Abstracts

Rationale: The primary objective is to demonstrate the reliability and validity of the StatNet portable EEG system, by rapidly diagnosing NCSE after hours (17:00-08:00) when conventional EEG is unavailable. Secondary objectives include developing and implementing a simplified set of clinical criteria to identify patients at risk of NCSE who require a stat EEG.Methods: We expanded the scope of usage of StatNet EEG electrode system for Phase 2. We trained the Neurology residents to preform StatNet EEG and began patient recruitment after hours. Bi-annual training sessions were offered during protected teaching time and lasted approximately one hour. While patients were recruited primarily from the emergency department, all departments were available for recruitment, so long as they did not have alternative access to conventional EEG. Each patient received a StatNet EEG and a conventional EEG by trained technologists, when available. We blinded and compared the two studies, assessing delay between requisition of stat EEG and acquisition of conventional EEG, setup time, amount of artifact, and detection of abnormal findings using conventional EEG as controls. The nonparametric Mann-Whitney two-sample T-test was used for comparisons. Results are expressed in mean minutes +/- standard deviation of the mean. Inter-observer reliability was assessed by Kappa score.Results: A total of 19 patients were collected. Two StatNet EEGs were excluded, as they were not interpretable due to generalized artifact. Mean age is 60y ±21.94y (17-93y range). 32% (N=9) are female, 68% (N=13) are male. The inter-observer agreement for detection of any abnormal findings was 0.54 (0.18, CI=0.19-0.89) for StatNet EEG and 0.73 (0.18, CI=0.37-1.0) for conventional EEG. Inter-observer agreement for epileptiform discharges was 0.76 (0.22, CI=0.33-1.0) for StatNet EEG and 0.76 (0.16, CI=0.43-1.0) for conventional EEG. Inter-observer agreement for NCSE was 1.00 (0, CI=1.00-1.00) for StatNet EEG and 0.64 (0.32, CI=0.0031-1.0) for conventional EEG, in the single case identified. The mean delay from time of StatNet EEG to conventional EEG was 26h 53min. Setup time was significantly shorter for placement of electrodes: 13:14 ± 5:24 StatNet EEG vs 18:07 ±5:35 conventional EEG (p=0.02). Measurement of impedance was insignificantly prolonged in StatNet EEG (4:50±5:48) vs conventional EEG (2:46±2:02) p=0.09.Conclusions: We found both high inter-rater reliability between the conventional and StatNet EEG groups for detection of abnormalities, epileptiform discharges, seizures and NCSE, as well as significant reduction in set up times for the StatNet EEG. This demonstrates that the StatNet portable EEG system is a reliable and effective tool that can be used in the appropriate clinical context to diagnose seizure activity, specifically in early recognition and treatment of NCSE. This has the potential to decrease morbidity and mortality associated with that diagnosis. Once the project is complete and StatNet is validated as a tool, we will ask for Health Canada approval to implement a pathway, allowing stat EEGs to be obtained on a routine basis.