Faculty Bibliography

OBJECTIVE:There is evidence for central nervous system complications of coronavirus disease 2019 (COVID-19) infection, including encephalopathy. Encephalopathy caused by or arising from seizures, especially nonconvulsive seizures (NCS), often requires electroencephalography (EEG) monitoring for diagnosis. The prevalence of seizures and other EEG abnormalities among COVID-19-infected patients is unknown. METHODS:Medical records and EEG studies of patients hospitalized with confirmed COVID-19 infections over a 2-month period at a single US academic health system (four hospitals) were reviewed to describe the distribution of EEG findings including epileptiform abnormalities (seizures, periodic discharges, or nonperiodic epileptiform discharges). Factors including demographics, remote and acute brain injury, prior history of epilepsy, preceding seizures, critical illness severity scores, and interleukin 6 (IL-6) levels were compared to EEG findings to identify predictors of epileptiform EEG abnormalities. RESULTS:Of 111 patients monitored, most were male (71%), middle-aged or older (median age 64 years), admitted to an intensive care unit (ICU; 77%), and comatose (70%). Excluding 11 patients monitored after cardiac arrest, the most frequent EEG finding was moderate generalized slowing (57%), but epileptiform findings were observed in 30% and seizures in 7% (4% with NCS). Three patients with EEG seizures did not have epilepsy or evidence of acute or remote brain injury, although all had clinical seizures prior to EEG. Only having epilepsy (odds ratio [OR] 5.4, 95% confidence interval [CI] 1.4-21) or seizure(s) prior to EEG (OR 4.8, 95% CI 1.7-13) was independently associated with epileptiform EEG findings. SIGNIFICANCE/CONCLUSIONS:Our study supports growing evidence that COVID-19 can affect the central nervous system, although seizures are unlikely a common cause of encephalopathy. Seizures and epileptiform activity on EEG occurred infrequently, and having a history of epilepsy or seizure(s) prior to EEG testing was predictive of epileptiform findings. This has important implications for triaging EEG testing in this population.

BACKGROUND:Invasive monitoring using subdural electrodes is often valuable for characterizing the anatomic source of seizures in intractable epilepsy. Covering the interhemispheric surface with subdural electrodes represents a particular challenge, with a potentially higher risk of complications than covering the dorsolateral cortex. OBJECTIVE:To better understand the safety and utility of interhemispheric subdural electrodes (IHSE). METHODS:We retrospectively reviewed the charts of 24 patients who underwent implantation of IHSE by a single neurosurgeon from 2003 to 2010. Generous midline exposure, meticulous preservation of veins, and sharp microdissection were used to facilitate safe interhemispheric grid placement under direct visualization. RESULTS:The number of IHSE contacts implanted ranged from 10 to 106 (mean = 39.8) per patient. Monitoring lasted for 5.5 days on average (range, 2-24 days), with an adequate sample of seizures captured in all patients before explantation, and with a low complication rate similar to that reported for grid implantation of the dorsolateral cortex. One patient (of 24) experienced symptomatic mass effect. No other complications clearly related to grid implantation and monitoring, such as clinically evident neurological deficits, infection, hematoma, or infarction, were noted. Among patients implanted with IHSE, monitoring led to a paramedian cortical resection in 67%, a resection in a region not covered by IHSE in 17%, and explantation without resection in 17%. CONCLUSION/CONCLUSIONS:When clinical factors suggest the possibility of an epileptic focus at or near the midline, invasive monitoring of the paramedian cortex with interhemispheric grids can be safely used to define the epileptogenic zone and map local cortical function.

Seizure-related head injury (SRHI) is an under-recognized condition frequently experienced by people with epilepsy (PWE). The purpose of this study is to investigate the potential impact of SRHI on health-related quality of life (HRQOL) among PWE receiving care in a tertiary epilepsy center. Consecutive adult PWE receiving care at the Baylor Comprehensive Epilepsy Center (BCEC) were recruited for the study. After their informed consent was obtained, patients were administered the QOLIE-31 to measure HRQOL and the NDDI-E to screen for depression. Simple linear regression was used to identify clinical variables associated with HRQOL and that included SRHI obtained systematically at each clinic visit. Data were also compared between the SRHI and non-SRHI groups. Participants included 172 subjects. Recurrent mild SRHI occurred in 50 (29%) subjects. Factors with a negative effect on HRQOL included depression (slope=-19.99 [95% CI -25.16, -14.81]; p<.0001), recurrent SRHI (-17.02 [-22.35, -11.69]; p<.0001), past SRHI (-13.46 [-18.43, -8.48]; p<.0001), and seizure frequency (-0.17 [-0.26, -0.07]; p=0.001) on univariate analysis. With stepwise multiple regression, depression and recurrent SRHI significantly impacted HRQOL with slopes (95% CI; p-value) of (-17.53 [-22.34, -12.73]; p<.0001) and (-14.03 [-18.78, -9.28]; p<.0001), respectively. Patient-derived HRQOL is negatively associated with depression and recurrent SRHI, independently. There has been a justifiable increased awareness of the potential effects of head injuries among healthy individuals. Our data suggest that head injuries can certainly be detrimental among PWE, and greater efforts should be made to recognize and formulate prevention strategies for SRHI.

Seizure-related head injuries (SRHIs) are among the most commonly encountered injuries in people with epilepsy (PWE). Whether head injury has an effect on preexisting epilepsy is not known. The purpose of this study was to systematically assess for any possible effects of SRHIs on seizure frequency and seizure semiology over a 2-year period. We identified 204 patients who have been followed at the Baylor Comprehensive Epilepsy Center from 2008 to 2010. SRHI occurred in 18.1% of the cohort. Most injuries (91%) were classified as mild. Though seizure frequency varied following head injury, overall seizure frequency was not significantly impacted by presence or absence of SRHI over the 2-year study period. Changes in seizure semiology were not observed in those with SRHIs. Although mild SRHI is common among PWE, it does not appear to have an effect on seizure characteristics over a relatively short period.

PURPOSE/OBJECTIVE:To describe the clinical outcomes of a compulsory switch from branded to generic levetiracetam (LEV) among people with epilepsy (PWE) in an outpatient setting. METHODS:We conducted a retrospective chart review of 760 unduplicated consecutive adult patients attending a tertiary care epilepsy clinic at Ben Taub General Hospital. On November 1, 2008 hospital policy required all patients receiving branded LEV to be automatically switched to generic LEV. We calculated the proportion of patients switching back to branded LEV and reasons for the switch back. KEY FINDINGS/RESULTS:Of the 260 patients (34%) being prescribed LEV (generic and brand name) during the study period, 105 (42.9%) were switched back to brand name LEV by their treating physicians. Reasons for switch back included increase in seizure frequency (19.6% vs. 1.6%; p < 0.0001) and adverse effects (AEs) (3.3%). AEs included headache, fatigue, and aggression. Patient age was associated with switchback when controlling for gender, epilepsy classification, and treatment characteristics [relative risk (RR) 2.44; 95% confidence interval (CI) 2.09-2.84; p < 0.05)]. An increase in seizure frequency subsequent to generic substitution was associated with polytherapy compared to monotherapy (3.225; 1.512-6.880; p < 0.05). SIGNIFICANCE/CONCLUSIONS:A significant proportion of patients in our cohort on generic LEV required switch back to the branded drug. Careful monitoring is imperative because a compulsory switch from branded to generic LEV may lead to poor clinical outcomes, with risk of AEs and increased seizure frequency.

We describe two patients with medication-resistant nonlesional mesial frontal lobe epilepsy and seizures that manifested with early face wiping prior to other motor phenomena. Ictal scalp monitoring either was nonlocalizing or involved the central regions. Intracranial monitoring demonstrated anterior mesial frontal ictal low-voltage gamma activity during the face wiping activity in both patients. Habitual seizures with the same clinical characteristics were induced during extraoperative functional mapping with stimulation of the same region. Ictal activation of mesial frontal regions can elicit early ictal face wiping activity, and this clinical sign may play a role in presurgical evaluation.

Eating-induced seizures are an uncommon presentation of reflex epilepsy, a condition characterized by seizures provoked by specific stimuli. Most reports have identified aetiology associated with malformations of cortical developmental, hypoxic brain injury, previous meningoencephalitis or static encephalopathy. We present a patient with eating-induced reflex seizures, which began several years after treatment for an opercular primitive neuroectodermal tumour (PNET), and who subsequently underwent in-depth clinical and video-EEG analysis for her seizures. This patient noted rapid improvement with decreased frequency of seizure activity after treatment with valproic acid. We discuss the aetiology of reflex epilepsy, the anatomical basis of eating-induced epilepsy, and review the current literature.

Though seizure-related injuries (SRIs) among people with epilepsy (PWE) have recently gained much attention in the literature, most studies are retrospective and data are gathered indirectly through questionnaires or medical record documentation. We investigated SRIs and their associated risks in PWE attending a tertiary care center with direct and systematic inquiries during routine clinic follow-up visits over a 2-year period (N = 306). Past SRIs occurred in 54% of all patients, and 24% experienced recurrent SRIs during the study period. On multiple regression analyses, past SRI was associated with tonic-clonic seizures (TCSs) (3.2, 95% CI = 1.7-5.8) and cognitive handicap (4.3, 95% CI 1.5-16.1), and recurrent SRI was associated with TCSs (3.5, 95% CI = 1.6-7.9). Most recurrent SRIs (72%) involved head injury. SRIs are common when assessed systematically in a tertiary care setting, and TCSs represent a risk factor for recurrent SRIs. The potential clinical impact of recurrent SRIs on PWE requires further study.

PURPOSE/OBJECTIVE:To investigate and compare injury rates, associated risk factors, circumstances, and medical record documentation in patients with pharmacoresistant temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE). METHODS:The study cohort consisted of fifty-two consecutive adults with treatment-resistant epilepsy and seizure classification confirmed by video-electrocardiography (EEG) (28 with TLE and 24 with ETLE) who consented to participate. All subjects had their seizures classified with prior video-EEG monitoring, were followed in a tertiary-care center in northwest New York City, and received a semistructured phone interview regarding injuries experienced since being diagnosed with epilepsy. RESULTS:Injuries were reported in 16 (57%) of the patients with TLE and 4 (17%) of the patients with ETLE (p = 0.004 after controlling for duration of epilepsy and seizure burden); 83% of all injuries were designated by patients as seizure-related. Most injuries (22 of 41; 54%) were classified as moderate or greater in severity. In addition, one motor vehicle accident (MVA) was reported in the TLE group and one episode of sudden unexpected death (SUDEP) was identified in the ETLE group. More than half (55%) of the injuries were not documented as seizure-related in medical records. CONCLUSION/CONCLUSIONS:A substantial number of potentially serious injuries are not documented as seizure related, even in a tertiary-care setting. Patients with pharmacoresistant TLE may be at higher risk for experiencing an injury than patients with pharmacoresistant ETLE.