Research project proposal of my MSc dissertation on cognitive functioning and eating disorders.
The National Institute of Health and Clinical Excellence (NICE) calculates that approximately 1.25 million people in the UK have an eating disorder, though, these numbers underestimate reality.
In the neuropsychological field, the current main lines of research have aimed to assess executive functions of female participants with eating disorders. A significant number of studies found an association between eating disorders and difficulties in central coherence, set-shifting, decision-making, and impulse control. Following a similar path, other studies explored theory of mind, socio-emotional processing and interoceptive awareness, and revealed difficulties in affect recognition and in interpreting internal body states. Lastly, some studies showed inconsistent results in the level of performance in speed processing, visuospatial attention, and verbal and visual processing tasks.
Eating disorders are complex conditions that impact on the patients’ lives and their environment. Psychological, family and social variables surrounding this illness are frequent guidelines in diagnosis and treatment selection, while neuropsychological factors are usually neglected. The following research proposes a neuropsychological investigation of eating disorders. It aims to compare the cognitive performance of participants who self-reported a history of eating disorders with a comparison group who did not report any such history; and within the group of participants who self-reported a history of eating disorders, it aims to compare the cognitive performance of those who met anorexia Body Mass Index criteria at the moment of assessment with those who did not meet such criteria.
Plan of investigation
Recruitment
The UK Biobank is a national health organisation that seeks to increase knowledge and improve the intervention of a wide variety of illnesses. Accordingly, this institution has created a major databank that can be accessed by investigators around the globe. The main purpose of this resource is to encourage research for enhancing prevention, diagnosis and treatment of health conditions of worldwide interest. The data for this research project will be accessed from the UK Biobank.
Participants
UK Biobank population
The UK Biobank began a longitudinal, population-based, cohort study in 2006, which is still ongoing. A baseline research was conducted between 2006 and 2010, and it recruited 502,649 participants who underwent medical, psychological, sociodemographic, and cognitive assessment. All participants belonged to 22 assessment centres in England, Scotland and Wales. The population included males and females, between 37 and 73 years of age. Participants were asked about their level of education and occupation, their ethnicity, lifestyle and health condition.
UK Biobank sample for this study
The exposed subjects, participants who self-reported a history of eating disorders, and the unexposed subjects, participants who did not report a history of eating disorders, will be ascertained from the UK Biobank population. No exclusion criteria will be applied, and the only inclusion criteria will be female gender and data regarding a history of eating disorders.
In multiple regression analyses, several self-reported covariates will be considered, including: age, level of education, area of deprivation, ethnicity, English as native language, smoking status, alcohol and drug consumption, self-report of other comorbid neurological and/or psychiatric illnesses, and pharmacological treatment at the moment of assessment.
Measures
The data will be collected from five cognitive instruments that were used during the baseline assessment. These instruments were designed by the UK Biobank to be used specifically in this study.
The cognitive tests are:
Reasoning task, which assessed verbal-numeric reasoning, executive functions, and intelligence. Participants were asked to answer thirteen logic questions, with verbal and numerical content, in a two-minute time limit.
Reaction Time task, which assessed reaction time in a go/no go format. Participants completed a timed test of symbol matching. The score on this task was the mean response time in milliseconds across trials.
Visuospatial Memory task, which assessed visuospatial memory and working memory. Participants were asked to memorize the positions of six card pairs, and then match them from memory while making as few errors as possible. The test had two versions, one with tree pairs and the other one with six pairs. The mistakes the participant made constituted the final score of the test.
Prospective Memory task, which assessed prospective memory. Participants were asked to engage in a specific behaviour later in the assessment. At the end of the tasks, they were shown four coloured symbols and asked to touch a blue square, however, to test their memory, they had to actually touch an orange circle, as instructed earlier. The participants scored zero or one, depending on whether they completed the task on first attempt or not.
Numeric Memory task, which assessed verbal working memory. Participants were shown a two-digit number, which they were asked to recall after a brief pause, in reversed order. The number of digits increased by one until the participant made an error, or until she reached the maximum of twelve digits.
Data analysis/Power calculation
Approximately 400 women with a self-reported history of eating disorders and thousands of women with no self-reported history of eating disorders have been identified in the UK Biobank population. The sample size provides sufficient power to detect even small differences in cognitive performance. The multiple regression analysis will consider different covariates and reduce the role of confounding.
Ethical Approval
The UK Biobank has already granted ethical approval for the study and for the data access for future investigations.
References
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