The neurophysiology and seizure outcomes of late onset unexplained epilepsy.

OBJECTIVE: To investigate neurophysiologic and neuroimaging characteristics of patients with late onset unexplained epilepsy (LOUE). METHODS: We performed a retrospective chart review of elderly patients with ICD9 diagnosis codes consistent with epilepsy/seizures. Inclusion criteria included unprovoked seizures, and absence of cortical lesions on magnetic resonance imaging (MRI). Electroencephalograms (EEGs) findings were also analyzed. MRI images were scored for degree of white matter hyperintensities (Fazekas Scale) and mesial temporal atrophy (MTA). Vascular risk factors, and Framingham Heart Study general cardiovascular disease (FHS-CVD) risk scores were compared to controls from the Harvard Aging Brain study (HABS). RESULTS: We identified 224 LOUE patients and 8% were drug resistant. Epileptiform abnormalities were captured on EEG in 35%. The location was temporal with left sided predominance in 49%. Fazekas scale consisted of 25% beginning of confluent lesions, and 10% large confluent lesions. MTA scores consisted of 21% moderate-severe hippocampal atrophy. LOUE patients had on average a 2.3% (adjusted), 7.4% (unadjusted) increased FHS-CVD score. CONCLUSIONS: Our findings highlight LOUE as pharmacosensitive and left temporal predominant. Given the higher prevalence of vascular risk factors, investigations are needed to study their role in pathophysiology. SIGNIFICANCE: Physicians caring for patients with LOUE should evaluate for vascular risk factors and investigate the presence of hippocampal atrophy.

Prediction of regaining consciousness despite an early epileptiform EEG after cardiac arrest.

OBJECTIVE: After cardiac arrest (CA), epileptiform EEG, occurring in about 1/3 of patients, often but not invariably heralds poor prognosis. We tested the hypothesis that a combination of specific EEG features identifies patients who may regain consciousness despite early epileptiform patterns. METHODS: We retrospectively analyzed a registry of comatose patients post-CA (2 Swiss centers), including those with epileptiform EEG. Background and epileptiform features in EEGs 12-36 hours or 36-72 hours from CA were scored according to the American Clinical Neurophysiology Society nomenclature. Best Cerebral Performance Category (CPC) score within 3 months (CPC 1-3 vs 4-5) was the primary outcome. Significant EEG variables were combined in a score assessed with receiver operating characteristic curves, and independently validated in a US cohort; its correlation with serum neuron-specific enolase (NSE) was also tested. RESULTS: Of 488 patients, 107 (21.9%) had epileptiform EEG <72 hours; 18 (17%) reached CPC 1-3. EEG 12-36 hours background continuity ≥50%, absence of epileptiform abnormalities (p < 0.00001 each), 12-36 and 36-72 hours reactivity (p < 0.0001 each), 36-72 hours normal background amplitude (p = 0.0004), and stimulus-induced discharges (p = 0.0001) correlated with favorable outcome. The combined 6-point score cutoff ≥2 was 100% sensitive (95% confidence interval [CI], 78%-100%) and 70% specific (95% CI, 59%-80%) for CPC 1-3 (area under the curve [AUC], 0.98; 95% CI, 0.94-1.00). Increasing score correlated with NSE (ρ = -0.46, p = 0.0001). In the validation cohort (41 patients), the score was 100% sensitive (95% CI, 60%-100%) and 88% specific (95% CI, 73%-97%) for CPC 1-3 (AUC, 0.96; 95% CI, 0.91-1.00). CONCLUSION: Prognostic value of early epileptiform EEG after CA can be estimated combining timing, continuity, reactivity, and amplitude features in a score that correlates with neuronal damage.

Racial and Ethnic Disparities in Postcardiac Arrest Targeted Temperature Management Outcomes.

OBJECTIVES: To evaluate racial and ethnic disparities in postcardiac arrest outcomes in patients undergoing targeted temperature management. DESIGN: Retrospective study. SETTING: ICUs in a single tertiary care hospital. PATIENTS: Three-hundred sixty-seven patients undergoing postcardiac arrest targeted temperature management, including continuous electroencephalogram monitoring. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical variables examined in our clinical cohort included race/ethnicity, age, time to return of spontaneous circulation, cardiac rhythm at time of arrest, insurance status, Charlson Comorbidity Index, and time to withdrawal of life-sustaining therapy. CT at admission and continuous electroencephalogram monitoring during the first 24 hours were used as markers of early injury. Outcome was assessed as good (Cerebral Performance Category 1-2) versus poor (Cerebral Performance Category 3-5) at hospital discharge. White non-Hispanic ("White") patients were more likely to have good outcomes than white Hispanic/nonwhite ("Non-white") patients (34.4 vs 21.7%; p = 0.015). In a multivariate model that included age, time to return of spontaneous circulation, initial rhythm, combined electroencephalogram/CT findings, Charlson Comorbidity Index, and insurance status, race/ethnicity was still independently associated with poor outcome (odds ratio, 3.32; p = 0.003). Comorbidities were lower in white patients but did not fully explain outcomes differences. Nonwhite patients were more likely to exhibit signs of early severe anoxic changes on CT or electroencephalogram, higher creatinine levels and receive dialysis, but had longer duration to withdrawal of lifesustaining therapy. There was no significant difference in catheterizations or MRI scans. Subgroup analysis performed with patients without early electroencephalogram or CT changes still revealed better outcome in white patients. CONCLUSIONS: Racial/ethnic disparity in outcome persists despite a strictly protocoled targeted temperature management. Nonwhite patients are more likely to arrive with more severe anoxic brain injury, but this does not account for all the disparity.