Association of Prenatal Exposure to Antiseizure Medications With Creative and Executive Function at Age 4.5 Years.

BACKGROUND AND OBJECTIVES: Neurodevelopmental effects of fetal antiseizure medication (ASM) exposure on creativity and executive functions are poorly understood. We previously found fetal valproate exposure to adversely affect measures of creativity and executive functions. In this study, we examine fetal exposure of newer ASMs on these functions in children of women with epilepsy (WWE) compared with children of healthy women (HW). METHODS: The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs study is a multicenter NIH-funded prospective observational cohort study of WWE and HW enrolled in pregnancy and their offsprings. This report examines blindly assessed creativity and executive functions in 4.5-year-old children of WWE vs HW. In addition, exposure-dependent ASM effects during the third trimester were examined in children of WWE, using a ratio of maximum observed ASM concentrations and ratio of defined daily dose (ratio DDD). For polytherapy, ratios were summed across ASMs. Linear regression models adjusted for multiple potential confounding factors were conducted for all analyses. The primary outcome for 4.5-year-old children was the Torrance Test of Creative Thinking-Figural Creativity Index. Secondary outcomes included the Global Executive Composite Score from the Behavior Rating Inventory of Executive Function-Preschool Version and subscales and other indexes of both measures. RESULTS: The primary analysis included 251 children of WWE and 73 of HW. No differences in creativity or executive function were found between children of WWE vs HW. No ASM exposure-dependent effects were found for the creativity measures, but exposure-dependent effects for executive function were present for ratio ASM concentration and ratio DDD. DISCUSSION: Our findings at 4.5 years show no differences in creative thinking between children of WWE vs HW (-3.2 [-9.0 to 2.7], p = 0.286) or associations with fetal exposure to ASMs (-2.6 [-11.0 to 5.7], p = 0.530). Secondary analyses revealed fetal exposure-dependent effects for executive function in children of WWE (7.0 [2.9-11.2], p = 0.001), which are most marked for levetiracetam (12.9 [4.2-21.6], p = 0.004). Our findings suggest that even for relatively safe ASMs, dosing needs to be adjusted to concentrations that prevent seizures, but balance risks to the fetus that high concentrations may pose. TRIAL REGISTRATION INFORMATION: The study is registered at ClinicalTrials.gov as NCT01730170.

Behavioral Outcomes and Neurodevelopmental Disorders Among Children of Women With Epilepsy.

Importance: The association of fetal exposure to antiseizure medications (ASMs) with outcomes in childhood are not well delineated. Objective: To examine the association of fetal ASM exposure with subsequent adaptive, behavioral or emotional, and neurodevelopmental disorder outcomes at 2, 3, and 4.5 years of age. Design, Setting, and Participants: The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is a prospective, observational cohort study conducted at 20 epilepsy centers in the US. A total of 456 pregnant women with epilepsy or without epilepsy were enrolled from December 19, 2012, to January 13, 2016. Children of enrolled women were followed up with formal assessments at 2, 3, 4.5, and 6 years of age. Statistical analysis took place from August 2022 to May 2023. Exposures: Exposures included mother's epilepsy status as well as mother's ASM blood concentration in the third trimester (for children of women with epilepsy). Women with epilepsy were enrolled regardless of ASM regimen. Main Outcomes and Measures: The primary outcome was the Adaptive Behavior Assessment System, Third Edition (ABAS-3) General Adaptive Composite (GAC) score among children at 4.5 years of age. Children of women with epilepsy and children of women without epilepsy were compared, and the associations of ASM exposures with outcomes among exposed children were assessed. Secondary outcomes involved similar analyses of other related measures. Results: Primary analysis included 302 children of women with epilepsy (143 boys [47.4%]) and 84 children of women without epilepsy (45 boys [53.6%]). Overall adaptive functioning (ABAS-3 GAC score at 4.5 years) did not significantly differ between children of women with epilepsy and children of women without epilepsy (parameter estimate [PE], 0.4 [95% CI, -2.5 to 3.4]; P = .77). However, in adjusted analyses, a significant decrease in functioning was seen with increasing third-trimester maximum ASM blood concentrations (PE, -7.8 [95% CI, -12.6 to -3.1]; P = .001). This decrease in functioning was evident for levetiracetam (PE, -18.9 [95% CI, -26.8 to -10.9]; P < .001) and lamotrigine (PE, -12.0 [95% CI, -23.7 to -0.3]; P = .04), the ASMs with sample sizes large enough for analysis. Results were similar with third-trimester maximum daily dose. Conclusions and Relevance: This study suggests that adaptive functioning of children of women with epilepsy taking commonly used ASMs did not significantly differ from that of children of women without epilepsy, but there was an exposure-dependent association of ASMs with functioning. Thus, psychiatric or psychological screening and referral of women with epilepsy and their offspring are recommended when appropriate. Additional research is needed to confirm these findings.

Initiation and Duration of Breastfeeding in the Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs Study.

BACKGROUND AND OBJECTIVES: Breastfeeding has important health benefits for both mother and child. We characterize breastfeeding initiation and duration in mothers with epilepsy relative to control mothers in a large prospective cohort. METHODS: The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs study is a prospective, multicenter observational, US cohort study. Pregnant individuals with and without epilepsy, aged 14-45 years, were enrolled between December 19, 2012, and February 11, 2016. Exclusion criteria included intelligence quotient (IQ) <70, and gestational age >20 weeks at enrollment. Breastfeeding was assessed through electronic diary and at study visits until 2 years postpartum. Odds of initiating breastfeeding was compared between cohorts using unadjusted and adjusted logistic regression models. Duration of breastfeeding was compared between cohorts using the log-rank test. RESULTS: Three hundred fifty-one pregnant individuals with epilepsy and 105 pregnant controls were enrolled. Breastfeeding data were available for 325 mothers with epilepsy and 98 controls. Study cohorts were similar demographically except race (p = 0.008); 84.9% of mothers with epilepsy and 71.4% of controls were White. The mean IQ was lower in mothers with epilepsy compared with that in controls (97.7 vs 104.2, p < 0.001). Breastfeeding was initiated by 74.8% mothers with epilepsy and 88.8% controls; this difference was significant in unadjusted logistic regression (odds ratio [OR] 0.4 [95% CI 0.2, 0.7], p = 0.004), but not in adjusted model (OR 0.5 [95% CI 0.2, 1.0], p = 0.051). Factors associated with breastfeeding were higher maternal education and IQ. There was no difference in duration of breastfeeding between mothers with and without epilepsy (median duration 8.5 months vs 9.9 months, p = 0.793). Among mothers with epilepsy, both convulsive seizures and all seizures that impair awareness during pregnancy were associated with lower breastfeeding initiation (OR 0.4 [95% CI 0.2, 0.8], p = 0.013) and (OR 0.4 [95% CI 0.2, 0.8], p = 0.003, respectively). Any peripartum seizures were associated with shorter breastfeeding duration (median 6 months vs 9.7 months, [p = 0.040]). DISCUSSION: Mothers with epilepsy were less likely to initiate breastfeeding compared with controls; however, this difference was not significant when controlling for maternal IQ and education level. Continuation of breastfeeding once initiated was not different between mothers with and without epilepsy. Seizure control was associated with breastfeeding initiation and duration in mothers with epilepsy. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov identifier NCT01730170.

Genetic Testing to Inform Epilepsy Treatment Management From an International Study of Clinical Practice.

Importance: It is currently unknown how often and in which ways a genetic diagnosis given to a patient with epilepsy is associated with clinical management and outcomes. Objective: To evaluate how genetic diagnoses in patients with epilepsy are associated with clinical management and outcomes. Design, Setting, and Participants: This was a retrospective cross-sectional study of patients referred for multigene panel testing between March 18, 2016, and August 3, 2020, with outcomes reported between May and November 2020. The study setting included a commercial genetic testing laboratory and multicenter clinical practices. Patients with epilepsy, regardless of sociodemographic features, who received a pathogenic/likely pathogenic (P/LP) variant were included in the study. Case report forms were completed by all health care professionals. Exposures: Genetic test results. Main Outcomes and Measures: Clinical management changes after a genetic diagnosis (ie, 1 P/LP variant in autosomal dominant and X-linked diseases; 2 P/LP variants in autosomal recessive diseases) and subsequent patient outcomes as reported by health care professionals on case report forms. Results: Among 418 patients, median (IQR) age at the time of testing was 4 (1-10) years, with an age range of 0 to 52 years, and 53.8% (n = 225) were female individuals. The mean (SD) time from a genetic test order to case report form completion was 595 (368) days (range, 27-1673 days). A genetic diagnosis was associated with changes in clinical management for 208 patients (49.8%) and usually (81.7% of the time) within 3 months of receiving the result. The most common clinical management changes were the addition of a new medication (78 [21.7%]), the initiation of medication (51 [14.2%]), the referral of a patient to a specialist (48 [13.4%]), vigilance for subclinical or extraneurological disease features (46 [12.8%]), and the cessation of a medication (42 [11.7%]). Among 167 patients with follow-up clinical information available (mean [SD] time, 584 [365] days), 125 (74.9%) reported positive outcomes, 108 (64.7%) reported reduction or elimination of seizures, 37 (22.2%) had decreases in the severity of other clinical signs, and 11 (6.6%) had reduced medication adverse effects. A few patients reported worsening of outcomes, including a decline in their condition (20 [12.0%]), increased seizure frequency (6 [3.6%]), and adverse medication effects (3 [1.8%]). No clinical management changes were reported for 178 patients (42.6%). Conclusions and Relevance: Results of this cross-sectional study suggest that genetic testing of individuals with epilepsy may be materially associated with clinical decision-making and improved patient outcomes.

EEG Abnormalities and Their Radiographic Correlates in a COVID-19 Inpatient Cohort.

Background and Objectives: To identify the prevalence of EEG abnormalities in patients with coronavirus disease 2019 (COVID-19) with neurologic changes, their associated neuroimaging abnormalities, and rates of mortality. Methods: A retrospective case series of 192 adult COVID-19-positive inpatients with EEG performed between March and June 2020 at 4 hospitals: 161 undergoing continuous, 24 routine, and 7 reduced montage EEG. Study indication, epilepsy history, intubation status, administration of sedatives or antiseizure medications (ASMs), metabolic abnormalities, neuroimaging pathology associated with epileptiform abnormalities, and in-hospital mortality were analyzed. Results: EEG indications included encephalopathy (54.7%), seizure (18.2%), coma (17.2%), focal deficit (5.2%), and abnormal movements (4.6%). Epileptiform abnormalities occurred in 39.6% of patients: focal intermittent epileptiform discharges in 25.0%, lateralized periodic discharges in 6.3%, and generalized periodic discharges in 19.3%. Seizures were recorded in 8 patients, 3 with status epilepticus. ASM administration, epilepsy history, and older age were associated with epileptiform abnormalities. Only 26.3% of patients presented with any epileptiform abnormality, 37.5% with electrographic seizures, and 25.7% patients with clinical seizures had known epilepsy. Background findings included generalized slowing (88.5%), focal slowing (15.6%), burst suppression (3.6%), attenuation (3.1%), and normal EEG (3.1%). Neuroimaging pathology was identified in 67.1% of patients with epileptiform abnormalities, over two-thirds acute. In-hospital mortality was 39.5% for patients with epileptiform abnormalities and 36.2% for those without. Risk factors for mortality were coma and ventilator support at time of EEG. Discussion: This article highlights the range of EEG abnormalities frequently associated with acute neuroimaging abnormalities in COVID-19. Mortality rates were high, particularly for patients in coma requiring mechanical ventilation. These findings may guide the prognosis and management of patients with COVID-19 and neurologic changes.

The Effect of Epilepsy on Sleep Quality During Pregnancy and Postpartum.

OBJECTIVE: This study seeks to understand how sleep is affected in pregnant women with epilepsy (WWE) relative to healthy pregnant women during pregnancy and postpartum and to non-pregnant WWE during comparative time periods. BACKGROUND: Sleep impacts maternal health and mood during pregnancy. Maternal sleep disturbances are related to poor fetal growth and increased fetal deaths. Epilepsy is the most common neurologic condition in pregnancy. Sleep disruption can worsen epileptic seizures. The interplay between epilepsy, pregnancy, and sleep is poorly understood. DESIGN: /Methods: The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is an NIH-funded, prospective, observational, multicenter study, enrolling women from December 2012 through January 2016. Sleep quality was assessed utilizing the average Pittsburgh Sleep Quality Index collected during pregnancy; postpartum; or analogous time periods. Sleep scores range from 0 to 21 with higher scores indicating worse sleep quality; scores > 5 are associated with poor sleep quality. RESULTS: Of 351 pregnant WWE, 105 healthy pregnant women, and 109 non-pregnant WWE enrolled in MONEAD, data from 241 pregnant WWE, 74 healthy pregnant women, and 84 non-pregnant WWE were analyzed. Pregnant WWE had worse sleep (higher mean sleep score) during pregnancy compared to healthy pregnant women in unadjusted analysis (p=0.006), but no longer significant in adjusted analysis (p=0.062), pregnant WWE (least square mean sleep score (95% CI) = 5.8 (5.5, 6.1)) vs. healthy pregnant women (5.1 (4.6, 5.7)). During postpartum, pregnant WWE (5.6 (5.4, 5.9)) had similarly impaired sleep compared to healthy pregnant women (5.7 (5.2, 6.2); adjusted p=0.838). Sleep was significantly worse in pregnant WWE vs non-pregnant WWE (for comparable time period) in pregnancy and postpartum in unadjusted and adjusted analyses. Adjusted scores for pregnant WWE in pregnancy (5.7 (5.4, 6.0)) and postpartum (5.7 (5.4, 6.0)) compared to non-pregnant WWE (4.7 (4.2, 5.3); p=0.002) and (4.1 (3.6, 4.7); p<0.001), respectively. Sleep quality between pregnancy and postpartum varied only in healthy pregnant women (change in mean score = 0.8 (0.2, 1.3); p=0.01), whose sleep was worse in postpartum. CONCLUSIONS: Pregnant WWE had worse sleep during pregnancy and postpartum than non-pregnant WWE during comparable periods in the adjusted analysis.The study is registered at clinicaltrials.gov as NCT01730170.

Multigene Panel Testing in a Large Cohort of Adults With Epilepsy: Diagnostic Yield and Clinically Actionable Genetic Findings.

BACKGROUND AND OBJECTIVES: Although genetic testing among children with epilepsy has demonstrated clinical utility and become a part of routine testing, studies in adults are limited. This study reports the diagnostic yield of genetic testing in adults with epilepsy. METHODS: Unrelated individuals aged 18 years and older who underwent diagnostic genetic testing for epilepsy using a comprehensive, next-generation sequencing-based, targeted gene panel (range 89-189 genes) were included in this cross-sectional study. Clinical information, provided at the discretion of the ordering clinician, was reviewed and analyzed. Diagnostic yield was calculated for all individuals including by age at seizure onset and comorbidities based on clinician-reported information. The proportion of individuals with clinically actionable genetic findings, including instances when a specific treatment would be indicated or contraindicated due to a diagnostic finding, was calculated. RESULTS: Among 2,008 individuals, a diagnostic finding was returned for 218 adults (10.9%), with clinically actionable findings in 55.5% of diagnoses. The highest diagnostic yield was in adults with seizure onset during infancy (29.6%, 0-1 year), followed by in early childhood (13.6%, 2-4 years), late childhood (7.0%, 5-10 years), adolescence (2.4%, 11-17 years), and adulthood (3.7%, ≥18 years). Comorbid intellectual disability (ID) or developmental delay resulted in a high diagnostic yield (16.0%), most notably for females (19.6% in females vs 12.3% in males). Among individuals with pharmacoresistant epilepsy, 13.5% had a diagnostic finding, and of these, 57.4% were clinically actionable genetic findings. DISCUSSION: These data reinforce the utility of genetic testing for adults with epilepsy, particularly for those with childhood-onset seizures, ID, and pharmacoresistance. This is an important consideration due to longer survival and the complexity of the transition from pediatric to adult care. In addition, more than half of diagnostic findings in this study were considered clinically actionable, suggesting that genetic testing could have a direct impact on clinical management and outcomes.

Intracranial EEG Biomarkers for Seizure Lateralization in Rapidly-Bisynchronous Epilepsy After Laser Corpus Callosotomy.

Objective: It has been asserted that high-frequency analysis of intracranial EEG (iEEG) data may yield information useful in localizing epileptogenic foci. Methods: We tested whether proposed biomarkers could predict lateralization based on iEEG data collected prior to corpus callosotomy (CC) in three patients with bisynchronous epilepsy, whose seizures lateralized definitively post-CC. Lateralization data derived from algorithmically-computed ictal phase-locked high gamma (PLHG), high gamma amplitude (HGA), and low-frequency (filtered) line length (LFLL), as well as interictal high-frequency oscillation (HFO) and interictal epileptiform discharge (IED) rate metrics were compared against ground-truth lateralization from post-CC ictal iEEG. Results: Pre-CC unilateral IEDs were more frequent on the more-pathologic side in all subjects. HFO rate predicted lateralization in one subject, but was sensitive to detection threshold. On pre-CC data, no ictal metric showed better predictive power than any other. All post-corpus callosotomy seizures lateralized to the pathological hemisphere using PLHG, HGA, and LFLL metrics. Conclusions: While quantitative metrics of IED rate and ictal HGA, PHLG, and LFLL all accurately lateralize based on post-CC iEEG, only IED rate consistently did so based on pre-CC data. Significance: Quantitative analysis of IEDs may be useful in lateralizing seizure pathology. More work is needed to develop reliable techniques for high-frequency iEEG analysis.

Acute Seizures Occurring in Association With SARS-CoV-2.

Seizures are an infrequent and serious neurological complication of SARS-CoV-2 infection, with limited data describing the etiology and the clinical context in which these occur or the associated electrographic and imaging findings. This series details four cases of seizures occurring in patients with COVID-19 with distinct time points, underlying pathology, and proposed physiological mechanisms. An enhanced understanding of seizure manifestations in COVID-19 and their clinical course may allow for earlier detection and improved patient management.

Painful Seizures: a Review of Epileptic Ictal Pain.

PURPOSE OF REVIEW: To summarize the literature regarding the prevalence, pathophysiology, and anatomic networks involved with painful seizures, which are a rare but striking clinical presentation of epilepsy. RECENT FINDINGS: Several recent large case series have explored the prevalence of the main cephalgic, somatosensory, and abdominal variants of this rare disorder. Research studies including the use of electrical stimulation and functional neuroimaging have demonstrated the networks underlying painful somatosensory or visceral seizures. Improved understanding of some of the overlapping mechanisms between migraines and seizures has elucidated their common pathophysiology. The current literature reflects a widening range of awareness and understanding of painful seizures, despite their rarity.

Intractable Generalized Epilepsy: Therapeutic Approaches.

PURPOSE OF REVIEW: To summarize recent developments in therapeutic options, both medical and surgical, for patients with drug-resistant generalized epilepsy syndromes, which continue to be a multifaceted challenge for patients and physicians. RECENT FINDINGS: Newer generation pharmaceutical options are now available, such as brivaracetam, rufinamide, lacosamide, perampanel, and cannabidiol. Less restrictive dietary options appear to be nearly as effective as classic ketogenic diet for amelioration of seizures. The latest implantable devices include responsive neurostimulation and deep brain stimulation. Corpus callosotomy is an effective treatment for some seizure types, and newer and less invasive approaches are being explored. Resective surgical options have demonstrated success in carefully selected patients despite generalized electrographic findings on electroencephalogram. The current literature reflects a widening range of clinical experience with newer anticonvulsant medications including cannabinoids, dietary therapies, surgical approaches, and neurostimulation devices for patients with intractable generalized epilepsy.

Validation of corpus callosotomy after laser interstitial thermal therapy: a multimodal approach.

ObjectiveDisconnection of the cerebral hemispheres by corpus callosotomy (CC) is an established means to palliate refractory generalized epilepsy. Laser interstitial thermal therapy (LITT) is gaining acceptance as a minimally invasive approach to treating epilepsy, but this method has not been evaluated in clinical series using established methodologies to assess connectivity. The goal in this study was to demonstrate the safety and feasibility of MRI-guided LITT for CC and to assess disconnection by using electrophysiology- and imaging-based methods.MethodsRetrospective chart and imaging review was performed in 5 patients undergoing LITT callosotomy at a single center. Diffusion tensor imaging and resting functional MRI were performed in all patients to assess anatomical and functional connectivity. In 3 patients undergoing simultaneous intracranial electroencephalography monitoring, corticocortical evoked potentials and resting electrocorticography were used to assess electrophysiological correlates.ResultsAll patients had generalized or multifocal seizure onsets. Three patients with preoperative evidence for possible lateralization underwent stereoelectroencephalography depth electrode implantation during the perioperative period. LITT ablation of the anterior corpus callosum was completed in a single procedure in 4 patients. One complication involving misplaced devices required a second procedure. Adequacy of the anterior callosotomy was confirmed using contrast-enhanced MRI and diffusion tensor imaging. Resting functional MRI, corticocortical evoked potentials, and resting electrocorticography demonstrated functional disconnection of the hemispheres. Postcallosotomy monitoring revealed lateralization of the seizures in all 3 patients with preoperatively suspected occult lateralization. Four of 5 patients experienced > 80% reduction in generalized seizure frequency. Two patients undergoing subsequent focal resection are free of clinical seizures at 2 years. One patient developed a 9-mm intraparenchymal hematoma at the site of entry and continued to have seizures after the procedure.ConclusionsMRI-guided LITT provides an effective minimally invasive alternative method for CC in the treatment of seizures associated with drop attacks, bilaterally synchronous onset, and rapid secondary generalization. The disconnection is confirmed using anatomical and functional neuroimaging and electrophysiological measures.

Electroencephalogram Abnormalities During Positional Changes in Brain Sagging Syndrome.

PURPOSE: Brain sagging after craniotomy and clipping of a ruptured aneurysm is a rare complication. Clinical and electrographic changes in patients with a final diagnosis of intracranial hypotension are not well described, and can be mistaken on rare occasions for other entities such as nonconvulsive status epilepticus. There may be resulting delay in the diagnosis and treatment of this potentially life-threatening disorder. METHODS: Case report and imaging. RESULTS: We present a case of intracranial hypotension in which concerning continuous electroencephalogram (cEEG) and quantitative EEG (qEEG) findings were noted during active sagging of the brain, which resolved with supine positioning. During upright seating, cEEG showed high-amplitude bilateral rhythmic 2-Hz slow-wave activity, and bilateral increase of spectral delta power on qEEG, in association with neurologic decline in function. When placed in supine position, the cEEG and qEEG abnormalities resolved in conjunction with the recovery of neurologic function. CONCLUSIONS: Brain sagging can be diagnosed using simple maneuvers such as supine positioning. This case report describes changes seen in cEEG and qEEG monitoring that accompany these maneuvers, which may provide further evidence for the diagnosis of brain sagging. Thus, cEEG and qEEG monitoring may have a role in the early detection and treatment of brain sagging.

Understanding variability in driving recommendations for patients with seizures.

BACKGROUND: There is lack of consensus regarding driving restrictions for patients with epilepsy. Regulations vary by state. New York State (NYS) recommends driving restrictions for one year in a person with an episode of loss of consciousness (LOC), with physician discretion. Often, providers make recommendations to permit their patients to drive after a shorter seizure-free period than proposed guidelines. The prevalence and reasons behind more lenient recommendations have not been elucidated. METHODS: Forty-one neurologists were surveyed anonymously in Nassau County, New York. They were questioned about the length of recommended driving restrictions (≤1, 3, 6, or ≥12months) that they typically provide to patients with suspected seizures in different clinical scenarios and overall reasons for doing so. Data about level of training, setting of practice, use of antiepileptic drug (AED) levels, and electroencephalogram (EEG) were also collected. RESULTS: Of the 41 neurologists surveyed, 72% reported recommending driving restrictions <12months for patients who experienced LOC, without a confirmed diagnosis of seizure. The majority also recommended driving restriction of <12months for other scenarios including acute symptomatic seizure, exclusively simple partial seizures, nocturnal seizures, psychogenic nonepileptic seizures (PNES), and seizures occurring with or during AED reduction. The most common rationale was to improve patient autonomy and independence. Less than a third of neurologists estimated that the majority of their patients were noncompliant with driving recommendations. CONCLUSION: We found that many neurologists' recommendations for limiting driving for patients with seizure-related episodes are shorter than those recommended by NYS. Furthermore, as there are no specific guidelines for questionable epileptic scenarios and seizures occurring nocturnally or without LOC, this appears to contribute to substantial variability in the duration of recommended driving restrictions. This opens a broad discussion about approaches towards advising driving limitations in order to protect public and patient safety while maintaining patient autonomy.

Seeing scenes: topographic visual hallucinations evoked by direct electrical stimulation of the parahippocampal place area.

In recent years, functional neuroimaging has disclosed a network of cortical areas in the basal temporal lobe that selectively respond to visual scenes, including the parahippocampal place area (PPA). Beyond the observation that lesions involving the PPA cause topographic disorientation, there is little causal evidence linking neural activity in that area to the perception of places. Here, we combined functional magnetic resonance imaging (fMRI) and intracranial EEG (iEEG) recordings to delineate place-selective cortex in a patient implanted with stereo-EEG electrodes for presurgical evaluation of drug-resistant epilepsy. Bipolar direct electrical stimulation of a cortical area in the collateral sulcus and medial fusiform gyrus, which was place-selective according to both fMRI and iEEG, induced a topographic visual hallucination: the patient described seeing indoor and outdoor scenes that included views of the neighborhood he lives in. By contrast, stimulating the more lateral aspect of the basal temporal lobe caused distortion of the patient's perception of faces, as recently reported (Parvizi et al., 2012). Our results support the causal role of the PPA in the perception of visual scenes, demonstrate that electrical stimulation of higher order visual areas can induce complex hallucinations, and also reaffirm direct electrical brain stimulation as a tool to assess the function of the human cerebral cortex.

Dominant frequencies of resting human brain activity as measured by the electrocorticogram.

The brain's spontaneous, intrinsic activity is increasingly being shown to reveal brain function, delineate large scale brain networks, and diagnose brain disorders. One of the most studied and clinically utilized types of intrinsic brain activity are oscillations in the electrocorticogram (ECoG), a relatively localized measure of cortical synaptic activity. Here we objectively characterize the types of ECoG oscillations commonly observed over particular cortical areas when an individual is awake and immobile with eyes closed, using a surface-based cortical atlas and cluster analysis. Both methods show that [1] there is generally substantial variability in the dominant frequencies of cortical regions and substantial overlap in dominant frequencies across the areas sampled (primarily lateral central, temporal, and frontal areas), [2] theta (4-8 Hz) is the most dominant type of oscillation in the areas sampled with a mode around 7 Hz, [3] alpha (8-13 Hz) is largely limited to parietal and occipital regions, and [4] beta (13-30 Hz) is prominent peri-Rolandically, over the middle frontal gyrus, and the pars opercularis. In addition, the cluster analysis revealed seven types of ECoG spectral power densities (SPDs). Six of these have peaks at 3, 5, 7 (narrow), 7 (broad), 10, and 17 Hz, while the remaining cluster is broadly distributed with less pronounced peaks at 8, 19, and 42 Hz. These categories largely corroborate conventional sub-gamma frequency band distinctions (delta, theta, alpha, and beta) and suggest multiple sub-types of theta. Finally, we note that gamma/high gamma activity (30+ Hz) was at times prominently observed, but was too infrequent and variable across individuals to be reliably characterized. These results should help identify abnormal patterns of ECoG oscillations, inform the interpretation of EEG/MEG intrinsic activity, and provide insight into the functions of these different oscillations and the networks that produce them. Specifically, our results support theories of the importance of theta oscillations in general cortical function, suggest that alpha activity is primarily related to sensory processing/attention, and demonstrate that beta networks extend far beyond primary sensorimotor regions.