S18 Supplement: Epilepsy and Quality of Life

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The Meaning of Quality of Life to Patientswith Epilepsy

Orrin Devinsky, M.D.

The past decade has witnessed an exponentialgrowth in the use of health-related quality-of-life(HRQOL) measures in clinical trials, nonexperimentaloutcome studies, cost–utility analyses, and studies ofquality of care. The incorporation of quality-of-lifemeasurements into the assessment of treatment out-comes is a critical concept in health care today, andreflects a shift away from sole reliance on physicalsigns and diagnostic studies. The new perspective ofphysicians takes into consideration how patients feeland function, that is, the patient’s perspective. Thispaper outlines health-related quality of life as it ap-plies to epilepsy.

Health-Related Quality of Life and Epilepsy

HRQOL consists of three principal dimensions: (1)physical health (e.g., daily function, general health,severity of physical symptoms, medication side ef-fects, pain, strength, endurance); (2) mental health(emotional well-being, self-esteem, perceived stigma,anxiety, depression, cognition); and (3) social health(social activities, relationships with family andfriends). These domains are important to evaluate inpatients with chronic disorders, because a range ofproblems in addition to disease symptoms character-ize these disorders. Epilepsy is the paradigm of such adisorder: seizures are typically infrequent while psy-chosocial problems and antiepileptic drug (AED)-as-sociated side effects are often chronic.

Doctors traditionally have received a minimum ofeducation and training in the psychosocial aspects ofepilepsy, even though these issues often affect patientsmore than their seizures and medications. Unless apatient with epilepsy is specifically asked aboutHRQOL issues, these concerns may be ignored in thedelivery of their routine medical care. Clinical practicetoday is still based largely on a model that values thephysician’s interpretation of how well the patient isdoing based on physical signs and diagnostic tests andsimultaneously devalues the patient’s perspective.Physicians have been taught that measures such asseizure frequency, seizure type, AED concentrations,

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and MRI scans are valid surrogate markers for thepatient’s perspective.

However, only the patient truly knows how he orshe feels and how the disorder affects his or her life.The patient’s perspective does not necessarily corre-late with the surrogate markers evaluated by physi-cians. The ways in which seizures and epilepsy impacta person’s life are as individual as fingerprints. Twopatients may have the same ictal symptoms, seizurefrequency and duration, and postictal symptoms andyet be affected differently by their epilepsy. Similarly,while certain issues, such as loss of self-esteem, driv-ing privileges, and independence; reduced opportuni-ties for education and employment; and fear of sei-zures, affect nearly everyone with epilepsy, the rela-tive importance of these and other psychosocial issuesvaries from patient to patient. The importance mayeven vary within a single patient over the course of hisor her lifetime.

Doctors measure seizures in terms of severity andfrequency and assume there is a direct correlationbetween the magnitude of these variables and theimpact on patients. A physician may characterize theseizure control in a patient with an occasional tonic–clonic seizure as acceptable. Yet to the patient, eachseizure, even if years apart, may be devastating andreinforce a lack of control over his or her life and fearabout venturing out or engaging in independent ac-tivity. Following epilepsy surgery, grade I outcome(the best outcome in this scale) is defined as the ab-sence of seizures that include impairment of con-sciousness. However, patients with postoperative sim-ple partial seizures have lower quality-of-life mea-sures than seizure-free patients. This is an example ofa discrepancy in the perspectives of physicians andpatients.

In other circumstances, the nature of treatmentgiven for seizures is out of proportion to the impact ofthose seizures on the patient’s quality of life. A patientmay have one complex partial seizure a week withoutany apparent disruption of her or his life. For such apatient, an arduous diagnostic evaluation for epilepsy

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S19Supplement: Epilepsy and Quality of Life

surgery or an aggressive approach to achieving sei-zure freedom with medications that results in debili-tating side effects may be unreasonable.

Just as the impact of seizures varies between pa-tients, so do the effects of medications. Some patientsmay have disabling side effects at subtherapeuticplasma concentrations while others tolerate “toxic”concentrations without any apparent problems. Thisvariability among patients is not yet fully appreciatedby physicians. The dictum “treat the patient, not theblood level” is gaining wider acceptance; however,“treat the patient” is commonly interpreted as “beguided by the patient’s seizure control and side ef-fects.” This advice must be broadened to incorporatequality-of-life issues: “care for the patient, don’t justtreat the seizures.”

Application of HRQOL Measures in Epilepsy

The development of HRQOL batteries and instru-ments has made possible the individualized assess-ment of the impact of seizures and epilepsy. HRQOLmeasures are being applied to three particular areas:(1) clinical AED trials, (2) measurement of the impactof treatment interventions (e.g., surgical, educational,and psychological), and (3) clinical practice as a proxyfor treatment success.

The Liverpool Battery. The Liverpool Battery wasone of the first HRQOL instruments to be developedfor epilepsy. The battery is psychometrically valid andhas been widely used in many epilepsy studies toassess HRQOL. Domains encompass measures ofphysical functioning, seizure frequency and severity,treatment side effects, and social and psychologicalfunctioning. A Life Fulfillment Scale has been de-signed by the group that developed the LiverpoolBattery to measure the degree of importance of 13different aspects of life. An additional scale, the Epi-lepsy-Specific Mastery Scale, quantifies the patient’sperception of his or her control over seizures.

The Epilepsy Surgery Inventory-55 (ESI-55). TheSI-55 was developed in the early 1990s to assessRQOL in epilepsy patients who had undergone ep-

lepsy surgery. Items from the RAND Health Surveya generic quality-of-life tool) were combined with 19pilepsy-specific items that were derived from a liter-ture review and interviews of clinician and patients.he ESI-55 contains 11 subscales categorized within

hree conceptual domains: mental functioning (emo-ional well-being and global QOL), physical function-ng (physical competence and physical pain), and cog-itive functioning (role limitations based on memory

and attention problems or other cognitive dysfunc-tion, emotional or physical disability). The validityand reliability of the ESI-55 were initially demon-strated on a sample of 200 adults who either had hadepilepsy surgery or were surgical candidates. Otherstudies since that time have provided additional datato support the psychometric properties of this HRQOLmeasure.

The Quality of Life in Epilepsy (QOLIE) instruments foradults. Developed in the mid-1990s, the QOLIE in-struments expanded on the ESI-55 and were designedfor use in patients who were not necessarily planningto undergo epilepsy surgery. Tested in a multicenterstudy of more than 300 epilepsy patients, the QOLIEinstrument, like the ESI-55 before it, included a genericcore (RAND 36-item Health Survey) with eight addi-tional epilepsy-specific multiitem scales. The epilepsy-specific items were derived from patient interviews,literature review, and expert opinion.

Three instruments were developed: the QOLIE-89(17 scales, 89 items; intended for research), theQOLIE-31 (7 scales, 31 items; intended as a brieferresearch scale and an extended clinical scale), and theQOLIE-10 screening questionnaire (10 items from the7 QOLIE-31 scales; intended as a brief HRQOL screen-ing instrument). The QOLIE-89 and QOLIE-31 showedgood reliability and construct validity.

Four principal factors were derived from analysis ofthe 17 QOLIE-89 scales: (1) epilepsy-specific, (2) cog-nitive, (3) mental health, and (4) physical health fac-tors. Epilepsy-specific issues included seizure sever-ity, fear of having a seizure and the resulting loss ofcontrol over one’s life, cognitive and behavioral dys-function, social limitations and stigma, sexual func-tioning, driving restrictions, and medication side ef-fects.

The QOLIE-89 has been shown to be reliable andvalid in both self-administered and telephone inter-view formats and between patient and proxy reports.The QOLIE-31 has been cross-culturally validated aswell. Although items selected for the QOLIE-10showed strong correlations with QOLIE-31 scales, for-mal psychometric analysis and prospective validationwere not performed. Scoring manuals for theQOLIE-89 and the QOLIE-31 provide additional psy-chometric details and further information about theirappropriate use.

The Quality of Life Instrument for Adolescents (QOLIE-AD-48). Using a methodology similar to that em-ployed in the development of the adult QOLIE instru-ments, the QOLIE-AD-48 was constructed and testedin a large multicenter study of 197 adolescents (11 to

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17 years old) with active epilepsy. Domains and spe-cific items were derived from several sources includ-ing existing measures, focus groups, the literature,and the experience of a panel of experts who guidedthe development process. Using the empirically rigor-ous approach of double cross-validation (split sampleprocedure), eight scales and 48 items were retained:epilepsy impact (12 items), memory/concentration(10), attitudes toward epilepsy (4), physical function-ing (5), stigma (6), social support (4), school behavior(4), health perceptions (3), and a total summary score.The questionnaire is self-administered and can becompleted in 15 to 20 minutes. Psychometric analysesdemonstrate that the QOLIE-AD-48 has good internaland external construct validity, internal consistencyreliability, and test–retest reliability.

Conclusions

As defined from the patient’s perspective, HRQOLencompasses seizure- and treatment-related variablesas well as aspects of mental and social health. Thenumber of HRQOL measures will continue to growand existing instruments will be refined. Ongoing andfuture research studies will further demonstrate theimportance of incorporating HRQOL as an assessmenttool for measuring the impact of a treatment interven-tion. In time, HRQOL will become the most importantmetric by which the outcomes of medical care forpatients with epilepsy are assessed.

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