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BACKGROUND: So far, previous research suggests positive effects of mental demands at the workplace. However, it may depend on how stressfull these demands are perceived on an individual level. OBJECTIVE: The aim was to build on previous research by investigating how mental demands are related to stress, overload, and work discontent and whether this relationship is mediated by individuals resources, such as resilience. METHOD: A sub-sample of the LIFE Adult Cohort (n = 480) was asked to answer questions on sociodemographic characteristics, objective stress (using the Trier Inventory of Chronic Stress (TICS)), and perceptions of stress with regard to verbal and executive mental demands at work. RESULTS: According to generalized linear regression models, higher verbal as well as executive mental demands were associated with higher levels of chronic stress, work overload and discontent. Higher levels of resilience were associated with lower levels of these outcomes. Analyses regarding interaction effects revealed that the interaction between resilience and perceived stress of verbal mental demands was significant only in terms of work overload. CONCLUSION: Higher perceived stressfulness of mental demands was associated with higher chronic stress, work overload and work discontent. Therefore, mental demands should be targeted by occupational interventions that aim to improve job conditions and employees' overall well-being. Besides resilience, other potential influencers or personal resources should be focused on in future studies to develop interventions.
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The present study examined the effects of stressful constraints during soccer trainings on psychological skill development and internal load when compared with control (nonstressful) trainings. A total of 51 elite male youth soccer players (27 in the experimental group, M = 16.54 years; 24 in the control group, M = 15.44 years) participated in the study. In a 12-week longitudinal survey, team resilience, using the Spanish version of the Characteristics of Resilience in Sports Teams Inventory, and anxiety, using the Sport Anxiety Scale, were measured at baseline (after 4 weeks of regular trainings), postprotocol (after 4 weeks of control or experimental trainings), and follow-up (after 4 weeks of regular trainings). Results show that, when compared with the control group, a program with stressful constraints helped young soccer players to develop better psychological skills: specifically, increased ability to cope with impairments in resilience (both resilience characteristics and team vulnerability under pressure; p < 0.001). Increases in anxiety (p = 0.06) and decreases in preoccupation (p < 0.001) and lack of concentration (p < 0.001) were also observed. The adaptation of human behavior to specific trainings may explain these results. In conclusion, the regular exposure of young soccer players to stressful situations during trainings shows benefits for their psychological skill development in soccer. Then, benefits on internal load were also observed.
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Desempenho Atlético , Futebol , Adolescente , Masculino , Humanos , Desempenho Atlético/psicologia , Ansiedade , Estudos Longitudinais , Transtornos de AnsiedadeRESUMO
OBJECTIVES: Growing evidence suggests a protective effect of high mental demands at work on cognitive function in later life. However, evidence on corresponding associations in older adults at increased risk for dementia is currently lacking. This study investigates the association between mental demands at work and cognitive functioning in the population of the AgeWell.de-trial. METHODS: Cross-sectional investigation of the association between global cognitive functioning (Montreal Cognitive Assessment) and mental demands at work in older individuals at increased risk for dementia (Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE)score ≥ 9; n = 941, age: 60-77 years). Occupational information was matched to Occupational Information Network (O*NET)-descriptors. Associations between cognitive function and O*NET-indices executive, verbal and novelty were investigated using generalized linear models. RESULTS: Higher values of index verbal (b = .69, p = .002) were associated with better cognitive function when adjusting for covariates. No association was observed for indices executive (b = .37, p = .062) and novelty (b = .45, p = .119). Higher education, younger age, and employment were linked to better cognitive function, while preexisting medical conditions did not change the associations. Higher levels of depressive symptomatology were associated with worse cognitive function. CONCLUSIONS: Higher levels of verbal demands at work were associated with better cognitive function for older adults with increased dementia risk. This suggests an advantage for older persons in jobs with high mental demands even after retirement and despite prevalent risk factors. Longitudinal studies are warranted to confirm these results and evaluate the potential of workplaces to prevent cognitive decline through increased mental demands.
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Disfunção Cognitiva , Demência , Idoso , Idoso de 80 Anos ou mais , Cognição , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/epidemiologia , Estudos Transversais , Demência/diagnóstico , Demência/epidemiologia , Humanos , Local de TrabalhoRESUMO
BACKGROUND: Work-life balance (WLB) is the extent to which individual's multiple life roles and demands carry over between each role. WLB can be divided into work interference with personal life (WIPL) and personal life interference with work (PLIW). This study aimed to investigate longitudinal associations between WIPL, PLIW and work ability outcomes. METHODS: In this cohort study, 224 employees in the energy and water sector in Sweden were followed-up over 2 years. Three questions derived from the Work Ability Index were used for measuring work ability outcome: current work ability compared with lifetime best; work ability regarding physical; and mental demands. Logistic regression models were used to analyse longitudinal associations between work ability and WIPL and WIPL respectively, controlling for workplace (company), position at work, experience of leadership quality, demographics, and work ability. RESULTS: Work ability compared to lifetime best were associated with WIPL in the adjusted logistic regression models (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.15-2.73), and PLIW (OR 3.34, 95% CI 1.66-6.74). Work ability regarding physical demands was associated with WIPL (OR 1.60, 95% CI 1.07-2.40). Work ability regarding mental demands was associated with WIPL (OR 1.59, 95% CI 1.03-2.44) and PLIW (OR 2.88, 95% CI 1.31-6.32). CONCLUSION: In this two-year longitudinal study, lower WIPL predicted good/excellent overall work ability compared with lifetime best, higher work ability regarding physical and mental demands, and lower PLIW predicted good/excellent overall work ability compared with lifetime best and higher work ability regarding and mental demands.
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Avaliação da Capacidade de Trabalho , Equilíbrio Trabalho-Vida , Estudos de Coortes , Humanos , Estudos Longitudinais , Inquéritos e Questionários , Suécia/epidemiologia , Água , Local de TrabalhoRESUMO
Several papers by Eckhard Hess from the 1960s and 1970s report that the pupils dilate or constrict according to the interest value, arousing content, or mental demands of visual stimuli. However, Hess mostly used small sample sizes and undocumented luminance control. In a first experiment (N = 182) and a second preregistered experiment (N = 147), we replicated five studies of Hess using modern equipment. Our experiments (1) did not support the hypothesis of gender differences in pupil diameter change with respect to baseline (PC) when viewing stimuli of different interest value, (2) showed that solving more difficult multiplications yields a larger PC in the seconds before providing an answer and a larger maximum PC, but a smaller PC at a fixed time after the onset of the multiplication, (3) did not support the hypothesis that participants' PC mimics the pupil diameter in a pair of schematic eyes but not in single-eyed or three-eyed stimuli, (4) did not support the hypothesis of gender differences in PC when watching a video of a male trying to escape a mob, and (5) supported the hypothesis that arousing words yield a higher PC than non-arousing words. Although we did not observe consistent gender differences in PC, additional analyses showed gender differences in eye movements towards erogenous zones. Furthermore, PC strongly correlated with the luminance of the locations where participants looked. Overall, our replications confirm Hess's findings that pupils dilate in response to mental demands and stimuli of an arousing nature. Hess's hypotheses regarding pupil mimicry and gender differences in pupil dilation did not replicate.
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Pupila , Pesquisa , Humanos , Masculino , Estimulação Luminosa , Fatores SexuaisRESUMO
PURPOSE: To determine if small-sided games (SSGs) could be designed to target specific task loads using the National Aeronautics and Space Administration task load index as well as reporting the influence of the physical and technical demands. METHODS: Using a within-session, repeated-measures design, 26 junior rugby league players completed 5 SSGs focused on physical, technical, temporal, cognitive, and frustration task loads. National Aeronautics and Space Administration task load index responses were evaluated after each game; the physical demands were recorded using microtechnology; and skill involvement recorded using video analysis. RESULTS: In each SSG, the task load emphasized (eg, physical load/physical game) emerged with a higher score than the other loads and SSGs. The physical demands were lowest during the physical game (effect size = -3.11 to 3.50) and elicited greater defensive involvements (effect size = 0.12 to 3.19). The highest physical demands and attacking involvements were observed during the temporal game. Lower intensity activities were generally negatively associated with physical, performance, temporal, and total load (η2 = -.07 to -.43) but positively associated with technical, effort, cognitive, and frustration (η2 = .01 to .33). Distance covered in total and at higher speeds was positively associated with physical, effort, performance, total load (η2 = .18 to .65), and negatively associated with technical, frustration, and cognitive load (η2 = -.10 to -.36). Attacking and defensive involvements generally increased the respective task loads (η2 = .03 to .41). CONCLUSION: Coaches and sport scientists can design SSGs specifically targeted at subjective task loads in a sport-specific manner and through manipulation of the physical and technical demands.
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Desempenho Atlético , Futebol Americano , Humanos , Microtecnologia , Esforço FísicoRESUMO
Much psychological research uses pupil diameter measurements to investigate the cognitive and emotional effects of visual stimuli. A potential problem is that accommodating at a nearby point causes the pupil to constrict. This study examined to what extent accommodation is a confounder in pupillometry research. Participants solved multiplication problems at different distances (Experiment 1) and looked at line drawings with different monocular depth cues (Experiment 2) while their pupil diameter, refraction, and vergence angle were recorded using a photorefractor. Experiment 1 showed that the pupils dilated while performing the multiplications, for all presentation distances. Pupillary constriction due to accommodation was not strong enough to override pupil dilation due to cognitive load. Experiment 2 showed that monocular depth cues caused a small shift in refraction in the expected direction. We conclude that, for the young student sample we used, pupil diameter measurements are not substantially affected by accommodation.
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Acomodação Ocular , Pupila , Sinais (Psicologia) , Emoções , HumanosRESUMO
OBJECTIVES: Previous studies have observed protective effects of high mental demands at work on cognitive functioning and dementia risk. However, it is unclear what types of demands drive this effect and whether this effect is subject to a person's genetic risk. We investigated to what extent eight different types of mental demands at work together with the APOE e4 allele, a major risk gene for late-onset Alzheimer's disease, affect cognitive functioning in late life. METHODS/DESIGN: The population-based German Study on Ageing, Cognition, and Dementia in Primary Care Patients (AgeCoDe, n = 2 154) followed cognitively healthy individuals aged 75 years and older in seven assessment waves. Cognitive functioning was assessed via the mini-mental status examination. RESULTS: Mixed-effects modeling (adjusted for education, gender, marital status, stroke, depression, and diabetes) indicated that participants who had an occupational history of working in jobs with high compared to low demands in "Language & Knowledge", "Pattern detection", "Information processing", and "Service" had a slower cognitive decline. APOE e4-allele carriers had an accelerated cognitive decline, but this decline was significantly smaller if they had a medium compared to a low level of demands in contrast to non-carriers. CONCLUSIONS: Our longitudinal observations suggest that cognitive decline could be slowed by an intellectually enriched lifestyle even in risk gene carriers. Fostering intellectual engagement throughout the life-course could be a key prevention initiative to promote better cognitive health in old age.
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Disfunção Cognitiva , Demência , Idoso , Envelhecimento , Alelos , Apolipoproteína E4/genética , Apolipoproteínas E/genética , Cognição , Disfunção Cognitiva/genética , Demência/genética , Humanos , Idioma , Atenção Primária à SaúdeRESUMO
OBJECTIVES: Research shows that mental demands at work affect later-life cognitive functioning and dementia risk, but systematic assessment of protective mental work demands (PMWDs) is still missing. The goal of this research was to develop a questionnaire to assess PMWDs. DESIGN: The instrument was developed in accordance with internationally recognized scientific standards comprising conceptualization, pretesting, and validation via confirmatory factor analysis (CFA), principal component analysis (PCA), and multiple regression analyses. PARTICIPANTS: We included 346 participants, 72.3% female, with an average age of 56.3 years. MEASUREMENT: Item pool, sociodemographic questions, and cognitive tests: Trail-Making Test A/B, Word List Recall, Verbal Fluency Test, Benton Visual Retention Test, Reading Minds in the Eyes Test. RESULTS: CFAs of eight existing PMWD-concepts revealed weaker fit indices than PCA of the item pool that resulted in five concepts. We computed multivariate regression analyses with all 13 PMWD-concepts as predictors of cognitive functioning. After removing PMWD-concepts that predicted less than two cognitive test scores and excluding others due to overlapping items, the final questionnaire contained four PMWD-concepts: Mental Workload (three items, Cronbach's α = .58), Verbal Demands (four, Cronbach's α = .74), Information Load (six, Cronbach's α = .83), and Extended Job Control (six, Cronbach's α = .83). CONCLUSIONS: The PMWD-Questionnaire intends to assess protective mental demands at the workplace. Information processing demands and job control make up the primary components emphasizing their relevance regarding cognitive health in old age. Long-term follow-up studies will need to validate construct validity with respect to dementia risk.
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Cognição , Fatores de Proteção , Medição de Risco , Inquéritos e Questionários , Local de Trabalho/psicologia , Demência/diagnóstico , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Fatores SociológicosRESUMO
OBJECTIVES: Previous work has shown that high mental demands are associated with better cognitive functioning in old age. As there is a lack of a general conceptual framework for this association, the aim of the study was to investigate how mental demands and other work-related factors relate to cognitive functioning as a foundation for developing such a framework. METHODS: An expert panel discussion was conducted with the aim of determining relevant work-related factors, which were then tested in a survey with 346 employees aged 50+ years, who were actively working. Assessment of cognitive functioning comprised complex attention, executive function, learning/memory, language, perceptual-motor, and social cognition. Confirmatory factor analysis was conducted to confirm factor belonging. Associations with cognitive functioning were analyzed using structure equation modelling to confirm associations and to identify additional direct and indirect paths. RESULTS: Only 42.3% (22/52) of the work-related factors and 19.0% (4/21) of the mediating paths suggested by the experts were significant with respect to cognitive functioning. Factor analysis and structural equation modeling indicated that high mental demands are only associated with better cognitive functioning in old age to the extent that they are intellectually stimulating and this effect is embedded in individual capacities and the social context. CONCLUSION: Based on the panel discussion and the empirical testing, we propose the Conceptual Framework of Social Dependency of Intellectual Stimulation on Cognitive Health. We recommend researchers and workplace health experts to pay attention to the component of this theory when assessing workplace risk.
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Cognição , Local de Trabalho , Função Executiva , Humanos , Idioma , Inquéritos e QuestionáriosRESUMO
Digitalization of knowledge work is essential for today's organizations, responding to diversified employee needs. Many organizations are already implementing some form of flexibility to help workers perform work and non-work duties, while maintaining high productivity. While these changes in workplaces, "New Ways of Working (NWW)", have been discussed in the literature, a systematic appraisal of evidence of NWW has not been conducted. Relating to poor work-related mental health worldwide, this systematic review analyzed the psychological impacts of NWW, and the quality and quantity of NWW research. Following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines, NWW studies targeting psychological outcomes were evaluated. Initial literature search on ProQuest, PsycINFO, Science Direct, and Google Scholar retrieved 308 titles, from which seven articles fulfilled all inclusion criteria. Our appraisal revealed that NWW research evaluated diverse psychological outcomes. While NWW can help workers' engagement, work-related flow, and connectivity among staff, NWW can also increase blurred work-home boundary, fatigue, and mental demands. The quality of NWW research was overall medium, needing more rigorous studies. Our findings can inform decision-makers in the workplace to effectively implement NWW, and researchers to improve the quality and the usefulness of future NWW studies.
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Fadiga , Saúde Mental , Local de Trabalho , Estudos Transversais , Feminino , Humanos , Masculino , Carga de TrabalhoRESUMO
High mental demands at work was examined as a possible protective factor to reduce the risk of dementia in 1,277 initially dementia-free participants, aged 60 years and older. The cohort was followed for a mean of 13.6 years. During follow-up, 376 participants developed all-cause dementia (Alzheimer's diseaseâ=â199; vascular dementiaâ=â145). The association between mental demands at work and dementia was analyzed with Cox hazard models, adjusted for a range of covariates. The results revealed no significant association between mental demands at work and incidence of dementia. Based on the measures used in this study, it was concluded that high mental demands at work may not reduce the risk of dementia later in life.
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Demência/prevenção & controle , Estresse Psicológico/psicologia , Trabalho/psicologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/prevenção & controle , Doença de Alzheimer/psicologia , Estudos de Coortes , Demência Vascular/prevenção & controle , Demência Vascular/psicologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Ocupações , Fatores de RiscoRESUMO
As higher mental demands at work are associated with lower dementia risk and a key symptom of dementia is hippocampal atrophy, the study aimed at investigating the association between mental demands at work and hippocampal volume. We analyzed data from the population-based LIFE-Adult-Study in Leipzig, Germany (n = 1,409, age 40-80). Hippocampal volumes were measured via three-dimensional Magnetic resonance imaging (MRI; 3D MP-RAGE) and mental demands at work were classified via the O*NET database. Linear regression analyses adjusted for gender, age, education, APOE e4-allele, hypertension, and diabetes revealed associations between higher demands in "language and knowledge," "information processing," and "creativity" at work on larger white and gray matter volume and better cognitive functioning with "creativity" having stronger effects for people not yet retired. Among retired individuals, higher demands in "pattern detection" were associated with larger white matter volume as well as larger hippocampal subfields CA2/CA3, suggesting a retention effect later in life. There were no other relevant associations with hippocampal volume. Our findings do not support the idea that mental demands at work protect cognitive health via hippocampal volume or brain volume. Further research may clarify through what mechanism mentally demanding activities influence specifically dementia pathology in the brain.
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Objectives: Mental demands at the workplace can be preventive against cognitive decline. However, personality shapes the way information is processed and we therefore assume that Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness, would moderate the beneficial effects of workplace stimulation on cognitive outcomes.Methods: We analyzed data from the population-based LIFE-Adult-Study (n = 6529). Cognitive outcomes were assessed via the Trail-Making Test (TMTA, TMTB) and the Verbal Fluency Test. Personality was assessed via the Personality Adjective List (16 AM). Mental demands were classified with the indices Verbal and Executive based on the O*NET database.Results: Multivariate regression analyses showed only two significant moderation effects of personality, i.e. in individuals with low scores on Conscientiousness/Openness, index Verbal was connected to better TMTB performance, while this effect disappeared for individuals with high values on the personality trait. However, the additional explained variance remained marginal.Conclusion: The findings suggest that personality does not modify associations between high mental demands at work and better cognitive functioning in old age; however, there is a tendency that high levels of Openness and Conscientiousness may offset effects of mental demands.
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Cognição , Extroversão Psicológica , Local de Trabalho , Humanos , Neuroticismo , PersonalidadeRESUMO
OBJECTIVE: Workplace-related mental demands (WPMDs) are considered to be protective factors for cognitive health in old age and are linked to delayed onset of dementia. Yet, what exactly is meant by WPMDs differs greatly between studies, putting an enormous challenge on researchers and practitioners. Aim of our study was thus to create a systematic overview on WPMD concepts and to depict their associations with dementia and cognitive decline. Thereby, we want to create a solid basis for further work and implementation. DATA SOURCE: PubMed, PsycINFO, Web of Science. INCLUSION/EXCLUSION CRITERIA: We included observational studies with populations older than 18 that addressed the association between WPMDs and dementia/cognitive functioning and that were published as journal articles. We excluded studies with emotional and physical demands, stress, and organizational frameworks such as exposure variables and quality of life, depressive symptoms, burnout, and Parkinson as outcome. Furthermore, we excluded study populations younger than 18 and students. DATA EXTRACTION: Standardized search string. DATA SYNTHESIS: Based on theoretical concepts. RESULTS: Thirty-four studies that employed concepts of WPMDs in 5 different categories: complexity with people/data/things, cognitive demands, job control, novelty, and mental workload. DISCUSSION: Challenges associated with categorizing WPMDs as well as theoretical and measurement-related implications are discussed. CONCLUSION: This review helps to better understand how workplaces can contribute to later life cognitive fitness, and it offers a conceptual overview for practitioners that want to create more protective working environments or improve existing ones.
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Disfunção Cognitiva/prevenção & controle , Demência/prevenção & controle , Local de Trabalho/psicologia , HumanosRESUMO
BACKGROUND: Enriched environment at work (EEW), in terms of high mental demands at work, may be of great relevance for preventative efforts against cognitive decline and dementia as previous studies have shown. Yet, there is the concern that high EEW mental demands may accelerate stress and cause burnout. OBJECTIVE: The aim of our study was to investigate how EEW mental demands are related to stress and burnout. METHOD: A convenience sample of employees in the city area of Leipzig, Germany, was asked to fill out the Copenhagen Burnout Inventory and indicate for each EEW mental demand the level experienced, demandingness, and stressfulness. RESULTS: Multivariate linear regression and structural equation modelling suggested that only some EEW mental demands were perceived as stressful when the level of the respective EEW mental demand was high. Higher stressfulness was associated with burnout symptoms - however, high levels of EEW mental demands were not significantly associated with burnout (neither directly nor indirectly). CONCLUSIONS: Our findings implied that subjectively perceived stressfulness seems to be a more relevant aspect than the actual level of the demand itself. However, further studies are necessary to validate our findings.
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Esgotamento Profissional/etiologia , Satisfação no Emprego , Local de Trabalho/normas , Esgotamento Profissional/psicologia , Estudos Transversais , Alemanha , Humanos , Estatísticas não Paramétricas , Estresse Psicológico/etiologia , Estresse Psicológico/psicologia , Inquéritos e Questionários , Local de Trabalho/psicologiaRESUMO
OBJECTIVES: The study investigated whether high mental demands at work, which have shown to promote a good cognitive functioning in old age, could offset the adverse association between social isolation and cognitive functioning. METHODS: Based on data from the population-based LIFE-Adult-Study, the association between cognitive functioning (Verbal Fluency Test, Trail Making Test B) and social isolation (Lubben Social Network Scale) as well as mental demands at work (O*NET database) was analyzed via linear regression analyses adjusted for age, sex, education, and sampling weights. RESULTS: Cognitive functioning was significantly lower in socially isolated individuals and in individuals working in low mental demands jobs-even in old age after retirement and even after taking into account the educational level. An interaction effect suggested stronger effects of mental demands at work in socially isolated than nonisolated individuals. CONCLUSIONS: The findings suggest that working in high mental-demand jobs could offset the adverse association between social isolation and cognitive functioning. Further research should evaluate how interventions that target social isolation and enhance mentally demanding activities promote a good cognitive functioning in old age.
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Envelhecimento/fisiologia , Disfunção Cognitiva/fisiopatologia , Emprego , Função Executiva/fisiologia , Testes Neuropsicológicos/estatística & dados numéricos , Isolamento Social , Apoio Social , Adulto , Idoso , Envelhecimento/psicologia , Emprego/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
INTRODUCTION: Previous studies have demonstrated that an overall high level of mental work demands decreased dementia risk. In our study, we investigated whether this effect is driven by specific mental work demands and whether it is exposure dependent. METHODS: Patients aged 75+ years were recruited from general practitioners and participated in up to seven assessment waves (every 1.5 years) of the longitudinal AgeCoDe study. Analyses of the impact of specific mental work demands on dementia risk were carried out via multivariate regression modeling (n = 2315). RESULTS: We observed a significantly lower dementia risk in individuals with a higher level of "information processing" (HR, 0.888), "pattern detection" (HR, 0.878), "mathematics" (HR, 0.878), and "creativity" (HR, 0.878). Yet, exposure-dependent effects were only significant for "information processing" and "pattern detection." DISCUSSION: Our longitudinal observations suggest that dementia risk may be reduced by some but not all types of mental work demands.
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Demência/epidemiologia , Demência/psicologia , Processos Mentais , Ocupações , Idoso , Demência/complicações , Análise Fatorial , Feminino , Seguimentos , Alemanha , Humanos , Modelos Logísticos , Estudos Longitudinais , Masculino , Probabilidade , Modelos de Riscos Proporcionais , Fatores SocioeconômicosRESUMO
PURPOSE: Most previous studies of concurrent physical and cognitive demands have addressed tasks of limited relevance to occupational work, and with dissociated physical and cognitive task components. This study investigated effects on muscle activity and heart rate variability of executing a repetitive occupational task with an added cognitive demand integral to correct task performance. METHODS: Thirty-five healthy females performed 7.5 min of standardized repetitive pipetting work in a baseline condition and a concurrent cognitive condition involving a complex instruction for correct performance. Average levels and variabilities of electromyographic activities in the upper trapezius and extensor carpi radialis (ECR) muscles were compared between these two conditions. Heart rate and heart rate variability were also assessed to measure autonomic nervous system activation. Subjects also rated perceived fatigue in the neck-shoulder region, as well as exertion. RESULTS: Concurrent cognitive demands increased trapezius muscle activity from 8.2% of maximum voluntary exertion (MVE) in baseline to 9.0% MVE (p = 0.0005), but did not significantly affect ECR muscle activity, heart rate, heart rate variability, perceived fatigue or exertion. CONCLUSION: Trapezius muscle activity increased by about 10%, without any accompanying cardiovascular response to indicate increased sympathetic activation. We suggest this slight increase in trapezius muscle activity to be due to changed muscle activation patterns within or among shoulder muscles. The results suggest that it may be possible to introduce modest cognitive demands necessary for correct performance in repetitive precision work without any major physiological effects, at least in the short term.
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Fenômenos Biomecânicos/fisiologia , Frequência Cardíaca/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Análise e Desempenho de Tarefas , Extremidade Superior/fisiologia , Adolescente , Adulto , Cognição/fisiologia , Eletromiografia/métodos , Feminino , Humanos , Ombro/fisiologia , Adulto JovemRESUMO
The effect of concurrent physical and cognitive demands on arm motor control is poorly understood. This exploratory study compared movement kinematics in a repetitive high-precision pipetting task with and without additional concurrent cognitive demands in the form of instructions necessary to locate the correct target tube. Thirty-five healthy female subjects performed a standardized pipetting task, transferring liquid repeatedly from one pick-up tube to different target tubes. In the reference condition, lights indicated the target tube in each movement cycle, while the target tube had to be deciphered from a row and column number on a computer screen in the condition with additional cognitive demands. Kinematics of the dominant arm was assessed using the central tendency and variability of the pipette-tip end-point trajectory and joint kinematics properties of the shoulder and elbow. Movements slowed down (lower velocities and higher area under the movement curves) and trajectory variability increased in the condition with additional cognitive demands, but there were no changes in the kinematics properties such as joint range of motion, times of acceleration and deceleration (as indicated by the time to peak velocity), average angles, or phase relationships between angle and angular velocity of shoulder or elbow movements between the two conditions. Further, there were also no differences in the size or structure of variability of the shoulder and elbow joint angles, suggesting that subjects could maintain the motor repertoire unaltered in the presence of these specific additional cognitive demands. Further studies should address motor control at other levels of concurrent cognitive demands, and with motor tasks that are less automated than the pipetting task used in the present study, so as to gain an increased understanding of the effect of concurrent cognitive demands for other activities of relevance to daily life.