Continuous EEG monitoring findings of critically ill patients with altered mental status in neurology intensive care unit associated with clinical,laboratory and neuroimaging findings

Background: This study examined the frequency of electrographic patterns (including such as periodic epileptiform discharges (PD), rhythmic spike waves (RSW), rhythmic delta activities (RDA), nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE)) in continuous videoEEG monitoring (cVEEG) of the critically ill patients with altered mental status and the presence of clinical and laboratory findings associated with these patterns.Material and Methods: Patients with altered mental status of the critically ill patients were consecutively monitored with cVEEG in the neurology intensive care unit between January 2009-December 2011. Their clinical, electrophysiological, radiological and laboratory findings were evaluated retrospectively.Results: This sample consisted of 57 patients (25 men and 32 women). Mean age was 68.2. Mean duration of cVEEG was 2532,61 minutes. The most common electrographic patterns were PD (33%) and NCS-NCSE (26,3%). The presence of NCS-NCSE was significantly associated with PD (57.9%, p<0.001). PD, NCS-NCSE were the most patterns in patients with acute ischemia stroke and encephalopathy. Electrographic patterns were seen more frequently in women (70.4%, p=0.040). Duration of monitoring was significantly longer in the group with PD and NCS-NCSE (p=0.004, p=0.014). Detection of any electrographic pattern in EEG before monitoring was associated with the presence of any pattern in cVEEG (59.3%, p<0.0001). Convulsive or nonconvulsive seizure during monitoring was common in patients with electrogrphic patterns (p<0.0001). 66.7% of NCS-NCSE was seen within the first 12 hours and 26.7% was seen within the 12-24 hours of the monitoring.Conclusion: The most common electrographic patterns were PD and NCS-NCSE. The length of monitoring was correlated with the presence of these patterns. Detection of any electrographic pattern in EEG before monitoring was associated with the presence of any pattern in cVEEG. This association was suggested that at least 24 hours monitoring of these patients should be useful for the diagnosis of clinical and/or electrographic seizures.