Table 1. Characteristics of Patients.
| Demographic and clinical findings | No./total No. (%) |
|---|---|
| Patients with positive RT-PCR results | 64/72 (89) |
| Patients with SARS-CoV-2–associated pneumonia on CT scan results | 59/68 (87) |
| COVID-19 severity, mean (SD)a | 5.32 (1.30) |
| Deceased patients at discharge | 7/78 (9) |
| Patients with medical comorbidities | 63/77 (82) |
| Cardiovascular disease | 40/77 (52) |
| Lung disease | 9/77 (12) |
| Diabetes | 25/76 (33) |
| Tobacco use | 16/75 (21) |
| Obesity | 16/76 (21) |
| Immunosuppression | 2/75 (3) |
| Cancer | 7/75 (9) |
| Patients requiring ICU admission | 49/78 (63) |
| Delay between the first COVID-19 symptoms and ICU admission, mean (SD), d | 12.4 (11.3) |
| Patients requiring antibiotics, neuroleptics, or anestheticsb | 40/71 (56) |
| Cardiopulmonary arrest | 4/78 (5) |
| Symptoms reported before EEG | |
| Anosmia | 12/66 (18) |
| Agueusia | 9/66 (14) |
| Headache | 8/75 (11) |
| Delirium | 44/78 (56) |
| Seizures | 10/78 (13) |
| Dizziness | 2/73 (3) |
| Visual disturbances | 1/75 (1) |
| Oculomotor disorders | 6/74 (8) |
| Movement disorders | 15/72 (21) |
| Sleep disorders | 4/72 (6) |
| Neurologic syndromes reported during hospital care | |
| Language disorder | 16/78 (21) |
| Disorder of consciousness | 28/78 (36) |
| Brainstem impairment | 7/78 (9) |
| Cerebellar syndrome | 5/78 (6) |
| Cognitive disorders | 36/78 (46) |
| Frontal syndrome | 15/78 (19) |
| Worsening of preexistent cognitive disorders | 7/78 (9) |
| Psychiatric disorders | 4/78 (5) |
| EEG findings | |
| Delay between the first COVID-19 symptoms and the EEG, mean (SD), d | 29.4 (21.3) |
| EEG performed in ICU | 41/78 (53) |
| EEG performed under anesthesia | 23/71 (32) |
| EEG performed in intubated patients | 14/78 (18) |
| Normal EEG | 9/78 (12) |
| Abnormal background activity | 63/78 (81) |
| Focal abnormality | 35/78 (45) |
| Frontal | 24/35 (69) |
| Temporal | 11/35 (31) |
| Other | 6/35 (17) |
| Epileptic activities (interictal, n = 4; seizures, n = 1)c | 4/78 (5) |
| Periodic discharges | 6/78 (8) |
| Encephalopathy pattern | 23/78 (30) |
| MRI findings | |
| Patients who underwent MRI | 57/78 (73) |
| Unremarkable MRI findings | 16/57 (28) |
| Hemorrhages | 21/57 (37) |
| Multiple microhemorrhages | 10/21 (48) |
| Corpus callosum injury | 4/21 (19) |
| Acute ischemic lesions | 13/57 (23) |
| Gray matter injury | 13/57 (23) |
| White matter enhancing lesions | 5/57 (9) |
| Basal ganglia abnormalities | 4/57 (7) |
| Hypoxic-ischemic lesions | 3/57 (5) |
| Metabolic abnormalities | 3/57 (5) |
| PRES lesions | 2/57 (4) |
| Leptomeningeal contrast enhancement | 2/57 (4) |
| CLOCC | 1/57 (2) |
| Perfusion abnormalities | 20/40 (50) |
| Hypoperfusion | 19/20 (95) |
| Frontal hypoperfusion | 14/19 (74) |
| Temporal hypoperfusion | 10/19 (53) |
| Other location hypoperfusion | 15/19 (79) |
| Hyperperfusion | 4/20 (20) |
| Frontal hyperperfusion | 3/4 (75) |
| Temporal hyperperfusion | 4/4 (100) |
| Other location hyperperfusion | 2/4 (50) |
| Biological findings the day of the EEG | |
| Patients with biological abnormalitiesd | 55/77 (71) |
| Hyponatremia (sodium, <135 mEq/L) | 11/76 (15) |
| Hypernatremia (sodium, >145 mEq/L) | 13/76 (17) |
| Hypocalcemia (calcium, <8 mg/dL) | 25/61 (41) |
| Renal insufficiency (according to creatinine clearance) | 32/67 (48) |
| Hepatic dysfunction (AST and/or ALT 3 times higher than the standard) | 10/65 (15) |
| Hypercapnia (>45 mm Hg) | 13/45 (29) |
| Hyperosmolarity (>310 mOsm/kg) | 13/40 (33) |
| Patients with lumbar puncture | 30/78 (39) |
| Delay between the first COVID-19 symptoms and the lumbar puncture, mean (SD), d | 29.2 (25.3) |
| Patients with positive RT-PCR results in CSF | 0/26 |
| Patients with increased CSF elements (>5/mm3) | 3/30 (10) |
| Patients with increased CSF proteins (>0.65 g/L) | 4/30 (13) |
Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CLOCC, cytotoxic lesion of the corpus callosum; COVID-19, coronavirus disease 2019; CSF, cerebrospinal fluid; CT, computed tomography; EEG, electroencephalogram; ICU, intensive care unit; MRI, magnetic resonance imaging; PRES, posterior reversible encephalopathy syndrome; RT-PCR, reverse transcription–polymerase chain reaction; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
SI conversion factors: To convert sodium to millimoles per liter, multiply by 1.0; and calcium to millimoles per liter, multiply by 0.25.
COVID-19 severity was evaluated according to the World Health Organization nadir scale11: 1, nonhospitalized patients without activity limitation; 2, nonhospitalized patients with activity limitation; 3, hospitalized patients without oxygen requirement; 4, hospitalized patients with oxygen requirement; 5, hospitalized patients with noninvasive ventilation; 6, hospitalized patients with invasive ventilation; and 7, deceased patient at discharge.
We evaluated all drugs taken by patient the day of the EEG.
One patient had both interictal epileptic activities and seizures.
Patients were assessed as having biological abnormalities if they presented with one of the following abnormalities: hyponatremia, hypernatremia, hypocalcemia, renal insufficiency, hepatic dysfunction, hypercapnia, or hyperosmolarity.