EEG patterns associated with present cortical SSEP after cardiac arrest.

BACKGROUND: After cardiac arrest (CA), present cortical somatosensory evoked potentials (N20 response of SSEPs) have low predictive value for good outcome and might be redundant with EEG. AIMS: To determine whether specific features, or rather global, standardized EEG assessments, are reliably associated with cortical SSEP occurrence after cardiac arrest (CA). METHODS: In a prospective CA registry, EEGs recorded within 72 hours were scored according to the ACNS nomenclature, and also categorized into "benign," "malignant," and "highly malignant." Correlations between EEGs and SSEPs (bilaterally absent vs present), and between EEGs/SSEPs and outcome (good: CPC 1-2) were assessed. RESULTS: Among 709 CA episodes, 532 had present N20 and 366 "benign EEGs." While EEG categories as well as background, epileptiform features, and reactivity differed significantly between patients with and without N20 (each P < .001), only "benign EEG" was almost universally associated with present N20: 99.5% (95%CI: 97.9%-99.9%) PPV. The combination of "benign EEG" and present N20 showed similar PPV for good outcome as "benign" EEG alone: 69.0% (95% CI: 65.2-72.4) vs 68.6% (95% CI: 64.9-72.0). CONCLUSION: Global EEG ("benign") assessment, rather than single EEG features, can reliably predict cortical SSEP occurrence. SSEP adjunction does not increase EEG prognostic performance toward good outcome. SSEP could therefore be omitted in patients with "benign EEG."

Hypophosphatemia compared to classical biomarkers of tonic clonic seizures.

BACKGROUND: Hypophosphatemia was recently reported as a potential marker of tonic-clonic (TC) seizures among patients with transitory loss of consciousness (TLOC). Its value compared to classical markers (creatine kinase [CK] and lactate) is however unknown. AIM: Compare the diagnostic performance of hypophosphatemia, plasma CK, and lactate levels for distinguishing TC seizures from other TLOCs, alone or in combination. METHODS: 128 patients aged 18-90, consecutively admitted to our hospital emergency department for TLOC were included. Diagnostic accuracy of plasma phosphate, CK, and lactate levels were compared with ROC curves. RESULTS: We found significantly higher CK (median 154 U/l, range 38-5608; vs 115.5, 37-2340 U/l; p = 0.037) and lower phosphatemia (median 0.79 mmol/l, 0.34-1.37; vs 0.93, 0.52-1.89 mmol/l, p = 0.007) in TC seizures compared to other TLOCs; lactatemia was not different, although using a smaller sample (n = 72). Hypophosphatemia was the only independent predictor of TC seizures, even in later samples (>2 h). Comparing ROC curves, Combining hypophosphatemia and hyperCKemia had higher diagnostic accuracy for TC seizures than hyper-CKemia alone (AUC 0.68, 95 % CI 0.571-0.783 vs. 0.59, 95 % CI 0.475-0.706; p = 0.018), but the combination was only marginally better than hypophosphatemia alone (AUC 0.67, 95 % CI 0.559-0.778). CONCLUSION: Hypophosphatemia seems to be more useful than CK levels for diagnosing TC seizures in patients assessed in an emergency setting for TLOC. Combining both parameters together does not significantly increase the diagnostic yield. No conclusion could be drawn regarding the comparison with lactate. A prospective study is needed.

Prognostic role of EEG identical bursts in patients after cardiac arrest: Multimodal correlation.

AIMS: EEG burst-suppression (BS) heralds poor outcome after cardiac arrest (CA). Within this pattern, identical bursts (IB) have been suggested to be absolutely specific, in isolation. We assessed IB prevalence and their added predictive value for poor outcome in a multimodal prognostic approach. METHODS: We retrospectively analyzed a registry of comatose adults with CA (April 2011-February 2019), undergoing EEG at 5-36 h and 36-72 h. SB and IB were visually assessed. Cerebral Performance Categories (CPC) at 3 months were dichotomized as "good" (CPC 1-2), or "poor" (CPC 3-5). Sensitivity, specificity, positive, negative predictive values of BS and IB for poor outcome were calculated. A multimodal prognostic score was created assigning one point each to unreactive and epileptiform EEG, pupillary light reflex and SSEPs absence, NSE > 75 µg/l. In a second score, IB were added; predictive performances were compared using Receiver Operating Characteristic (ROC) curves. RESULTS: Of 522 patients, 147 (28%) had BS in any EEG (10 [7%] had good outcome and 129 [88%] died). Of them, 53/147 (36%, 10% of total) showed IB, 47/53 (89%) of which within 36 h. IB were 100% specific for poor outcome, and associated with higher serum NSE than BS. However, there was no significant difference between the scores with and without IB for CPC 3-5 (p = 0.116). CONCLUSION: IB occur in 10% of patients after CA. In our multimodal context, IB, albeit being very specific for poor outcome, seem redundant with other predictors.

Added value of somato-sensory evoked potentials amplitude for prognostication after cardiac arrest.

AIMS: Bilateral absence of cortical somato-sensory evoked potentials (SSEPs) robustly predicts poor outcome after cardiac arrest (CA), but it is uncertain if SSEP amplitudes provide additional information. Here, we examined the prognostic value of cortical SSEP amplitude in comparison with other known outcome predictors. METHODS: We retrospectively determined SSEP amplitudes in a prospective CA registry, identified an amplitude cut-off for worst Cerebral Performance Category (CPC) within three months, and examined correlations of SSEP amplitude with pupillary light reflex (PLR), myoclonus, peak serum neuron specific enolase (NSE), and 24-36 h and 36-72 h EEG (reactivity, epileptiform features). RESULTS: Among 158 patients, 54% awoke. Amplitudes correlated with EEG findings, present PLR, myoclonus, NSE. A cut-off for cortical SSEP ≤ 0.41 µV was 100% specific for poor outcome (95% CI: 96-100%); sensitivity increased marginally vs. SSEPs absence [47% (35-59%) vs 46% (34-58%)] for CPC 4-5. Adding SSEPs ≤0.41 µV to a multimodal prognostic model including EEG, clinical features, and NSE improved prediction for mortality, but not for CPC 3-5 at three months. No statistical correlation between amplitudes and good outcome was observed. SSEP amplitudes correlated inversely with CPC at three months in the overall cohort (r = -0.332; p < 0.0001) but not in the subgroup with present SSEPs (r = -0.102; p = 0.256). CONCLUSION: Decreased SSEPs amplitudes are associated with poor outcome after cardiac arrest; however, adding this to a multimodal prognostic approach including EEG, clinical and blood biomarkers, improves slightly prediction of mortality, but not of poor or good outcome.

Standardized EEG analysis to reduce the uncertainty of outcome prognostication after cardiac arrest.

PURPOSE: Post-resuscitation guidelines recommend a multimodal algorithm for outcome prediction after cardiac arrest (CA). We aimed at evaluating the prevalence of indeterminate prognosis after application of this algorithm and providing a strategy for improving prognostication in this population. METHODS: We examined a prospective cohort of comatose CA patients (n = 485) in whom the ERC/ESICM algorithm was applied. In patients with an indeterminate outcome, prognostication was investigated using standardized EEG classification (benign, malignant, highly malignant) and serum neuron-specific enolase (NSE). Neurological recovery at 3 months was dichotomized as good (Cerebral Performance Categories [CPC] 1-2) vs. poor (CPC 3-5). RESULTS: Using the ERC/ESICM algorithm, 155 (32%) patients were prognosticated with poor outcome; all died at 3 months. Among the remaining 330 (68%) patients with an indeterminate outcome, the majority (212/330; 64%) showed good recovery. In this patient subgroup, absence of a highly malignant EEG by day 3 had 99.5 [97.4-99.9] % sensitivity for good recovery, which was superior to NSE < 33 µg/L (84.9 [79.3-89.4] % when used alone; 84.4 [78.8-89] % when combined with EEG, both p < 0.001). Highly malignant EEG had equal specificity (99.5 [97.4-99.9] %) but higher sensitivity than NSE for poor recovery. Further analysis of the discriminative power of outcome predictors revealed limited value of NSE over EEG. CONCLUSIONS: In the majority of comatose CA patients, the outcome remains indeterminate after application of ERC/ESICM prognostication algorithm. Standardized EEG background analysis enables accurate prediction of both good and poor recovery, thereby greatly reducing uncertainty about coma prognostication in this patient population.

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.

An Italian multicentre study of perampanel in progressive myoclonus epilepsies.

Perampanel (PER) is a novel anti-seizure medication useful in different types of epilepsy. We intended to assess the effectiveness of PER on cortical myoclonus and seizure frequency in patients with progressive myoclonus epilepsy (PME), using quantitative validated scales. Forty-nine patients aged 36.6 ±â€¯15.6 years with PME of various aetiology (18 EPM1, 12 EPM2, five with sialidosis, one with Kufs disease, one with EPM7, and 12 undetermined) were enrolled between January 2017 and June 2018. PER at the dose of 2-12 mg (5.3 ±â€¯2.5) was added to existing therapy. Myoclonus severity was assessed using a minimal myoclonus scale (MMS) in all the patients before and after 4-6 months of steady PER dose, and by means of the Unified Myoclonus Rating Scale (UMRS) in 20 patients. Logistic regression analysis was used to identify the factors potentially predicting treatment efficacy. Four patients dropped out in the first two months due to psychiatric side effects. In the remaining patients, PER reduced myoclonus severity as assessed using MMS (Wilcoxon test: p < 0.001) and UMRS (p < 0.001), with the 'Action myoclonus' section of the UMRS showing the greatest improvement. The patients with EPM1 or EPM1-like phenotype were more likely to improve with PER (p = 0.011). Convulsive seizures which have recurred at least monthly in 17 patients were reduced by >50%. Side effects occurred in 22/49 (44.8%) patients, the most common being irritability followed by drowsiness. PER is effective in treating myoclonus and seizures in PME patients. The frequency of psychiatric side effects suggests the need for careful patient monitoring.

Transcutaneous vagal nerve stimulatio (t-VNS): An adjunctive treatment option for refractory epilepsy.

PURPOSE: The aim of this trial was to investigate the efficacy and safety of transcutaneous vagal nerve stimulation (t-VNS) in the palliative treatment of drug resistant epileptic patients ineligible for surgery. METHODS: Twenty adult patients received four hours of t-VNS per day for six months (T1), followed by a two-month washout period (T2). The frequency and type of seizures recorded at T1 and T2 were compared with those occurring in the three months preceding study entry (T0). Responders (>30% reduction in the total number of seizures) subsequently received two hours of t-VNS per day for further six months (T3). All patients underwent electroencephalography (EEG) and completed the Quality of Life in Epilepsy questionnaire at baseline and T1. RESULTS: At T1 six patients were considered responders. In these patients, at T3 the average reduction in seizure frequency was 60% compared to T0 (p = 0.043), and 51% compared to T2 (p = 0.043). Responders had more often seizures with falls (5 of 6; 83.3%) compared with non-responders (3 of 14; 21.4%) (p = 0,010) and t-VNS reduced their frequency by a percentage ranging from 47.5 to 100%. There was no change in responders' EEG findings after stimulation. At the end of the trial, three responders continued t-VNS, one implanted VNS. CONCLUSIONS: t-VNS had no or minimal side effects and significantly reduced seizures in about one third of the enrolled patients. Further studies should be planned to assess whether t-VNS is a suitable tool to predict the efficacy of implanted VNS.