Assaying for Neuronal Injury in Patients with Frequent Subclinical Seizures: Early Findings Using Serum Neuron Specific Enolase
Abstract number :
3.245
Submission category :
Year :
2000
Submission ID :
718
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Eliot A Licht, Raman Sankar, Rebecca Jacobsen, Don Shin, Denson G Fujikawa, VA Greater Los Angeles Healthcare System, Sepulveda, CA; UCLA Medical Ctr, Los Angeles, CA.
Rationale: In vivo markers of brain damage from recurrent or prolonged seizures offer a valuable tool for quantitating degree of brain injury. Serum neuron specific enolase (s-NSE), is an easily assayed, highly specific and reliable marker of neuronal injury. Elevated levels of s-NSE have been reported in humans following generalized convulsive, nonconvulsive, and complex partial subtypes of status epilepticus, and even after single seizures. To our knowledge no previous investigators have reported levels of s-NSE in patients with frequent subclinical seizures. We previously reported on a population of patients with frequent subclinical frontotemporal seizures and demonstrated cognitive impairment with formal neuropsychological testing. We now sought to determine if their subclinical seizures might also be associated with neuronal injury. Methods: Blood was collected at clinic visits and when possible, the same day as an EEG. Healthy non-epileptic volunteers were used for controls. A commercial RIA kit (Pharmacia) was used to determine s-NSE. Qualitative comparisons were emphasized due to sample size limitations. Results: Five samples from 3 patients, and 4 samples from 4 controls were analyzed. The mean s-NSE level from patients was 7.05 g/L (range: 5.14-9.37); mean s-NSE level from controls was 8.27 g/L (range: 4.09-9.95). Two patients had an EEG within hours of their blood test and 1 patient's EEG was done four days prior to the blood test. All 3 EEGs were abnormal, with up to 10% of background activity occupied by 2.5-3 Hz frontotemporal spike and wave discharges (SWDs). Discussion: The s-NSE levels in our patients were not elevated when EEGs showed up to 4% SWDs (same day testing) or 10% SWDs (four days prior to testing). Prior EEGs in these patients showing subclinical seizure activity have had up to 88% of background activity as SWDs. Increased sampling of s-NSE, coordinated with same day EEG testing, is needed to establish if subclinical seizures can produce neuronal injury, and the severity of seizure activity (e.g., % SWDs) required. Expanded studies are underway to address this issue.