Abstracts

Rationale: To investigate the clinical correlates and impact on outcome of lateralized periodic discharges (LPDs, a.k.a. PLEDs) in patients without acute brain injury. Methods: From a prospective database of patients undergoing continuous EEG monitoring (CEEG), we retrospectively identified 37 patients who presented with LPDs and had no acute brain injury. We identified 37 controls, matched for age and etiology (type of remote bran injury and/or history of epilepsy). Collected variables included functional status prior to admission (modified Rankin Scale), clinical seizures prior to CEEG, level of consciousness at time of admission, seizures during CEEG, use of sedation during CEEG, and outcome (modified Rankin scale-mRS). Univariate analyses were carried out by using Fisher's exact test for categorical data. Multivariate regression model was used to evaluate relationship of different variables to the outcome. Results: In univariate analysis, the presence of metabolic abnormalities and localizing exam were not significantly different between the two groups. However, the presence of encephalopathy on admission (defined as confusion, disorientation and/or lethargy; 33 vs.21; p= 0.005), the use of sedation (17 vs.8; p= 0.0482), and the presence of any seizures (clinical or non-convulsive) during CEEG (26 vs 9; p=0.002) were significantly more common in patients with LPDs than controls. Patients with LPDs were less likely to be discharged home than control (9 vs 23; p=0.0021) and had a higher risk of functional decline by at least one point on the mRS (23 vs 10; p =0.0047). In multivariate regression model, the presence of LPDs, but not sedation or seizures during CEEG, was significantly associated (p=0.0187; OR= 2.27; and 95% CI 1.14-4.34) with encephalopathy on admission. Similarly, the presence of LPDs (p=0.0406; OR= 1.96 and 95% CI 1.03-3.73) and encephalopathy (p = 0.0019; OR = 3.84; 95% CI 1.64-8.97) on admission, but not seizures during CEEG, were both associated with functional worsening of at least one point on the mRS Conclusions: In patients with remote brain injury and/or a history of epilepsy, the presence of LPDs was independently associated with encephalopathy and worse outcome, despite the absence of acute brain injury.