Study design and participant selection
This is a descriptive cross-sectional study that included 226 participants, healthy older adults from the town of Salamanca, over 60 years of age, who participated in the Geriatric Revitalisation, Muscle Re-education and Occupational Therapy and Fall Prevention Programmes, carried out at the University of Salamanca with the collaboration of the Faculty of Nursing and Physiotherapy, through an agreement with the city council’s Department for the Elderly and various associations.
The sample was selected by means of a random cluster sampling of 9 associations in the city and, from each of these, the participants were randomly selected from the set of people who were willing to complete the study. The data recruitment period ran from May to October 2019.
In order to be included and be able to participate in the study, the participants had to meet the following inclusion criteria: be of either sex, over 60 years of age, not present cognitive impairment, participate in the Geriatric Revitalisation, Muscle Re-education and Occupational Therapy and Falls Prevention programmes, and voluntarily accept their inclusion in the study by signing the informed consent form. The exclusion criteria were: not being able to read or write and having severe hearing loss or blindness. The following withdrawal criteria were also taken into account after inclusion: abandonment of the study in any of its phases despite having signed the informed consent form, and completion of less than 50% of the scales administered.
The variables included in the study were sociodemographic and health characteristics and the assessment instruments, the scale to be validated, ECB, and the comparison scales considered to be the gold standard for cognitive assessment, the Rapid Assessment of Cognitive Function (RACF), and the Instrumental Activities of Daily Living (IADL) assessment scale.
All data collected through the participant assessments was gathered by the same person, the principal investigator.
Translation of the Everyday Cognition Battery Assessment Scale into Spanish
The translation(23,24) of the ECB scale into Spanish was carried out following the method recommended by Beaton et al.(25), in the following stages: translation from the original language (English) into Spanish, by two independent translators; synthesis and comparison of the two translated versions; back-translation or reverse translation into the original language of the scale; evaluation of the two translations by a research group or committee (made up of two doctors from the health field with doctorates from the University of Salamanca, an external researcher specialising in cognitive impairment and the principal researcher) with the aim of resolving any discrepancies and consolidating a pre-final version of the instrument to be used in the final-stage pilot test, to be administered to a reduced sample of participants with similar characteristics to the target population in order to check the adaptation and understandability of the ECB translated into Spanish, to identify possible shortcomings and to rectify any errors.
Questionnaires
The sociodemographic characteristics assessed in the study were age; sex; marital status (single, married, widowed or divorced); level of education according to the International Standard Classification of Education 2011 (none, primary, secondary or higher); living arrangements, whether they live alone or not; physical exercise habits, whether they do physical exercise or not and the days per week they exercise; and drug treatment only including the two large pharmacological groups that can modify the cognitive level of patients, benzodiazepines and opiates. All these sociodemographic characteristics were recorded in a document entitled Clinical History.
The assessment scales used in the study were, apart from the ECB scale, those considered to be the gold standard for assessing cognitive function and IADL.
The RACF(26) is a neuropsychological test that assesses cognitive ability and allows a rapid assessment of possible cognitive impairment. This scale is validated for the Spanish population.
After analysis of the results obtained in the pilot test, the inclusion of an IADL assessment scale in the study was positively assessed, the scale selected being the Lawton and Brody Index. This scale assesses the activities considered necessary for individuals to be able to maintain themselves independently at home and remain independent in the community; it is also validated for the Spanish population.
Statistical analysis
The statistical analysis included a descriptive analysis of the sociodemographic characteristics of the sample and the scores from each of the assessment instruments used, as well as an analysis of the psychometric properties of the Spanish version of the ECB.
For the descriptive analysis we used the mean, standard deviation, minimum and maximum for quantitative variables, and counts and percentages for qualitative variables.
To ascertain the psychometric properties of the Spanish version of the ECB, various tests were used to assess the validity and reliability of the instrument.
Reliability: as the questionnaire comprises several subscales, each of which measures a different dimension of the same phenomenon, the reliability of each of the subscales has been assessed. Reliability has been assessed by means of internal consistency, the most commonly used statistic being Cronbach’s alpha coefficient(27–29). To interpret Cronbach’s alpha coefficient values, we followed the recommendations of George Mallery (2003)(30).
Validity: the validity analysis was carried out using correlation tables, the statistical resource used being Spearman's correlation coefficient -Spearman's rho- which presents values between -1 and 1(29,31). Correlations were made between the Spanish version of the total ECB and its four subscales with the scale considered as the gold standard for cognition in the study, the RACF, and with the IADL assessment scale, the Lawton and Brody Index.
The Statistical Package for Social Science (SPSS), version 26 (IBM Corp., 2019) was used to analyse the data.
Ethical and legal aspects
This study complies with the requirements of the Ethics Committee of the University of Salamanca and the Code of Ethics of the World Medical Association (Declaration of Helsinki). All the information on the results has been processed and stored in a strictly confidential and anonymous manner in accordance with the provisions of Organic Law 15/1999 of 13 December on the Protection of Personal Data. The study was approved by the Bioethics Committee of the University of Salamanca on 31 October, 2018. The project was also approved and included in the Clinical Trials Register (Clinical Trials. Gov. PRS) with registration number: NCT 04169633.