described as analgesic and conditioning also happened. Pain ratings and expectations were measured verbally throughout the procedure. Optimism was measured with the LOT-R. Placebos were measured by comparing pain for non-placebo and placebo stimuli. Results showed no difference between OLP and DP groups (F(1, 58) = .155, p = .695, ηp2 = .003). Analgesic placebo effects were found for both groups (F(1, 58) = 26.111, p < .005, ηp2 = .310). Expectations significantly predicted the placebo effect in the DP group (β = -.348; t(27) = -5.153, p < .05), and the OLP group, however for which the results needed to be interpreted with caution., This implies that higher pain expectations led to smaller placebo effects. No effect for optimism was found. Results suggest that both OLP and DP groups produce a similar analgesic effect. This finding implies that in future treatments, it could be considered to use OLP versions of placebo treatments as a more ethical and efficient version of the deceptive placebo treatments. Future research could further specify the individual characteristics that could enhance the success of placebo treatments in a more ethical way.Show less
