Abstracts

Rationale: Epilepsy-related disability is increasingly recognized as a significant predictor of health-related quality of life in patients with epilepsy (PWE). Existing measures for assessing disability in PWE are largely generic or developed for other chronic disease populations. The objective of this study is to develop and validate a new single-item measure for assessing epilepsy-related disability in adults with epilepsy, the Global Assessment of Epilepsy-Related Disability (GAERD) scale.Methods: We validated a single item measure of disability due to epilepsy in a cohort of 250 consecutive epilepsy patients enrolled in the NEurological diseasE and Depression Study (NEEDS), a study addressing the burden, course and impact of depressive disorders in neurological patients in Calgary, Alberta, Canada. Spearman s correlation coefficient and multiple linear regression analyses were used to examine the construct validity of this measure. Results: The mean age of the patient population was 40.6 years (SD = 14.8), and the average duration of epilepsy was 17.7 years. About 29% of the patients reported disability-free epilepsy , while more than 12% reported a very disabling form of epilepsy. There were no statistically significant differences between patients with severe and less-severe seizure types on several demographic characteristics, including: age, gender, current working status, marital status, education, and duration of disease. There were statistically significant associations between the level of self-reported disability due to epilepsy and seizure frequency (r = 0.42, p < 0.0001), disease severity (r = 0.57, p < 0.0001), number of anti-epileptic drugs (r = 0.18, p < 0.01), side effects from anti-epileptic drugs(r = 0.27, p < 0.0001), and depression symptoms (r = 0.28, p < 0.001).Conclusions: The GAERD scale is significantly correlated with epilepsy severity, frequency of seizures, depression, and adverse events caused by anti-epileptic drugs. That is, individuals with greater self-perceived disabling epilepsy are more likely to report more severe epilepsy and an increased number of seizures, endorse more depression symptoms, and experience side effects from anti-epileptic drugs. These results suggest that the GAERD scale is a simple and accurate indicator of disease severity in PWE, and that disability due to severity of epilepsy is an important marker of disease severity in epilepsy patient populations. The brevity of GAERD scale makes it easier to administer in busy clinical settings. Further research is needed to examine the discriminant validity and other psychometric properties of this instrument.