Role of Epileptic Activity in Older Adults With Delirium, a Prospective Continuous EEG Study

Abstract

Background/Objectives: Delirium occurs in up to 50 % of hospitalized old patients and is associated with increased morbidity and mortality. Acute medical conditions favor delirium, but the pathophysiology is unclear. Preliminary evidence from retrospective and prospective studies suggests that a substantial minority of old patients with unexplained delirium have non-convulsive seizures or status epilepticus (NCSE). Yet, seeking epileptic activity only in unexplained cases of delirium might result in misinterpretation of its actual prevalence. We aimed to systematically investigate the role of epileptic activity in all older patients with delirium regardless of the underlying etiology.Design, Setting: Prospective observational study in a tertiary medical center. Adults >65 years with delirium underwent at least 24 h of continuous electro-encephalographic monitoring (cEEG). Background patterns and ictal and interictal epileptic discharges were identified, as well as clinical and biological characteristics.Participants: Fifty patients were included in the study.Results: NCSE was found in 6 (12%) patients and interictal discharges in 15 (30%). There was no difference in the prevalence of epileptic activity rates between delirium associated with an acute medical condition and delirium of unknown etiology.Conclusion: Epileptic activity may play a substantial role in the pathophysiology of delirium by altering brain functioning and neuronal metabolism. No clinical or biological marker was found to distinguish delirious patients with or without epileptic activity, underlining the importance of cEEG in this context.

EEG characteristics of mechanically ventilated critically ill patients at high risk of delirium

“…Seizures are known to be associated with a poor outcome in patients in ICU (27) and can be found in patients with delirium of any cause and in patients with sepsis like the majority of our patients (2,28). The co-occurrence of seizures in septic patients may be seen as a potential marker of brain dysfunction with prognostic signi cance (2,28,29). On the other hand, presence of epileptiform activity may worsen and/or may even trigger delirium in some patients (30).…”

“…Generalized EEG slowing (increased delta and theta frequency) is frequently found in patients with delirium (9,29). However slowing is also common in ICU patients and related with various causes of altered mental status, decreased arousal, including coma, sleep, and sedation (35).…”

Electroencephalography of mechanically ventilated patients at high risk of delirium

“… 1 , 27 The co‐occurrence of seizures in septic patients may be seen as a potential marker of brain dysfunction with prognostic significance. 1 , 27 , 28 On the other hand, the presence of epileptiform activity may worsen and/or may even trigger delirium in some patients. 29 Periodic discharges without seizures were also more prominent in delirium patients; studies in neurologic ICU patients suggest that periodic discharges are independent predictors of poor outcome.…”

Does continuous electroencephalography influence therapeutic decisions in neurocritical care?

“…Our results confirm that SE is common in patients in neurocritical care, but the prevalence of seizure activity in this study is even higher than previously reported. A review of the literature on cEEG and detection of status epilepticus and seizures in adults published in the past 5 years are provided in Table 3 14,17–40 . 51–59 Most studies on seizures activity and cEEG performed in neurocritically ill patients are from the United States.…”