Measuring knowledge of Alzheimer’s: development and psychometric testing of the UJA Alzheimer’s Care Scale

Increased life expectancy and decreasing birth rates are among the causes of population ageing worldwide [1]. It is estimated that between 2015 and 2050, the proportion of the world’s population over 60 years of age will increase from 12 to 22% (from 900 million to about 2000 million people) [2]. Dementia is one of the major health problems affecting older people according to the World Health Organization [2]. Age is the factor responsible for the greatest increase in the risk of dementia, as both the incidence and prevalence of dementia double every 5 years from the age of 65 [3]. Alzheimer’s disease (AD) is the most frequent form of dementia (60–70% of cases), followed by vascular dementia (12.5–25%) [4]. In Spain, the figures of dementia prevalence range from 5 to 14.9% in people aged 65 or older and from 9 to 17.2% in those older than 70 [5, 6].

To address the needs of the ageing population, particularly of people with dementia, the health systems in most countries have had to adapt by modifying socio-economic policies, changing available resources and designing new intervention strategies [2]. The implementation of clinical practice guidelines (CPGs) has a basic role in providing high-quality healthcare for people with dementia. Good CPGs must be developed by multidisciplinary teams and using recommendations based on the best available evidence [7]. However, there is still a gap between knowledge and usual clinical practice. Health professionals know the recommendations for AD care, but frequently do not put them into practice [8, 9]. Specific training for health professionals providing care for AD or those with other forms of dementia is a key factor for quality care in all settings. The literature contains a number of studies measuring the knowledge of health professionals concerning dementia and AD care, using well-validated questionnaires. Education is important as most such studies have concluded that Registered Nurses (RNs) have higher knowledge than Assistant Nurses (ANs) [10, 11]. A wide range of professionals participate in dementia care, with different education and specific training [12]. General practitioners (GPs) have considerable knowledge regarding the diagnosis and treatment of dementia, but relatively low knowledge of epidemiology. These professionals also have difficulties in communicating the dementia diagnosis to patients, coordinating with social services and managing behavioural changes [13]. In nursing homes and other residential facilities, ANs or eldercare staff provide most of the basic care for people with dementia, but these professionals have the lowest levels of training [14]. In some cases, family carers of people with dementia may have greater knowledge regarding care than nurses and other care workers [15]. Some authors highlight that the level of knowledge regarding dementia is not only influenced by training, but also experience and real contact with people with dementia [16]. Low knowledge of AD care can lead to diagnostic mistakes and inadequate treatment, among other issues [12]. Hughes et al. (2008) show that nursing home care staff have little training in the needs of the elderly, especially with regard to mental health, depression and dementia. Improving the training of healthcare staff has a major impact on care. The education of health professionals and specific training are the main factors driving organizational changes and better care. Interactive training and blended learning are the best ways of achieving small but lasting improvements in professional practice [17, 18]. It is also important to consider knowledge of dementia care among healthcare students in the fields of nursing and medicine, inter alia. Several studies have found that clinical placements and mentorship play an important role in improving outcomes [19, 20].

To design appropriate dementia care education programmes for healthcare workers, it is very important to measure the level of knowledge and identify the issues that are not well known. A number of questionnaires and scales have been developed and tested to measure knowledge of dementia and AD. These instruments have different psychometric characteristics and have been validated among different populations [12, 21, 22]. According to the year of publication, some of the most relevant questionnaires are the following: the Alzheimer’s Disease Knowledge Test (ADKT) [23]; the Alzheimer’s Disease Knowledge Scale (ADKS) [11]; the Dementia Knowledge Assessment Tool Version 2 (DKAT2) [24]; the Dementia Knowledge Assessment Scale (DKAS) [10, 16]. All these questionnaires have been developed and tested in English-speaking countries. Searching the literature, we have found no questionnaire on dementia knowledge developed or culturally adapted to Spanish-speaking countries. There are differences in both the culture and health context between Anglo-Saxon countries and Spain and other Spanish-speaking countries. This is the reason that led us to develop and validate a questionnaire specifically targeting Spanish-speaking countries based on recommendations of both international and Spanish guidelines on dementia care. The new developed questionnaire should be focused on nursing care for people with Alzheimer’s disease, covering a range of topics including palliative care. The aim of this study was to develop and test a scale measuring the knowledge about dementia and AD, useful for nursing professionals and nursing students.

This research has focused on the development and validation of a new tool to measure knowledge of care for people with AD and dementia in Spain, that could be used in or easily adapted to other Spanish-speaking context. The UJA Alzheimer’s Care Scale comprises 23 items based on recommendations extracted from current CPGs on AD care and treatment. This scale could be used by a range of nursing staff, from RNs to ANs and to eldercare workers, as well as by nursing students. It is not intended for use in GPs because the scale is focused on nursing care, but not in treatment or diagnosis topics. The scale has good content validity based on the wording of items from clinical recommendations and a robust process of review by a panel of experts. The UJA Alzheimer’s Care Scale shows adequate psychometric values for validity and reliability. It is a scale easy to administer and can usually be completed in 5–10 min. The scale could be obtained through the project web site [38] also as Additional file 1.

It is important to highlight that this scale has three response options, including the “I don’t know” option. Several authors have stated that having three response options is better than two options (Yes, No) in knowledge scales because respondents can acknowledge their ignorance concerning a specific theme, avoiding the need to mark “Yes” or “No” at random [39, 40]. Our results concur with those of other studies in that internal consistency increases with the inclusion of the third response option in the knowledge scale [41]. This feature of the scale allows the identification of those topics on which staff or students have erroneous knowledge (errors) vs topics of which respondents recognize having no knowledge. We think that this is useful information when planning educational activities.

The newly developed UJA Alzheimer’s Care Scale contains items exploring person-centred care, like the DKAS [10], as opposed to other scales focusing predominantly on biomedical issues [11, 21, 23, 42].

Our scale has a robust building process, starting from CPGs and including the collaboration of a large panel of 15 experts. Having a panel with a sufficient number of experts is an important point for content validation when developing scales. Most of the previously developed AD knowledge questionnaires have had between 4 and 10 experts [24, 42‐44] or the authors acting as experts [11]. Only the DKAS, with 18 experts, had a higher number than ours [10].

Our purpose was to develop a final version of this scale able to measure the latent variable “Knowledge of AD and dementia care” among a wide range of nursing professionals, so we needed to include items with different levels of difficulty. Through the item analysis, some of the easy or very easy items were deleted because they made no contribution to the discriminant capacity of the scale. Analysis with the Rasch model confirmed that the 23-item final version has a good fit and has items with different levels of difficulty. The scale works well with both nursing staff from nursing homes and nursing students, although there are five items that present differential functioning in professionals and in student, namely: the caregiver burden; nutritional care; behavioural symptom management; agitation and aggressiveness management.

The UJA Alzheimer’s Care Scale is a one-dimensional scale that produces a total score to measure the amount of knowledge concerning AD, just by adding up the number of correct answers. Although the process of writing the items started by grouping them into several categories according to the CPG recommendations (such as Basic care; Caregivers; Diagnosis; Behavioural symptoms; End of life decisions), when the scale is used by nursing staff or students, there are no data to support an internal structure with sub-scales or factors. We consider that this one-dimensional structure is an advantage in its use, because it has just one score and is easy to use. Also, it is comparable with studies that have used most dementia knowledge tools, such as DKAT2 [24] or ADKS [11].

Overall, the new scale has good evidence of validity. Convergent validity is strong when it is compared with the DKAT2 scale, which has been well validated and widely used in recent research [15, 24, 45]. Our research also provides evidence of construct validity for the UJA Alzheimer’s Care Scale. This scale is able to discriminate between people with different levels of knowledge [21]. Our data agree with some other validation studies for the ADKS [11], KAML-C [43], UAB-ADKT [21], DK-20 [44], DKAT2 [24] and DKAS [10].

This new scale also has evidence of reliability, high internal consistency with values similar to other scales for nurses, DKAT2 [24]; ADKS [11]; AUB-ADKT [21]; also for nursing students, DQ [42], DKAS [10] and KAML-C [43]. The measures of AD knowledge produced by this new scale appear to be stable over time. Only a few validation studies have conducted a test-retest – ADKS [11], AUB-ADKT [21] and DK-20 [44] – but our data are consistent with most of them. Overall, our research provides data to support the reliability of the UJA Alzheimer’s Care Scale for use by both nursing staff and students.

The UJA Alzheimer’s Care Scale is a tool useful for measuring knowledge of AD or dementia care among nursing professionals and nursing students in Spain and useful for other Spanish-speaking countries. The English version of this scale should be tested in samples of English-spoken nurses and students. It is a self-administered scale, easy to use in both the paper and electronic versions. The initial validation study has obtained good psychometric properties for validity and reliability. This scale could be used in research as a tool to measure knowledge in intervention studies or in education for nursing home staff or nurses in general and also as a tool to identify areas that need improvement and to plan training activities.