Introduction 1 2 3 5 6 4 7 9 8 10 3 7 11 12 13 19 14 20 21 22 23 24 25 26 21 7 17 19 27 28 In this paper the aim is to investigate the usefulness of six self-report measurement scales for OQOL, by studying whether they can be administered reliably and validly in a large group of nursing home residents, and whether this is related to cognitive impairment. We hypothesized that if all scales measure OQOL in nursing home patients validly and reliably, they would correlate highly, within all cognition groups. Moreover, the scales should be related to observational scales that measure OQOL. Methods Data were collected in ten nursing homes in the Netherlands. The Medical Ethics Committee of the VU University Medical Center had approved the research proposal, and written informed consent was obtained from the participants or their legal representative. Data were collected on a maximum sample of 30 residents over a period of 3 months per nursing home, with an equal distribution of residents with mainly physical handicaps (in so-called ‘somatic’ units) and mainly dementia syndromes (in so-called ‘psychogeriatric’ units). The principal investigator (DLG, a trained psychologist) administered the self-report OQOL scales and the cognitive test (see later), while the nursing staff carried out the observational assessments. The completeness of the interview data depended on the resident’s cognitive and physical abilities and willingness to answer questions. The scales were administered in random order. The administration of a scale was terminated when a resident proved to be unwilling or unable to respond to the questions that were asked. To assure the validity of cross-sectional comparisons, the self-report and observational scales for each resident were both assessed within the same 4-week period. Measurement instruments The scales that were selected to measure OQOL had been used before in published research among nursing home residents or frail elderly populations. A distinction was made between scales that ask about OQOL literally, scales that focus on positive affect, negative affect or life-satisfaction, and scales that indicate clinical depression. Self-report OQOL scales 7 22 29 30 30 31 24 21 25 24 32 32 33 34 Other scales 35 36 37 38 37 39 40 41 41 42 Analyses 43 36 44 45 Results Sample description N 1 Table 1 Descriptives and practical utility of self-report overall quality of life-scales  Scales (max. range) Descriptives total group Available MMSE scores a Mean (range) SD N N 22–30 13–21 5–12 0–4 Positive GEN-QOLQ (1–5) 2.7 (1–5) 1.0 119 117 35 36 35 43 43 54 4 36 PGCMS (0–17) 10.3 (0–17) 4.5 112 110 34 36 36 43 39 54 1 36 PAS (0–10) 4.4 (0–10) 2.6 102 98 30 30 31 32 34 36 3 14 Negative NAS (0–10) 1.6 (0–7) 1.9 98 94 30 30 30 31 31 33 3 14 DL (0–30) 8.0 (0–26) 5.4 143 135 23 23 26 27 65 65 21 49 GDS (0–30) 10.8 (0–26) 7.0 106 102 37 37 39 43 26 36 0 14 a Due to practical considerations and the frailty of the residents, not all scales were administered to all residents. Therefore, the number of completed scales varied. Proportion of completed scales 1 high cognition group moderate cognition group low cognition group very low cognition group N Internal consistency 2 Table 2 Internal consistency of self-report overall quality of life-scales for different cognition groups   Total group High cognition MMSE ≥22 Moderate cognition MMSE <22 & ≥13 Low cognition MMSE <13 & ≥5 a  b N c Alpha (miic) N Alpha (miic) N Alpha (miic) N Positive d .72 (.17) 108 .81 (.26) 33 .53 (.14) 35 .83 (.22) 38 PAS .55 (.18) 98 .47 (.20) 29 .77 (.25) 30 .68 (.18) 32 Negative NAS .72 (.18) 97 .68 (.16) 29 .81 (.31) 30 .71 (.17) 31 DL .81 (.22) 139 .87 (.30) 22 .72 (.15) 26 .79 (.21) 64 GDS .91 (.24) 98 .90 (.24) 34 .92 (.29) 37 .89 (.22) 23 a b c N N N d Construct validity Construct validity, inter-relationship 3 2 Table 3 Spearman correlation coefficients between self-report overall quality of life scales, for the separate MMSE score-groups   GEN-QOLQ PGCMS PAS NAS DL a MC LC HC MC LC HC MC LC HC MC LC HC MC LC Positive PGCMS  .38* .61** .22             N 34 35 37             PAS .01 .30 .47** .19 .21 .34          N 30 30 31 29 31 32          Negative NAS −.06 −.32 .13 −.51** −.69** −.47** −.17 −.10 .16       N 30 29 29 29 30 30 30 30 31       DL −.43* −.28 −.35* −.75** −.79** −.76** −.36 −.27 −.25 .45 .62** .44*    N 23 21 43 23 21 39 19 21 34 19 21 31    GDS −.47** −.60** −.36 −.80** −.66** −.65** −.20 −.43* −.25 .64** .65** .49* .88** .77** .69** N 35 34 24 34 35 25 30 30 23 30 29 22 23 20 26 a P P 3 P Construct validity, relationship with GIP-S and DRS 4 4 N N N N Table 4 Relationships of self-report overall quality of life-scales with observational measures for overall quality of life, for the separate MMSE score-groups   Positive Negative N N N N DL N = 143 N a MC LC HC MC LC HC MC LC HC MC LC HC MC LC HC MC LC GIP-S rho −.26 −.41* −.28 −.24 −.40* −.06 .01 .01 −.08 .36 .50** .02 .37 .42* .14 .39 .43** .01 N N 35 31 42 34 32 39 30 28 33 30 27 30 23 23 64 37 35 25 DRS rho −.43* −.25 −.09 −.36* −.36* −.06 .03 −.24 .11 .23 .30 −.12 .12 .51* .17 .44** .52** .30 N N 32 33 41 32 34 37 27 29 32 27 28 29 22 24 63 34 37 25 a P P Discussion 8 In addition to residents being able to complete a scale, the resulting psychometric properties of the scales are of importance. It appeared that all scales, with the exception of the PAS and, to a lesser extent, the PGCMS, had an acceptable internal consistency. Although the alphas varied across the cognition groups, there was no linear trend of decreasing consistency with increasing cognitive impairment. With regard to validity, the PGCMS, DL and GDS (and the NAS to a lesser extent), were strongly interrelated in all cognition groups, although the correlations in the low cognition group overall were somewhat lower. These four scales also had the strongest relationships with the observational scales for OQOL. However, these relationships were not very strong. Moreover, in the low cognition group the scales were not related to the observational scales. This suggests that level of cognitive impairment has a substantial influence on the validity of self-report OQOL-scales. 21 Although the DL and the GDS have been developed as screening instruments for depression, they correlated very strongly with the PGCMS, which is a scale for life satisfaction. Studying the item content of the scales, it appeared that the items of these three scales have many similarities. The items of the DL and the GDS contain positive as well as negative affects and also contentment (e.g. ‘satisfied’, ‘happy’ and ‘hopeful’). Remarkably, although the PGCMS is considered to be a positive scale, it has more items that contain negative affects or cognitions (12 out of 17; 71%) than the GDS (20 out of 30; 67%), and especially the DL (7 out of 15; 47%). Therefore, despite the fact that the names of the GDS and the DL suggest a negative scale, they both contain ample positive items. Likewise, the PGCMS cannot be considered to be a solely positive scale. So, with adapted scoring methods, each of these scales could be used as a single measure for OQOL, covering both positive and negative aspects. 2 46 49 46 48 26 7 50 In conclusion, measuring overall quality of life reliably and validly through self-report may not be possible in nursing home residents with at least moderate cognitive impairment. The quality of observational assessment of OQOL may also be lower in cognitively impaired residents. Before drawing definite conclusions about the usefulness of self-report scales, it is necessary to study their reproducibility. Nevertheless, in clinical practice, using self-report scales will provide interesting information on the experience of the residents, and is therefore in itself a valuable addition to observational data. The Depression List is a useful scale in this respect, especially for the assessment of nursing home residents with mild to moderate cognitive impairment.