Elsevier

Epilepsy & Behavior

Volume 13, Issue 1, July 2008, Pages 202-211
Epilepsy & Behavior

Self–proxy agreement and correlates of health-related quality of life in young adults with epilepsy and mild intellectual disabilities

https://doi.org/10.1016/j.yebeh.2008.02.005Get rights and content

Abstract

This study investigated health-related quality of life (HRQOL) in young adults with epilepsy and intellectual disabilities. First, agreement between self-reports and proxy reports of HRQOL was examined. Second, medical and psychological contributions to HRQOL were explored. Thirty-six patients were interviewed using the Quality of Life in Epilepsy inventory (QOLIE-31), the Hospital Anxiety and Depression Scale, and the Neuroticism and Extraversion scales of the NEO Five-Factor Inventory. Medical data were taken from files. Professional caregivers completed rephrased QOLIE-31-questionnaires. The perspectives on HRQOL differed systematically: Caregivers underrated their clients’ HRQOL on average. Few correlations with medical characteristics emerged, whereas all psychological variables were strongly related to HRQOL. Neuroticism, Age at Disability Onset, and their interaction explained 71% of the HRQOL variance. Results indicate that proxy reports do not provide valid substitutes for most of the self-reported HRQOL subscales. Psychological treatment of negative affectivity and after critical life events in adolescence may improve HRQOL in young adults with epilepsy and mild intellectual disabilities.

Introduction

Epilepsies are often associated with a multitude of adverse effects beyond the core symptom of seizures. To cover the potentially broad effects of the chronic disease and, furthermore, to optimize treatment and care, health-related quality of life (HRQOL) is increasingly used as an outcome measure in epilepsy research. Some consensus exists regarding operational definitions of HRQOL as a multifaceted construct that comprises physical, psychological, social, and functional domains of well-being as the minimal components to be assessed from the patients’ view [1], [2]. With respect to epilepsy, an extended definition of HRQOL including educational and financial losses is frequently used [3], [4]. Specific inventories for the assessment of HRQOL in epilepsy cover the impact of both the chronic disease and its treatment. The Quality of Life in Epilepsy inventory (QOLIE-31) [5] is one such disease-specific instrument that has been adapted for international use and was employed in this study.

The evaluation of experiences from a subjective point of view is an integral part of HRQOL definitions. It is widely endorsed that the persons concerned should rate their condition themselves. Even data on HRQOL in children [6] should be collected primarily via self-reports. Hence, external ratings from a person who knows the patient well enough to provide sufficiently accurate information (i.e., a proxy report) are not meant to be used for validation of self-reports. They should, rather, be considered additional information from an external perspective (cf. [7], [8]).

Nevertheless, the first aim of this study was to compare self-reported HRQOL with proxy reports. Patients may be unable or unwilling to complete a comprehensive questionnaire personally, for example, because of cognitive limitations. Omitting these persons from analyses may lead to biased results. Thus, it may be reasonable to obtain such information through another person familiar with the patient (cf. [8], [9]). In this study, we employed professional caregivers as proxies. We assumed that they know their clients well enough to provide adequate information. Moreover, caregivers should be sensitive to their clients’ needs and share their view of problematic and problem-free areas of life to ensure appropriate patient-centered support. Therefore, we explored self–proxy agreement regarding HRQOL by investigating the congruence of ratings from the patients’ perspective (obtained in standardized interviews conducted by a neutral interviewer) and from their caregivers’ perspective (obtained in questionnaires). In addition, we examined age, sex, frequency of contact, and other characteristics as variables potentially related to the variance in self–proxy agreement.

A second aim of the study was to investigate correlates of HRQOL in young adults with epilepsy and mild intellectual disabilities. Epilepsy research has focused mostly on disease characteristics and psychological disorders as variables influencing HRQOL. With respect to disease parameters, seizure frequency appears to influence HRQOL: Findings suggest that patients with frequent seizures have the worst HRQOL, and patients with few seizures or longlasting seizure control, the best HRQOL [10], [11], [12], [13], [14], [15]. Effects of antiepileptic drugs (AEDs) on HRQOL have also been documented [11], [16]. With respect to other disease-related characteristics such as seizure type [17], number of seizure types [11], duration of epilepsy [13], [17], [18], [19], or age at epilepsy onset [18], [19], [20], the findings are more controversial.

Numerous studies have demonstrated that depression and anxiety are the most frequent psychological comorbid conditions among patients with epilepsy [21], [22], [23], [24], [25], [26], [27]. HRQOL in epilepsy is frequently found to be related to depression [16], [17], [28]. Depressive and coexistent anxiety disorders contribute independently to decreased HRQOL in epilepsy [29], [30]. Various studies have reported a stronger relationship of HRQOL to psychological variables than to treatment or disease characteristics such as seizure frequency, seizure type, laterality of seizure onset, duration of epilepsy, and number of AEDs [17], [30], [31], [32], [33], [34].

Although there is a long history of examining personality disorders in people with epilepsy, trait dimensions, covering the full range of normal personality, are rarely considered [34], [35]. A seminal work of psychological quality-of-life (QOL) research demonstrated that positive affect and negative affect are not bipolar opposites of one dimension but form two different clusters that relate to measures of happiness independently [36]. Thus, QOL is more than the mere absence of negative affect. Costa and McCrae [37] introduced the relatively stable personality dispositions extraversion and neuroticism as independent sources to explain differences in individuals’ tendencies to be either happy or unhappy. These assumptions have been supported by longitudinal studies [37] and have been widely replicated with other samples and instruments (e.g., [38]). We followed the rationale of this personality psychological perspective and included traits that appear to be strong determinants of well-being in the general population [37], [38], [39]. Moreover, with extraversion, rarely considered positive resources of happiness were taken into account. In sum, to identify correlates of HRQOL, psychopathological (depression and anxiety) and personality (extraversion and neuroticism) variables were included next to medical features of disease and treatment. We intended to investigate whether previous research findings are generalizable to the subgroup of patients with epilepsy and additional mild intellectual disabilities.

The subgroup of people with epilepsy and additional disabilities can be differentiated into individuals with mental retardation and those with mild cognitive limitations. Participants in this study were from a population of young adults with mild intellectual disabilities who require special care: These young adults have difficult-to-treat seizures and mild intellectual disability, and typically aspire to function normally in everyday life.

Section snippets

Sample

Our sample comprised young adults with epilepsy living in the Wohnheimverbund für junge Erwachsene mit Epilepsie (WJE) of the Bethel Institute, Bielefeld, Germany. The WJE is a care unit providing time-limited residential rehabilitation training, usually over a 3-year period [40]. The WJE accepts patients whose chronic epilepsy and cognitive limitations have resulted in profound problems in psychosocial functioning: clients have difficulty becoming independent from the family home, have

Indices of self–proxy agreement

Table 1 lists means and standard deviations of the self- and proxy-rated QOLIE scales as well as indices of self–proxy agreement. Differences in all of the subscales and the total score reflected a systematic pattern of proxies’ underrating their clients’ HRQOL on average. Differences in means ranged from 2.92 to 24.15 on the 0–100 scale. Tests of mean differences were significant for five scales. t tests for dependent samples were highly significant for Social Functioning, t(35) = 4.4, P < 0.001,

Discussion

Definitions of HRQOL agree on the necessity to obtain data from the patients’ perspective. As the first aim of this study, we were interested in the agreement between self-reported HRQOL of young adults with epilepsy and additional mild intellectual disabilities and proxy reports by their professional caregivers. A second aim was to explore correlates of self-reported HRQOL in this special population. We examined contributions of personality dimensions, psychopathological variables, and medical

References (80)

  • J. Lehrner et al.

    Health-related quality of life (HRQOL), activity of daily living (ADL) and depressive mood disorder in temporal lobe epilepsy patients

    Seizure

    (1999)
  • M. Reuber et al.

    Somatization, dissociation and general psychopathology in patients with psychogenic non-epileptic seizures

    Epilepsy Res

    (2003)
  • J.D. Fargo et al.

    Accuracy of self-reported neuropsychological functioning in individuals with epileptic or psychogenic nonepileptic seizures

    Epilepsy Behav

    (2004)
  • T.W. May et al.

    Psychometric properties of the German translation of the QOLIE-31

    Epilepsy Behav

    (2001)
  • M.A. Leone et al.

    Epilepsy and quality of life in adults: a review of instruments

    Epilepsy Res

    (2005)
  • M.J. McEwan et al.

    A systematic review of the contribution of qualitative research to the study of quality of life in children and adolescents with epilepsy

    Seizure

    (2004)
  • J. Magaziner et al.

    Patient–proxy response comparability on measures of patient health and functional status

    J Clin Epidemiol

    (1988)
  • G.N. Meldolesi et al.

    Factors associated with generic and disease-specific quality of life in temporal lobe epilepsy

    Epilepsy Res

    (2006)
  • M. Endermann

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

    Epilepsy Behav

    (2006)
  • K.H. Townshend et al.

    Development and validation of a measure of the impact of epilepsy on a young person’s quality of life: Glasgow Epilepsy Outcome Scale for Young Persons (GEOS-YP)

    Epilepsy Behav

    (2008)
  • E. Diener

    Traits can be powerful, but are not enough: lessons from subjective well-being

    J Res Pers

    (1996)
  • M. Bullinger

    Assessing health related quality of life in medicine: an overview over concepts, methods and applications in international research

    Restorative Neurol Neurosci

    (2002)
  • G.H. Guyatt et al.

    Measuring health-related quality of life

    Ann Intern Med

    (1993)
  • J.A. Cramer et al.

    Development and cross-cultural translations of a 31-item quality of life in epilepsy inventory

    Epilepsia

    (1998)
  • C. Eiser et al.

    A review of measures of quality of life for children with chronic illness

    Arch Dis Child

    (2001)
  • M. Bullinger

    Lebensqualität-Aktueller Stand und neuere Entwicklungen der internationalen Lebensqualitätsforschung

  • R.D. Hays et al.

    Agreement between self reports and proxy reports of quality of life in epilepsy patients

    Qual Life Res

    (1995)
  • G.A. Baker et al.

    Quality of life of people with epilepsy: a European study

    Epilepsia

    (1997)
  • R.S. McLachlan et al.

    Health-related quality of life and seizure control in temporal lobe epilepsy

    Ann Neurol

    (1997)
  • M. Djibuti et al.

    Influence of clinical, demographic, and socioeconomic variables on quality of life in patients with epilepsy: findings from Georgian study

    J Neurol Neurosurg Psychiatry

    (2003)
  • N.K. Leidy et al.

    Seizure frequency and the health-related quality of life of adults with epilepsy

    Neurology

    (1999)
  • G.L. Birbeck et al.

    Seizure reduction and quality of life improvements in people with epilepsy

    Epilepsia

    (2002)
  • F. Gilliam

    Optimizing health outcomes in active epilepsy

    Neurology

    (2002)
  • L.S. Boylan et al.

    Depression but not seizure frequency predicts quality of life in treatment-resistant epilepsy

    Neurology

    (2004)
  • N.H.J. Engelberts et al.

    Cognition and health-related quality of life in a well-defined subgroup of patients with partial epilepsy

    J Neurol

    (2002)
  • M.V. Lambert et al.

    Depression in epilepsy: etiology, phenomenology, and treatment

    Epilepsia

    (1999)
  • R. Torta et al.

    Behavioral, psychotic, and anxiety disorders in epilepsy: etiology, clinical features, and therapeutic implications

    Epilepsia

    (1999)
  • B.P. Hermann et al.

    Psychiatric comorbidity in chronic epilepsy: identification, consequences, and treatment of major depression

    Epilepsia

    (2000)
  • B. Vazquez et al.

    Epilepsy and anxiety

    Epilepsy Behav

    (2003)
  • A.M. Kanner

    Depression in epilepsy: A frequently neglected multifaceted disorder

    Epilepsy Behav

    (2003)
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