Quality of life among people with epilepsy and mild intellectual disabilities in residential care

Epilepsy & Behavior 8 (2006) 703–712 www.elsevier.com/locate/yebeh

Quality of life among people with epilepsy and mild intellectual disabilities in residential care Michael Endermann

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von Bodelschwinghsche Anstalten Bethel, Psychosozialer Dienst im Stiftungsbereich Behindertenhilfe Bielefeld, Remterweg 58, 33617 Bielefeld, Germany Received 13 December 2005; revised 17 February 2006; accepted 23 February 2006 Available online 18 April 2006

Abstract This study examined quality-of-life (QOL) evaluations among people with epilepsy and mild intellectual disabilities in residential care to determine their covariation and potential determinants. Participants were 111 clients of the Bethel Institute, Bielefeld, Germany. They completed questionnaires on their overall QOL and life satisfaction, the PESOS scales on epilepsy-related QOL, the Brief Symptom Inventory (BSI), and scales on activities of daily life and work-related problems in face-to-face-interviews. QOL evaluations differed in the various domains and tended to be better on more concrete items. Correlations of generic QOL parameters with scales on epilepsy-related QOL were only weak. BSI scores reflecting the current emotional state were identified as the most influential predictors of all QOL measures. The weak relationship between non-health-related parameters of subjective QOL and epilepsy-related QOL requires further investigation and theoretical explanation, whereas the influence of negative affect on different QOL dimensions is in line with previous QOL findings.  2006 Elsevier Inc. All rights reserved. Keywords: Epilepsy; Mild intellectual disabilities; Overall quality of life; Life satisfaction; Epilepsy-related quality of life

1. Introduction Studies on quality of life (QOL) have been performed (1) as population surveys, (2) with a focus on health-related QOL, and (3) with respect to specific subpopulations such as people with intellectual disabilities. Clear distinctions cannot always be drawn. Generally, QOL has come to be identified more and more with subjective QOL. 1. Social scientific and psychological studies of the past decades have examined life satisfaction, happiness, or emotional well-being and have, for example, tried to identify the impact of socioeconomic variables on such parameters [1]. These are basically psychological variables, and may be regarded as aspects of subjective

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QOL. Studies within this context have found that chronic disease negatively influences emotional well-being [2]. 2. During the 1990s, the number of publications on epilepsy-related QOL increased. QOL investigations in the field of epilepsy follow the WHO definition that health-related QOL refers to evaluation by the patient and is a multidimensional construct [3,4]. Studies have dealt with the development and psychometric evaluation of appropriate epilepsy-specific questionnaires, with comparisons of different epilepsy groups, and with comparisons of people with epilepsy in different countries [5– 8]. Moreover, epilepsy-related QOL was established as a measure of outcome, in addition to seizure control, in studies on the effects of epilepsy treatments [9,10]. This is the field in epilepsy in which the clinical importance of the QOL construct is most striking. 3. Publications on QOL of people with intellectual disabilities do not always follow the WHO definition of health-related QOL. Studies have been conducted with a focus on

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objective circumstances, as well as on subjective appraisals of the living situation. Moreover, proxy ratings seemed to be the only way to gain information on QOL on people whose verbal communication competency was insufficient for life evaluations [11,12]. In reference to sociopolitical principles such as normalization and self-determination, in studies on subjective QOL, people with only mild intellectual disabilities were often asked how satisfied they were with their living situation and opportunities for social participation. Differences were expected to emerge dependent on different living conditions and care modalities [13], but service evaluation by users with QOL measures has been markedly criticized as well [14]. Despite the frequency of such QOL research, neither studies in the field of epilepsy nor those in the field of intellectual disability have, to the author’s knowledge, investigated both QOL aspects with differentiation, that is, generic non-healthrelated subjective QOL and specific epilepsy-related QOL. This study of people with epilepsy and mild intellectual disabilities in residential care aims to analyze the relationship between these different aspects of subjective QOL. In this context, there is no theoretical differentiation between subjective QOL, life satisfaction, and emotional well-being, and these terms are regarded as largely synonymous [11,15]. Instead, the differentiation is made between generic non-health-related QOL, composed of two scales, and epilepsy-related QOL, composed of four scales. The questions asked are: 1. How do people with epilepsy and mild intellectual disabilities in residential care evaluate their overall QOL and their satisfaction with daily life? 2. How do they evaluate their epilepsy-related QOL? 3. Are overall QOL, satisfaction with daily life, and epilepsy-related QOL related? 4. Which variables are the predominant predictors of these different QOL domains? 2. Methods 2.1. Sample One hundred eleven people with epilepsy from residential units of the Bethel Institute took part in the study. Participants were volunteers representing nearly all of three units for patients with epilepsy. Four clients did not participate either for personal reasons or because of insufficient verbal competency. The sample consisted of 44 female (39.6%) and 67 male (60.4%) clients, with a mean age of 38.9 (SD = 14.2, range = 19–74). The clients’ disabilities were a combination of (1) difficult-to-treat-epilepsy, (2) mild intellectual disabilities, and (3) psychosocial disturbances. Information on these three areas of diagnosis was based on the Institute’s clinical files: 1. The mean number of different seizure types was 2.4 (SD = 1.1, range = 1–5). The most frequently documented type of seizure was generalized tonic–clonic, followed by complex partial, simple partial, absence, and tonic. During the 6 months prior to data collection, 74 residents (66.7%) had seizures; the remainder of the sample were seizure-free. Mean age at onset of epilepsy for the sample was 7.1

(SD = 5.9, range = 0–24), and mean duration of epilepsy was 31.9 years (SD = 16.1, range = 4–68). On average, clients were being treated with 2.1 (SD = 1.0, range = 1–5) antiepileptic drugs (AEDs). Valproate was most frequently prescribed, followed by lamotrigine and carbamazepine. 2. All participants were able to communicate verbally. Current IQ scores were not available. Physicians had rated 78 residents (70.3%) in the sample as having learning disabilities or mild mental retardation. The majority of 89 residents (80.2%) held employment in sheltered workshops of the Bethel Institute; the others either were retired or did not work for other reasons at the time of the study. 3. Current psychiatric diagnoses based on ICD-10 or DSM-IV were also not available. Information from the residential files indicated past or chronic psychiatric symptoms in a majority of 81 participants (73.0%). This large proportion resulted from the classification of all patients whom physicians had diagnosed with psychological or behavior problems as psychiatric cases. Prescriptions of psychotropic medication were judged as additional information on current psychiatric symptomatology: Thirty-nine people with epilepsy (35.1%) were taking psychotropic medication in addition to AEDs.

2.2. Measures 2.2.1. Overall QOL and satisfaction with daily life The single item overall QOL had to be rated on an 11-point scale (0 = ‘‘It could not be worse,’’ 10 = ‘‘It could not be better’’). This one-dimensional overall QOL measurement has frequently been used in social scientific studies [16]. The item was also included in the Quality of Life in Epilepsy Inventory (QOLIE), a widely used questionnaire on epilepsy-related QOL [17]. Satisfaction with various aspects of daily life and social interaction was evaluated using eight questions regarding (1) personal independence, (2) home, (3) caregiving, (4) neighbors, (5) friends/partnership, (6) relationship to relatives, (7) social support in personal problems, and (8) work. The items were selected with respect to the particular living conditions—residential care. The scale resembled other life satisfaction questionnaires that have, since Cummins, proved their utility in people with intellectual disabilities when certain cognitive basic requirements are met [18]. Each item had to be answered on a 5-point scale (0–4), ranging from ‘‘not at all satisfied’’ to ‘‘extremely satisfied.’’ Raw scores were converted to scores ranging from 0 to 100, with 100 representing highest satisfaction. A composite score was calculated by dividing the sum of the item scores by the number of items. 2.2.2. Epilepsy-related QOL Epilepsy-related QOL was measured using four subscales of the PESOS questionnaire (PESOS = performance, sociodemographic aspects, subjective estimation). The PESOS questionnaire is a self-rating tool developed in the Epilepsy Centre Bethel and psychometrically evaluated with samples from German tertiary care epilepsy centers [19,20]. For use in residential care, some inappropriate items dealing with work/education or driving cars/motorcycles were eliminated, and a 5-point scale was chosen to score all subscales to prevent confusion [21]. The 11 items of the resulting subscale Restrictions in Daily Life (‘‘During the past 6 months, have you felt restricted by epilepsy in the following domains?’’) encompass functional, social, physical, and psychological dimensions that are generally stressed as central aspects of health-related QOL in generic questionnaires [22]. Three other epilepsy-related PESOS subscales deal with psychosocial aspects, the importance of which for people with epilepsy is discussed extensively elsewhere [23]. Since the 1990s, these aspects have sometimes been regarded as epilepsy-related QOL components [24]: 12 items refer to epilepsy-related fear (e.g., ‘‘Are you afraid of seizures while going out?’’), 3 Items refer to [felt] stigma (e.g., ‘‘Do others withdraw because of your epilepsy?’’), and 6 items refer to emotional adaptation to epilepsy (e.g., ‘‘Do you think things go wrong in your life because of your epilepsy?’’). PESOS raw scores were analogous to scores on

M. Endermann / Epilepsy & Behavior 8 (2006) 703–712 the life satisfaction scale converted to a range between 0 and 100, with higher scores reflecting more epilepsy-related problems, thus indicating a lower epilepsy-related QOL. 2.2.3. Other psychosocial variables Based on PESOS items, which are not directly related to epilepsy, two more self-rating scales were developed: One comprised 21 items of a questionnaire on activities of daily living (ADL) and covered important aspects of self-sufficiency, mobility, leisure, and social activity (e.g., ‘‘Do you take your meals regularly?’’ ‘‘Do you leave your home on your own?’’ and ‘‘How often do you have dates with friends?’’). The other scale comprised 10 items of a questionnaire on problems at work dealing with aspects of achievement and social integration (e.g., ‘‘Do you have memory difficulties at work?’’ ‘‘Do you have conflicts with your supervisor?’’). Scoring, coding, and conversion of these two scales were done in accordance with the PESOS scales on epilepsyrelated QOL. Finally, emotional distress was measured with the German version of the Brief Symptom Inventory (BSI) [25]. The BSI is a standardized self-rating and internationally recognized screening tool for detecting clinical symptoms. Its utility has already been demonstrated for people with mild intellectual disabilities, including those with epilepsy [26,27]. Fifty-three questions on symptoms are answered on a 5-point scale (0–4), ranging from ‘‘not at all’’ to ‘‘extremely.’’ The items define a broad spectrum of perceived restrictions due to physical and psychological symptoms occurring in the preceding week. As a measure of global distress, only the Global Severity Index (GSI), the composite score of the BSI, was used in this study. Based on the German normative sample, BSI raw scores were converted to T scores with respect to gender. 2.2.4. Epilepsy variables As previously mentioned (see Section 2.1), information on seizure control, that is, information on occurrence of seizures during the 6 months prior to data collection, was gathered from the residential files. In addition, clients were asked about the tolerability of their AED treatment (from ‘‘very good’’ or ‘‘good’’ to ‘‘indifferent’’ to ‘‘dissatisfying,’’ the last meaning the adverse effects were not tolerable).

2.3. Data collection Because of the possible reading, attentional, and motivational problems of the clients in residential care, all questionnaires were administered in face-to-face-interviews. They were read aloud to each individual by a member of the Psychological Service of the Bethel Institute. Most of the clients were able to understand the questionnaires and the 5-point scoring of the items, but in some cases the PESOS scales on epilepsy-related QOL caused problems: The term restriction and other more abstract words such as self-esteem were sometimes not understood. If more detailed explanations using more concrete examples did not make a phrase fully comprehensible, the scores of these scales were rejected from further data analysis. This factor accounts for a maximum of only 106 cases in the statistical procedures on epilepsy-related QOL.

2.4. Data analysis SPSS for Windows (Version 8.0) was used for data analysis. As a measure of the scales’ internal consistency, Cronbach’s a was calculated. Relations between scales were analyzed using Spearman’s rank correlation coefficients due to skewed distribution of scores. Two-tailed t tests were performed to look for group differences. As the data analysis was heuristic in nature, no a error correction was conducted despite multiple group comparisons. Finally, stepwise regression analyses were performed to look for the percentage of variance explanations by different groups of variables. The only variables entered as possible predictors were those that had demonstrated a significant relationship (P < 0.05) with QOL criteria in the preceding univariate data analyses.

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3. Results 3.1. Overall QOL and life satisfaction: Distribution of scores, internal consistency, and gender differences Taking into account the differences in score scaling, that is, 0–10 versus 0–100, the overall QOL item was rated lower than the items on the life satisfaction scale (Table 1). Percentiles and floor and ceiling effects on the satisfaction scale refer to a skewed score distribution with an especially high frequency of ceiling effect on items dealing with satisfaction with friends/partnership and satisfaction with work. The internal consistency of the satisfaction with daily life scale was 0.67 according to Cronbach’s a. Although items on the satisfaction with daily life scale correlated moderately with the scale’s composite score, correlation coefficients between the items on the scale were relatively low (Table 2). Among these low coefficients, scores on satisfaction with self-sufficiency, with home, and with work were still the most highly correlated with all other aspects. Comparable values were also computed between the scale’s items and the overall QOL item. Scores on satisfaction with different social groups of relevance were partly more independent: There were substantial relationships between satisfaction with friends and satisfaction with neighbors, as well as between satisfaction with social support, satisfaction with caregiving, and satisfaction with relatives, but satisfaction with neighbors, satisfaction with relatives, and satisfaction with friends were, for example, not related to satisfaction with caregiving. Satisfaction with relatives did not correlate with satisfaction with friends or satisfaction with neighbors. Female and male clients did not differ significantly on the overall QOL item and on the composite score for satisfaction with daily life. 3.2. Epilepsy-related QOL: Distribution of scores, internal consistency, and gender differences As has been already demonstrated in more detail [21], the distribution of PESOS scores on epilepsy-related QOL differed markedly between the residential population and epilepsy patients from German tertiary care centers (Table 1): In residents of the Bethel Institute, a floor effect was observed much more frequently, indicating fewer epilepsy-related problems. On all four measures, 27% of clients had, on average, zero scores. The internal consistency of the four PESOS scales on epilepsy-related QOL consistently exceeded Cronbach’s a of 0.75 in residential care. Female clients scored significantly higher (P < 0.05) on the scale Restrictions due to Epilepsy; they also tended to manifest more problems (P < 0.10) with respect to the scale Emotional Adaptation to Epilepsy. 3.3. Relations between measures of subjective QOL A moderate correlation coefficient was computed between the overall QOL item and the composite score

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Table 1 Satisfaction with daily life, overall QOL, and epilepsy-related QOL: Floor and ceiling effects, mean values, and percentiles Floor %

Ceiling %

Mean

SD

10%

25%

50%

75%

90%

2.7 6.3 5.4 4.5 1.8 8.2 3.8 5.7 0 2.7

24.5 28.8 25.2 44.1 59.1 39.1 37.5 40.0 3.6 13.6

71.14 68.47 66.89 72.30 81.82 70.00 74.76 75.95 72.66 6.25

23.51 28.55 27.83 29.84 26.43 31.73 26.42 27.50 15.29 2.36

50.00 25.00 25.00 25.00 27.50 25.00 37.50 25.00 54.13 3.00

50.00 50.00 50.00 50.00 75.00 50.00 56.25 75.00 62.50 5.00

75.00 75.00 75.00 75.00 100.00 75.00 75.00 75.00 75.00 6.00

81.25 100.00 100.00 100.00 100.00 100.00 100.00 100.00 84.38 8.00

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 92.90 10.00

32.1 (6.5) 21.7 (1.9) 36.8 (38.2) 17.9 (2.8)

0.0 (0.2) 0.0 (0.8) 0.0 (1.3) 1.9 (5.5)

12 (34) 18 (49) 23 (24) 26 (54)

14 (24) 20 (24) 26 (28) 25 (27)

0 (4) 0 (18) 0 (0) 0 (15)

0 (15) 2 (30) 0 (0) 8 (30)

7 (31) 13 (50) 17 (13) 21 (55)

21 (48) 28 (67) 42 (43) 34 (75)

30 (70) 48 (82) 67 (69) 55 (90)

a

Items on satisfaction with daily life (N = 111): Satisfaction with personal independence ... Home ... Caregiving ... Neighbors ... Friends/partnership ... Relationship to relatives ... Social support in case of personal problems ... Work Satisfaction with daily life (composite score) Overall QOL (single item)b PESOS-scales on epilepsy-related QOL (N = 106)c: Restrictions in daily life Epilepsy-related fear Stigma Emotional adaptation to epilepsy a

Range of items and scale: 0–100 (higher scores = more satisfaction). Range of the item: 0–10 (higher scores = more satisfaction). c Range of PESOS scales: 0–100; higher scores indicate more problems, i.e., worser QOL. Data in parentheses are for epilepsy patients from German tertiary care centers (N > 800) according to May et al. [19]. b

Table 2 Correlation coefficients within the scale on satisfaction with daily life and correlations between satisfaction items and the item on overall QOL (Spearman correlation coefficients) Items of the scale on satisfaction with daily life

Overall QOL (single item)

Scale on satisfaction with daily life (composite score)

Personal independence Home Caregiving Neighbors Friends Relatives Social support Work

0.35a 0.35a 0.19 0.23b 0.13 0.23b 0.27a 0.42a

0.57a 0.65a 0.53a 0.51a 0.48a 0.47a 0.51a 0.64a

a b c

Items of the scale on satisfaction with daily life (= satisfaction with): Personal independence 0.28a 0.36a 0.28a 0.19b 0.20b 0.27a 0.37a

Home

Caregiving

0.39a 0.31a 0.22b 0.19b 0.17 0.38a

0.13 0.06 0.08 0.29a 0.40a

Neighbors

0.35a 0.03 0.09 0.20b

Friends

Relatives

0.06 0.08 0.24b

0.28a 0.24b

Social support

0.19c

P < 0.01 (two-tailed). P < 0.05 (two-tailed). P < 0.10 (two-tailed).

on the satisfaction with daily life scale. Correlation coefficients between the four PESOS scales on epilepsy-related QOL turned out to be somewhat higher, with a mean q of 0.49. Coefficients of correlation between epilepsy-related QOL and the more generic QOL parameters, that is, overall QOL and life satisfaction, were very low: The mean coefficient between the four PESOS scales on epilepsy-related problems and the overall QOL item was q = 0.18; the mean coefficient between these PESOS scales and the satisfaction with daily life scale was q = 0.23. Among the PESOS scales, Emotional Adaptation to Epilepsy was correlated most highly with overall QOL and satisfaction with daily life (Table 3).

3.4. Relations between QOL measures and other psychosocial parameters as well as epilepsy variables Table 3 also refers to the relationship between subjective QOL and other variables: The highest mean correlation coefficient, q = 0.45, was that between the QOL measures and the BSI composite score indicating general emotional distress. BSI scores significantly correlated with all QOL measures. All of the QOL measures also correlated significantly with the problems at work scale, but coefficients were somewhat lower. Scores on the ADL scale were related only to overall QOL, satisfaction with life, and the Restrictions due to Epilepsy scale from the domain of epilepsy-related

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Table 3 Relations between different QOL-domains, between QOL domains and other psychosocial variables, and between QOL domains and epilepsy variables (Spearman correlation coefficients and t tests) Subjective QOL Overall QOL (item) QOL dimensions Satisfaction with daily life Restrictionsa Feara Stigmaa Adaptationa Other psychosocial variables ADL scaleb Problems at workb BSIc Epilepsy variables Seizure controld AED tolerabilityd a b c d e f g

Epilepsy-related QOL Satisfaction with daily life

Restrictionsa

Feara

Stigmaa

0.40e 0.10 0.16g 0.17g 0.28e

0.21f 0.25f 0.17g 0.30e

0.45e 0.28e 0.45e

0.54e 0.58e

0.61e

0.20f 0.24f 0.43e

0.36e 0.38e 0.48e

0.21f 0.35e 0.31e

0.09 0.48e 0.52e

0.13 0.32e 0.46e

e

e

g

e

Adaptationa

0.12 0.44e 0.49e f e

PESOS scales on epilepsy-related QOL . Self-constructed scales based on other PESOS-scales. ADL, activities of daily life. Composite-score GSI of the Brief Symptom Inventory (T score). Groups without seizure control and low AED tolerability scored higher on PESOS scales, i.e., had lower epilepsy-related QOL. P < 0.01 (two-tailed). P < 0.05 (two-tailed). P < 0.10 (two-tailed).

QOL. The reliability of the ADL and problems at work scales had previously been confirmed as satisfactory, with Cronbach a scores > 0.70. Finally, it can be seen that only measures of epilepsy-related QOL reflected differences on the epilepsy variables seizure control and AED tolerability: Clients with epileptic seizures during the 6 months prior to data collection indicated significantly (P < 0.05) more problems on all four epilepsy-related QOL scales; clients with lower AED tolerability indicated significantly (P < 0.05) more problems on the Restrictions due to Epilepsy and Emotional Adaptation to Epilepsy scales. 3.5. Prediction of QOL measures In addition to the univariate results, stepwise regression analyses were performed to predict the six QOL variables

(overall QOL, satisfaction with daily life, and four measures of epilepsy-related QOL) from different sets of independent variables. With respect to single predictors, results of these analyses largely resembled the univariate analyses already discussed. Therefore, Table 4 outlines only the amount of variance explained by different groups of variables: Generally, most of the variance in QOL parameters can be explained by the remaining QOL parameters; a smaller proportion of the variance, by the other psychosocial parameters. Epilepsy parameters explained only epilepsy-related QOL variance. It is worth mentioning that for overall QOL and satisfaction with life, the almost equal proportions of variance were explained by the remaining QOL parameters and by psychosocial variables. With respect to epilepsy-related QOL parameters, an especially large part of the variance was explained by the remaining variables for epilepsy-related QOL. But findings

Table 4 Regression models to predict QOL parameters Subjective QOL Overall QOL (item)

Epilepsy-related QOL Satisfaction with daily life

Restrictionsa

Feara

Stigmaa

Adaptationa

Prediction of QOL parameters from I. Other QOL parameters Regression model (always P = 0.000) F(103/2) = 19.91 F(104/1) = 32.24 F(103/2) = 17.09 F(103/2) = 58.15 F(103/2) = 63.39 F(102/3) = 59.52 Variance explanation (corrected R2) .27 .23 .24 .52 .54 .63 II. Psychosocial variables Regression model (always P = 0.000) F(101/2) = 12.96 F(102/2) = 27.58 F(100/2) = 10.48 F(100/2) = 31.31 F(101/1) = 31.20 F(100/2) = 32.17 .34 .16 .37 .23 .28 Variance explanation (corrected R2) .19 III. Epilepsy variables Regression model (always P < 0.05) Variance explanation (corrected R2) a

PESOS scales on epilepsy-related QOL.

F(103/2) = 24.36 F(104/1) = 8.94 .31 .08

F(104/1) = 4.13 .03

F(103/2) = 7.40 .11

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on the PESOS scale Restrictions due to Epilepsy contradicted this pattern: The largest part of the variance was explained by epilepsy variables; the other QOL variables and the psychosocial variables had less influence. 4. Discussion The four questions asked at the beginning of this article can now be answered: 1. Clients with epilepsy and mild intellectual disabilities in residential care scored relatively high on satisfaction with daily life: 72.7 on a scale ranging from 0 to 100. They scored lower on overall QOL: 6.3 on a scale ranging from 0 to10. 2. Clients in residential care also scored relatively high on epilepsy-related QOL. This conclusion is drawn from the low PESOS scores on epilepsy-related problems. 3. Covariation between satisfaction with daily life and overall QOL was moderate. Covariation within epilepsy-related QOL, that is, between measures of epilepsyrelated QOL, was also moderate. But life satisfaction and overall QOL were only slightly, if at all, correlated with measures of epilepsy-related QOL. Consequently, the data collected in this study do not strongly support the notion that subjective QOL is a homogeneous theoretical construct. 4. If the influence of QOL parameters on each other is not taken into account, BSI scores as indicators of emotional distress were the variables in this study that were most highly correlated with all of the subjective QOL parameters. Epilepsy variables were connected only to epilepsy-related QOL, especially to the scale Restrictions due to Epilepsy. 4.1. Question 1 From the distribution of scores on the life satisfaction scale, we infer that most of the clients in residential care at the Bethel Institute seemed to have accepted their living conditions. Their scores were similar to those obtained on surveys on life satisfaction conducted in different samples of the general population in Western nations: Cummins concluded that a population standard for life satisfaction can be expressed as 75% (SD = 2.5) of the measurement scale maximum score [2]. Satisfaction scales developed for the general population usually consist of more items than does this scale on satisfaction with daily life [28]. Here, as part of an assessment tool, relatively few items were chosen because of possible deficits in concentration of clients in residential care. Usually, the risk involved in using a smaller number of items is diminished reliability of the scale, and the scale’s internal consistency did indeed not reach the statistical convention of a Cronbach a > 0.70. Nevertheless, the scale was accepted for use as a heuristic questionnaire. Reliability scores between 0.60 and 0.70 have already been reported

for other QOL scales specially designed for people with mild intellectual disabilities [29]. The only moderate reliability of this scale and the somewhat low correlation coefficients between the items provide an idea of the domain specificity of the clients’ evaluations and of content validity: Satisfaction with different social reference groups, such as neighbors and relatives or relatives and friends, was evaluated independently, whereas satisfaction with neighbors did correlate with satisfaction with friends; these are two groups that overlap to a great degree, especially in residential care. Satisfaction with social support was correlated to satisfaction with caregiving, as well as satisfaction with relatives, that is, people who can be considered natural or requested sources of support. Friends did not play a role in the context of social support, a situation, again, most likely reflecting living conditions specific to residential care. The relatively consistent correlation between satisfaction with personal independence, with home, and with work and all of the other items on the scale seems to indicate that satisfaction with one’s own abilities tends to generalize and have positive effects in many areas. Clients scored an overall QOL 6.3 on a scale ranging from 0 to 10, obviously lower than their life satisfaction score on more concrete items of daily and social life. This finding is interesting, as Cummins [2], in his overview, reported a large conformity of total scores on subjective QOL to single items on overall QOL. In contrast to data on satisfaction with daily life, data from this study on overall QOL were not in accordance with the ‘‘gold standard’’ of 75% (SD = 2.5) of the measurement’s maximum score mentioned before. But the low overall QOL score in this study is less unusual with respect to special subpopulations: Whereas Cummins [2] detected no difference in satisfaction with life between the general population and people with intellectual disabilities, he reported lower QOL scores for persons with chronic disease, whose mean satisfaction with life score was 4 SD below that of the normative sample and, thus, more like the overall QOL score for the patients with epilepsy in residential care in the present study. Evaluation of overall QOL with a single item allows approximate comparisons with other studies of patients with epilepsy: Two items of the QOLIE, for example, ask for estimates of overall QOL, which form the basis of a summary score on overall QOL ranging from 0 to 100. This score, as well as other overall QOL estimates, differ greatly in different studies and seem, at least partly, to reflect not only seizure frequency, but the severity of epilepsy: Patients whose epilepsy treatment was in the process of being modified had low scores (maximum = 64) [30,31]. Patients treated in tertiary care centers had better scores (67 or 72) [17,32]. However, German patients on monotherapy who were not being treated by specialists had the highest scores; in conformity with the general population they rated their overall QOL 7.7 on a scale ranging from 0 to 10 [22]. Together, the data from the present study are conflicting: Scores on overall QOL are in line with life satisfaction scores of people with chronic disease, scores on

M. Endermann / Epilepsy & Behavior 8 (2006) 703–712

satisfaction with daily life correspond to those of the general population, including people with intellectual disabilities. One possible reason for this contradiction could be that overall QOL evaluations reflect an entire life, whereas evaluations of satisfaction with daily life reflect the current state, and unlike comparable scales [28], questions did not at all touch generic aspects of physical and psychological health. The low score on overall QOL could therefore be a manifestation of an identity as a disabled person resulting from cumulative frustrations over the life span. 4.2. Question 2 In this sample, the internal consistency of the PESOS scales on epilepsy-related QOL had to be regarded as satisfactory, and correlation with seizure frequency and AED tolerability was viewed as an important clue to validity. On the other hand, the distribution of the PESOS scores clearly differed from those of clinical epilepsy samples [19]: Epilepsy-related problems were noted less often by the clients in residential care. As indicated elsewhere [21], this difference could only be attributed partly to the higher seizure frequency of patients in tertiary care, and therefore, the influence of other factors must be taken into account: First, in residents with multiple disabilities, the unique impact of the epilepsy may have been reduced. Second, living conditions in residential care may have been better suited to the everyday needs of people with epilepsy, for which the particularly low scores on the restrictions subscale argue. [3] Finally, living together with other people with epilepsy may have promoted coping skills and adaptation to epilepsy. In total, the low scores on epilepsy-related PESOS scales, indicating only a few problems, are in line with the relatively high scores on the satisfaction with daily life scale. Within the epilepsy-related QOL scales, it was again striking that more general items, as on the subscales Stigma and Emotional Adaptation to Epilepsy, tended to elicit higher scores than more concrete items such as those on the scale Restrictions due to Epilepsy. Similar to the arguments on overall QOL, it seems reasonable to assume that more general items evoke an evaluation of earlier and overall experience with chronic disease or disability. Gender differences on epilepsy-related QOL in residential care may result predominantly from the fact that seizure control and gender were confounded: Only 10 (22.7%) female clients, compared with 27 (40.3%) male clients, had been free of seizures during the 6 months prior to data collection. One could cast doubt on the interpretation of the PESOS scores by arguing that the low scores indicating fewer problems, especially the floor effect, may have resulted from a lack of understanding or a generally low IQ of the subjects. Yet this explanation does not seem very likely: First, with respect to all the scales

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used in this study, the clients generally tended not to neglect problems; they had, for instance, a high ‘‘case’’ rate according to BSI scores that are discussed later. Second, there was no evidence of acquiescence; evaluation of overall QOL, for example, did not reach the expected 75% of the measurement’s maximum score as discussed by Cummins [2]. Third, the distributions of the PESOS scales differed. Extreme scores resulting from a lack of understanding should have been obtained on more abstract items, but, in fact, the opposite occurred: A particularly large floor effect was observed on the subscale Restrictions due to Epilepsy, where interviewers from the Psychological Service failed to recognize problems in understanding. The floor effect was smaller on the subscale Emotional Adaptation to Epilepsy with more abstract items. The floor effect on the scale Stigma also appeared not to account for problems with understanding, as the percentage was similar to that of the clinical reference sample. 4.3. Question 3 Interestingly, data from this study demonstrated only a low correlation of epilepsy-related QOL with overall QOL and life satisfaction. This finding seems to be based only partly on the selected measures: The overall QOL item has been used in social science for decades, and the satisfaction with daily life scale resembles other scales on life satisfaction [18,22,28]. The validity of the epilepsy-related PESOS scales was proven, among others, by the significant relationship to QOLIE scores for patients from tertiary care epilepsy centers: In these patients, contradictory to the results of this study, QOLIE items on overall QOL also correlated with PESOS scales: r = 0.55 for Restrictions due to Epilepsy and with r = 0.45 for Epilepsy-Related Fear [31]. The low covariation of epilepsy-related QOL with overall QOL and life satisfaction probably is due to residential care: Epilepsy may lose its overwhelming meaning when it is no longer experienced as the most influential factor in life planning. Satisfaction with daily life refers to living under conditions in which support is available. Overall QOL, probably more than other aspects of QOL, reflects possible discrepancies between actual life and previous or current longing for a ‘‘normal’’ life or changes in the living situation. These elements together could result in a more fragmentary or less homogeneous evaluation of QOL domains, being more than a methodical artifact resulting from this scale on life satisfaction without health-related items. 4.4. Question 4 It seems reasonable to stress at the beginning of this section that two major findings of previous health-related QOL research were replicated. On the one hand, many investiga-

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tions with different epilepsy samples have already shown that seizure activity negatively influences epilepsy-related QOL, whereas seizure freedom is associated with higher QOL [33–36]. On the other hand, the association between BSI scores and QOL is in line with many studies provided that emotional distress or negative affect is the latent construct of all self-rating scales on clinical psychological symptoms [37]: In patients with epilepsy, epilepsy-related QOL correlated with neuroticism [38,39] or depression [40,41]; neuroticism has also been found to correlate with non-health-related subjective QOL in nonclinical populations [42,43]. Other aspects that have been less emphasized or have only recently gained attention are: (1) the influence of other variables on QOL; (2) the either specific or global influence of variables on QOL dimensions; and (3) the relative importance of predictors. It is also not yet clear (4) which conclusions are to be drawn from the association between QOL and psychological distress. 1. In this study univariate analyses revealed more variables, such as AED tolerability and problems at work, to be associated with QOL dimensions. Nevertheless, explanation of QOL variance by all of the variables that were not included as QOL dimensions was only moderate. Considering the relative heterogeneity of QOL dimensions, the construct validity of QOL may be questioned. But results of the regression analyses indicate that the QOL construct alternatively cannot simply be reduced to medical or other psychological concepts. 2. Some variables were more specifically related to QOL dimensions, others more generally, but together these relationships argue for plausibility and underline content validity. On the one hand, specific relationships stressed the content specifics of the QOL evaluations: The ADL scale corresponded predominantly to overall QOL and satisfaction with daily life. Here, epilepsy variables such as seizure control and AED tolerability corresponded only to epilepsy-related QOL, whereas other studies have yielded contrasting results, with an influence of seizure frequency on overall QOL [31,44]. On the other hand, variables such as problems at work and BSI scores were universally related to all of the subjective QOL evaluations, with comparatively the highest correlation coefficients on BSI scores indicating emotional distress. 3. It must be noted that most subscales on epilepsy-related QOL were also moderated to a higher degree by BSI scores than by epilepsy variables. The scale Restrictions due to Epilepsy was the only exception: Therefore, it may prove worthwhile to investigate whether this scale is reacting with special sensitivity to epilepsy treatments and, also, if the remaining PESOS scales on epilepsy-related QOL have a higher potential for detecting psychotherapeutic, emotionally stabilizing effects on patients. 4. As already outlined at the beginning of this section, the association between QOL and BSI scores refers to the results of many other investigations. But what does this association indicate? Does psychological dis-

tress affect QOL? Does low QOL cause psychological symptoms? Is the relationship reciprocal? Based on a correlational study design, negative affect was considered a factor underlying QOL. But even within the framework of this assumption, it is yet unclear whether QOL is grounded more on largely time-stable and uncontrollable personality dimensions such as neuroticism or is moderated by more variable affective disorders that may be treated effectively. In this context, the BSI scores of the residential sample are, unfortunately, anything but clear: They have already been demonstrated to be sensitive to change and to reflect psychotherapeutic treatments, for example [45], but their relative time stability has already been documented as well [46]. Additionally, it seems important to consider the distribution of BSI scores presented in this study: The total score was slightly above the average of the normative sample, and following the cutoff criterion (T score P 63), 25.5% of the sample was either prone to developing or actually had a psychological disorder. When this finding is taken into consideration, the relatively positive QOL evaluations have to be restricted: Most of the clients in residential care at the Bethel Institute seemed to be satisfied with their current living situation, although a large percentage had psychological problems. 4.5. Consequences In addition to the questions asked at the beginning of this article, data from this study on patients with epilepsy in residential care suggest that: • QOL was rated with a clear content specificity, but emotional distress is the common component in all QOL dimensions. • The use of QOL composite scores as aggregations of data from different QOL dimensions should be discouraged, as important information may be lost. • QOL scores may easily obscure emotional problems, including psychological disorders, if comparative data on QOL of other samples or additional data on emotional distress are not taken into account. • Evaluations of the current living situation paint an altogether more optimistic picture than more general and abstract evaluations, which may include the entire life span. • Central epilepsy variables such as seizure control pertain only to epilepsy-related QOL among nonclinical patients with longstanding, chronic epilepsy and mild intellectual disabilities. As the results of this investigation may, in part, be sample-specific artifacts, the relationship between overall QOL, satisfaction with daily life, and health-related QOL requires further clarification. The only weak covariation of these

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