TABLE 3.
Continuous EEG Characteristics and Neurotoxicity Outcomes
| Patient ID | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Age (years) | 22 | 16 | 16 | 6 | 15 | 13 | 16 |
| Neurotoxicity grade | 4 | 4 | 3 | 4 | 4 | 3 | 2 |
| CRS grade | Severe | Severe | Mild | Mild | Mild | Mild | Mild |
| EEG duration | 75 hours | 60 hours | 48 hours | 58 hours | 52 hours | 32 hours | 14 hours |
| Clinical symptoms | Focal seizures, decreased level of consciousness | Coma | Generalized seizure, decreased level of consciousness | Focal seizures, decreased level of consciousness | Focal seizures, decreased level of consciousness | Decreased level of consciousness, abnormal movements | Drowsiness and confusion |
| Background | 2–3 Hz slowing, decreased R sided voltages, slight improvement toward end of recording | 0.5–3 Hz slowing, initially discontinuous, FIRDA, improving over time of recording | 1–3 Hz slowing, no change throughout recording | 0.5–6 Hz slowing, becoming discontinuous after 12 hours, then continuous again after 36 hours | 1–7 Hz slowing, initial voltage attenuation, improving throughout recording | 0.5–6 Hz slowing, improving markedly throughout recording | 2–5 Hz slowing, stable |
| PDR | Present at beginning and end | No | No | No | No | No | No |
| Focal slowing | Yes | No | No | Yes | Yes | Yes | No |
| Sleep architecture | No | No | Intermittent | No | No | No | Yes |
| Interictal epileptiform | R occipital periodic discharges | No | Multifocal sharps and spikes | Lateralized periodic discharges | Focal rhythmic discharges | No | No |
| Ictal-interictal continuum | R occipital periodic discharges at 1–2 Hz, without evolution or response to treatment, persist throughout recording | No | No | Lateralized periodic discharges at 0.5–1 Hz, resolved on day 2 | No | No | No |
| Seizure | Multiple R > L occipital seizures, with and without clinical manifestations | No | Generalized electroclinical seizure at EEG initiation | Multiple focal seizures, with and without clinical manifestations | Many focal seizures, with or without clinical manifestations | No | No |
| Sedating infusions | None | None | None | Midazolam first 12 hours (for seizures) | Midazolam (for seizures), dexmedetomidine, fentanyl (for sedation) | Propofol at the beginning (for sedation) | None |
| Bolus medications during recording | LEV, PHT | LEV | Lorazepam, LEV | Lorazepam, LEV, PHT, PHB | LEV, PHT | LEV | LEV |
| Acute MRI findings | R > L occipital cortical diffusion restriction, bilateral thalamic T2 prolongation | New diffuse symmetric white matter T2 prolongation | No acute changes, chronic white matter increased T2 signal | Bilateral thalamic and symmetric white matter T2 prolongation | Symmetric diffusion restriction and T2 prolongation in thalami, pons, and white matter | Mild symmetric white matter T2 hyperintensities | Normal |
| Neurologic outcome > 28 days | Focal epilepsy | Mild cognitive complaints | Normal | Normal | Normal | Normal | Return to baseline (patient with trisomy 21) |
Details are shown for all 7 patients who had cEEG. Neurotoxicity grade denotes overall neurotoxicity as determined by the most severe sign or symptom on the CTCAE scale that was present during the entire course: 0, no neurotoxicity; 1, mild; 2, moderate; 3, severe; 4, life threatening.
CRS, cytokine release syndrome; CTCAE, Common Terminology Criteria for Adverse Events; FIRDA, frontal intermittent rhythmic delta activity; LEV, levetiracetam; MRI, magnetic resonance imaging; PDR, posterior dominant rhythm; PHB, phenobarbital; PHT, fosphenytoin.