Sleep, Memory, And Aging. The Link between Slow-Wave Sleep and Episodic Memory Changes from Younger to Older Adults.
Sleep, Memory, And Aging. The Link between Slow-Wave Sleep and Episodic Memory Changes from Younger to Older Adults.
Introduction
An interesting modern healthcare development has been found in the discovery of slow wave sleep in the reactivation of episodic memories. It, however, decreases its effect while the age of the patient is increasing. Also, little research has been found on the use of slow wave sleep on the elderly with the majority of the volunteers for the test being of the younger adult age group. It provides an interesting topic that needs further elaboration, on whether there is a connection between the developments of the episodic memory and slow wave sleep. The research would need to be concentrated on the aspect of age and whether any recognizable elements can help elaborate its influence on slow wave sleep. The manner of which slow wave sleep catalyzes the function of the human memory involves the scientific discovery that can be summarized as episodic memory.
Past studies that recorded cells of the brain showed an elaborately repeated firing from the neocortical and hippocampal then back. In theory, memories are transmitted from the short-term hippocampal storage to the long-term neocortical memory storage in these cells. In much simpler terms, it can be described as the avid recollection of information that the brain may have picked up on the day. The transfer is known as consolidation that has been known to improve the capacity of the hippocampus to retain memories. The relevance of consolidating memories with the use of slow wave sleep has been noted to recur to the younger segment of the conventional human population.
It might explain why memory loss happens to the elderly at some point in their senior life. It provides a critical basis for the research questions to be answered in the proposal. “Do episodic memory decline with an increase in age? Do episodic memory developments have a direct influence on the frequency of slow wave sleep? Does the high rate of slow wave sleep explain why older adults have a much lighter sleep in comparison to their younger compatriots?”
Based on the research questions elaborated above, the research program proposed would be built on the following hypotheses that will also guide the contents of data to be analyzed:
H1: Episodic memory does not decline with an increase in age.
H0: Episodic memory developments have a direct influence on the frequency of slow wave sleep.
H1: Episodic memory development does not have a direct impact on the incidence of slow wave sleep.
H0: The high rate of slow wave sleep reduces the rate of relaxation in sleep.
H1: The high incidence of slow wave sleep does not lessen the rate of relaxation in sleep.
Literature Review
In the past, research delved into finding a scientific explanation on a cognitive aid as developments in the quantities of slow wave sleep. Scientists have made commendable steps in trying to justify that augment memory can be boosted in the elderly through pharmacologically altering the level of slow wave sleep. A research on rodent test subjects sought to confirm whether the increase in age has a positive or negative influence on the link between memories and sleep. The research posted results that indicated a replay of memories in normal rodent models as opposed to older rodents, which showed several sequences of temporal disorganization. Wolkove (2007) added on with a performance analysis of the Morris Water Maze task in aged rodents. The models indicated the lack of significant correlation between the times they slept to the performance of their memories. The contradiction is found in the conclusion, at the researcher sought to identify that if memory deprivation is affected by sleep, then rodent models that have slept for longer ought to have much poorer retention of the experiment. The results were inconclusive as no correlation, positive or negative was confirmed.
Nevertheless, the study of slow wave sleep about vigilance on human test subjects has the potential to shed reason on the possibility of the clouding of the sleep-cognition aspect amongst the elderly. Past studies have indicated a decrease in fatigue accumulated during the daytime, among young adults with large quantities of slow wave sleep. On critical example is Wiersynski & Lubenov (2009) who contributed the suggestion that the connection between cognitive performance and slow wave sleep is likely to reduce with aging. It was a reaction to the research that showed young adults with lower levels of slow wave sleep were less vigilant the following day. It gets interesting when one delves into the available literature on studies about aging and deprivation of sleep; that suggest that sleep may be severe cognition in the younger segment of the community but not the older. In addition to that, it goes without question that any form of sleep deprivation, whether partial or complete, has a direct influence on the cognitive nature of younger minds.
The theory that elaborates memory functions during sleep are a production of the preservation of memory traces from interference also constitute the presumption that the brain switches off during sleep. Research on neural activity, while the human brain is asleep, was proven when through the noticing of REM (rapid eye movement) sleep. Elaborately, it provides that the brain not is homogenous during sleep but rotates through several qualitative stages of function. The resultant effect over the years saw the discovery of means of telling the difference between the stages of non- REM sleep and REM sleep.
The number of non-REM or REM stages of sleep per night averages between five and six 90-minute intervals. The time spent in each stage is based on the total time spent sleeping. The first stage of non-REM sleep is entered during the transitional phase between staying awake and falling asleep. The second stage is widely regarded as true sleep. There is considerably low EEG activity about periods of rest while awake. Collectively, these steps can be termed as light sleep as there is a higher frequency of a human to wake as opposed to not. the third and fourth stage follow in quick succession and have a characteristic dilapidated level of activity on the EEG that reads between 1 and 4 Hz with low oscillations of negative 1.
The frontal regions that encompass the medial prefrontal cortex are collectively known as neocortex and is responsible for the generation of the slow oscillations. Also, it is believed to be also responsible for the activation of sleep spindles, scientifically known as thalamocortical neurons as well as the sharp wave ripples, which are also referred to as the hippocampal-cortical neurons. When all these factors such as ripples, spindles and consolations are disregarded studies specializing in positron emission tomography show that the brain is the least active drive the latter pair of non-REM stages of sleep. It is also known as deep sleep.
The research proposed in this paper circulates how sleeping patterns are associated with the conventional aging process.
The development of sleeping patterns is related to bot chronologic and maturation stages of growth albeit the lack of comprehensive studies on the difference between young adults and the elderly to that effect. It should be noted that in elderly citizens, chronologic age is not always a mat to the physiologic age. As such, developments in the pattern of sleep can occur much earlier in life or older in others. Technically the epidemiologic studies available today indicate that sleep pattern disturbance in the modern day older generation member is attributed to the type of medication accessed and not their age.
Therefore, the research proposal seeks to identify a better elaboration of normative sleep and memory retention, across the relative life span of humans through identification of age-related developments in comprehensively observed sleeping patterns of volunteering components through Meta-analyses. Also, it will enable the clarification of whether the lack of influence on certain relevant variables has an effect on the sleep patterns of individuals representing different age groups.
Methods
Design
The entities that are encompassed in the research namely slow wave sleep, age and cognitive memory need to be correlated to understand their influence on each other. As such, the research would need to gather information from an elaborate case study taking into consideration that there has been little development on the consideration of age as a determining factor of the capacity for a human being to retain memories through slow wave sleep. The type of design used will be qualitative. This is because the organization of a primary form of a collection of information about the research will be expensive and time-consuming. It would require the identification of case studies, the organization of correspondents, inclusive of facilitators of interviews to collect the data needed. In qualitative research, the sources of information will be past works of literature. In this manner, the research will focus on analyzing past research programs about slow wave sleep memory detainment about age.
Sampling Strategy
The studies of interest will be based on predefined stipulations of the Meta-analyses needed. The first criteria are ensuring that all the research programs analyzed have carried out clinical tests. It would involve the selection of volunteering correspondents representing different age groups. The participants named in these research programs ought to be at least five years old and older. It would enable the analysis of samples of school going children, teenagers, young adults and the elderly. The measures about sleep should be encompassing actigraphy or PSG all through the night with a consideration of stipulated variables. These variables are inclusive of the efficiency of sleeping, the latency of sleeping, stage one and two levels of sleep, REM sleep, slow wave sleep, REM latency as well as TST.
The articles will also need to encompass statistically elaborated numerical data. They also need to have been recently published within the last decade to obtain information that may still be dependable in modern say research surveys. The databases from which these works of literature will be sourced ought to be dependable and have a background in medical research. The databases of interest began with PubMed, followed by Science Citation Index and ending with PsyInfo. To elaborately search for the correct publications, some keywords were also predefined. They included heath care, slow wave sleep, normative and normal sleep, and cognitive memory. If the works of literature found will be insufficient, there will be an alternate option is the screening of the citations in the documents that have been already found. The screening will be done as a means of ensuring that research articles containing the same information are revised amidst themselves.
Procedure/Measures
The reports collected will each be individually reviewed based on six conditions. The first is that each should encompass at least one key variable. The sampling techniques regarding some correspondents and recruitment exercises were dependable comes in second. Thirdly, the statistical results of the data analysis done were relevant to at least one key variable. In fourth, central tendency measures such as the means or the variability referred to at least one variable. What follows is the identification of age brackets and a summary of tests done based on the same. The correlation between cognitive memory and slow wave sleep is elaborated the last qualification.
Data Analysis
The reports that recorded good results to the first four criterion, as well as one between the fifth and sixth, were interpreted more keenly. A summary of the key elements would be done inclusive of the observable background, the volunteering process of the correspondents, modes of intervention, the criteria used in their selection, constitutes of the sampling process, assessment of variables and the general outcome of the research.
If the research program of interest has more than a couple of nights of recording PSG activity, the initial night outcomes will be considered as irrelevant especially if data from all the nights when the exercise was conducted is available. To calculate the effect sizes, which are the indices that quantify the level of difference of one group from another. These effect sizes can be analyzed by either standardizing the differences between two categories or calculating the correlation between an individual score on the dependent variable and the classified independent variable.
The ideal analysis method is standardized differences as it enables the use of Cohen’s d. it is the difference between the means of two groups. If the research article being analyzed do not provide standard deviations or means for the relevant variables, the effect size can be calculated from the coefficients of correlation, variance analysis or event tests. The effect sizes will be calculated using Comprehensive Meta-Analysis. It is a statistical software package created by Biostat. It enables the correction of effect sizes from errors that arise during sampling. It is ideal if the research program of interest has a low sampling size. The Hedges and Olkin formula can be used to obtain an unbiased estimate. It reads d=d*(1-[three/ {four (M1+M2-9}]). The d values will be obtained based on the Cohen guidelines. Effect sizes that post at .2 will be elaborated, as small, medium ones will be at .5 with the large ones setting at .8. As such, a positive outcome of the effect size shows an increase with the age of the key variables while a negative outcome will be regarded as a decrease with age. The close it is to zero, the smaller the difference regarding age.
Ethical Issues
The predominant issue with the use of other works of literature is authentication and permission to use the information encompassed within the research. It is critical that the research team ensure that the sources of information all have a legitimate permission to obtain and paraphrase the data encompassed within the respective pages. Due to the aspect of critically analyzing other works of literature from different authors, it imperative that the research team does not plagiarize the authors as well. It is critical that the manner with which the information will be transferred to the research proposed to be legitimate and authentic, and it does not, in any way steal, or misquote the authors of these sources. It is important for the research team to maintain some form of discretion about the correspondents encompassed in the research programs selected for analysis. If the correspondents do not know which their personal information or identification to be revealed, it is important for the research team to respect these wishes, just as the author of the source did.
Conclusion
The use of normative data in the analysis of the development of the architecture of sleep during a human being’s lifespan is critical to the understanding of the changes regarding sleeping patterns while one continues to age. The effect REM sleep and slow-wave sleep as it evolves with age should be researched. It should be confirmed whether the constant readings of TST in young adults is due to biological or environmental changes. The confirmation of the change in levels of REM sleep while a child matures into adulthood has something to do with their age. It should confirm that the latency of sleep increases with age due to the reduction of cognitive memory during the initial stages of sleep.
A research program that focuses on the meta-analysis of past research programs on these topics has the potential to shed light on the need for better screening methodologies in the study of sleeping patterns to accommodate the age factor. Such methodologies are because the best results about the age factor would be best recorded over a significant period of the correspondent’s lifespan, preferably during a transitional phase from one age group to another.
References
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