Alexandra Popescu

Clinically distinct electroencephalographic phenotypes of early myoclonus after cardiac arrest

We tested the hypothesis that there are readily classifiable electroencephalographic (EEG) phenotypes of early postanoxic multifocal myoclonus (PAMM) that develop after cardiac arrest.

Panic attack symptoms differentiate patients with epilepsy from those with psychogenic nonepileptic spells (PNES)

Psychogenic nonepileptic spells (PNES) are frequently challenging to differentiate from epileptic seizures. The experience of panic attack symptoms during an event may assist in distinguishing PNES from seizures secondary to epilepsy. A retrospective analysis of 354 patients diagnosed with PNES (N=224) or with epilepsy (N=130) investigated the thirteen Diagnostic and Statistical Manual-IV-Text Revision panic attack criteria endorsed by the two groups. We found a statistically higher mean number of symptoms reported by patients with PNES compared with those with epilepsy. In addition, the majority of the panic attack symptoms including heart palpitations, sweating, shortness of breath, choking feeling, chest discomfort, dizziness/unsteadiness, derealization or depersonalization, fear of dying, paresthesias, and chills or hot flashes were significantly more frequent in those with PNES. As patients with PNES frequently have poor clinical outcomes, treatment addressing the anxiety symptomatology may be beneficial.

Medical comorbidities in patients with psychogenic nonepileptic spells (PNES) referred for video-EEG monitoring

Differentiating between psychogenic nonepileptic spells (PNES) and epileptic seizures without video-EEG monitoring is difficult. The presence of specific medical comorbidities may discriminate the two, helping physicians suspect PNES over epilepsy earlier. A retrospective analysis comparing the medical comorbidities of patients with PNES with those of patients with epilepsy was performed in 280 patients diagnosed with either PNES (N = 158, 74.7% females) or epilepsy (N = 122, 46.7% females) in the Epilepsy Monitoring Unit (EMU) of the University of Pittsburgh Medical Center over a two-year period. Patients with PNES, compared to those with epilepsy, were mostly female, significantly more likely to have a history of abuse, had more functional somatic syndromes (fibromyalgia, chronic fatigue syndrome, chronic pain syndrome, tension headaches, and irritable bowel syndrome), and had more medical illnesses that are chronic with intermittent attacks (migraines, asthma, and GERD). The presence of at least of one these disorders may lead physicians to suspect PNES over epilepsy and expedite appropriate referral for video-EEG monitoring for diagnosis.

Continuous EEG monitoring enhances multimodal outcome prediction in hypoxic–ischemic brain injury

OBJECTIVE Hypoxic brain injury is the largest contributor to disability and mortality after cardiac arrest. We aim to identify electroencephalogram (EEG) characteristics that can predict outcome on cardiac arrest patients treated with targeted temperature management (TTM). METHODS We retrospectively examined clinical, EEG, functional outcome at discharge, and in-hospital mortality for 373 adult subjects with return of spontaneous circulation after cardiac arrest. Poor outcome was defined as a Cerebral Performance Category score of 3-5. Pure suppression-burst (SB) was defined as SB not associated with status epilepticus (SE), seizures, or generalized periodic discharges. RESULTS In-hospital mortality was 68.6% (N=256). Presence of both unreactive EEG background and SE was associated with a positive predictive value (PPV) of 100% (95% confidence interval: 0.96-1) and a false-positive rate (FPR) of 0% (95% CI: 0-0.11) for poor functional outcome. A prediction model including demographics data, admission exam, presence of status epilepticus, pure SB, and lack of EEG reactivity had an area under the curve of 0.92 (95% CI: 0.87-0.95) for poor functional outcome prediction, and 0.96 (95% CI: 0.94-0.98) for in-hospital mortality. Presence of pure SB (N=87) was confounded by anesthetics use in 83.9% of the cases, and was not an independent predictor of poor functional outcome, having a FPR of 23% (95% CI: 0.19-0.28). CONCLUSIONS An unreactive EEG background and SE predicted poor functional outcome and in-hospital mortality in cardiac arrest patients undergoing TTM. Prognostic value of pure SB is confounded by use of sedative agents, and its use on prognostication decisions should be made with caution.

Thoughts, emotions, and dissociative features differentiate patients with epilepsy from patients with psychogenic nonepileptic spells (PNESs)

Psychogenic nonepileptic spells (PNESs) are often very difficult to treat, which may be, in part, related to the limited information known about what a person experiences while having PNESs. For this retrospective study, thoughts, emotions, and dissociative features during a spell were evaluated in 351 patients diagnosed with PNESs (N=223) or epilepsy (N=128). We found that a statistically higher number of thoughts, emotions, and dissociative symptoms were endorsed by patients with PNESs versus patients with epilepsy. Patients with PNESs reported significantly more anxiety and frustration, but not depression, compared with those with epilepsy. Emotions and dissociations, but not thoughts, and a history of any type of abuse were endorsed significantly more often by patients with PNESs. Patients with PNESs are prone to having poor outcomes, and interventions focusing on their actual experiences may be helpful for treatment planning.

Detection of high-frequency oscillations by hybrid depth electrodes in standard clinical intracranial EEG recordings.

High-frequency oscillations (HFOs) have been proposed as a novel marker for epileptogenic tissue, spurring tremendous research interest into the characterization of these transient events. A wealth of continuously recorded intracranial electroencephalographic (iEEG) data is currently available from patients undergoing invasive monitoring for the surgical treatment of epilepsy. In contrast to data recorded on research-customized recording systems, data from clinical acquisition systems remain an underutilized resource for HFO detection in most centers. The effective and reliable use of this clinically obtained data would be an important advance in the ongoing study of HFOs and their relationship to ictogenesis. The diagnostic utility of HFOs ultimately will be limited by the ability of clinicians to detect these brief, sporadic, and low amplitude events in an electrically noisy clinical environment. Indeed, one of the most significant factors limiting the use of such clinical recordings for research purposes is their low signal to noise ratio, especially in the higher frequency bands. In order to investigate the presence of HFOs in clinical data, we first obtained continuous intracranial recordings in a typical clinical environment using a commercially available, commonly utilized data acquisition system and “off the shelf” hybrid macro-/micro-depth electrodes. These data were then inspected for the presence of HFOs using semi-automated methods and expert manual review. With targeted removal of noise frequency content, HFOs were detected on both macro- and micro-contacts, and preferentially localized to seizure onset zones. HFOs detected by the offline, semi-automated method were also validated in the clinical viewer, demonstrating that (1) this clinical system allows for the visualization of HFOs and (2) with effective signal processing, clinical recordings can yield valuable information for offline analysis.

Short-term neurocognitive outcomes following anterior temporal lobectomy

Changes in cognitive function are a well established risk of anterior temporal lobectomy (ATL). Deficits in verbal memory are a common postoperative finding, though a small proportion of patients may improve. Postoperative evaluation typically occurs after six to 12months. Patients may benefit from earlier evaluation to identify potential needs; however, the results of a formal neuropsychological assessment at an early postoperative stage are not described in the literature. We compared pre- and postoperative cognitive function for 28 right ATL and 23 left ATL patients using repeated measures ANOVA. Changes in cognitive function were compared to ILAE seizure outcome. The mean time to postoperative neuropsychological testing was 11.1weeks (SD=6.7weeks). There was a side×surgery interaction for the verbal tasks: immediate memory recall (F(1,33)=20.68, p<0.001), short delay recall (F(1,29)=4.99, p=0.03), long delay recall (F(1,33)=10.36, p=0.003), recognition (F(1,33)=5.69, p=0.02), and naming (F(1,37)=15.86, p<0.001). This indicated that the left ATL group had a significant decrement in verbal memory following surgery, while the right ATL group experienced a small but significant improvement. For the right ATL group, there was a positive correlation between ILAE outcome and improvement in immediate recall (r=-0.62, p=0.02) and long delay recall (r=-0.57, p=0.03). There was no similar finding for the left ATL group. This study demonstrates that short-interval follow-up is effective in elucidating postoperative cognitive changes. Right ATL was associated with improvement in verbal memory, while left ATL resulted in a decrement in performance. Improvement in the right ATL group was related to improved seizure outcome. Short-interval follow-up may lend itself to the identification of patients who could benefit from early intervention.

Corpus callosum lipoma

A 24-year-old man was referred for uncontrolled generalized tonic-clonic seizures since childhood. Physical examination was unremarkable. Brain MRI revealed a large corpus callosum lipoma (CCL) and severe dysgenesis of the corpus callosum …

Effect of sedation on quantitative electroencephalography after cardiac arrest

BACKGROUND Electroencephalography (EEG) has clinical and prognostic importance after cardiac arrest (CA). Recently, interest in quantitative EEG (qEEG) analysis has grown. The qualitative effects of sedation on EEG are well known, but potentially confounding effects of sedatives on qEEG after anoxic injury are poorly characterized. We hypothesize that sedation increases suppression ratio (SR) and decreases alpha/delta ratio (ADR) and amplitude-integrated EEG (aEEG), and that the magnitude of sedation effects will be associated with outcome. METHODS We routinely monitor comatose post-arrest patients with EEG for 48-72h. We included comatose EEG-monitored patients after CA who had protocolized daily sedation interruptions. We used Persyst v12 to quantify qEEG parameters and calculated medians for 10min immediately prior to sedation interruption and for the last 5min of interruption. We used paired t-tests to determine whether qEEG parameters changed with sedation cessation, and logistic regression to determine whether these changes predicted functional recovery or survival at discharge. RESULTS 78 subjects were included (median age 56, 65% male). Interruptions occurred a median duration of 34h post-arrest and lasted a median duration of 60min. Prior to interruption, higher aEEG predicted survival, while lower SR predicted both survival and favorable outcome. During interruption, SR decreased (p<0.001), aEEG increased (p=0.002), and ADR did not change. Larger decreases in SR predicted decreased survival (OR=1.04 per percent change; 95% CI 1.00-1.09). CONCLUSION Higher aEEG and lower SR predict survival after CA. Sedation alters aEEG and SR, but importantly does not appear to affect the relationship between these parameter values and outcome.