Visual cortex responds to sound onset and offset during passive listening.

Sounds enhance our ability to detect, localize, and respond to co-occurring visual targets. Research suggests that sounds improve visual processing by resetting the phase of ongoing oscillations in visual cortex. However, it remains unclear what information is relayed from the auditory system to visual areas and if sounds modulate visual activity even in the absence of visual stimuli (e.g., during passive listening). Using intracranial electroencephalography (iEEG) in humans, we examined the sensitivity of visual cortex to three forms of auditory information during a passive listening task: auditory onset responses, auditory offset responses, and rhythmic entrainment to sounds. Because some auditory neurons respond to both sound onsets and offsets, visual timing and duration processing may benefit from each. In addition, if auditory entrainment information is relayed to visual cortex, it could support the processing of complex stimulus dynamics that are aligned between auditory and visual stimuli. Results demonstrate that in visual cortex, amplitude-modulated sounds elicited transient onset and offset responses in multiple areas, but no entrainment to sound modulation frequencies. These findings suggest that activity in visual cortex (as measured with iEEG in response to auditory stimuli) may not be affected by temporally fine-grained auditory stimulus dynamics during passive listening (though it remains possible that this signal may be observable with simultaneous auditory-visual stimuli). Moreover, auditory responses were maximal in low-level visual cortex, potentially implicating a direct pathway for rapid interactions between auditory and visual cortices. This mechanism may facilitate perception by time-locking visual computations to environmental events marked by auditory discontinuities.NEW & NOTEWORTHY Using intracranial electroencephalography (iEEG) in humans during a passive listening task, we demonstrate that sounds modulate activity in visual cortex at both the onset and offset of sounds, which likely supports visual timing and duration processing. However, more complex auditory rate information did not affect visual activity. These findings are based on one of the largest multisensory iEEG studies to date and reveal the type of information transmitted between auditory and visual regions.

Visual speech differentially modulates beta, theta, and high gamma bands in auditory cortex.

Speech perception is a central component of social communication. Although principally an auditory process, accurate speech perception in everyday settings is supported by meaningful information extracted from visual cues. Visual speech modulates activity in cortical areas subserving auditory speech perception including the superior temporal gyrus (STG). However, it is unknown whether visual modulation of auditory processing is a unitary phenomenon or, rather, consists of multiple functionally distinct processes. To explore this question, we examined neural responses to audiovisual speech measured from intracranially implanted electrodes in 21 patients with epilepsy. We found that visual speech modulated auditory processes in the STG in multiple ways, eliciting temporally and spatially distinct patterns of activity that differed across frequency bands. In the theta band, visual speech suppressed the auditory response from before auditory speech onset to after auditory speech onset (-93 to 500 ms) most strongly in the posterior STG. In the beta band, suppression was seen in the anterior STG from -311 to -195 ms before auditory speech onset and in the middle STG from -195 to 235 ms after speech onset. In high gamma, visual speech enhanced the auditory response from -45 to 24 ms only in the posterior STG. We interpret the visual-induced changes prior to speech onset as reflecting crossmodal prediction of speech signals. In contrast, modulations after sound onset may reflect a decrease in sustained feedforward auditory activity. These results are consistent with models that posit multiple distinct mechanisms supporting audiovisual speech perception.

Outcomes of seizures, status epilepticus, and EEG findings in critically ill patient with COVID-19.

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has a myriad of neurological manifestations and its effects on the nervous system are increasingly recognized. Seizures and status epilepticus (SE) are reported in the novel coronavirus disease (COVID-19), both new onset and worsening of existing epilepsy; however, the exact prevalence is still unknown. The primary aim of this study was to correlate the presence of seizures, status epilepticus, and specific critical care EEG patterns with patient functional outcomes in those with COVID-19. METHODS: This is a retrospective, multicenter cohort of COVID-19-positive patients in Southeast Michigan who underwent electroencephalography (EEG) from March 12th through May 15th, 2020. All patients had confirmed nasopharyngeal PCR for COVID-19. EEG patterns were characterized per 2012 ACNS critical care EEG terminology. Clinical and demographic variables were collected by medical chart review. Outcomes were divided into recovered, recovered with disability, or deceased. RESULTS: Out of the total of 4100 patients hospitalized with COVID-19, 110 patients (2.68%) had EEG during their hospitalization; 64% were male, 67% were African American with mean age of 63 years (range 20-87). The majority (70%) had severe COVID-19, were intubated, or had multi-organ failure. The median length of hospitalization was 26.5 days (IQR = 15 to 44 days). During hospitalization, of the patients who had EEG, 21.8% had new-onset seizure including 7% with status epilepticus, majority (87.5%) with no prior epilepsy. Forty-nine (45%) patients died in the hospital, 46 (42%) recovered but maintained a disability and 15 (14%) recovered without a disability. The EEG findings associated with outcomes were background slowing/attenuation (recovered 60% vs recovered/disabled 96% vs died 96%, p < 0.001) and normal (recovered 27% vs recovered/disabled 0% vs died 1%, p < 0.001). However, these findings were no longer significant after adjusting for severity of COVID-19. CONCLUSION: In this large multicenter study from Southeast Michigan, one of the early COVID-19 epicenters in the US, none of the EEG findings were significantly correlated with outcomes in critically ill COVID-19 patients. Although seizures and status epilepticus could be encountered in COVID-19, the occurrence did not correlate with the patients' functional outcome.

Patient navigation in epilepsy care.

The concept of patient navigation was first introduced in 1989 by the American Cancer Society and was first implemented in 1990 by Dr. Harold Freeman in Harlem, NY. The role of a patient navigator (PN) is to coordinate care between the care team, the patient, and their family while also providing social support. In the last 30 years, patient navigation in oncological care has expanded internationally and has been shown to significantly improve patient care experience, especially in the United States cancer care system. Like oncology care, patients who require epilepsy care face socioeconomic and healthcare system barriers and are at significant risk of morbidity and mortality if their care needs are not met. Although shortcomings in epilepsy care are longstanding, the COVID-19 pandemic has exacerbated these issues as both patients and providers have reported significant delays in care secondary to the pandemic. Prior to the pandemic, preliminary studies had shown the potential efficacy of patient navigation in improving epilepsy care. Considering the evidence that such programs are helpful for severely disadvantaged cancer patients and in enhancing epilepsy care, we believe that professional societies should support and encourage PN programs for coordinated and comprehensive care for patients with epilepsy.

Effect of seizure timing on long-term survival in patients with brain tumor.

OBJECTIVE: Seizures often occur in patients with primary brain tumor (BT). The aim of this study was to determine if there is an association between the time of occurrence of seizures during the course of BT and survival of these patients. METHODS: This retrospective cohort study at Henry Ford Hospital, an urban tertiary referral center, included all patients who were diagnosed with primary BTs at Henry Ford Health System between January 2006 and December 2014. Timing of seizure occurrence, if occurred at presentation or after the tumor diagnosis during follow-up period, in different grades of BTs, and survival of these patients were analyzed. RESULTS: Of the 901 identified patients, 662 (53% male; mean age: 56 years) were included in final analysis, and seizures occurred in 283 patients (43%). Patients with World Health Organization (WHO) grade III BT with seizures as a presenting symptom only had better survival (adjusted hazard ratio (HR): 0.27; 95% confidence interval (CI), 0.11-0.67; P = 0.004). Seizures that occurred after tumor diagnosis only (adjusted HR: 2.11; 95% CI, 1.59-2.81; P < 0.001) in patients with WHO grade II tumors (adjusted HR: 3.41; 95% CI, 1.05-11.1; P = 0.041) and WHO grade IV tumors (adjusted HR: 2.14; 95% CI, 1.58-2.90; P < 0.001) had higher mortality. Seizures that occurred at presentation and after diagnosis also had higher mortality (adjusted HR: 1.34; 95% CI, 1.00-1.80; P = 0.049), in patients with meningioma (adjusted HR: 6.19; 95% CI, 1.30-29.4; P = 0.021) and grade III tumors (adjusted HR: 6.19; 95% CI, 2.56-15.0; P < 0.001). CONCLUSION: Seizures occurred in almost half of the patients with BTs. The association between seizures in patients with BT and their survival depends on the time of occurrence of seizures, if occurring at presentation or after tumor diagnosis, and the type of tumor. Better survival was noted in patients with WHO grade III BTs who had seizures at presentation at the time of diagnosis, while higher mortality was noted in WHO grade II tumors who had seizure at presentation and after tumor diagnosis, and in grade IV tumors after tumor diagnosis.

Joint Encoding of Auditory Timing and Location in Visual Cortex.

Co-occurring sounds can facilitate perception of spatially and temporally correspondent visual events. Separate lines of research have identified two putatively distinct neural mechanisms underlying two types of crossmodal facilitations: Whereas crossmodal phase resetting is thought to underlie enhancements based on temporal correspondences, lateralized occipital evoked potentials (ERPs) are thought to reflect enhancements based on spatial correspondences. Here, we sought to clarify the relationship between these two effects to assess whether they reflect two distinct mechanisms or, rather, two facets of the same underlying process. To identify the neural generators of each effect, we examined crossmodal responses to lateralized sounds in visually responsive cortex of 22 patients using electrocorticographic recordings. Auditory-driven phase reset and ERP responses in visual cortex displayed similar topography, revealing significant activity in pericalcarine, inferior occipital-temporal, and posterior parietal cortex, with maximal activity in lateral occipitotemporal cortex (potentially V5/hMT+). Laterality effects showed similar but less widespread topography. To test whether lateralized and nonlateralized components of crossmodal ERPs emerged from common or distinct neural generators, we compared responses throughout visual cortex. Visual electrodes responded to both contralateral and ipsilateral sounds with a contralateral bias, suggesting that previously observed laterality effects do not emerge from a distinct neural generator but rather reflect laterality-biased responses in the same neural populations that produce phase-resetting responses. These results suggest that crossmodal phase reset and ERP responses previously found to reflect spatial and temporal facilitation in visual cortex may reflect the same underlying mechanism. We propose a new unified model to account for these and previous results.

Anesthetic and Obstetric Management of Syringomyelia During Labor and Delivery: A Case Series and Systematic Review.

BACKGROUND: Syringomyelia is a rare, slowly progressive neurological condition characterized by the presence of a syrinx within the spinal cord. Consensus regarding the safest mode of delivery and anesthetic management in patients with syringomyelia remains controversial and presents management dilemmas. This study reviews the cases of syringomyelia at our institution and provides a systematic review of the literature to guide decisions regarding labor and delivery management. METHODS: A retrospective review of cases at our hospital from 2002 to 2014 and a systematic review of the literature from 1946 to 2014 were undertaken. Hospital records and electronic databases were interrogated using International Classification of Diseases, 10th Revision codes and the keywords "syringomyelia," "syringobulbia," and "pregnancy." Data regarding demographics, diagnosis, radiology reports, neurological symptoms, mode of delivery, anesthetic management, and maternal-fetal outcomes were collected. RESULTS: We collected and analyzed data on a total of 43 pregnancies in 39 patients. The most common location for syrinx was in the cervicothoracic region (41.9%). The large majority of patients (n = 34; 87%) demonstrated signs and symptoms associated with syringomyelia before delivery. Syringomyelia associated with Arnold Chiari malformation was documented in 49% (n = 21) cases. General anesthesia was the most commonly used (n = 21/30, 70%) anesthetic technique for cesarean delivery. The majority (n = 9/13, 69%) of patients had an epidural sited for labor analgesia. There were no maternal or neonatal complications associated with neuraxial anesthesia; however, 3 cases (14%) raised concerns regarding general anesthesia including difficult intubation, transient worsening of neurological symptoms postpartum, and prolonged muscle paralysis after atracurium. CONCLUSIONS: Despite concerns regarding aggravation of the syrinx with vaginal delivery, this mode of delivery has never caused any documented long-term worsening of neurological condition. All techniques of anesthesia have been performed successfully without major lasting complications. All cases necessitate patient counseling and individualized multidisciplinary involvement to ensure maternal safety.

Long-term seizure and psychosocial outcomes of vagus nerve stimulation for intractable epilepsy.

Vagus nerve stimulation (VNS) is a widely used adjunctive treatment option for intractable epilepsy. Most studies have demonstrated short-term seizure outcomes, usually for up to 5 years, and thus far, none have reported psychosocial outcomes in adults. We aimed to assess long-term seizure and psychosocial outcomes in patients with intractable epilepsy on VNS therapy for more than 15 years. We identified patients who had VNS implantation for treatment of intractable epilepsy from 1997 to 2013 at our Comprehensive Epilepsy Program and gathered demographics including age at epilepsy onset and VNS implantation, epilepsy type, number of antiepilepsy drugs (AEDs) and seizure frequency before VNS implantation and at the last clinic visit, and the most recent stimulation parameters from electronic medical records (EMR). Phone surveys were conducted by research assistants from May to November 2014 to determine patients' current seizure frequency and psychosocial metrics, including driving, employment status, and use of antidepressants. Seizure outcomes were based on modified Engel classification (I: seizure-free/rare simple partial seizures; II: >90% seizure reduction (SR), III: 50-90% SR, IV: <50% SR; classes I to III (>50% SR)=favorable outcome). A total of 207 patients underwent VNS implantation, 15 of whom were deceased at the time of the phone survey, and 40 had incomplete data for medical abstraction. Of the remaining 152, 90 (59%) were contacted and completed the survey. Of these, 51% were male, with the mean age at epilepsy onset of 9.4 years (range: birth to 60 years). There were 35 (39%) patients with extratemporal epilepsy, 19 (21%) with temporal, 18 (20%) with symptomatic generalized, 5 (6%) with idiopathic generalized, and 13 (14%) with multiple types. Final VNS settings showed 16 (18%) patients with an output current >2 mA and 14 (16%) with rapid cycling. Of the 80 patients with seizure frequency information, 16 (20%) had a modified Engel class I outcome, 14 (18%) had class II, 24 (30%) had class III, and 26 (33%) had class IV. Eighty percent said having VNS was worthwhile. Among the 90 patients, 43 patients were ≥ 18 years old without developmental delay in whom psychosocial outcomes were further analyzed. There was a decrease in the number of patients driving (31% vs 14%, p=0.052) and working (44% vs 35%, p=0.285) and an increase in the number of patients using antidepressant medication (14% vs 28%, p=0.057) at the time of survey compared to before VNS. In this subset, patients with >50% SR (60%) were taking significantly fewer AEDs at the time of survey compared to patients with unfavorable outcomes (median: 3 vs 4, p=0.045). The associations of >50% SR with the psychosocial outcomes of driving, employment, and antidepressant use were not significant, although 77% of this subset said VNS was worthwhile. This is the first study that assesses both seizure and psychosocial outcomes, and demonstrates favorable seizure outcomes of >50% SR in 68% of patients and seizure freedom in 20% of patients. A large majority of patients (80%) considered VNS therapy worthwhile regardless of epilepsy type and psychosocial outcomes.

Long-term seizure and psychosocial outcomes after resective surgery for intractable epilepsy.

Resective surgery is considered an effective treatment for refractory localization-related epilepsy. Most studies have reported seizure and psychosocial outcomes of 2-5 years postsurgery and a few up to 10 years. Our study aimed to assess long-term (up to 15 years) postsurgical seizure and psychosocial outcomes at our epilepsy center. The Henry Ford Health System Corporate Data Store was accessed to identify patients who had undergone surgical resection for localization-related epilepsy from 1993 to 2011. Demographics including age at epilepsy onset and surgery, seizure frequency before surgery, and pathology were gathered from electronic medical records. Phone surveys were conducted from May 2012 to January 2013 to determine patients' current seizure frequency and psychosocial metrics including driving and employment status and use of antidepressants. Surgical outcomes were based on Engel's classification (classes I and II=favorable outcomes). McNemar's tests, chi-square tests, two sample t-tests, and Wilcoxon two sample tests were used to analyze the relationships of psychosocial and surgical outcomes with demographic and surgical characteristics. A total of 470 patients had resective epilepsy surgery, and of those, 50 (11%) had died since surgery. Of the remaining, 253 (60%) were contacted with mean follow-up of 10.6±5.0years (27% of patients had follow-up of 15 years or longer). Of the patients surveyed, 32% were seizure-free and 75% had a favorable outcome (classes I and II). Favorable outcomes had significant associations with temporal resection (78% temporal vs 58% extratemporal, p=0.01) and when surgery was performed after scalp EEG only (85% vs 65%, p<0.001). Most importantly, favorable and seizure-free outcome rates remained stable after surgery over long-term follow-up [i.e., <5 years (77%, 41%), 5-10 years (67%, 29%), 10-15 years (78%, 38%), and >15 years (78%, 26%)]. Compared to before surgery, patients at the time of the survey were more likely to be driving (51% vs 35%, p<0.001) and using antidepressants (30% vs 22%, p=0.013) but less likely to be working full-time (23% vs 42%, p<0.001). A large majority of patients (92%) considered epilepsy surgery worthwhile regardless of the resection site, and this was associated with favorable outcomes (favorable=98% vs unfavorable=74%, p<0.001). The findings suggest that resective epilepsy surgery yields favorable long-term postoperative seizure and psychosocial outcomes.

Analysis of scalp EEG and quantitative MRI in cases of temporal lobe epilepsy requiring intracranial electrographic monitoring.

Abstract Purpose. Contradictory scalp electroencephalographic (sEEG) and discordant imaging features are common in temporal lobe epilepsy (TLE). We assessed the relative importance of sEEG features and their relation to quantitative magnetic resonance (MR) imaging measures in regard to surgical outcome. Methods and materials. Patients with a putative TLE underwent extraoperative electrocorticography (eECoG) with bitemporal subdural electrodes for clarification of the ictogenic source. Patients were categorized by sEEG ictal patterns (IPs) as showing unilateral or bilateral onset. Concordance with the side of resection, as determined by eECoG, to that suggested by the predominant sEEG IP was further analysed as: (a) entirely ipsilateral eECoG IPs with discordant nonelectrographic data; (b) ipsilateral preponderant (> 80%) eECoG IPs; and c) contralateral preponderant (> 80%) eECoG IPs. Quantitative hippocampal volumes and signal characteristics were applied for comparison. Results. Of 26 patients, eECoG confirmed a unilateral IP on sEEG in 19 (73%). Of these 19, exclusively ipsilateral sEEG interical epileptiform discharges (IEDs) were identified in 9 (47%). When bilateral, generalized, absent or contralateral IEDs were found, 6 cases (60%) still showed a preponderantly ipsilateral IP identifying the epileptogenic side. In patients with sEEG bilateral IPs, 5 (71%) also had bilateral IEDs. Of the 16 patients who underwent resection, 14 (87.5%) achieved favourable outcomes and 9 (56%), seizure cessation. Hippocampal volumetry in 23 patients correctly lateralized 7 (30%) whereas fluid-attenuated inversion recovery (FLAIR) signal measures applied in 23 patients lateralized 9 (39%). Conclusions. Favourable surgical outcomes are attainable following eECoG in cases where ambiguity exists regarding the laterality of TLE on sEEG, even for those in whom bilateral IPs and either bilateral or no IEDs are demonstrated on sEEG. Neither volumetric nor FLAIR signal ratios were sufficiently reliable for lateralizing TLE in the majority of cases.

AAN Epilepsy Quality Measures in clinical practice: a survey of neurologists.

Epilepsy Quality Measures (EQM) were developed by the American Academy of Neurology (AAN) to convey standardization and eliminate gaps and variations in the delivery of epilepsy care (Fountain et al., 2011 [1]). The aim of this study was to identify adherence to these measures and other emerging practice standards in epilepsy care. A 15-item survey was mailed to neurologists in Michigan, USA, inquiring about their practice patterns in relation to EQM. One hundred thirteen of the 792 surveyed Michigan Neurologists responded (14%). The majority (83% to 94%) addressed seizure type and frequency, reviewed EEG and MRI, and provided pregnancy counseling to women of childbearing potential. Our survey identified gaps in practice patterns such as counseling about antiepileptic drug (AED) side effects and knowledge about referral for surgical therapy of intractable epilepsy. Statistical significance in the responses on the AAN EQM was noted in relation to number of years in practice, number of epilepsy patients seen, and additional fellowship training in epilepsy. Practice patterns assessment in relation to other comorbidities revealed that although bone health and sudden unexplained death in epilepsy are addressed mainly in patients at risk, depression is infrequently discussed. The findings in this study indicate that additional educational efforts are needed to increase awareness and to improve quality of epilepsy care at various points of health care delivery.

Prolonged postictal hemianopsia after a focal extraoccipital onset seizure.

We report a case of a prolonged postictal hemianopsia occurring after a focal extraoccipital seizure. A 55-year-old man with a history of neurosyphilis, treated with penicillin, presented to our epilepsy monitoring unit (EMU) for diagnostic evaluation of his spells occurring for 2 years. The spell semiology was stereotypical, described as oral and manual automatisms, speech difficulty and unresponsiveness. During the EMU stay, after his typical seizure was recorded, he experienced right hemianopsia lasting for 2 hours. Electrographically, the ictal pattern was prominent over the left temporal derivation and propagated to the left occipital derivation as the seizure progressed. Interictal epileptiform activity was over the left temporal derivations. We support the view that postictal phenomenon may represent merely a seizure termination zone and not be necessarily localising to the seizure onset zone. Furthermore, prolonged isolated postictal symptom of hemianopsia could also be noted in rare situations.

Intubation for Psychogenic Non-Epileptic Attacks: Frequency, Risk Factors, and Impact on Outcome.

PURPOSE: Patients with psychogenic non-epileptic attacks (PNEA) sometimes receive aggressive treatment leading to endotracheal intubation. We sought to identify the frequency, risk factors, and impact on outcome of intubation for PNEA. METHODS: We retrospectively reviewed all PNEA patients admitted via the emergency department (ED) who had an episode of PNEA documented by continuous video electroencephalography (vEEG) at Henry Ford Hospital between January 2012 and October 2017. Patients with comorbid epilepsy were excluded. Clinical features, treatments, and vEEG reports were compared between intubated and non-intubated patients. RESULTS: Of 80 patients who were admitted via the ED and had PNEA documented by vEEG, 12 (15%) were intubated. Compared with non-intubated PNEA patients, intubated patients had longer duration of convulsive symptoms (25 [IQR 7-53] vs 2 [IQR 1-9] minutes, P = 0.01), were less likely to have a normal Glasgow Coma Scale score of 15 (33% vs 94%, P < 0.001), received higher doses of benzodiazepines (30 [IQR 16-45] vs 10 [IQR 5-20] mg of diazepam equivalents, P = 0.004), and were treated with more antiepileptic drugs (AEDs, 2 [IQR 1-3] vs 1 [IQR 1-2], P = 0.01). Hospital length of stay was longer (3 [IQR 3-5] vs 2 [IQR 2-3], P = 0.001), and the rate of complications (25% vs 4%, P = 0.04) and re-hospitalization from a recurrent episode of PNEA within 30 days was higher among intubated PNEA patients (17% vs 0%, P = 0.02). CONCLUSION: Fifteen percent of patients hospitalized for vEEG-documented PNEA were intubated. Intubated patients had longer length of stay, more in-hospital complications, and a high rate of re-hospitalization from recurrent PNEA symptoms. Prolonged duration of convulsive symptoms, depressed level of consciousness, and aggressive treatment with benzodiazepines were associated with intubation for PNEA.

Contribution of Quantitative Amygdalar MR FLAIR Signal Analysis for Lateralization of Mesial Temporal Lobe Epilepsy.

BACKGROUND AND PURPOSE: This study evaluates the contribution of an automated amygdalar fluid-attenuated inversion recovery (FLAIR) signal analysis for the lateralization of mesial temporal lobe epilepsy (mTLE). METHODS: Sixty-nine patients (27 M, 42 F) who had undergone surgery and achieved an Engel class Ia postoperative outcome were identified as a pure cohort of mTLE cases. Forty-six nonepileptic subjects comprised the control group. The amygdala was segmented in T1-weighted images using an atlas-based segmentation. The right/left ratios of amygdalar FLAIR mean and standard deviation were calculated for each subject. A linear classifier (ie, discriminator line) was designed for lateralization using the FLAIR features and a boundary domain, within which lateralization was assumed to be less definitive, was established using the same features from control subjects. Hippocampal FLAIR and volume analysis was performed for comparison. RESULTS: With the boundary domain in place, lateralization accuracy was found to be 70% with hippocampal FLAIR and 67% with hippocampal volume. Taking amygdalar analysis into account, 22% of cases that were found to have uncertain lateralization by hippocampal FLAIR analysis were confidently lateralized by amygdalar FLAIR. No misclassified case was found outside the amygdalar FLAIR boundary domain. CONCLUSIONS: Amygdalar FLAIR analysis provides an additional metric by which to establish mTLE in those cases where hippocampal FLAIR and volume analysis have failed to provide lateralizing information.

Controllable yawning expressed as focal seizures of frontal lobe epilepsy.

Excessive yawning was described in some neurological conditions as part of periictal or ictal manifestations of epilepsy, most commonly temporal lobe. We present the first case of controllable yawning as a primary seizure semiology with dominant frontal lobe involvement in a 20-year-old man. Video electroencephalography recorded 8 yawning episodes accompanied with right arm movement correlating with rhythmic diffuse theta range activity with left hemispheric predominance. Magnetoencephalography coherence source imaging was consistent with persistent neuronal networks with areas of high coherence reliably present over the left lateral orbitofrontal region. Epileptogenic areas may have widespread networks involving the dominant frontal lobe in unique symptomatogenic areas.

DTI-based response-driven modeling of mTLE laterality.

PURPOSE: To develop lateralization models for distinguishing between unilateral and bilateral mesial temporal lobe epilepsy (mTLE) and determining laterality in cases of unilateral mTLE. BACKGROUND: mTLE is the most common form of medically refractory focal epilepsy. Many mTLE patients fail to demonstrate an unambiguous unilateral ictal onset. Intracranial EEG (icEEG) monitoring can be performed to establish whether the ictal origin is unilateral or truly bilateral with independent bitemporal ictal origin. However, because of the expense and risk of intracranial electrode placement, much research has been done to determine if the need for icEEG can be obviated with noninvasive neuroimaging methods, such as diffusion tensor imaging (DTI). METHODS: Fractional anisotropy (FA) was used to quantify microstructural changes reflected in the diffusivity properties of the corpus callosum, cingulum, and fornix, in a retrospective cohort of 31 patients confirmed to have unilateral (n = 24) or bilateral (n = 7) mTLE. All unilateral mTLE patients underwent resection with an Engel class I outcome. Eleven were reported to have hippocampal sclerosis on pathological analysis; nine had undergone prior icEEG. The bilateral mTLE patients had undergone icEEG demonstrating independent epileptiform activity in both right and left hemispheres. Twenty-three nonepileptic subjects were included as controls. RESULTS: In cases of right mTLE, FA showed significant differences from control in all callosal subregions, in both left and right superior cingulate subregions, and in forniceal crura. Comparison of right and left mTLE cases showed significant differences in FA of callosal genu, rostral body, and splenium and the right posteroinferior and superior cingulate subregions. In cases of left mTLE, FA showed significant differences from control only in the callosal isthmus. Significant differences in FA were identified when cases of right mTLE were compared with bilateral mTLE cases in the rostral and midbody callosal subregions and isthmus. Based on 11 FA measurements in the cingulate, callosal and forniceal subregions, a response-driven lateralization model successfully differentiated all cases (n = 54) into groups of unilateral right (n = 12), unilateral left (n = 12), and bilateral mTLE (n = 7), and nonepileptic control (23). CONCLUSION: The proposed response-driven DTI biomarker is intended to lessen diagnostic ambiguity of laterality in cases of mTLE and help optimize selection of surgical candidates. Application of this model shows promise in reducing the need for invasive icEEG in prospective cases.

Intracranial electrographic analysis of preictal spiking and ictal onset in uni- and bitemporal epilepsy.

AIM: Ictal onset patterns in bilateral mesial temporal lobe epilepsy have not been comprehensively studied. A retrospective review of intracranial electrographic data was undertaken to establish whether it is possible to distinguish between unilateral and bilateral mesial temporal lobe epilepsy based on ictal onset patterns, including periodic preictal spiking. METHODS: A total of 470 ictal onset patterns were analyzed by bitemporal extraoperative electrocorticography in 13 patients with medically intractable mesial temporal lobe epilepsy. Ictal onset patterns were categorized, by frequency, as type A (<12 Hz), type B (12-40 Hz) and type C (>40 Hz). Preictal rhythmic spiking, of at least five seconds duration, and time to contralateral propagation were also measured with each ictal event. We determined if the proportion of "ictal onset pattern frequencies" or "incidence of preictal spiking" differed between unilateral and bilateral mesial temporal lobe epilepsy. RESULTS: Seven patients with unilateral mesial temporal lobe epilepsy received surgery and achieved Engel class I outcomes, while the remaining six did not undergo resective surgery, due to the bilateral ictal onsets in extraoperative electrocorticography. The proportion of patients experiencing any preictal spikes was higher in unitemporal than in bitemporal cases (100% vs 50%;p=0.069). Ofthe470 ictal onset patterns analyzed (174 unitemporal and 296 bitemporal), a significant greater percentage of preictal spikes was found in unilateral cases (78% unitemporal vs 14% bitemporal; p=0.002). Low-frequency patterns were more evident in bitemporal cases (45%) than in unitemporal (10%), although the difference was not statistically significant (p=0.129). No differences were detected between the unitemporal and bitemporal groups regarding age at onset or at presentation. CONCLUSION: A greater proportion of pre ictal spiking, based on extraoperative electrocorticography, was present in unilateral, compared to bilateral, mesial temporal lobe epilepsy. Further studies are warranted to determine the causal significance of preictal spiking in mesial temporal lobe epilepsy.