In the search for a more affordable, less invasive biomarker to accurately diagnose and prognose Alzheimer’s disease (AD), measuring cortical thickness via magnetic resonance imaging is a promising...Show moreIn the search for a more affordable, less invasive biomarker to accurately diagnose and prognose Alzheimer’s disease (AD), measuring cortical thickness via magnetic resonance imaging is a promising method. Specific regions on the cortex are found to be related to AD, referred to as AD signature regions, but evidence for the persistence of the relationship between cortical thickness and cognitive decline in the preclinical phase of the disease is lacking. The aim of this study is to investigate whether a lower cortical thickness is related to worse cognitive performance and can predict cognitive decline over time. Furthermore, it is hypothesized that this trend is influenced by the presence of other AD biomarkers, e.g. amyloid status. In a cross-sectional and longitudinal study, we investigated 189 cognitively normal older adults (91 twin pairs and 7 single twins) and measured cortical thickness via magnetic resonance imaging, cognitive performance during neuropsychological assessment and amyloid pathology in positron emission tomography and cerebrospinal fluid. Neuropsychological assessment was repeated after approximately two years. Cognitive performance was divided into four domains: memory, attention, executive functions and language. Participants were on average 70.23 (SD = 7.46) years and 107 (57%) were female. Cross-sectionally, we found that lower cortical thickness was related to worse memory performance (b = 0.133 [SE = 0.046], p = 0.004). When cortical thickness on separate AD signature regions was examined, we found that certain regions were related to performance on memory and executive functioning. Longitudinally, we found that cortical thickness at baseline could not predict cognitive performance over time. When examining the role of amyloid status in these relationships cross-sectionally, we found that both lower cortical thickness and positive amyloid status were related to worse memory performance (respectively, b = 0.237 [SE = 0.053], p = <.001 and b = -0.240 [SE = 0.108], p = 0.026), yet the interaction effect was not significant. These results provide evidence for the cross-sectional relationship between lower cortical thickness and worse cognitive performance, more specifically worse memory and executive functions performance. Future research must determine whether cortical thinning in contrast to cortical thickness, can predict cognitive performance over time. In that case, individuals at risk of AD can be easier identified in a more affordable and less invasive way.Show less
The ability to inhibit behavior is known to be an important predictor for future successes in life. Following up on Mischel’s marshmallow experiment in 1970, this study investigated how to improve...Show moreThe ability to inhibit behavior is known to be an important predictor for future successes in life. Following up on Mischel’s marshmallow experiment in 1970, this study investigated how to improve children’s self-control. An adaptation of the Standford marshmallow test was used in this research to measure delay of gratification (part of self-control). 228 families were selected to participate in this study. The Video-feedback Intervention to Promote Positive Parenting – Twins (VIPP-Twins) targeted 82 families with children from eight to twelve years old, to increase the children’s ability to delay gratification. This intervention targeting parents decreases the duration of intervention and would depend less on the intrinsic motivation of children than behavioral and attentional interventions targeting children often used in the past. It was hypothesized that children improve more in delaying gratification in the randomized VIPP-Twins intervention group than children in a randomized control group, in which parents did not receive an intervention. Also, because of ambiguous results in previous literature, it was investigated whether there was a gender difference in delay of gratification and the effectivity of the VIPP-Twins intervention. This study found no statistically significant effects. A methodological adaptation of the measurement of delay of gratification in this study could be adopted in future research. Multiple assessment methods of inhibition could be used to better highlight the gender differences in self-control present in previous literature.Show less
Anxiety symptoms and disorders in older adults are both prevalent and disabling. At the moment little is known about how age of onset of anxiety problems is related to the clinical characteristics...Show moreAnxiety symptoms and disorders in older adults are both prevalent and disabling. At the moment little is known about how age of onset of anxiety problems is related to the clinical characteristics of older adults. The current study aimed to explore clinical differences between older adults with early-onset (before the age of 50) anxiety problems and later-life onset (after the age of 50) anxiety problems. Differences in the severity and type of anxiety were assessed, as well as differences in health care use, quality of life, functional impairment, comorbid depressive complaints, comorbid somatic problems and positive mental health. This crosssectional study included 161 participants that experienced anxiety problems (aged 55-75). Multiple one-way ANOVAs were used to compare the early- and late-onset groups regarding clinical factors. A chi-square test, followed by a post-hoc z-test was performed to examine if certain types of anxiety more often had a late-onset. Results showed no significant differences in clinical factors between the early- and late-onset group. Generalized anxiety was significantly more often reported with a late-onset than early-onset (χ2 = 14.516, p = <.001) This finding underscores the need for further research on late-onset types of anxiety. Older adults with early vs. late-onset anxiety might differ on other clinical factors than those studied in the current article. Therefore, further research into potential similarities and differences between early- and late-onset groups should include a wide variety of clinical factors.Show less
Conflict is ever present in human society, and we endeavour to better understand the psychological mechanisms and decisions behind this conflict. Further expanding on work of the attacker-defender...Show moreConflict is ever present in human society, and we endeavour to better understand the psychological mechanisms and decisions behind this conflict. Further expanding on work of the attacker-defender game (ADG), while employing a principal-agent system, we examine sanctioning behaviour in this paradigm. This research finds that there is significantly more positive sanctioning for successful outcomes compared to failed outcomes in the ADG, for both attack and defence (H1/2). In comparing sanctioning for attack and defence, a significant difference was observed, with more positive sanctions awarded to attack outcomes compared to defence outcomes (H3). Similarly, overall successful outcomes were significantly more positively sanctioned when compared to failed outcomes (H4). Finally, a low-level significant interaction in a 2 x 2 model was observed for attack, defence and successful, failed outcomes in the ADG (H5). This research sets the foundations for further examination of sanctioning behaviour on decisions in the ADG.Show less
The aim of this study was to investigate if parental verbal threat vs. safe comments paired with strangers led to children having more fear beliefs and attention towards the stranger paired with...Show moreThe aim of this study was to investigate if parental verbal threat vs. safe comments paired with strangers led to children having more fear beliefs and attention towards the stranger paired with threat comments, while also looking if temperament (measured as behavioral inhibition (BI)) would have a moderating role. It was expected that children would have more fear beliefs and attention towards the stranger paired with parental verbal threat comments compared to the stranger paired safe comments and that BI would have a moderating role on the effect of parental verbal comments. The sample consisted of 4-6-year-olds. In the experiment a manipulation was used where one stranger was paired with threat comments and the other one with safe comments, both given by the parent. Then, the children encountered the strangers during a social and interaction task. The results show that children’s fear beliefs about the stranger paired with parental threat comments were significantly higher than about the stranger paired with parental safe comments. This was not the case for children’s attention towards the strangers. So, parental verbal threat comments paired with a stranger led to more fear beliefs but did not increase attention. Furthermore, the moderating role of temperament was not significant. To conclude, this study supports the growing evidence that children's fear beliefs can be changed by giving information but did not found this effect for attention. Also, the effect of verbal threat information on fear beliefs and attention did not differ as a function of child temperament.Show less
Background: Studies in the last couple of years revealed that nocebo effects, i.e., adverse treatment outcomes which are not caused by the active components of the treatment itself, negatively...Show moreBackground: Studies in the last couple of years revealed that nocebo effects, i.e., adverse treatment outcomes which are not caused by the active components of the treatment itself, negatively influence therapy results. Placebo effects could occur when participants know a treatment is inactive (i.e., open-label design). However, more research is needed to understand the effects of an open-label design with verbal suggestion on the nocebo effect. Secondly, more research is needed to detangle which personality factors are relevant to the nocebo effect. Objective: The present study aimed to investigate whether open-label conditioning combined with verbal suggestion can induce a nocebo effect. Furthermore, this research aimed to explore the relationship of pain catastrophizing and the nocebo response and investigate if this relationship was mediated by state anxiety. Design: A single blind, within-subjects, open-label design was used for the study. The nocebo effect was induced in 82 healthy females, via conditioning and verbal suggestion, using pressure pain. Before the experiment, participants filled in the State-Trait Anxiety Inventory and the Pain Catastrophizing Scale to measure state anxiety and pain catastrophizing. Results: This study showed that open-label conditioning combined with verbal suggestions was effective in inducing increased pain after the conditioned stimulus when compared to the control stimulus, indicating the presence of the nocebo effect. No significant results were found to support the hypothesis that pain catastrophizing is correlated with the nocebo effect, nor that this effect is mediated by state anxiety. Conclusion: These findings highlight the possibility to investigate the nocebo effect using a more ethical open-label design. Future research can implement an open-label approach when designing treatment procedures in a clinical population. More research is needed to clarify the role of pain catastrophizing and state anxiety on the nocebo effect.Show less
As previous studies show a positive relationship between present time orientation and psychological well-being, the purpose of the current within-subjects study is to examine whether a present time...Show moreAs previous studies show a positive relationship between present time orientation and psychological well-being, the purpose of the current within-subjects study is to examine whether a present time orientation, and otherwise mindfulness, can be found in word use of suicidal musicians over time. Fewer words referring to the present, compared to the past and the future were expected. Moreover, a decrease in the use of present time words, and an increase in the use of past and future time words, closer to the moment of suicide, was expected. The different means of the time categories were calculated with the Linguistic Inquiry and Word Count (LIWC). The Wilcoxon Signed Rank Test was used to test for differences in these means. To test for change over time in the time categories, the Kendall’s Tau B correlation coefficients were used. Present time orientation (M = 8.449) had a mean greater than both the mean of past time orientation (M = 2.308) and the future time orientation (M = 1.500). Moreover, future time orientation had a mean greater than past time orientation. I found that these differences were statistically significant. There was a significant decrease in words referring to the past (τb = -.113, p = .005) and a non-significant decrease in words referring to the future (τb = -.071, p = .081). Lastly, there was a significant decrease in words referring to the present (τb = -.153, p < .001). The finding of a decrease in present time, and the finding of less words referring to the future, compared to the past, are in line with previous studies on this topic. It is concluded that fewer words referring to the future, compared to the past and present, and a decrease in present time words over time can be an indication of suicide risk.Show less
Het bezitten van een hoge mate van zelfcontrole hangt samen met positieve uitkomsten zoals betere studieresultaten en minder alcoholmisbruik, blijkt uit meerdere, niet experimentele, studies....Show moreHet bezitten van een hoge mate van zelfcontrole hangt samen met positieve uitkomsten zoals betere studieresultaten en minder alcoholmisbruik, blijkt uit meerdere, niet experimentele, studies. Zelfcontrole wordt hier gedefinieerd aan de hand van impulsinhibitie. Hierbij hangt een hoge mate van impulsiviteit en een lage mate van zelfcontrole samen met een lagere mate van Delay of Gratification (DoG). DoG wordt hier gemeten door middel van het Delay Discounting paradigm (DD). Het DD paradigm onderzoekt in hoeverre iemand bereid is om te wachten op een (hypothetische) geldsom als, door het wachten, deze beloning groter wordt. Uit eerder onderzoek onder jong-adolescenten blijkt een samenhang tussen zelfcontrole en chaos. Dit onderzoek kijkt of een dergelijke samenhang ook bestaat bij laatadolescenten. De verwachting is dat studentes met een meer chaotische thuisomgeving een mindere mate van zelfcontrole hebben. In dit onderzoek is gebruik gemaakt van drie instrumenten verzameld tijdens de studie Moeders van Morgen, een onderzoek uitgevoerd door de Universiteit Leiden. Er is gebruik gemaakt van de DoG computertaak, de DoG naturalistische vraag en de CHAOS-vragenlijst. Participanten die een antwoord gaven bij de DoG naturalistische vraag die geassocieerd wordt met meer zelfcontrole, kozen significant vaker voor antwoorden in de DoG computertaak die geassocieerd worden met meer zelfcontrole. Het verwachte verband tussen zelfcontrole en chaos is niet gevonden. Vervolgonderzoek, waarbij meer participanten, andere meetinstrumenten om zelfcontrole te meten en meerdere observaties van chaos aanbevolen zijn, is noodzakelijk.Show less
