Liverpool Seizure Severity Scale revisited.

The purpose of the study was to examine the psychometric properties of the revised Liverpool Seizure Severity Scale. The scale has been adapted to increase its content validity and its potential for detecting change attributable to antiepileptic drug treatment. Ninety-seven patients completed the revised scale of which 32 completed it for both major and minor seizures. Reliability of the revised scale was conducted using assessment of internal consistency and test-retest. T-tests were conducted to assess the ability of patients to differentiate between major and minor seizures on scores of the seizure-severity scale. The psychometric properties of the scale were not adversely affected by either the increase in the number of items or the additional response scores. Patients completing the two scales of major and minor seizures were able to reliably differentiate between the two. We have attempted to improve the Liverpool Seizure Severity Scale in order to enhance its reliability, validity and sensitivity to change. The amendments we have made have not adversely affected its psychometric properties and we hope that it will make it more acceptable for use in clinical trials of new antiepileptic drug treatment. The revised scale is currently being applied to a number of clinical trials.