EEG Abnormalities and Their Radiographic Correlates in a COVID-19 Inpatient Cohort

ABSTRACT:Objective:To identify the prevalence of EEG abnormalities in patients with COVID-19 with neurologic changes, their associated neuroimaging abnormalities and rates of mortality.Methods:A retrospective case series of 192 adult COVID-19 positive inpatients with EEG performed between March and June 2020 at 4 hospitals: 161 undergoing continuous, 24 routine, and 7 reduced- montage EEG. Study indication, epilepsy history, intubation status, administration of sedatives or antiseizure medications, metabolic abnormalities, neuroimaging pathology associated with epileptiform abnormalities, and in-hospital mortality were analyzed.Results:EEG indications included encephalopathy (54.7%), seizure (18.2%), coma (17.2%), focal deficit (5.2%), and abnormal movements (4.6%). Epileptiform abnormalities occurred in 39.6% of patients: focal intermittent epileptiform discharges in 25.0%, lateralized periodic discharges in 6.3%, and generalized periodic discharges in 19.3%. Seizures were recorded in 8 patients, 3 with status epilepticus. Antiseizure medication administration, epilepsy history, and older age were associated with epileptiform abnormalities. Only 26.3% of patients with any epileptiform abnormality, 37.5% with electrographic seizures, and 25.7% patients with clinical seizures had known epilepsy. Background findings included generalized slowing (88.5%), focal slowing (15.6%), burst suppression (3.6%), attenuation (3.1%), and normal EEG (3.1%). Neuroimaging pathology was identified in 67.1% of patients with epileptiform abnormalities, over two-thirds acute. In-hospital mortality was 39.5% for patients with epileptiform abnormalities, 36.2% for those without. Risk factors for mortality were coma and ventilator support at time of EEG.Significance:This article highlights the range of EEG abnormalities frequently associated with acute neuroimaging abnormalities in COVID-19. Mortality rates were high, particularly for patients in coma requiring mechanical ventilation. These findings may guide the prognosis and management of patients with COVID-19 and neurologic changes.

Fulminant subacute sclerosing panencephalitis (SSPE) presented with acute hemiparesis in a 13-year-old girl with perinatally acquired HIV infection

A 13-year-old girl with perinatally acquired HIV infection was admitted to us with acute onset, right-sided hemiparesis of 30 days duration and right-sided myoclonic jerks of 2 days duration affecting the face, upper and lower limbs. On examination, she exhibited increased tone and a pyramidal pattern of weakness in her right upper and lower limbs, along with spontaneous multifocal myoclonic jerks in the affected area. IgG levels in the serum and cerebrospinal fluid for measles were significantly elevated. Brain MRI depicted T2-weighted-hyperintensities in the subcortical white matter. The electroencephalogram demonstrated evidence of lateralised long interval periodic discharges. This patient had no past behavioural problems or poor academic performance. This case underlines the fact that, though subacute sclerosing panencephalitis (SSPE) is a chronic disease, a rare fulminant form of SSPE might develop acutely and atypically, with an increased proclivity for HIV-infected patients.

Periodic discharges with triphasic morphology: a differential diagnosis and therapeutic approaches

The article presents two clinical cases of intensive care unit (ICU) patients with periodic discharges. Examination according to the American Clinical Neurophysiology Society (ACNS) protocol with the use of electroencephalography and functional probes allows differential diagnosis of periodic discharges, which makes it possible to conduct early pathophysiological treatment, to assess its effectiveness in dynamics and to avoid unjustified prescription of antiepileptic drugs. At the same time, the prognosis of the disease and the effectiveness of treatment are largely determined by the etiology of the disease. Evaluation of periodic discharges of three-phase morphology in ICU, considering its nosological nonspecificity, is rational to carry out according to the ACNS recommendations, indicating the ictal genesis, background activity, response to antiepileptic drugs.

Can Spectral Power Be Used as a Candidate Seizure Marker of the Periodic Discharges Pattern?

Introduction: It remains controversial whether the periodic discharges (PDs) pattern is an ictal or interictal phenomenon. The aims of the study are to apply time-frequency and power spectrum analysis to study the PDs pattern and prediction of seizures.Methods: We retrospectively searched continuous electroencephalography (cEEG) recordings to identify patients exhibiting the PDs pattern. Artifact-free cEEG segments demonstrating the PDs pattern with stable baselines were chosen for time-frequency and power spectrum analysis.Results: In total, 72 patients (1.3%) exhibited the PDs pattern, with a mean age 36.0 ± 20.7 years (range, 8–76 years). The median spectral power of PDs with a length of 60 s was 70.94 μV2 and that of PDs with a length of 20 s was 195.80 μV2. During follow-up, patients with spectral power of PDs of length 60 and 20 s lower than 28.65 and 36.09 μV2, respectively, exhibited no seizure. For predicting seizures, when the spectral power for PDs of 60 and 20 s equaled to 17.26 and 21.40 μV2, respectively, the diagnostic sensitivity was 100% and specificity was 86%. The locations of maximal spectral power of PDs, crude seizure onset zone (SOZ) judged from scalp EEG, and the most prominent regions of hyper- or hypo-metabolism on FDG-PET were congruent.Conclusions: Spectral power might be a candidate seizure marker of the PDs pattern. High spectral power predicted a high risk of seizures, and low spectral power was associated with a low risk of seizures.

Lateralized Periodic Discharges During Remifentanil Infusion

Lateralized periodic discharges (LPDs) are a common electroencephalographic (EEG) pattern in the neurointensive care unit setting. LPDs are typically observed in association with acute structural lesions of the brain with different etiologies. There are no reports describing a link between the occurrence of LPDs and the administration of remifentanil. Remifentanil is a rapid-acting pure μ-opioid receptor agonist, which is indicated to provide analgesia and sedation in mechanically ventilated patients in intensive care units. We present a case of an 84-year-old man with neuroglycopenia who developed LPDs while sedated with remifentanil. We report, for the first time, a potential relationship between remifentanil and the induction of LPDs.

Lateralized Periodic Discharges in a Patient With Dural Arteriovenous Fistula: SPECT and DWI Studies Suggest They are Ictal

Lateralized periodic discharges (LPDs) are unilateral electroencephalography (EEG) waveforms, recurring at regular intervals. There has been a long-lasting debate about whether they represent ictal or interictal phenomena. Very few patients in the literature have been investigated with multimodal functional imaging techniques. Here, we present a 58-year-old male patient with symptomatic epilepsy who had cerebral venous sinus thrombosis in the right temporo-parietal area and dural arteriovenous fistula (dAVF) over the left fronto-parietal region. He developed acute speech disturbances and altered mental status after a generalized tonic–clonic seizure. Video-EEG monitoring (VEEGM) demonstrated LPDs over the left fronto-central area, overlapping in part with the dAVF. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) sequences revealed restricted diffusion compatible with cytotoxic edema, whereas single-photon emission computed tomography (SPECT) indicated hyperperfusion in the same region, leading to the conclusion that he was having possible nonconvulsive status epilepticus (NCSE). An increase in antiseizure medications led to gradual improvement in clinical status and the disappearance of LPDs.

Periodic discharges with high frequency oscillations recorded from a cerebellar gangliocytoma in an epileptic infant

Background: Subcortical epilepsies associated with developmental tumors in the cerebellum are rarely experienced. As supportive evidence of the intrinsic epileptogenicity of cerebellar tumors, previous electroencephalogram (EEG) studies with intratumoral depth electrodes demonstrated epileptiform or ictal discharges. Recent studies have demonstrated that high frequency oscillations (HFOs) can be regarded as a new biomarker of epileptogenesis and ictogenesis; however, there are few evidence about HFOs in cases of epilepsy associated with cerebellar tumors. Case Description: A 6-month-old Japanese male infant presented to our hospital with drug resistant epilepsy. We underwent subtotal resection of a cerebellar gangliocytoma and obtained good seizure outcomes. Intraoperative EEG in the tumor depicted HFOs in the form of ripples, riding on periodic discharges. Conclusion: Our findings provide further supportive evidence for the intrinsic epileptogenicity of cerebellar tumors.