Prognostic Implications of Periodic Epileptiform Discharges

Abstract

Background: Periodic epileptiform discharges (PEDs) are an abnormal finding on electroencephalograms (EEGs), the significance of which is uncertain. Objective: To investigate long-term outcome in patients with PEDs. Design: We retrospectively analyzed the outcomes of patients who had PEDs diagnosed during a 7-year period. We abstracted and tabulated clinical parameters from the time of EEG, imaging findings, EEG measurements, and subsequent clinical outcome from medical records. We used descriptive, inferential, and logistic regression analysis to determine the factors associated with clinical outcomes in patients with PEDs. We divided PEDs into the following subgroups: periodic lateralized epileptiform discharges (PLEDs), generalized PEDs, and bilateral PEDs and analyzed these subgroups individually. Setting: University-affiliated teaching hospital. Subjects: One hundred sixty-two patients with PEDs. Results: We obtained complete clinical, neuroimaging, neurophysiologic, and long-term outcome data in 118 patients. In the subgroup of patients with PLEDs, absence of seizures at onset (odds ratio, 0.21 per point; 95% confidence interval, 0.04-0.97) and an acute etiology for the PLEDs (odds ratio, 0.14 per point; 95% confidence interval, 0.03-0.72) were associated with death. A nonneoplastic cause for PLEDs was associated with independent functionality (odds ratio, 0.45 per point; 95% confidence interval, 0.3-0.67). Conclusion: In patients with PLEDs, the absence of clinical seizures at the time of detection and presumed acute etiology are associated with death, whereas a nonneoplastic etiology was associated with a good clinical outcome.

Bilateral independent periodic discharges are associated with electrographic seizures and poor outcome: A case-control study

“…Our findings are in line with previous studies (Table 3) (De la Paz and Brenner, 1981; Snodgrass et al, 1989; Fitzpatrick and Lowry, 2007; Orta et al, 2009), albeit with some differences. With the exception of one study that focused on post-cardiac arrest patients (San-Juan and Costello, 2009), others have repeatedly found stroke, CNS infections, anoxic brain injury and metabolic encephalopathy to be the most common etiologies of BIPDs.…”

“…This association was not significant in previous studies (Ruiz et al, 2016; Struck et al, 2017), probably due to the unmatched design of the first one and the small size (N = 6) of the subgroup of patients with BIPDs in the latter, thus further highlighting the importance of multicenter collaborative case-control studies for uncommon EEG patterns. We confirm that the mortality associated with B]PDs is high and that poor outcome is common (De la Paz and Brenner, 1981; Fitzpatrick and Lowry, 2007; Orta et al, 2009). Although this association likely depends on the underlying etiology, it remained significant after matching for etiology, age and coma and controlling for the presence of electrographic seizures.…”

Bilateral independent periodic discharges are associated with electrographic seizures and poor outcome: A case-control study

“…Our findings are in line with previous studies (Table 3) (De la Paz and Brenner, 1981; Snodgrass et al, 1989; Fitzpatrick and Lowry, 2007; Orta et al, 2009), albeit with some differences. With the exception of one study that focused on post-cardiac arrest patients (San-Juan and Costello, 2009), others have repeatedly found stroke, CNS infections, anoxic brain injury and metabolic encephalopathy to be the most common etiologies of BIPDs.…”

“…This association was not significant in previous studies (Ruiz et al, 2016; Struck et al, 2017), probably due to the unmatched design of the first one and the small size (N = 6) of the subgroup of patients with BIPDs in the latter, thus further highlighting the importance of multicenter collaborative case-control studies for uncommon EEG patterns. We confirm that the mortality associated with B]PDs is high and that poor outcome is common (De la Paz and Brenner, 1981; Fitzpatrick and Lowry, 2007; Orta et al, 2009). Although this association likely depends on the underlying etiology, it remained significant after matching for etiology, age and coma and controlling for the presence of electrographic seizures.…”

Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

“…Similar to the other periodic findings described, a combination of subcortical and cortical injuries are common in GPDs ( Yemisci et al, 2003 ), though isolated subcortical lesions are present in 30% ( San juan Orta et al, 2009 ).…”

“…In a retrospective study of 21 patients with BIPDs, the mortality was 52%, much higher than the overall mortality rate of patients with LPDs (27%) ( Fitzpatrick and Lowry, 2007 ). In a separate study including 23 patients with BIPDs, 39.1% had a fatal outcome, while only 21.7% had an independent recovery; this was significantly worse than the 24–29% mortality in patients with LPDs and GPDs ( San juan Orta et al, 2009 ).…”

Electrocortical Pathology in a Rat Model of Penetrating Ballistic-Like Brain Injury

“…Reports of PED caused by TBI are surprisingly rare (Husain et al, 1999;Orta et al, 2009). However, in our rat model of PBBI, PEDs were detected in 45% (18/45) of the animals subjected to 10% and 12.5% injury severities.…”

Bilateral independent periodic discharges are associated with electrographic seizures and poor outcome: A case-control study

“…Our findings are in line with previous studies (Table 3) (De la Paz and Brenner, 1981; Snodgrass et al, 1989; Fitzpatrick and Lowry, 2007; Orta et al, 2009), albeit with some differences. With the exception of one study that focused on post-cardiac arrest patients (San-Juan and Costello, 2009), others have repeatedly found stroke, CNS infections, anoxic brain injury and metabolic encephalopathy to be the most common etiologies of BIPDs.…”

“…This association was not significant in previous studies (Ruiz et al, 2016; Struck et al, 2017), probably due to the unmatched design of the first one and the small size (N = 6) of the subgroup of patients with BIPDs in the latter, thus further highlighting the importance of multicenter collaborative case-control studies for uncommon EEG patterns. We confirm that the mortality associated with B]PDs is high and that poor outcome is common (De la Paz and Brenner, 1981; Fitzpatrick and Lowry, 2007; Orta et al, 2009). Although this association likely depends on the underlying etiology, it remained significant after matching for etiology, age and coma and controlling for the presence of electrographic seizures.…”

Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

“…Similar to the other periodic findings described, a combination of subcortical and cortical injuries are common in GPDs ( Yemisci et al, 2003 ), though isolated subcortical lesions are present in 30% ( San juan Orta et al, 2009 ).…”

“…In a retrospective study of 21 patients with BIPDs, the mortality was 52%, much higher than the overall mortality rate of patients with LPDs (27%) ( Fitzpatrick and Lowry, 2007 ). In a separate study including 23 patients with BIPDs, 39.1% had a fatal outcome, while only 21.7% had an independent recovery; this was significantly worse than the 24–29% mortality in patients with LPDs and GPDs ( San juan Orta et al, 2009 ).…”

Electrocortical Pathology in a Rat Model of Penetrating Ballistic-Like Brain Injury

“…Reports of PED caused by TBI are surprisingly rare (Husain et al, 1999;Orta et al, 2009). However, in our rat model of PBBI, PEDs were detected in 45% (18/45) of the animals subjected to 10% and 12.5% injury severities.…”

Bilateral independent periodic discharges are associated with electrographic seizures and poor outcome: A case-control study

“…Our findings are in line with previous studies (Table 3) (De la Paz and Brenner, 1981; Snodgrass et al, 1989; Fitzpatrick and Lowry, 2007; Orta et al, 2009), albeit with some differences. With the exception of one study that focused on post-cardiac arrest patients (San-Juan and Costello, 2009), others have repeatedly found stroke, CNS infections, anoxic brain injury and metabolic encephalopathy to be the most common etiologies of BIPDs.…”

“…This association was not significant in previous studies (Ruiz et al, 2016; Struck et al, 2017), probably due to the unmatched design of the first one and the small size (N = 6) of the subgroup of patients with BIPDs in the latter, thus further highlighting the importance of multicenter collaborative case-control studies for uncommon EEG patterns. We confirm that the mortality associated with B]PDs is high and that poor outcome is common (De la Paz and Brenner, 1981; Fitzpatrick and Lowry, 2007; Orta et al, 2009). Although this association likely depends on the underlying etiology, it remained significant after matching for etiology, age and coma and controlling for the presence of electrographic seizures.…”

Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

“…Similar to the other periodic findings described, a combination of subcortical and cortical injuries are common in GPDs ( Yemisci et al, 2003 ), though isolated subcortical lesions are present in 30% ( San juan Orta et al, 2009 ).…”

“…In a retrospective study of 21 patients with BIPDs, the mortality was 52%, much higher than the overall mortality rate of patients with LPDs (27%) ( Fitzpatrick and Lowry, 2007 ). In a separate study including 23 patients with BIPDs, 39.1% had a fatal outcome, while only 21.7% had an independent recovery; this was significantly worse than the 24–29% mortality in patients with LPDs and GPDs ( San juan Orta et al, 2009 ).…”

Electrocortical Pathology in a Rat Model of Penetrating Ballistic-Like Brain Injury

“…Reports of PED caused by TBI are surprisingly rare (Husain et al, 1999;Orta et al, 2009). However, in our rat model of PBBI, PEDs were detected in 45% (18/45) of the animals subjected to 10% and 12.5% injury severities.…”