A CLINIMETRIC APPROACH TO ASSESSING QUALITY-OF-LIFE IN EPILEPSY

Clinimetrics is a concept involving the use of rating scales for clinical phenomena ranging from physical examinations to functional performance. Clinimetric or rating scales can be used for defining patient status and changes that occur during long-term observation. The scores derived from such scales can be used as guidelines for intervention, treatment, or prediction of outcome. In epilepsy, clinimetric scales have been developed for assessing seizure frequency, seizure severity, adverse effects related to antiepileptic drugs (AEDs), and quality of life after surgery for epilepsy. The VA Epilepsy Cooperative Study seizure rating scale combines frequency and severity in a weighted scoring system for simple and complex partial and generalized tonic-clonic seizures, summing all items in a total seizure score. Similarly, the rating scales for systemic toxicity and neurotoxicity use scores weighted for severity for assessing specific adverse effects typically related to AEDs. A composite score, obtained by adding the scores for seizures, systemic toxicity, and neurotoxicity, represents the overall status of the patient at a given time. The Chalfont Seizure Severity Scale also applies scores relative to the impact of a given item on the patient, without factoring in seizure frequency. The Liverpool Seizure Severity Scale is a patient questionnaire covering perceived seizure severity and the impact of ictal and postictal events. The UCLA Epilepsy Surgery Inventory (ESI-55) assesses quality of life for patients who have undergone surgery for epilepsy using generic health status instruments with additional epilepsy-specific items. The need is apparent for a single comprehensive instrument that assesses all aspects of epilepsy (e.g., effects of seizures and AEDs on patient medical status, psychosocial function, and quality of life). Quality-of-life assessment should come primarily from the patient, with ancillary material provided by family and health care providers. Only the patient can evaluate his or her current status vis-a-vis expectations. The balance between perceived and desired status is the essence of the quality-of-life equation.