Dimensions of the Epilepsy Foundation Concerns Index

Abstract

We performed principal component analysis (PCA) of the Epilepsy Foundation Concerns Index scale in 189 patients undergoing evaluation for epilepsy surgery. We identified a five-factor solution in which there were no varimax-rotated factors consisting of fewer than two questions. Factor 1 reflects affective impact on enjoyment of life, Factor 2 reflects general autonomy concerns, Factor 3 reflects fear of seizure recurrence, Factor 4 reflects concern of being a burden to one’s family, and Factor 5 reflects a perceived lack of understanding by others. Multiple regression using the Quality of Life in Epilepsy—89 question version; Minnesota Multiphasic Personality Inventory—2; Wechsler Adult Intelligence Scale—third edition; and verbal and visual memory tests as predictors demonstrated a different pattern of association with the factor and summary scores. We conclude that the Epilepsy Foundation Concerns Index is multidimensional, and using a global score based on all items may mask specific concerns that may be relevant when applied to individual patients.

Introduction

Epilepsy effects have traditionally been characterized with respect to clinical variables such as seizure frequency and severity, psychological factors such as cognitive and psychosocial effects, and psychiatric comorbidities. More recently, however, there has been increasing interest in the interaction between disease effects and patient response to epilepsy-imposed limitations. This interaction can be characterized by health-related quality of life (QoL). In epilepsy, QoL measures have been used not only to characterize disease burden, but also to reflect the effects of AED treatment [1], [2], [3], seizure severity [4], and epilepsy surgery [5], [6], [7]. Quality-of-life measures differ from many other epilepsy measures because disease effects are characterized by individual patient perceptions.

The most widely employed QoL measure in epilepsy is the Quality of Life in Epilepsy, 89-question version (QOLIE-89). In addition to assessing general quality of life, the QOLIE-89 includes health-related epilepsy-specific domains including cognitive factors such as attention, concentration, and memory, and disease and treatment influences including seizure worry, medication effects, and work and driving limitations.

A newer scale reflecting the experience of epilepsy on everyday activities is the Epilepsy Foundation (EF) Concerns Index [8] see (Table 1). This scale consists of 20 items in which patients rate specific epilepsy concerns (e.g., being a burden or worry to family), and was derived from patients who listed their concerns of living with recurrent seizures in order of importance [9]. The Concerns Index has been successful in demonstrating the beneficial effects of anterior temporal lobectomy (ATL). In one report, patients who were seizure free following surgery had lower global summary scores compared with those who continued to have seizures [9], and in a subsequent report, the adverse effects of epilepsy were reported to be lower on 16 of 20 questions in patients who had undergone surgery [8]. However, the differential relationships among the individual items have not yet been formally investigated, even though the correlation of individual items with the total summary score is reported to be high (ranging from 0.65 to 0.85 for all but two items) [9].

Despite its apparent utility for objectively assessing epilepsy-specific patient concerns, the validity from a psychometric perspective has not yet been fully established. In the present article, we report on the factor structure of the EF Concerns Index in a mixed sample of epilepsy surgery candidates. We also relate derived factor scores to other QoL and neuropsychological variables.