Sleep physiology in patients with epilepsy: Influence of seizures on rapid eye movement (REM) latency and REM duration.

OBJECTIVE: A well-established bidirectional relationship exists between sleep and epilepsy. Patients with epilepsy tend to have less efficient sleep and shorter rapid eye movement (REM) sleep. Seizures are far more likely to arise from sleep transitions and non-REM sleep compared to REM sleep. Delay in REM onset or reduction in REM duration may have reciprocal interactions with seizure occurrence. Greater insight into the relationship between REM sleep and seizure occurrence is essential to our understanding of circadian patterns and predictability of seizure activity. We assessed a cohort of adults undergoing evaluation of drug-resistant epilepsy to examine whether REM sleep prior to or following seizures is delayed in latency or reduced in quantity. METHODS: We used a spectrogram-guided approach to review the video-electroencephalograms of patients' epilepsy monitoring unit admissions for sleep scoring to determine sleep variables. RESULTS: In our cohort of patients, we found group- and individual-level delay of REM latency and reduced REM duration when patients experienced a seizure before the primary sleep period (PSP) of interest or during the PSP of interest. A significant increase in REM latency and decrease in REM quantity were observed on nights where a seizure occurred within 4 h of sleep onset. No change in REM variables was found when investigating seizures that occurred the day after the PSP of interest. Our study is the first to provide insight about a perisleep period, which we defined as 4-h periods before and after the PSP. SIGNIFICANCE: Our results demonstrate a significant relationship between seizures occurring prior to the PSP, during the PSP, and in the 4-h perisleep period and a delay in REM latency. These findings have implications for developing a biomarker of seizure detection as well as longer term seizure risk monitoring.

Source Imaging of Triphasic Waves and Other Encephalopathies.

PURPOSE: Triphasic waves (TWs) are defined as high-amplitude positive waveforms with preceding and after-going negative waves, typically seen in medically ill patients. TWs manifest in similar clinical presentations as other EEG encephalopathies; however, electrographically, they appear different. To better understand the difference, the authors used two different source localization software programs to find a reproducible and unique signature for TW. METHODS: EEGs performed at Johns Hopkins Hospital and Duke University Hospital were retrospectively analyzed. EEG samples of TW, Delta, Theta-Delta, and Frontal Intermittent Rhythmic Delta Activity were selected. The authors did source localization via Commercial Curry 8 and open-source Brainstorm software. A minimum of 10 stereotypical waveforms per subject were selected. The authors used the Boundary Element Method for the head model, which was derived from the Montreal Neurological Institute averaged imaging data set. Dipole and current density analyses were performed. RESULTS: Twenty-eight patients were selected (10 TW, 4 Frontal Intermittent Rhythmic Delta Activity, 6 Theta-Delta, and 8 Delta). The findings suggest the activation of anterior frontal and midline structures for TW. Frontal Intermittent Rhythmic Delta Activity had a similar localization but without a moving dipole. In comparison, the Delta and Delta-Theta appeared to have a more diffuse origin. CONCLUSIONS: Source analysis of TW via two different software suggests the anterior midline location of TW with anterior to posterior propagation. These findings correlate with the previous hypotheses of TW origin. Retrospective analysis, low number of recording electrodes, and difficult analysis of slow waves limit the interpretation of these results. Nonetheless, this article opens the prospect of future studies in this field.

Cervical Artery Dissection in Patients of African Ancestry.

BACKGROUND AND PURPOSE: The majority of published data in cervical artery dissection (CeAD), a common cause of stroke in young adults, derive from populations of European ancestry (EA), including a recent genome-wide study identifying an association with the rs9349379 polymorphism of the PHACTR1 gene. Little is known about CeAD in individuals of African ancestry (AA) despite robust epidemiological data showing increased risk of stroke at younger ages. We hypothesize that AA patients with CeAD have different epidemiology and clinical profiles compared to those of EA, and a different genetic architecture related to rs9349379 of the PHACTR1 gene. METHODS: We searched a single-center database of CeAD to identify AA and EA patients. We compared differential prevalence of CeAD versus all young stroke between AA and EA patients. We characterized clinical profiles via electronic medical record review. Data include descriptive statistics reported as medians or percentages. We also obtained publicly available allele frequencies of rs9349379 in AA and EA populations. RESULTS: AA patients comprise 7% of CeAD cases and 27% of young stroke cases while EA patients comprise 90% of CeAD cases and 70% of young stroke cases. Prevalence of hypertension, diabetes mellitus, and hyperlipidemia were 74, 30, and 50%, respectively, in AA patients compared to 37, 6, and 25% in EA patients. Allele frequencies for the CeAD risk allele, rs9349379(A), are higher in AA populations compared to EA populations. CONCLUSION: AA patients represent a smaller proportion of CeAD cases compared to young stroke cases at our center. AA patients suffering CeAD have higher prevalence of both vascular risk factors and frequency of the CeAD risk allele compared to EA patients. These findings suggest a complex interplay between traditional vascular risk factors and genetic predisposition underlying CeAD pathogenesis. Further prospective research is needed to clarify these associations and disparities.

F2-isoprostanes as a biomarker of oxidative stress in the mouse bladder.

PURPOSE: We theorized that progressive bladder dysfunction due to clinical diagnoses such as outlet obstruction occurs as a result of cyclical oxidative stress events. We hypothesized that measurement of F2-isoprostane, a marker of lipid peroxidation, could serve as a biomarker of oxidative stress in the murine bladder. MATERIALS AND METHODS: At age 5 to 6 weeks oophorectomized female mice were subjected to 1 of 2 bladder injury models, that is partial bladder outlet obstruction or acute bladder distension. The time points studied after injury included 4, 8 and 16 weeks after obstruction, and 0 to 48 hours after acute bladder distension. In a separate group short-term repetitive acute bladder distension was performed every other day for 14 days. Bladder samples were analyzed for F2-isoprostane using gas chromatography and mass spectroscopy. Mean tissue F2-isoprostane levels were compared. RESULTS: F2-isoprostane increased significantly after 4 weeks of partial bladder outlet obstruction from 1.46 ng/gm in controls to 2.31 ng/gm at 4 weeks (p = 0.01). Eight and 16 weeks after partial bladder outlet obstruction F2-isoprostane remained significantly elevated (2.39 and 2.48 ng/gm, respectively). Acute bladder distension resulted in a significant increase in F2-isoprostane immediately after distension compared to controls (1.6 vs 0.75 ng/gm, p = 0.04). In mice that underwent repetitive acute bladder distension F2-isoprostane did not change. CONCLUSIONS: Measurement of tissue F2-isoprostane in the bladder reflects the progression of oxidative stress, primarily in chronic injury models such as partial bladder outlet obstruction. The usefulness of F2-isoprostane measurements in shorter term injury models requires further study.