Acute and Long-Term Outcomes of Lateralized Rhythmic Delta Activity (LRDA) Versus Lateralized Periodic Discharges (LPDs) in Critically Ill Patients

Background To assess the acute and long-term outcomes for patients with lateralized rhythmic delta activity (LRDA) compared to patients with lateralized periodic discharges (LPDs). Methods A single-center retrospective study examining consecutive patients older than 10 years who had LRDA, LPDs, or both on continuous electroencephalographic (cEEG) between 12/01/2015 and 12/31/2017. Outcomes included inpatient mortality, functional outcome at follow-up, inpatient electrographic seizures, and the presence of new epilepsy at follow-up. Patients were classified into 4 groups: LRDA-only (without LPDs), LPDs-only (without LRDA), LRDA/LPDs, and control (without LRDA or LPDs). Results Twenty-nine patients (2.7%) were in the LRDA-only group, 76 (7%) patients were in the LPDs-only group, and 25 (2.3%) patients had both patterns (LRDA/LPDs group). 68 patients were identified as a control group. Only one patient (3%) in the LRDA-only group died during their hospitalization, compared to 21 patients (28%) in the LPDs-only group, 2 (8%) LRDA/LPDs group and 7 (10%) in the control group ( p 0.003). Patients in the LPDs-only group had three times higher odds of adjusted mortality compared to the control group ( p 0.05), while there was no difference in the mortality odds between the LRDA-only and control groups. Patients with LRDA-only had higher odds of good functional outcome at clinic follow-up ( p 0.04). When compared to control, patients with both IIC patterns (LRDA/LPDs group) had 24.3 higher odds of acute electrographic seizures ( p