Bilateral Independent Periodic Discharges and Poor Seizure Outcomes

epilepsy, seizures, seizure, EEG
epilepsy, seizures, seizure, EEG
Investigators assessed the frequency of bilateral independent periodic discharges in patients experiencing electrographic seizures and their effect on patient mortality and clinical outcomes.

The occurrence of bilateral independent periodic discharge (BIPD), which is caused by bilateral acute brain injury, is associated with electrographic seizures and is reported in nearly half of those with the injury. A retrospective case-control study of patients with BIPD, compared with patients without periodic discharges (No PD) and patients with lateralized period discharges (LPD), was conducted through 8 member centers of the Critical Care EEG Monitoring Research Consortium, with results published in Clinical Neurophysiology.

The investigators sought to establish the clinical correlates of BIPD and their relationship with electrographic seizures and outcomes. A total of 85 patients were included in each of the 3 groups: BIPD, No PD, and LPD. The most common etiologies of BIPD included central nervous system infections, stroke, and anoxic brain injury.

Acute bilateral cerebral injury was reported more often in the BIPD arm than in the No PD and LPD arms (70%, 37%, and 35%, respectively; P <.0001 for both comparisons). The occurrence of electrographic seizures was more common with BIPD than in the absence of PDs (45% vs 8%, respectively).

Patient outcomes were worse in the BIPD group than in the No PD group, with mortality rates higher in the BIPD arm (36%) than in the No PD arm (18%); P <.001. Moreover, fewer patients with BIPD (18%) compared with No PD (36%) attained a good outcome (ie, moderate disability or better; P <.001) but not compared with the LPD group (24% mortality; 26% good outcome).

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Multivariate analysis demonstrated that BIPD continued to be associated with mortality (odds ratio, 3.0; 95% CI, 1.4-6.4) and with poor outcome (OR, 2.9; 95% CI, 1.4-6.2).

The investigators concluded that although the occurrence of BIPD is uncommon, the identification among critically ill patients has potential important implications with respect to both prognostication and clinical management.


Osman G, Rahangdale R, Britton JW, et al. Bilateral independent periodic discharges are associated with electrographic seizures and poor outcome: a case-control study. Clin Neurophysiol. 2018;129(11):2284-2289.