Nonconvulsive status epilepticus presenting as isolated cognitive deficits: a case series

Abstract

Background: Focal status epilepticus (SE) manifesting with non-motor symptoms represents a diagnostic challenge. Cognitive SE, a rare variant, presents as isolated disturbances in language, thought processes, or specific higher cortical dysfunctions. Objective: To report a series of SE cases characterized by exclusive cognitive manifestations. Methods: Retrospective analysis of three patients diagnosed with cognitive SE through integrated clinical and electroencephalographic (EEG) evaluation. Results: Patient (1), a 69-year-old male engineer with long-standing controlled epilepsy, presented with breakthrough seizures during acute meningoencephalitis. Following systemic stabilization and seizure control, he developed cognitive impairment, specifically dyscalculia and psychomotor slowing. Neurological examination identified apraxia and aphasia. EEG demonstrated left frontal status epilepticus, while brain MRI was unremarkable. Management with oral anti-seizure medications led to significant electrographic and cognitive resolution. Patient (2), a 66-year-old female previously treated with phenobarbital, was admitted for rapidly progressive functional decline, predominantly amnestic dysfunction, and aphasia. Symptoms followed an intermittent course over six months, with sustained deterioration in the fortnight preceding admission. Neuroimaging and CSF analysis were non-contributory. However, initial EEG revealed recurrent frontal focal seizures (exceeding 20% of the record), confirming SE. Despite continuous midazolam infusion and subsequent burst-suppression, seizures recurred after four days. Following pharmacological titration, the patient achieved improved communication and partial functional restoration. Patient (3), a 44-year-old female with resected pinealoblastoma and structural focal epilepsy, presented with acute confusion and executive dysfunction. Clinical assessment identified a complete Gerstmann syndrome (digital agnosia, agraphia, acalculia, and right-left disorientation) alongside expressive aphasia. EEG confirmed focal SE in the left posterior temporal region. Intensive care management resulted in clinical-electrographic remission. Conclusion: Cognitive syndromes related to SE are rare but important in the differential diagnosis of acute neurological decline. During investigation, it is necessary to look for subtle ictal signs, such as déjà vu, automatisms, or brief periods of loss of contact. The suspicion that seizures underlie the clinical presentation should prompt an EEG, although surface recordings have limitations for deep discharges. Diagnosis is based on the EEG findings associated with clinical improvement after starting treatment. Therefore, diagnostic suspicion is essential, considering the possibility of symptom reversibility and functional recovery after seizure control.