A systematic review of ‘knowledge of dementia’ outcome measures

Abstract

Knowledge of dementia measures are key to identifying areas of misinformation and establishing knowledge levels, thus guiding educational programmes and interventions.

A three-step literature search was undertaken to identify measures of knowledge in dementia. An evaluation framework was employed articulating quality indicators for the psychometric properties of measures, based on their development and use within research studies.

Five measures were identified: the Alzheimer's Disease Knowledge Test (ADKT, Dieckmann et al., 1988); the University of Alabama Alzheimer's Disease Knowledge Test for Health Professionals (UAB-ADKT, Barrett et al., 1997); the Dementia Quiz (DQ, Gilleard and Groom, 1994); the Knowledge of Aging and Memory Loss and Care (KAML-C, Kuhn et al., 2005) and the Alzheimer's Disease Knowledge Scale (ADKS, Carpenter et al., 2009). All measures followed a standard scale development process, generally with acceptable reliability and validity. Many studies used measures on populations beyond the target sample, without re-establishing the psychometric properties of the scales.

There are limitations with all the measures, including weaknesses in psychometric properties, being outdated and having limited scope. Although the ADKT was once suited to international use and has established psychometric properties, some items are now outdated. The ADKS positions itself as an updated version of the ADKT, yet has not been used beyond the original development study. The DQ is most the suitable for family carers. All measures require periodic updates, to keep pace with the expanding field of dementia. More robust, contemporary measures of knowledge are required.

Introduction

In the UK, the ‘National Dementia Strategy’ (DoH, 2009) underlines the importance of improved knowledge of dementia. Raising awareness is linked with early detection, as this affords the person with dementia choices, and the power of decision making in planning their own care (DoH, 2009). Theoretically, the more one knows about dementia, the more likely one is to seek help (Ayalon and Arean, 2004) and poor knowledge of dementia may hinder seeking professional aid among patients and family members.

Staff involved in dementia care come from a variety of backgrounds and vary greatly in their amount of formal training and levels of knowledge of dementia. Pucci et al. (2003) found that experts’ knowledge of Alzheimer's disease (AD) was significantly better than general practitioners’, while levels of knowledge among nurses was lower than that of general practitioners (Barrett et al., 1997). Poor knowledge among healthcare professionals could result in a delay in diagnosis (Knopman et al., 2000) and a tendency to misrepresent symptoms, leading to inappropriate treatment (Edwards et al., 2000). Moreover, increasing the level of knowledge of dementia in health care professionals can help dispel unhelpful or biased attitudes towards dementia, which may influence discussions around resource allocation (Turner et al., 2004).

Measures of knowledge of dementia provide baseline data that highlight the potential gaps and inconsistencies of knowledge among those working in related treatment and care (Dieckmann et al., 1988, Barrett et al., 1997). Information gleaned from measures can be thus used for guiding educational programmes and interventions (Carpenter et al., 2009). Furthermore, knowledge of dementia can be viewed as an important outcome variable in examining the efficacy of psychosocial interventions (Cooke et al., 2001). Utilising a standardised and recognised tool for such purposes helps avoid biased results and serves to increase the methodological strength of studies (Burgio et al., 2001). Thus it is important that such measurement scales are of good quality with established psychometric properties.

The steps taken during the scale development process are imperative for instituting validity and reliability. Two phases are generally recommended (Allen and Yen, 1979). Firstly, the conceptual development phase involves development of the construct, consultation of expert opinion and focus groups, formation of an ‘item pool’, piloting on a representative sample, and retaining items selected on the basis of satisfying statistically based item-analysis procedures. Item analysis criteria that are generally used include item discrimination, item difficulty index, and pre-and post-test difference index (PPDI). In the second phase, the empirical evaluation should involve large-scale sampling with the target population and the validation study should include the sample for which the measure was developed (Bowling, 2009). It would be anticipated that a good quality measure would follow the said conceptual and empirical development process in preparation for general use.

The aim of the present study is to provide a systematic review and critical appraisal of published knowledge of dementia measures, in order to examine their strengths and limitations and to guide selection of the most appropriate tool for use within a particular research context.