Please note! This essay has been submitted by a student.
New research and findings are released everyday into the public, typically through a public press release of the data reinterpreted by the media. Being given the research information, it can often be a very fine line between whether the hypothesis being tested is a cause and effect relationship or if the factors are simply just associated with eachother. This fine line is crossed by writers and journalists trying to get information out there in a shorter, easier to read article. A good example of this misinterpretation would be an article with a headline to the effect of “Eating Breakfast Everyday will Make You Lose Weight”. Studies have been done to show only that there is a correlation between eating breakfast and weight lose, but never a distinct cause and effect relationship as there are many other factors to be considered with this topic. A similar situation has occurred with another study. In the peer-reviewed article Poor Sleep Quality is Associated with Increased Cortical Atrophy in Community-Dwelling Adults written by Claire Sexton, Andreas Storsve, Kristine Walhovd, etc. , the relationship between sleep quality and hippocampal and cortical volume was assessed. This article was released after the study was complete and a popular press article titled Lack of Sleep May Shrink your Brain written by Val Willingham emerged shortly after. This press article isn’t relaying to readers wrong information though, just in the titles alone both articles suggest that the research findings were only correlational and not causal.
In the peer-reviewed article, their hypothesis stated that a decreased volume and elevated atrophy of the orbitofrontal cortex (OFC) and medial prefrontal cortex(mPFC) was linked to inadequate sleep. The hypothesis was expanded to test the possible correlations affecting parietal, temporal, and frontal lobes of the brain as well. The independent variable was the quality of sleep people got and the dependent variable being the overall volume at each vertex of the brain and PSQI scores (Sexton, 2014). Participants were gathered using an ad in a newspaper, and then specific participants were invited for follow-up assessments after they were all health scene for eligibility. Putting their hypothesis to the test, the regular sleep quality of 147 community-dwelling adults was recorded utilizing the Pittsburg Sleep Quality Index (PSQI). Using an MRI machine, the volume and atrophy of the OFC and mPFC was measured and found to be negatively correlated with the findings from the PSQI (Sexton, 2014). This shows that as sleep quality decreased, the severity of brain atrophy worsened. Two separate MRI scans were conducted on the same subjects, once before they completed a questionnaire about their sleep habits, and then one more time approximately three and a half years later. The studies did show a much faster decline in brain volume in those subjects that had poor sleep habits, or conditions such as insomnia that limit the quality of sleep the subject received (Sexton,2014). The hypothesis of this study was proven in the sense that there is cause to believe that these factors are related as their findings did show that sleep quality did effect atrophy of the frontal, temporal,and parietal lobes as well as the OFC, but it not associated with atrophy of the mPFC. Furthermore, the hypothesis cannot be stated as a causal relationship because there are many more variables to be considered (Sexton, 2014). There is also no way of telling whether quality of sleep causes brain deterioration or if sleep quality is a product of brain deterioration. While sleep quality may be connected to brain atrophy, there are many more factors that could be at play such as the subjects genetics, past family history of illnesses affecting the brain, and their overall health as an individual could play a big role in the “health” of their brains.
In the popular press released article the design of the experiment was briefly explained. After laying out the details of who participated in the study and how the data was gathered the results of the study were discussed. In the article it states that only 35% of participants in the study met the stands of having poor sleep health and further explained that the participants that had sleep issues also showed a deeper level of brain atrophy compared to people with health sleep habits (willingham, 2015). It is also stated that a shortage of sleep can lead to loss of memory as well, but in the peer-reviewed article no associations between hippocampal atrophy and sleep were made (Willingham, 2015). A quote in the press-release article made by Dr. Neal Maru does imply that sleep and mental health issues are causally related, but the article overall stresses only that the two factors are correlated with each other (Willingham, 2015). The end of the article implies that while it seems they are related, more research would need to be conducted to further diagnose a causal relationship between brain atrophy and sleep quality. The information from the peer-peer-reviewed article was only partially reported in the press-release article.
The basics of the design study were given, but no full analysis of the results was provided. It seems as if the author read the peer-reviewed article and then gave his/her opinion of the topic and what she believed to be true. A causal relationship wasn’t implied through the press-article but the findings of study weren’t properly reported either. The popular press-release consisted mostly of quotations and opinions of doctors unrelated to the study instead of relaying information found directly from the study. Correlational studies cannot produce causal relationships because not all variables are being tested in a correlational study. Another variable could be the cause of whatever issuing tested, this is referred to as a third variable problem. Therefore, this type of study can only suggest that two factors may be related to each other. Any amount of third variables could be added to support that sleep quality is associated with brain structure. One of these variables would be the age and overall mental development of the participant. Age can have a large effect of brain development and atrophy, as we grow, our brains continue to develop further, and as we enter older ages, some peoples brains tend to deteriorate. This variable could be added to the design of the study and tested on a smaller variety of age groups to further narrow down the results.