Research Methods in Neuroscience
The article under review is titled, “Ten-year longitudinal trajectories of older adults’ basic and everyday cognitive abilities.” by Yam et al (2014). It was published on the November edition of the Neuropsychology journal. The main objective of undertaking this study was with a view to determining the participants’ daily longitudinal trajectories with such cognitive abilities as inductive reasoning, vocabulary and verbal memory. The independent variables used in the study include: age, vision, general health, sex, years of education, marital status, as well as reasoning ability. On the other hand, the independent variables of interest to the study included: speed, everyday cognition, vocabulary, reasoning, and memory.
In terms of methodology, the study population of 698 participants consisted was drawn from a randomized trial of a study by Willis et al (2006). Assessments were carried out at five baselines namely, after 1 year, after 2 years, after 3 years, after 5 years, and after 10 years. Data analysis was carried out via latent growth models.
Explanation of Results
Results from the latent growth models indicated a quadratic trajectory across the various cognitive domains that the study sought to examine. In terms of the fundamental cognitive predictors, the slope and level of daily cognition was highly linked to the slope and level of participant’s reasoning. It is important also to note that this association was also highly associated with gain in individual participants’ level of everyday cognition. Consequently, the study findings revealed a close association between inductive reasoning and everyday cognition among healthy older adults. At each of the five baselines adopted by the study over a span of 10 years, it emerged that reasoning on its own could be used to explain most differences in an individual’s daily cognition. While everyday cognition may not be free from possible decline, it can nonetheless, be preserved better in comparison with say, visual processing speed or verbal memory.
Strengths and weaknesses of the article
One of the key strengths of this study is that it was based on longitudinal analysis. The nature of this method of research affords the researcher an ample timeline to closely observe participants and thus reveal patterns of variables under study over time. Moreover, longitudinal studies help to reveal associations between various events over a prolonged time-frame, which may not be possible with other research designs. On the other hand, the study is characterised by a number of weaknesses. To begin with, the researchers relied on a narrow set of fundamental cognitive predictors. It would have been better if they had chosen a more detailed neuropsychological tool to assess various elements of executive functioning, along with the subsets of processing and memory speed. This would have enabled us to have a better comprehension of the fundamental cognitive elements of daily cognition (Wechsler, 2008). A further weakness for the study has to do with the selective nature of the participants. The researchers deliberately chose a healthy sample at the baseline, devoid of any cognitive decline. Nevertheless, the chosen sample can be broadly compared with related longitudinal researches on aging based on sex and age variables (Rabbit et al., 2004).
Suggestions for improvement
In order to ascertain the clinical utility of an individual’s daily cognitive measures, it is important that future studies endeavour to assess the associations that Yam et al (2014) attempted to establish but this time, the study population should encompass more participants with cognitive impairment.
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of older adults’ basic and everyday cognitive abilities’, Neuropsychology, 28(6), 819