Faculty Bibliography

The two most common types of temporal lobe epilepsy are medial temporal sclerosis epilepsy (TLE-MTS) and MRI-normal temporal lobe epilepsy (TLE-no). TLE-MTS is specified by its stereotyped focus and spread pattern of neuronal damage, with pronounced neuronal loss in the hippocampus. TLE-no exhibits normal-appearing hippocampus and more widepsread neuronal loss. In both cases neuronal loss spread appears to be constrained by the white matter connections. Both varieties of epilepsy reveal pathological abnormalities in increased mean diffusivity (MD). We model MD distribution as a simple consequence of the propagation of neuronal damage. By applying this model on the structural brain connectivity network of healthy subjects we can predict at group level the mean diffusivity gray matter change in the epilepsy cohorts relative to a control group. DTI images were acquired from 10 patients with TLE-MTS, 11 patients with TLE-no, and 35 healthy subjects. Statistical validation at the group level suggests high correlation with measured neuronal loss (R = 0.56 for the TLE-MTS group and R = 0.364 for the TLE-no group). The results of this exploratory work pave the way for potential future clinical application of the proposed model on individual patients, including predicting neuronal loss spread, identification of seizure onset zones, and helping in surgical planning.

INTRODUCTION: Tuberous Sclerosis Complex (TSC) has an incidence of 1/6,000 in the general population. Overall care may be very complex and costly. We examine trends in healthcare utilization and outcomes of TSC patients over the last decade. METHODS: The National Inpatient Sample (NIS) database for inpatient hospitalizations was searched for admission of patients with TSC. RESULTS: During 2000-2010, the NIS captured 5655 TSC patients. The majority patients were admitted to teaching hospitals (71.7%). Over time, the percentage of craniotomies performed per year remained stable (p = 0.351). Relevant diagnoses included neuro-oncologic pathology (5.4%), hydrocephalus (6.5%), and epilepsy (41.2%). Hydrocephalus significantly increased length of stay and hospital charges. A higher percentage of patients who underwent craniotomy had hydrocephalus (29.8% versus 5.3%; p < 0.001), neuro-oncologic pathology (43.5% versus 3.4%; p < 0.001), other cranial pathologies (4.2% versus 1.2%; p < 0.001), and epilepsy (61.4% versus 40.1%; p < 0.001). CONCLUSION: Our study identifies aspects of inpatient healthcare utilization, outcomes, and cost of a large number of patients with TSC. These aspects include related diagnoses and procedures that contribute to longer length of stay, increased hospital cost, and increased in-hospital mortality, which can inform strategies to reduce costs and improve care of patients with TSC.

BACKGROUND: Mutations in the KIAA2022 gene have been reported in male patients with X-linked intellectual disability, and related female carriers were unaffected. Here, we report 14 female patients who carry a heterozygous de novo KIAA2022 mutation and share a phenotype characterised by intellectual disability and epilepsy. METHODS: Reported females were selected for genetic testing because of substantial developmental problems and/or epilepsy. X-inactivation and expression studies were performed when possible. RESULTS: All mutations were predicted to result in a frameshift or premature stop. 12 out of 14 patients had intractable epilepsy with myoclonic and/or absence seizures, and generalised in 11. Thirteen patients had mild to severe intellectual disability. This female phenotype partially overlaps with the reported male phenotype which consists of more severe intellectual disability, microcephaly, growth retardation, facial dysmorphisms and, less frequently, epilepsy. One female patient showed completely skewed X-inactivation, complete absence of RNA expression in blood and a phenotype similar to male patients. In the six other tested patients, X-inactivation was random, confirmed by a non-significant twofold to threefold decrease of RNA expression in blood, consistent with the expected mosaicism between cells expressing mutant or normal KIAA2022 alleles. CONCLUSIONS: Heterozygous loss of KIAA2022 expression is a cause of intellectual disability in females. Compared with its hemizygous male counterpart, the heterozygous female disease has less severe intellectual disability, but is more often associated with a severe and intractable myoclonic epilepsy.

Introduction: The role of sleep in learning and memory has gained significant attention in cognitive neuroscience. We report our experience with a healthy subject population at a sleep research center. Methods: We recruited subjects for a daytime nap and overnight sleep study by advertising at an urban university over one year. Subjects were eligible if aged 18 to 35, English-speaking, and scored above 26 on the Montreal Cognitive Assessment (MOCA). They were excluded for any diagnosis of a neurologic or psychiatric disorder, including a sleep disorder (as identified by the insomnia symptom questionnaire, STOP-BANG, and Morningness-Eveningness scale); used psychoactive medications, alcohol or recreational drugs; or recent travel across time zones. Subjects participated in cognitive tasks and slept with simultaneous EEG-PSG, which was scored by a board-certified sleep neurologist. Results: We obtained 40 nap studies and 20 nighttime studies. Screening questionnaires identified eligible subjects with a low risk of insomnia (0.22 +/- 0.52), low r isk of sleep apnea (0.82 +/- 0.75), and inter mediate ci rcadian preferences (47.15 +/- 0.75). There was a wide var iance in sleep efficiency (0.68 +/- 0.29) and total sleep time (TST, 69.86 +/- 33.78 min) during naps; with less variance seen during nocturnal studies (SD 0.84 +/- 0.08; TST 454.13 +/- 45.0 min). Three (15%) nap subjects demonstrated excessive daytime REM. Two nap subjects (5%) and three (15%) nighttime subjects were diagnosed with OSA. One nap subject (2.5%) and two nighttime subjects (10%) were diagnosed with periodic limb movements of sleep (PLMS). Conclusion: Our experience with a healthy subject population suggests a wide variance in daytime sleep behavior and a notable prevalence of sleep disorders such as OSA, PLMS, and excessive daytime REM. These variables should be considered in planning and analysis of sleep and cognition studies

The neural mechanisms that support working memory (WM) depend on persistent neural activity. Within topographically organized maps of space in dorsal parietal cortex, spatially selective neural activity persists during WM for location. However, to date the necessity of these topographic subregions of human parietal cortex for WM remain unknown. To test the causal relationship of these areas to WM, we compared the performance of patients with lesions to topographically organized parietal cortex to controls on a memory-guided saccade (MGS) task as well as a visually-guided saccade (VGS) task. The MGS task allowed us to measure WM precision continuously with great sensitivity, while the VGS task allowed us to control for any deficits in general spatial or visuomotor processing. Compared to controls, patients generated memory-guided saccades that were significantly slower and less accurate, while visually-guided saccades were unaffected. These results provide key missing evidence for the causal role of topographic areas in human parietal cortex for WM, as well as the neural mechanisms supporting WM.

INTRODUCTION: Perampanel is an AMPA receptor antagonist recently approved for the treatment of partial and generalized epilepsies with tonic-clonic seizures as an add-on therapy. METHODS: This single-center postmarketing study retrospectively evaluated the efficacy of perampanel in patients with partial onset and other seizure types, with a special emphasis on its efficacy, safety, and tolerability. RESULTS: Review of medical records revealed that adequate data were available on 101 patients taking perampanel. Fifty-seven patients were female. Sixteen patients were of pediatric age range. The average dose of perampanel was 6.5mg, and average treatment duration was 8.2months. After treatment, median seizure frequency reduction was 50% overall, 50% in children, and 33% in adults; 44% in primary generalized, 38% in secondarily generalized, and 33% in partial seizures. Responder rate (50% seizure frequency reduction) was 51% overall, 63% in children, and 49% in adults; 60% in partial seizures, 43% in secondarily generalized tonic-clonic seizures, 53% in primary generalized tonic-clonic seizures, and 56% in other seizure types. Seizure freedom was attained in 6% of cases. Most common adverse events were sleepiness/fatigue (35%), behavioral problems (30%), and dizziness (22%). Adverse events were correlated with dosage. Average dose was 7.3mg in patients with adverse events vs. 5.5mg in those without adverse events. Patients who developed fatigue, cognitive decline, headaches, and weight gain were more likely to discontinue perampanel than those patients who experienced coordination issues and behavioral problems. CONCLUSIONS: These findings suggest that perampanel is safe, well-tolerated, and effective in treatment of various types of adult and pediatric epilepsy syndromes. Fatigue, cognitive decline, headache and weight gain were the main causes of perampanel discontinuation.

Interactions between the hippocampus and the cortex are critical for memory. Interictal epileptiform discharges (IEDs) identify epileptic brain regions and can impair memory, but the mechanisms by which they interact with physiological patterns of network activity are mostly undefined. We show in a rat model of temporal lobe epilepsy that spontaneous hippocampal IEDs correlate with impaired memory consolidation, and that they are precisely coordinated with spindle oscillations in the prefrontal cortex during nonrapid-eye-movement (NREM) sleep. This coordination surpasses the normal physiological ripple-spindle coupling and is accompanied by decreased ripple occurrence. IEDs also induce spindles during rapid-eye movement (REM) sleep and wakefulness-behavioral states that do not naturally express these oscillations-by generating a cortical 'down' state. In a pilot clinical examination of four subjects with focal epilepsy, we confirm a similar correlation of temporofrontal IEDs with spindles over anatomically restricted cortical regions. These findings imply that IEDs may impair memory via the misappropriation of physiological mechanisms for hippocampal-cortical coupling, which suggests a target for the treatment of memory impairment in epilepsy.

OBJECTIVE: To describe the phenomenology of monitored sudden unexpected death in epilepsy (SUDEP) occurring in the interictal period where death occurs without a seizure preceding it. METHODS: We report a case series of monitored definite and probable SUDEP where no electroclinical evidence of underlying seizures was found preceding death. RESULTS: Three patients (two definite and one probable) had SUDEP. They had a typical high SUDEP risk profile with longstanding intractable epilepsy and frequent generalized tonic-clonic seizures (GTCS). All patients had varying patterns of respiratory and bradyarrhythmic cardiac dysfunction with profound electroencephalography (EEG) suppression. In two patients, patterns of cardiorespiratory failure were similar to those seen in some patients in the Mortality in Epilepsy Monitoring Units Study (MORTEMUS). SIGNIFICANCE: SUDEP almost always occur postictally, after GTCS and less commonly after a partial seizure. Monitored SUDEP or near-SUDEP cases without a seizure have not yet been reported in literature. When nonmonitored SUDEP occurs in an ambulatory setting without an overt seizure, the absence of EEG information prevents the exclusion of a subtle seizure. These cases confirm the existence of nonseizure SUDEP; such deaths may not be prevented by seizure detection-based devices. SUDEP risk in patients with epilepsy may constitute a spectrum of susceptibility wherein some are relatively immune, death occurs in others with frequent GTCS with one episode of seizure ultimately proving fatal, while in others still, death may occur even in the absence of a seizure. We emphasize the heterogeneity of SUDEP phenomena.

Sudden unexpected death in epilepsy (SUDEP) is the most common cause of epilepsy-related mortality. We hypothesized that electrocardiography (ECG) features may distinguish SUDEP cases from living subjects with epilepsy. Using a matched case-control design, we compared ECG studies of 12 consecutive cases of SUDEP over 10 years and 22 epilepsy controls matched for age, sex, epilepsy type (focal, generalized, or unknown/mixed type), concomitant antiepileptic, and psychotropic drug classes. Conduction intervals and prevalence of abnormal ventricular conduction diagnosis (QRS >/=110 msec), abnormal ventricular conduction pattern (QRS <110 msec, morphology of incomplete right or left bundle branch block or intraventricular conduction delay), early repolarization, and features of inherited cardiac channelopathies were assessed. Abnormal ventricular conduction diagnosis and pattern distinguished SUDEP cases from matched controls. Abnormal ventricular conduction diagnosis was present in two cases and no controls. Abnormal ventricular conduction pattern was more common in cases than controls (58% vs. 18%, p = 0.04). Early repolarization was similarly prevalent in cases and controls, but the overall prevalence exceeded that of published community-based cohorts.

PURPOSE: To ascertain the cause of mortality and incidence of sudden unexpected death in epilepsy (SUDEP) in patients with supernumerary isodicentric chromosome 15 (idic15). METHODS: Cases were obtained from those reported to the Dup15q Alliance (www.dup15q.org) between April 2006 and June 2012; ~709 families were registered in their database. We performed a case-control study comparing reported SUDEP cases to living patients with epilepsy from the Dup15q Alliance registry who volunteered to be interviewed to examine clinical risk factors. KEY FINDINGS: There were nineteen deaths with idic15; 17 had epilepsy, and nine deaths were due to probable or definite SUDEP (4 females, median age of death was 13.5years, range: 3-26years). Possible SUDEP occurred in 2 others. The remainder died from status epilepticus (3), pneumonia (3), aspiration (1), and drowning (1). Nonambulatory status and lack of seizure control were more common among SUDEP cases than living dup15q patients. SIGNIFICANCE: Our findings suggest that SUDEP is a common cause of death among children and young adults with isodicentric chromosome 15q11.2q13 duplications and patients with the most severe neurologic dysfunction may be at highest risk. Further studies are needed to examine if this specific genetic defect plays a role in the mechanism of SUDEP in these patients.