Generalized paroxysmal fast activity in EEG: An unrecognized finding in genetic generalized epilepsy.

OBJECTIVE: To study generalized paroxysmal fast activity (GPFA) in patients with genetic generalized epilepsy (GGE). INTRODUCTION: GPFA is an electroencephalographic (EEG) finding in patients with symptomatic generalized epilepsy consisting of 15-25Hz bifrontally predominant generalized fast activity seen predominantly in sleep. Historically GPFA is linked to epileptic encephalopathy with drug resistant epilepsy and intellectual disability. However, GPFA has been rarely described as an atypical finding in patients with GGE without negative prognostic implication. We report cognitive profile and seizure characteristics in seven patients with GGE and GPFA. METHODS: The Vanderbilt EMU and EEG reports were searched for the keywords "idiopathic generalized epilepsy", "GPFA"and "generalized spike and wave discharges (GSWD)". We reviewed the EEG tracings and the electronic medical records of patients thus identified. The seizure type, frequency, neurological work-up, clinical profile and imaging data were recorded. RESULTS: Awake and sleep states were captured on EEGs of all patients. On EEG tracing review six patients were confirmed to have GSWD and GPFA; one patient had GPFA but no GSWD. All patients had normal cognitive function. Four had a normal brain MRI and one a normal head CT (two were never imaged). None of the patients had tonic seizures. The main seizure type was generalized tonic-clonic seizures (GTCS) in five patients, absence in two. Age at onset of epilepsy ranged from 4 to 24years. The mean GTC seizure frequency at the time of EEG was 3; two patients were seizure free on two antiepileptic drugs (AEDs). CONCLUSIONS: GPFA can be an unrecognized electrographic finding in patients with genetic generalized epilepsy. While GPFA remains an important diagnostic EEG feature for epileptic encephalopathy (Lennox-Gastaut syndrome) it is not specific for this diagnosis. Thus, GPFA may have a spectrum of variable phenotypic expression. The finding of GPFA is not necessarily indicative of unfavorable outcome.

Non-convulsive status epilepticus and non-convulsive seizures in neurological ICU patients.

BACKGROUND: Non-convulsive seizures (NCS) or non-convulsive status epilepticus (NCSE) has been reported in 8-20 % of critically ill patient populations, and delayed diagnosis and treatment of NCSE may lead to increased mortality. This study seeks to better understand the risk factors, characteristics, and outcome of NCS/NCSE in the neurological ICU. METHODS: This is a prospective observational study, recruiting consecutive patients admitted to the adult neurological ICU with altered mental status. Patients with anoxic brain injury were excluded from the study. Data were collected and analyzed for prevalence of NCSE/NCS, EEG patterns, associated risk factors, treatment response, and final outcome. RESULTS: NCSE/NCS was detected in 21 % of 170 subjects. Clinical seizures preceded EEG diagnosis of NCSE/NCS in 25 % of cases. Significant risk factors for NCSE/NCS were a past medical history of intracranial tumor, epilepsy, or meningitis/encephalitis, or MRI evidence of encephalomalacia. Subtle clinical findings such as twitching of oral or ocular muscles and eye deviations were found on exam in 50 % of the NCSE/NCS group. Mortality was increased in NCSE cases as 31 % of NCSE/NCS patients died compared to 14 % in non-NCSE/NCS group. CONCLUSIONS: Specific clinical features along with history and imaging findings may be used to identify patients at high risk of NCSE/NCS in the neurological ICU.

Simulation-Based Assessments and Graduating Neurology Residents' Milestones: Status Epilepticus Milestones.

BACKGROUND: The American Board of Psychiatry and Neurology and the Accreditation Council for Graduate Medical Education (ACGME) developed Milestones that provide a framework for residents' assessment. However, Milestones do not provide a description for how programs should perform assessments. OBJECTIVES: We evaluated graduating residents' status epilepticus (SE) identification and management skills and how they correlate with ACGME Milestones reported for epilepsy and management/treatment by their program's clinical competency committee (CCC). METHODS: We performed a cohort study of graduating neurology residents from 3 academic medical centers in Chicago in 2018. We evaluated residents' skills identifying and managing SE using a simulation-based assessment (26-item checklist). Simulation-based assessment scores were compared to experience (number of SE cases each resident reported identifying and managing during residency), self-confidence in identifying and managing these cases, and their end of residency Milestones assigned by a CCC based on end-of-rotation evaluations. RESULTS: Sixteen of 21 (76%) eligible residents participated in the study. Average SE checklist score was 15.6 of 26 checklist items correct (60%, SD 12.2%). There were no significant correlations between resident checklist performance and experience or self-confidence. The average participant's level of Milestone for epilepsy and management/treatment was high at 4.3 of 5 (SD 0.4) and 4.4 of 5 (SD 0.4), respectively. There were no significant associations between checklist skills performance and level of Milestone assigned. CONCLUSIONS: Simulated SE skills performance of graduating neurology residents was poor. Our study suggests that end-of-rotation evaluations alone are inadequate for assigning Milestones for high-stakes clinical skills such as identification and management of SE.

Mirror Image Video Artifact: An Under-Reported Digital Video-EEG Artifact.

Synchronous video recording can be helpful in EEG recordings, especially in recognition of seizures and in rejection of artifacts. However, video recordings themselves are also subject to the risk of contamination by artifacts. We report a unique case in which a digital video artifact was identified, occurring during synchronous video-EEG recording, albeit independently of the EEG tracing itself. A synchronous digital video-EEG recording was performed on a 67-year-old male who presented in focal motor status epilepticus. During the initial review of the data, right-sided abnormalities on EEG apparently corresponded with (ipsilateral) right arm motor activity on video, suggesting a nonsensical anatomical localization. However, review of the patient's chart and discussion with the EEG technologist led to the recognition that the video data recorded a mirror image of the true findings of left arm motor activity. Review of the software settings led to the discovery that the video recording was inverted along the vertical axis, leading to mirror image video artifact. Recognition of this video artifact allowed for accurate interpretation of the study-that right hemispheric EEG abnormalities correlated appropriately with (contralateral) left arm twitching. Effective communication between the EEG reading physician, the treating team, and the EEG technologist is critical for recognition of such artifacts, for proper EEG interpretation, and for appropriate patient management. Mirror image video artifact affirms that bedside evaluation, astute technologists, and attentive EEG reading physicians remain important, even in the presence of video recording.

Mimickers of generalized spike and wave discharges.

Overinterpretation of benign EEG variants is a common problem that can lead to the misdiagnosis of epilepsy. We review four normal patterns that mimic generalized spike and wave discharges: phantom spike-and-wave, hyperventilation hypersynchrony, hypnagogic/ hypnopompic hypersynchrony, and mitten patterns.

De novo generalized periodic discharges related to anesthetic withdrawal resolve spontaneously.

Pentobarbital and propofol are used for the treatment of refractory status epilepticus or elevated intracranial pressure, typically with continuous EEG monitoring. We report a series of patients who developed generalized periodic discharges related to anesthetic withdrawal (GRAWs), different from previous seizure activity. At times, this pattern was misinterpreted as recurrent seizure activity, leading to reinstitution of drug-induced coma, but resolved spontaneously without additional treatment.We identified five patients who developed GRAWs during pentobarbital or propofol withdrawal. Two patients received pentobarbital for increased intracranial pressure. One patient received pentobarbital and propofol for encephalopathy accompanied by a rhythmic EEG pattern erroneously thought to be ictal. Two patients received pentobarbital for refractory partial status epilepticus. In all cases, anesthetic agents were withdrawn after 24 to 48 hours of burst suppression on EEG. We analyzed the course of GRAWs on EEG and the associated clinical outcomes.All five patients developed GRAWs, consisting of periodic 1 to 4 Hz generalized periodic discharge, not previously seen on EEG. In all cases, the pattern eventually resolved spontaneously, over 12 to 120 hours. However, in three cases, the pattern was initially thought to represent ictal activity, and drug-induced coma was reinitiated. The pattern recurred during repeated anesthetic withdrawal, was then recognized as nonictal, and then resolved without further treatment. In all cases but one, the patients exhibited improvement to near-baseline mentation.Generalized periodic discharges related to anesthetic withdrawal may occur de novo after pentobarbital or propofol withdrawal. They should resolve spontaneously without treatment and without recurrence of clinical seizure activity. However, GRAWs are not likely to represent status epilepticus and should not prompt resumption of drug-induced coma, unless there is reappearance of original electrographic seizure activity.

Generalized paroxysmal fast activity and tonic seizures in older adults.

Generalized paroxysmal fast activity is an uncommon ictal EEG pattern usually associated with tonic seizures. Patients with generalized paroxysmal fast activity typically have multiple seizure types beginning in childhood and are refractory to antiepileptic drug therapy. We describe 3 hospitalized adult patients (age, older than 55 years) with new-onset tonic movements, noted during an acute illness, associated with generalized paroxysmal fast activity on EEG. These seizures were characterized by subtle stiffening of the arms, trunk, and face for up to 3 seconds. All patients had multiple medical problems and polypharmacy. None had a history of static encephalopathy, other epileptiform abnormalities on EEG, other seizure types, or significant neuroimaging abnormalities. In contrast to previously described reports in children, all three adults responded to antiepileptic drug monotherapy. EEG played a critical role in differentiating tonic seizures from nonepileptic movements in these three cases.