CumulativeStress and Cognitive Ageing
CumulativeStress and Cognitive Ageing
APA Format Citation
Marshall,A. C., Segrave, R., Cooper, N. R., & Geeraert, N. (2015). TheEffects of Long-Term Stress Exposure on Ageing Cognition: ABehavioral and EEG Investigation. Neurobiologyof Ageing, 36(6),2136-2144.
Why We Should Care
Stresshas profound impacts on the ageing process and cognition. However,the impacts of long-term stress exposure on the ageing of the generalpopulation still remain an under-researched area. The purpose of thisstudy was to explore and understand the association existing betweencognitive ageing and cumulative stress levels and try answer thequestion whether high-stress levels profoundly impacts theperformance the human memory.
Three Background Facts
Morethan 75% of individuals above the age of 65, highly depend on welfareand healthcare systems due to cognitive decline. This perpetuates theestablishment of a body of research devoted towards explaining andunderstanding the various influences likely to cause varying rates ofcognition with an increase in age. Cumulative or chronic stress isone such influence, capable of causing adverse effects to theneocortex and the hippocampus, resulting to impaired cognitivefunctioning.
Stresshormones and stress-related blood hypertonic flow are the main causesof cognitive ageing. Stress hormones such as the glucocorticoidinhibit neurogenesis of the hippocampus due to the production of thedendritic atrophy. Moreover, high-stress levels lead to a hypertonicblood flow which according to scientists, highly produce microlesions, which in turn inhibits proper functioning of the neocortex(Rabbit, 2005. as cited by Marshall, 2015). For this reason,cumulative stress has been singled out as a major factor leading toimpaired cognition and conditions such as dementia and Alzheimer’samong the older people.
Accordingto Peavy et al. (2009), as cited by Marshall (2015), longitudinalstudies proved that chronic stress levels experienced over a periodof 2 years, led to a cumulative decline in the cognition and theoverall memory functioning among the elderly. Moreover, Dickson etal. (2013), as cited by Marshall (2015), reported thatcross-sectional studies explain the association between long-termexposure to stress levels and impaired memory performance regardlessof education status.
Forthose reasons, Marshall’s (2015) study was aimed to explore furtherthe association between cognitive ageing and cumulative stress,taking into consideration the wide array of other mediating factors.Moreover, this is study was purposed to investigate through whichchronic stress levels impacted maturation and functioning of thehuman mind. To do so, a number of research questions need adequateattention they include, do high levels of stress relate to animpaired performance on the human behavioural and EEG memory task? Documulative stress experiences affect cognitive ageing? And finally,what is the association between cognitive ageing and cumulativestress experience?
Forthis study, the researchers embarked on a correlational experimentstudy design whereby they concentrated on a sample of 30 elderlyvolunteers between ages 60-80 and 30 young volunteers between ages19-30. The young volunteers were recruited through emailing whereasthe elderly volunteers through presentations made in local societiesand clubs. The samples were relevant since, given the fact that theelderly sample was 3 times older than the young sample, they musthave experienced more stressful events that the young. Theindependent variable under study was the adverse effects of chronicstress and how it resulted to cognitive ageing. To enable insights ofthe neural process under effect by stress, behavioural performanceswere linked with the electroencephalogram (EEG) recordings. Bothyoung and the elderly were recorded by the EEG (a neuroimagingtechnology) while performing two different memory tasks, the N-backand the Sternberg. To access their performance, the gamma, alpha andtheta levels in the cortical oscillatory were measured.
Three Specific Results
Theelectrophysiological findings revealed an extremely high level ofreduced gamma and alpha synchronisations, amongst the elderlyvolunteers (Marshall, 2015). These findings mean that high chronicstress levels among the elderly volunteers may have impacted theirabilities to maintain an active impetus in their functioning memoryand impede inessential occurrences affecting efficacious maintenance.
Experiencedstress adversely impacted the elderly volunteers’ performanceregardless of education level this explains the low test scores onboth the N-back and Sternberg behavioural tasks among the elderly.The findings prove beyond doubt that cumulative or chronic stressnegatively impacts cognition. Marshall’s (2015) findings backed upthe previous cross-sectional and longitudinal research that lackedenough documentation.
Furthermore,due to the fact that no cognitive defects were found among the youngvolunteers including those who have encountered stressful events,prove that only long-term exposures to chronic stressful events causecognitive impairment. Additionally, failure to account for theimpacts of perceived stress portrays that cognitive ageing is notcaused by the inner feeling generated by stress, but by the actualexperience of the stressful event.
Take Home Message
Theresults showed that experienced stress and chronic ageing aredirectly proportional variables in that, the higher the rate ofstressful events, the higher the rate of chronic ageing. This study,therefore, proves that overall amount of stressful events experiencedthroughout an individual’s lifespan, may adversely impact cognitiveperformance and accelerate the rate of cognitive ageing.
Despitethe concrete research findings, I do believe that the results wouldhave been much stabilised and accurate had the researchers controlledother mediating factors that cause cognitive ageing, such asperceived stress. Moreover, the researchers refrained fromelaborating the major effects of the stress caused and instead theyfocused on the association between the cumulative stress andcognitive ageing.
Comparedwith the young volunteers, the elderly people obviously had higherstress levels since they have lived for many years. Therefore, abetter approach would have been to concentrate on either of the agegroups. This way, the different test scores could reveal differentreasons for varied cognitive ageing among the young for example.
Suggestions for Improvement
Thefindings of this study would have been much pertinent had theresearchers dwelt on accessing the stress levels of the different agegroups instead of making a comparison between the young and the old
Stressis an unavoidable circumstance it is a natural physical response.However, we need to watch out on our stress levels as chronic orcumulative stress could have adverse impacts to our bodies whenunder chronic stress our body releases stress hormones that pose adanger to our neocortex and hippocampus, accelerating cognitiveageing which in turn result to memory loss conditions such asdementia. Cognitive abilities refer to the human mental skillsessential to carry out simple to complex tasks. Such mental skillsinclude reasoning, memory, perception, handling information andawareness. However, these abilities slowly degrade as we age.Cognitive decline is a normal part of ageing but is howeverintensified to dangerous levels by stressful experiences. Therefore,stress management skills are essential for an intact cognition and aproper cognitive functioning.
Aspects of the dissection I did well
Idid a good job in trying to elaborate the purpose, rationale,methodology and results of this study. Moreover I gave strongcritiques and pointed out possible confounds and biases associatedwith the study. I also recommended a possible way forward in handlingsuch a study.
Aspects of the dissection that are not my best work
Inaddition to the behavioral study on stress, I would have accountedfor other health-related factors that lead to cognitive ageing, suchas, prolonged substance abuse, physical disability and more.