The development of positive psychology outcome measures and their uses in dementia research: A systematic review

Abstract

Positive psychology is gaining credence within dementia research but currently there is a lack of outcome measures within this area developed specifically for people with dementia. Authors have begun adopting positive psychology measures developed with other populations but there is no consensus around which are more appropriate or psychometrically robust. A systematic search identified measures used between 1998 and 2017 and an appraisal of the development procedure was undertaken using standardised criteria enabling the awarding of scores based on reporting of psychometric information. Twelve measures within the constructs of identity, hope, religiosity/spirituality, life valuation, self-efficacy, community and wellbeing were identified as being used within 17 dementia studies. Development procedures were variable and scores on development criterion reflected this variability. Of the measures included, the Herth Hope Index, Systems of Belief Inventory and Psychological Wellbeing Scale appeared to be the most robustly developed and appropriate for people with dementia.

Keywords

psychometrics outcome measures dementia Alzheimer’s hope spirituality community wellbeing

Introduction

In the last 20 years there have been efforts to explore dementia from a positive methodology perspective rather than just a narrative of decline, centred on the medical model. Historically, behavioural and psychological symptoms of dementia were viewed as being caused solely by a somatic organic illness (Dawson & Reid, 1987) and people with dementia were often viewed as dependent and unable to contribute to society (Lyman, 1989). Person-centred theory (Kitwood, 1993) represented a shift from the prevailing biomedical view point to a more holistic approach, in which social and individual factors contributed to a unique experience of dementia for each person (Kitwood, 1997).

This shifting awareness and empowerment for people with dementia was also represented through the use of outcome measurement within research. Previously, there was the view that people with dementia were unable to make accurate judgements within research and proxy rated outcome measures were often relied upon (Dawson, Welsh-Bohmer, & Siegler, 2000). Furthermore, outcome measures used were based on deficits or problem such as depression (Alexopoulos, Abrams, Young, & Shamoian, 1988), anxiety (Shankar, Walker, Frost, & Orrell, 1999) or neuropsychiatric symptoms (Cummings, 1997). Quality of life is now recognised as a desired outcome for psychosocial research (Logsdon, Gibbons, McCurry, & Teri, 1999) and people with dementia are being asked to complete outcome measures themselves, in conjunction with proxy report.

Positive psychology may be the next step within this framework and refers to the use of empirical approaches to examine human strengths and capabilities that contribute to wellbeing, sometimes called ‘flourishing’ (Seligman, 2002). This theory is beginning to be applied to dementia populations, for example, the role of hope (Wolverson, Clarke, & Moniz-Cook, 2010) and humour (Clarke & Irwin, 2016). People with dementia are capable of using these strengths to actively seek enjoyment and pleasure but there has been no quantitative research to supplement the qualitative findings. As positive psychology refers to the scientific study of wellbeing, quantative measurement of positive constructs is needed.

The use of outcome measures has long been held as a gold standard in research and they often undergo a rigorous development procedure (Moniz-Cook et al., 2008). However, currently there is a lack of positive psychology outcome measures developed for this population (Clarke, Wolverson, Stoner, & Spector, 2016).

Existing measures of positive psychology have begun to be applied within dementia research but there is no consensus as to which are more appropriate or psychometrically robust. This review aimed to identify those measures currently in use for dementia populations and conduct an appraisal of the measures’ psychometric properties including data from dementia populations in order to guide future choice of measures in research and practice.

Methods

Design

A systematic search of positive psychology outcome measures used within research for people with dementia was undertaken. Systematic principles for searching, screening and appraising studies were followed (Moher, Liberati, Tetzlaff, Altman, & PRISMA Group, 2009) and searches were then conducted to identify development information of included measures.

Search strategy

PsychInfo, PubMed and MedLine were searched for results from 1998 to 2017. Search terms were self-efficacy, life satisfaction, hope, resilience, wisdom, growth, coherence, control, autonomy, pleasure, self-realisation, sense of agency, gratitude, happiness, optimism, transcendence, positive, dignity, social participation, social inclusion, self-concept, reciprocity, connectedness, engagement, humour, creativity, flow, spirituality, love, compassion, benefit finding, community integration, opportunity, social adjustment, mindfulness, acceptance, successful aging, wellbeing, quality of life, independence and social health (Seligman, 1998). These search terms were then combined again with dementia, Alzheimer, cognitive impairment, senile and vascular. Truncations of search terms were used where appropriate.

Terms indicative of related fields were also included (quality of life; wellbeing; social health) and in-depth search strategy was employed in order to fully capture positive psychology measures. Titles were included if the study reported on a dementia population, abstracts were then screened for methodology indicative of the use of outcome measures and full texts were sought for the remaining results to identify positive psychology outcome measures. Ambigious titles or abstracts were included until a decision could be made, including research with ‘dyads’.

Inclusion criteria

Use of positive psychology outcome measure as identified within the search terms.

Use of above measure(s) within a dementia population.

Both development of measures and use of measures published within a peer-reviewed journal.

Published between 1998 and 2017.

Exclusion criteria

Studies published in a language other than English if a translation was not available.

Only used proxy-reporting.

Development information for outcome measures was not freely available.

Appraisal of psychometric properties

Included measures were grouped and a quality assessment was undertaken using an established criteria (Terwee et al., 2007) (Table 1), which assesses development procedures of measures and has been used successfully in other reviews (Stoner, Orrell, & Spector, 2015; Windle, Bennett, & Noyes, 2011). For each item within the criterion, a score of two was awarded if the study was adequately designed and appropriate statistics given, a score of one was awarded if there were methodological shortfalls such as inadequate design. If, despite adequate design, the study produced results indicating poor psychometric properties or no information was reported, a zero was awarded (possible range 0–18). Two authors (CRS and JS) undertook this analysis independently and a consensus meeting was held to ensure reliability of reporting (Table 2).

Table 1.

Terwee criteria.

Property		Definition	Quality criteria
1	Content validity	The extent to which the domain of interest is comprehensively sampled by the items in the questionnaire (the extent to which the measure represents all facets of the construct under question)	2	A clear description of measurement aim, target population, concept(s) that are being measured, and the item selection AND target population (investigators OR experts) were involved in item selection
			1	A clear description of the above-mentioned aspects in lacking OR only target population involved OR doubtful design or method
			0	No target population involvement OR no information found on target population involvement
2	Internal consistency	The extent to which items in a (sub)scale are inter-correlated, thus measuring the same construct	2	Factor analyses performed on adequate sample size (7* #items and ≥100) AND Cronbach’s alpha(s) calculated per dimension AND Cronbach’s alpha(s) between 0.70 and 0.95
			1	No factor analysis OR doubtful design or method
			0	Cronbach’s alpha(s) <0.70 or >0.95, despite adequate design and method OR No information found on internal consistency
3	Criterion validity	The extent to which scores on a particular questionnaire relate to a gold standard	2	Convincing arguments that gold standard is ‘gold’ AND correlation with gold standard ≥0.70
			1	No convincing arguments that gold standard is ‘gold’ OR doubtful design or method
			0	Correlation with gold standard <0.70, despite adequate design and method OR no information found on criterion validity
4	Construct validity	The extent to which scores on a particular questionnaire relate to other measures in a manner that is consistent with theoretically derived hypotheses concerning the concepts that are being measured	2	Specific hypotheses were formulated AND at least 75% of the results are in accordance with these hypotheses
			1	Doubtful design or method (e.g. no hypotheses)
			0	Less than 75% of hypotheses were confirmed, despite adequate design and methods OR no information found on construct validity
5	Reproducibility
5.1	Agreement	The extent to which the scores on repeated measures are close to each other (absolute measurement error)	2	SDC < MIC OR MIC outside the LOA OR convincing arguments that agreement is acceptable
			1	Doubtful design or method OR (MIC not defined AND no convincing arguments that agreement is acceptable)
			0	MIC ≤ SDC OR MIC equals or inside LOA despite adequate design and method OR no information found on agreement
5.2	Reliability	The extent to which patients can be distinguished from each other, despite measurement errors (relative measurement error)	2	ICC or weighted Kappa ≥ 0.70
			1	Doubtful design or method
			0	ICC or weighted Kappa < 0.70, despite adequate design and Method OR no information found on reliability
6	Responsiveness	The ability of a questionnaire to detect clinically important changes over time	2	SDC or SDC < MIC OR MIC outside the LOA OR RR > 1.96 OR AUC ≥ 0.70
			1	Doubtful design or method
			0	SDC or SDC ≥ MIC OR MIC equals or inside LOA OR RR ≤ 1.96 or AUC <0.70, despite adequate design and methods OR no information found on responsiveness
7	Floor and ceiling effects	The number of respondents who achieved the lowest or highest possible score	2	≤15% of the respondents achieved the highest or lowest possible scores
			1	Doubtful design or method
			0	>15% of the respondents achieved the highest or lowest possible scores, despite adequate design and methods OR no information found on interpretation
8	Interpretability	The degree to which one can assign qualitative meaning to quantitative scores	2	Mean and SD scores presented of at least four relevant subgroups of patients and MIC defined
			1	Doubtful design or method OR less than four subgroups OR no MIC defined
			0	No information found on interpretation

AUC: area under the curve; MIC: minimal important change (this is the smallest difference in score in the domain of interest which patients perceive as beneficial and would agree to, in the absence of side effects and excessive costs); RR: responsiveness ratio; SDC: smallest detectable difference (this is the smallest within person change, above measurement error. A positive rating is given when the SDC or the limits of agreement are smaller than the MIC); SEM: standard error of measurement.

Table 2.

Quality assessment of development procedures.

Construct	Scale	Content validity	Internal consistency	Criterion validity	Construct validity	Reproducibility reliability	Floor/ceiling effect	Interpretability	Total
Identity	Self-Identity in Dementia Questionnaire	2	0	0	1	0	0	0	3
Hope/optimism	Herth Hope Index	2	0	2	1	2	2	1	10
	Adult Hope Scale	2	2	2	2	2	0	1	11
	Life Orientation Test-Revised	2	2	0	2	0	0	0	7
Religiosity/spirituality	Systems of Belief Inventory	2	2	1	1	2	2	1	11
Religiosity/spirituality	Royal Free Interview for Religious and Spiritual Beliefs	1	0	1	1	2	0	1	6
Life valuation	Meaning in Life Scale	2	2	0	2	0	0	0	6
Life valuation	Terrible Delightful Scale	0	0	0	1	0	2	0	3
Self-efficacy	General Self-efficacy Scale	0	2	0	1	0	2	1	6
Self-efficacy	The Self-efficacy Scale	1	2	1	2	0	0	0	6
Community	Brief Sense of Community Scale	1	2	0	2	0	0	0	5
Wellbeing	Ryff Psychological Wellbeing Scale	1	1	0	2	2	0	1	7

Results

After limitations were applied and duplicates removed, 3910 results were identified of which 2363 were included on title. The 1547 papers excluded at this stage did not report on a dementia population. At the second stage, 828 abstracts were included, for which full texts were sourced. Of these, the vast majority were excluded as no positive psychology outcome measures were identified (568) or measures were used in caregiver studies with no outcomes used for the person with dementia (78) (Figure 1). Twelve studies were subsequently excluded as development information for the measures used was not published in a peer-reviewed journal or was not freely available. This left a total of 12 positive psychology outcome measures used within 17 studies for analysis (Table 3). Of the studies included here, three used a combination of self and proxy-reporting (Cohen-Mansfeld et al., 2010; Hilgeman et al., 2014; Jolley et al., 2010). The remainder used self-report only for the measures included here. Development scores were variable, with scores ranging from 3 to 11. CRS and JS agreed on most ratings, apart from the interpretability section of the Terwee criteria. Disagreements were discussed until a consensus could be reached.

Figure 1.

Review process.

Table 3.

Description of included studies.

Construct	Outcome measure	Study authors	Characteristics of participants with dementia	Methods	Results pertaining to measures
Identity	Self-Identity in Dementia Questionnaire (SID) (Cohen-Mansfeld, Golander, & Arnheim, 2000)	Caddell and Clare (2012)	50 PwD* (52% female, 64% married, 22% widowed, 90% secondary education level)	Multiple regression analyses to determine the possibility of predicting variance in mood and quality of life (QoL) from aspects of identity	Depression significantly predicted by model containing Tennessee Self-Concept Scale physical and personal items subtotals and SID family and leisure subscales (F4,44 = 4.66, p <.01, RA2 = 0.234)
		Caddell and Clare (2013a)	50 PwD (52% female, 64% married, 22% widowed, 90% secondary education)	Cross-sectional questionnaire-based study to examine the profile of identity in early-stage dementia and healthy older people	Within both groups, family role was reported as strongest, occupational weakest
		Caddell and Clare (2013b)	50 PwD (mean age 77.8; SD 7.4, 52% female, 76% Alzheimer’s disease (AD), 90% secondary education)	Cross-sectional study investigating relationships between identity and cognitive and functional abilities of people in early-stage dementia	Positivity of identity was significantly predicted by a model containing CERAD (cognitive battery) naming, constructional praxis and constructional praxis recall scores and Functional Activities Questionnaire (FAQ) total score F(4,41) = .4557, p<.01, RA2 = .240
		Cohen-Mansfeld, Thein, Dakheel-Ali, and Marx (2010)	193 PwD in nursing home (mean age 86, 78% female, 81% Caucasian, 65% widowed)	Examination of identity roles on engagement in tasks. Participants presented with stimulus twice, one with explanation of how stimulus should be used and once without modelling	Self-identity most salient was family self-identity (87%), followed by leisure (62%). Positive relationship between self-identity and engagement duration, attention and attitude. All p<.001
Hope	Herth Hope Index (HHI) (Herth, 1992)	Johnston et al. (2016)	7 PwD (mean age 78.4, 71.43% male)	Mixed methods, feasibility study with a pre- and post-design. Intervention was Dignity Therapy	No discussion of significant findings. One participant had difficulty completing HHI. Pre- and post-percentage scores available for four participants:Participant one: −18.7%Participant two: +6.25%Participant three: +2.08%Participant four: 0% change
	Adult Hope Scale (Snyder et al., 1991)	Meeks et al. (2016)^a	26 PwD (mean age 76.7; SD 10.23, 61.5% female, 88.5% white American	Study of biological markers to capture allostasis as an index of psychological resilience, relating to other baseline resources including hope and optimism	Non-significant z-stasis index (markers) of hope .33Optimism and hope significantly negatively correlated (p<.01)
	Life Orientation Test-Revised (LOT-R) (Scheier, Carver, & Bridges, 1994)	Meeks et al. (2016)^a	As above	As above	Optimism and hope (Adult Hope Scale) significantly negatively correlated (p<.01)
Religiosity/spirituality	Systems of Belief Inventory (SBI-15) (Holland et al., 1998)	Katsuno (2003)	23 PwD (mean age 79; SD 6.2, 78% female, 78% White)	Descriptive mixed methods study. Observational, cross-sectional examining spirituality in early-stage dementia	22 completed SBI-15. Average score of 32.8, range of 11–45. Positive correlation between SBI and quality of life .44, p<.05. Not between Health/Functioning subscale of QoL measure
Religiosity/spirituality	Royal Free Interview for Religious and Spiritual Beliefs (King & Speck, 1995)	Jolley et al. (2010)	29 PwD (89.7% female, 10.3% male, 96.6% White, mean Mini Mental State Examination (MMSE) score of 24)	Observational questionnaire study of PwD drawn from a memory clinic	Strength of belief rated as most important. No statistical differences between carer and PwD ratings of own spiritual belief
Life valuation	Meaning in Life Scale (Krause, 2004)	Hilgeman et al. (2014)	19 dyads (PwD mean age 82.8; SD 6.46, 68.4% female, 94.7% White)	Randomised to either intervention of minimal support group. Four sessions of intervention. Focus on maintaining identity through PIPAC intervention	No significant effect of intervention on meaning in life (p=.71)
Life valuation	Terrible Delightful Scale (TDS) (Michalos, 1980)	St. John and Montgomery (2010)	58 PwD (mean age 82.9, 60.3% female)	Observational study examining overall life satisfaction with its subscales and to examine the impact of cognition on life satisfaction	Life satisfaction broken down into two subscales: material and social. Moderate correlation between scales (p<.001). PwD had significantly lower life satisfaction on subscales
Self-efficacy	General Self-efficacy scale (GSE) English version (Schwarzer & Jerusalem, 1995)	Fankhauser, Drobetx, Mortby, Maercker, and Forstmeier (2014) (German version)	229 adults (mean age 74, 64 Mild Cognitive Impairment (MCI), 47 AD, 118 no impairment	Investigated a mediation relationship of motivation (self-efficacy, decision regulation, activation regulation and motivation regulation) on the relationship between social support and depression	Early AD: social support not correlated with depression (r= −.16, p= .30) Motivational processes predicted depression significantly in regression (β = 0.39, p<.001)
		Buettner and Fitzsimmons (2009) (English version)	89 PwD (mean age experimental group 81.4, mean MMSE 25.6, 48 male, 41 female)	Evaluation of 12-week health promotion course for PwD	Investigated impact of a health promotion course on well-being. No significant findings at post-test for self-efficacy
	The Self-efficacy Scale (Sherer et al., 1982)	Dawson, Powers, Krestar, Yarry, and Judge (2013)	131 PwD (mean age 77.15; SD 9.45, mean MMSE 22.48; SD 5.84, 55.7% female, 61.8% married, 85.5% Caucasian, 26.8% college graduate)	Stress process modelling for PwD, using strains and QoL outcomes	Self-efficacy perception emerged as a significant and unique predictor of QoL (β= .30, p<.001)
Community	Brief Sense of Community Scale (BSCS) (Peterson, Speer, & McMillan, 2008)	Low, Russell, McDonald, and Kauffman (2015)	40 older adults (mean age 91, 80% female, 80% cognitive impairment)	Randomised controlled trial of 12-week programme of ‘Grandfriends’– intergenerational intervention	No significant effects of group by time interaction (p=.168)
Wellbeing	Ryff Psychological Wellbeing scale (RPWB)	Mak (2011)	91 PwD (mean age 75.28; SD 9.23, 70 females, 51% African American, 47% European American, 2% Filipino American	Randomised trial of goal-directed activity. Used Purpose in Life Subscale from RPWB)	Alpha for purpose in life α = .73, lower than original study (α= .90) Positive correlation between purpose in life and goal pursuit (r = .53, p<.001), significant correlation between dementia severity and purpose in life (r = .35, p<.001). Prediction analysis indicated people with higher goal pursuit were more likely to score higher on purpose in life, regardless of dementia severity
	Ryff Psychological Wellbeing scale (RPWB)	Gonzalez, Mayordomo, Torres, Sales, and Meléndez (2015)	42PwD (mean age 80.24; SD 9.22; 69 female, 31 male, 59.5 widowed, 31 married, average MMSE 20; SD 2.55	Quasi-experimental in two retirement homes, measure effect of reminiscence therapy. 23 experimental, 19 control	PWB all dimensions significant except for purpose in life. Significant increase in self-acceptance (p= .002), positive relations with others (p= .019), autonomy (p=.001) and environmental mastery (p=.003) for interaction effect of time and group
		Wettstein et al. (2014)	35 PwD (mean age 74.1; SD 7.1, 60% male)	Used Environmental Mastery Subscale of RPWB. Observational study of out of home behaviour using Global Positioning System (GPS) tracking, and self-report questionnaires	Higher walking distances and higher levels of walking speed were significantly related to higher environmental mastery (r=.40 and 45 respectively p<.05)

PwD*: people/ person living with dementia.

Identity

The Self-identity in Dementia (SID; Cohen-Mansfeld et al., 2000) (3/18) was the only measure identified to have been developed within a dementia population. It was notably lacking all psychometric information on the assessment criteria apart from content validity, for which it scored two points, and construct validity for which it scored one point. This was due to the involvement of the target population and experts in item development and a clear description of the aims and domains to be measures. In a predictive analysis of variance in mood and quality of life from aspects of identity, authors suggested a model including aspects of identity could predict depression. More specifically, scores on the SID family and leisure subscales, significantly predicted depression (p<.01) (Caddell & Clare, 2012) lending evidence to the SID’s predictive validity. An indication of discriminant validity was found between identity and cognition, as Caddell and Clare (2013a) observed no significant correlation between mean SID scores and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) cognitive battery. The SID was also used in an additional study examining differences in identity of people with dementia and older adults without dementia. Both groups scored family role as the strongest aspect of their identity and occupational identity as their weakest, suggesting that dementia may not negatively affect identity, within early stages. This provides a further indication of the SID’s content validity and is supported by an additional study that reported family identity as being most important (87%) (Cohen-Mansfeld et al., 2010). Evidence of the SID’s convergent validity was also observed between self-identity, engagement duration, attention and attitude (p<.001). Healthy older adults reported significantly more distress relating to identity than people with dementia (Caddell & Clare, 2013b), possibly indicating some degree of interpretability or discriminant validity.

Hope

The Herth Hope Index (HHI; Herth, 1992) and Adult Hope Scale (AHS; Snyder et al., 1991) were the most robustly developed measures (10/18 and 11/18) and The Life Orientation Test-Revised (LOT-R; Scheier et al., 1994) scored less (7/18). All three measures failed to define a minimal important change to assess the responsiveness of the measure and the HHI reported an internal consistency indicative of multicollinearity (α=.97). The HHI was used in a small scale feasibility study for Dignity Therapy for people with dementia (Johnston, et al., 2016). Pre- and post-intervention scores, as percentage changes, on the HHI were only available for four participants and were variable. The maximum increase was 6.25% and one participant had a decrease of 18.7%. This may indicate an issue with sensitivity to change as the HHI was found to be stable over a two-week period (.91) during the development stage. However, as this was a feasibility study, the sample size was small and no firm conclusions can be drawn for the sensitivity of the HHI in people with dementia.

The AHS was the most thoroughly developed measure of all the measures included here. Notably, it had high levels of construct and convergent validity with correlations being observed between a number of scales including life orientation, self-esteem, hopelessness and depression. Furthermore, discriminant validity was established between hope and self-consciousness.

The LOT-R was reported as having a good level of internal consistency (.82) and convergent validity was established between dispositional optimism, self-mastery, trait anxiety, neuroticism and self-esteem. Both the AHS and the LOT-R were used in a study examining biological markers of allostasis (the ability to maintain stability in a changing environment through psychological or behavioral change) as an index of psychological resilience. These biological markers were compared to baseline resources including hope (Meeks, et al., 2016). However, the authors reported no significant findings in relation to allostasis and hope.

Religiosity/spirituality

The Systems of Belief Inventory (SBI-15; Holland et al., 1998) and the Royal Free Interview for Religious and Spiritual Beliefs (RFIRSB; King & Speck, 1995) scored 11/18 and 5/18, respectively. Internal consistency for the SBI-15 was excellent (.93) as was test-retest reliability (.95) for both religious and non-religious groups. Furthermore, criterion validity was adequate, with the SBI-15 correlating with other measures of religiosity and there was a significant difference between scores for religious and non-religious participants, indicating discriminant validity. A small-scale study utilised the SBI to examine spiritual beliefs in people with early stage dementia (Katsuno, 2003) and a positive correlation was observed between spirituality and quality of life (p<.05) indicating convergent validity between these measures.

The RFIRSB was developed with the use of experts and population involvement but the internal consistency analysis indicated an issue with the philosophical belief subscale (.60) and the overall internal consistency was not provided. However, test-retest reliability was adequate over a one-week period for both philosophical and spiritual subscales (.91 and .95, respectively). Furthermore, construct validity was established as there was a significant relationship between spirituality and the frequency of practice of religious faith (p<.0005) and people with dementia appeared to rate the strength of belief as most important (Jolley et al., 2010), suggesting additional content validity of the measure.

Life valuation

The Meaning in Life Scale (MLS; Krause, 2004) and the Terrible Delightful Scale (TDS; Michalos, 1980) scored 6/18 and 3/18, resepctively. The MLS was developed in a large sample of older adults. Whilst item selection did not involve target population or experts, the internal consistency (.925) and factor analysis yielded satisfactory results. No significant effects or trends of MLS were reported in a trial of advanced care planning and identity for people with dementia (p=.71) (Hilgeman et al., 2014), potentially indicating an issue with sensitivity or low sample size and study design.

The TDS was developed without the input of experts or the use of a target population and was not awarded points for content validity. Michalos (1980) undertook an extensive pathway analysis but did not report the internal consistency. However, it was one of the few papers to report the floor and ceiling effects of the measure. Predictive validity of the TDS was examined in an observational study examining the relationship life satisfaction and functional impairment (St. John & Montgomery, 2010). Within this study, people with dementia or Mild Cognitive Impairment had slightly lower overall life satisfaction than those without.

Self-efficacy

The General Self-efficacy Scale (GSE; Schwarzer & Jerusalem, 1995) and the Self-efficacy Scale (SES; Sherer et al., 1982) both scored moderately (6/18). Authors did not report on aspects of content validity of the GSE but internal consistency was .86. Subgroups were explored but no minimal important change was defined, limiting the measures interpretability. The GSE was used in an evaluation of a health promotion course for 89 people with dementia (Buettner & Fitzsimmons, 2009) but no significant differences between pre- and post-testing were reported. However, this may be an issue with intervention fidelity, as the authors reported significant findings in an earlier unpublished pilot study.

Authors of the SES did report some aspects of content validity but failed to report responsiveness, floor and ceiling effects or interpretability. The authors reported the internal consistency for both subscales (.86 and .71) but not the overall internal consistency. However, the measures demonstrated a high level of convergent validity with locus of control, ego strength, interpersonal competency and self-esteem. Clements-Cortes (2013) used the SES to assess the effectiveness of a choir group for older adults, an unclear proportion of which had dementia. It is, therefore, not possible to draw conclusions about the content validity of this measure for people with dementia. Furthermore, the authors were not able to demonstrate the measures responsiveness on either subscale following the intervention (p=.20, .37) but this may be attributable to the low sample size.

Community

The Brief Sense of Community Scale (BSCS; Peterson et al., 2008) scored moderately low (5/18) lacking information regarding test-retest reliability, responsiveness, skew of data and interpretability. There was no target population involvement or information regarding item selection. However, convergent validity was established between the BSCS and measures of community participation, depression and intrapersonal psychological empowerment (p<.01). Within a dementia setting, the measure was used to assess the efficacy of an intergenerational intervention but no significant were found (p= .168) (Low et al., 2015). Authors reported no significant findings of other measures in the study including agitation and quality of life, possible indicating issues with study design.

Wellbeing

The Ryff Psychological Wellbeing Scale (PWB) (7/18) contains six subscales that measure self-acceptance, positive relations with others, autonomy, environmental mastery, purpose in life and personal growth. It was found to have robust criterion validity and interpretability but lacked information on stability and responsiveness. One study utilised the measure in its entirety (Gonzalez et al., 2015), one used the environmental mastery subscale (Wettstein et al., 2014) and one used the purpose in life subscale (Mak, 2011). Gonzalez et al. (2015) examined the effect of reminiscence therapy within two retirement homes. The authors found significant improvements on all dimensions of the PWB, except for the purpose in life subscale, indicating the measures ability to detect change. There was a significant interaction effect of time and group for self-acceptance (p=.002), positive relations with others (p=.019), autonomy (p=.001) and environmental mastery (p=.003). The second study utilised the environmental mastery subscale of the PWB in an observational study and provided further evidence for the measures construct validity noting that higher walking distances and walking speed were significantly related to higher environmental mastery (r=.40 and r=.45, p<.05) (Wettstein et al., 2014). Mak (2011) utilised the purpose in life scale in a randomised trial and reported the internal consistency as .73, lower than the original reported alpha of .90 but still satisfactory. A positive correlation was observed between purpose in life and goal pursuit (p<.001), further evidencing construct validity.

Discussion

Twelve positive psychology outcome measures were identified within the constructs of identity, hope, religiosity/spirituality, life valuation, self-efficacy, community and wellbeing as being used in 17 research studies of people with dementia. Only one of these measures was developed for people with dementia (SID). Most outcome measures identified scored moderately on their development procedures, with hope scales developed the most robustly and identity the least robustly.

Whilst the development information was lacking for the SID, it has been used in a number of studies successfully and suggests the measure is an appropriate tool for assessing identity for people with dementia. Despite the AHS scoring slightly higher than the HHI at the quality assessment stage, it is possible that the HHI may be more applicable as hope for people with dementia appears to be more generalised in nature (Wolverson et al., 2010), rather than goal oriented (Snyder et al., 1991). Therefore, the HHI may hold more content validity for this population. Spirituality and religiousness appears to be a pervading concept, in that spirituality and religiousness hold significance in the self-concept and change, hope for the future and positive attitudes for people with dementia (Dalby, Sperlinger, & Boddington, 2011). The SBI-15 appears to be an adequate tool to detect and measure spiritual beliefs, as development procedures were robust and some psychometric properties have been found to be satisfactory in dementia populations. Both the TDS and the MLS scored moderately for their development procedures. Whilst the TDS appeared to be more successful within a dementia population, it is recommended that both measures are in need of further psychometric examination before they are routinely used. Both self-efficacy scales and the BSCS scale failed to show sensivitiy to their respective interventions. Whilst this may be due to issues with the study design, rather than the measures, it is recommeneded that a more detailed examination of self-efficacy scales and community scales for people with dementia is needed.

Of the scales included, Ryff’s PWB appeared to be the most successful, in terms of its development procedures and the studies in which it was used. The lower alpha reported within a dementia population is still within the acceptable range and is sensitive to change. It would then appear that this scale is appropriate for people with dementia and it is recommended for use within research.

Methodological problems

All measures included here failed to define a minimal important change, which is a requirement of the Terwee criteria for interpretability. This meant that it was nearly impossible to award scores for responsiveness. Reporting on reliability was mixed with only four studies reporting the test-retest reliability of measures. Inferring sensitivity of change of measures within dementia studies included here was problematic, due mostly to study design including low sample sizes. A large majority of the studies included were feasibility studies and were not powered to detect effect sizes. Additionally, obtaining the development papers of included measures was sometimes difficult and could only be accomplished by extensive searching.

Limitations

Whilst an effort was made to include search terms that were all-encompassing and indicative of positive psychology, it is noted that definitions of what constitutes this theory vary. Consequently, broad search terms including the related fields were used resulting in a large number of studies excluded. The criteria used here is one of the few comprehensives enough to cover most aspects of a measures psychometric properties. However, it may have been overly constraining as responsiveness and interpretability were rarely reported. Future authors may wish to include such information for the purpose of reviews or for measure selection.

Future research

These studies highlight the need for authors to consider psychometric analyses when designing their research. All measures included here provided no information regarding responsiveness to change. This is particularly important when considering interventional research as most studies here failed to find a significant effect of the interventions detailed. Whilst this may be due to a range of factors including low sample size or the effectiveness of the actual intervention, it is recommended that future researchers select measures that have been established as sensitive to intervention to ensure the most accurate appraisal of efficacy of their intervention.

Furthermore, only one measure identified here was developed within a sample of people with dementia, drawing on their perceptions and experiences. The majority of studies included here used measures developed for other populations and, as such, may not have been suitable to detect meaningful change for a person with dementia. It is possible that positive dementia specific measures such as those developed for quality of life (e.g. Logsdon et al., 1999) may be a more valid tool for detecting change within interventional research. It is, therefore, also recommended that dementia specific measures of positive psychology are developed to ensure valid and reliable tools are consistently used in this emerging area of research.

Whilst positive experiences have been an emerging theme for people with dementia, it is often within a ‘coping’ paradigm in which positive experiences are conceptualised as a strategy to adapt or retain normality when faced with negative experiences and loss (Clare et al., 2013). This prevailing model of positive psychology and dementia is not supported within the qualitative literature (see Wolverson, Clarke, & Moniz-Cook, 2015 for a review) and this should be reflected in future outcome measure development or adaptation. By reducing positive psychology to coping or as a means of denial (de Boer et al., 2007), potentially valuable positive characteristics are at risk of being not investigated properly. Future researchers should be wary of assuming that content validity remains the same, despite using measures with populations they were not designed for. This is exampled through the use of the AHS, despite multidimensional hope measures potentially being more applicable.

Conclusion

Twelve positive psychology outcome measures, with development information available, have been used within dementia research. However, the quality of the development procedures was variable, with authors failing to report important aspects of psychometric analyses including responsiveness and stability. The HHI, SBI-15 and PWB appear to be the most psychometrically sound and appropriate for people with dementia and it is recommended that future authors explore these concepts.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Charlotte R Stoner is a research associate at the Institute of Neurology, University College London (UCL). Her PhD at UCL entailed developing and evaluating positive psychology outcome measures for older adults with dementia. Research interests include psychometric testing, positive psychology, outcome measures and cognition. Charlotte is currently working on validating the cognitive footprint concept as part of the University College London Hospital Biomedical Research Centre’s Dementia Theme.

Jacki Stansfeld is a current PhD student at UCL and concurrently a senior research assistant at North East London NHS Foundation Trust (NELFT). Her PhD entails a re-examination of sense of competence, through a positive psychology framework, for carers or supporters of those living with dementia. Jacki has recently published a systematic review evaluating positive psychology outcome measures for carers and her research interests include sense of competence, positive psychology and structural equation modelling.

Martin Orrell is the director of the Institute of Mental Health at the University of Nottingham. He is a visiting professor at City University and honorary professor at the University of Liverpool. Martin is chair of the Memory Services National Accreditation Panel (MSNAP) and the editor of Aging & Mental Health. He is currently the chief investigator for the Economic and Social Research Council/National Institute of Health Research (ESRC/NIHR) funded Promoting Independence in Dementia (PRIDE) trial.

Aimee Spector is a reader in Clinical Psychology and co-ordinates older adults teaching on the Clinical Psychology Doctorate course at UCL. Her research focuses on developing and evaluating psychosocial interventions for people living with dementia. As part of her PhD she developed and evaluated Cognitive Stimulation Therapy (CST), which is now recommended by the National Institute of Clinical Excellence (NICE). Aimee’s research interests also include staff training, development of outcome measures and quality of life.

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