Faculty Bibliography

This study reports the existence of patients requiring prolonged monitoring with video-electroencephalography to make an accurate diagnosis and to quantify how often this occurs. The authors performed a retrospective review of 248 consecutive adult patients admitted to the epilepsy monitoring unit during 12 months for event characterization or presurgical evaluation. For the diagnosis of definite epilepsy, at least one epileptic seizure must have been recorded with video-electroencephalography. The median time to first diagnostic event, whether epileptic seizure or nonepileptic event, was 2 days; 35% required 3 or more days and 7% >1 week. Twelve percent of those with definite epilepsy never had interictal epileptiform discharges and 17% of those with nonepileptic events had interictal epileptiform discharges. Six percent of patients with definite epilepsy had neither epileptic seizures nor interictal epileptiform discharges until day 3 or after. Based on our results, it is common to require 3 or more days in an epilepsy monitoring unit to record and diagnose the nature of paroxysmal episodes and not rare to require more than a week. Interictal electroencephalography alone cannot reliably distinguish between those with epileptic seizures and nonepileptic events.

PURPOSE/OBJECTIVE:Depression is a highly prevalent, relatively underdiagnosed and undertreated comorbid condition in epilepsy. The purpose of this study was to determine the effect of using a validated self-reporting depression scale on the ability to detect depression in people with epilepsy receiving care in a busy clinical setting. METHODS:The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is a 6-item questionnaire validated to screen for depression in people with epilepsy. We performed a retrospective chart review of 192 consecutive patients who had completed the NDDI-E while receiving care at a seizure clinic in the largest public hospital in Houston, Texas. For comparison, charts of 192 consecutive patients receiving care immediately prior to the implementation of the NDDI-E in the same clinic were assessed. RESULTS:Fifty-five (28.6%) of patients screened positive for depression with the NDDI-E. They subsequently received a semi-structured psychiatric interview based on the DSM-IV model and 89% (n=49) were confirmed to have major depression. Use of the NDDI-E thus resulted in the detection of active depression in 25.5% (n=49) of the patients, whereas only 2.6% (n=5) of patients in the group not systematically screened were found to have active depression (p<0.0001). Thirty-two of the 49 (65%) patients with depression detected by screening were not previously diagnosed or treated. Multivariate analysis revealed that a history of depression, seizure frequency, and topiramate use were independent predictors of depression. Lamotrigine use was protective against depression. DISCUSSION/CONCLUSIONS:Use of the NDDI-E significantly improved the ability to detect depression in epilepsy patients in a busy clinical practice.

PURPOSE/OBJECTIVE:Prolonged electroencephalographic monitoring has facilitated the detection of nonconvulsive seizures. Compressed displays of EEG frequency spectra (such as compressed spectral array, CSA) can facilitate interpretation of continuous EEG by allowing the reader to observe on a single screen patterns evolving over many minutes or hours. METHODS:Patients were identified retrospectively over a 4-year period as displaying a cycling pattern of seizures on CSA. RESULTS:We describe a pattern of seizures recurring in a cyclic fashion in a series of 13 critically ill patients of all ages. Several patients had a gradual buildup of EEG power prior to each seizure. CONCLUSION/CONCLUSIONS:We believe that while not rare, this pattern is difficult to recognize on standard EEG recording but it is readily apparent on CSA. The underlying pathophysiology of cyclic seizures is not known, but we speculate that cyclic seizures represent a form of status epilepticus in which the usual seizure terminating factors are present and transiently effective, but are inadequate to prevent resumption of the seizure activity. Studying these patients may provide insight into the pathophysiology of seizure initiation and cessation.