Faculty Bibliography

Introduction: About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials within the first year of treatment. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Methods: In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer's disease. We review accumulating evidence linking neurovascular dysfunction with BBB hyperpermeability to primary MDD without neurological comorbidity, and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. Results: Evidence of an association between MDD and neurovascular dysfunction is indirect, deriving primarily from studies assessing peripheral vascular endothelial dysfunction in MDD and from epidemiological data associating MDD with vascular disorders. The relative uptake ratio (RUR) of blood flow after hyperemic challenge has been validated as an index of endothelial function in clinical settings. A prospective cohort showed that the unadjusted mean RUR was significantly lower among 23 participants with MDD and 23 with minor depressive disorder compared with 277 nondepressed controls (P = .001); this effect remained significant after adjusting for age, sex, socioeconomic factors, medical comorbidity, andmedications (P!

There is a lack of consensus regarding how health-care providers should address SUDEP with patients. The purpose of this study was to describe various health-care providers' practices regarding discussion of SUDEP with patients. Separate focus groups were conducted with epileptologists, neurologists, and advanced practice nurses. Across all disciplines, reasons for discussing SUDEP included Practical Accountability, Moral Accountability, Proactivity, and Reactivity. For nurses only, an additional reason was Patient Advocacy. In terms of when not to discuss SUDEP, for all disciplines, and especially the physicians, the theme Not at First emerged. Additional themes that emerged for this question included, in the case of neurologists and epileptologists, Moral Accountability and Out of Options. Ways in which SUDEP is discussed included, in all groups, Discussion and Written Materials. In addition, prevalent in all groups was the finding that procedures for discussing SUDEP with patients and families need to be somewhat standardized. Implications for practice are discussed.

We report 2 pediatric patients who presented initially with seizures followed by subacute language regression characterized by a verbal auditory agnosia. These previously normal children had no evidence of expressive aphasia during their symptomatic periods. Further, in both cases, auditory agnosia was associated with sleep-activated electroencephalographic (EEG) epileptiform activity, consistent with Landau-Kleffner syndrome. However, both cases are unique since the episodic auditory agnosia and sleep-activated EEG epileptiform activity rapidly responded to combination therapy with pulse benzodiazepine and corticosteroids. Further, in each case, recurrences were characterized by similar symptoms, EEG findings, and beneficial responses to the pulse benzodiazepine and corticosteroid therapy. These observations suggest that pulse combination high-dose corticosteroid and benzodiazepine therapy may be especially effective in Landau-Kleffner syndrome.

OBJECTIVE: We examined the complex relationship between depression, anxiety, and seizure control and quality of life (QOL) outcomes after epilepsy surgery. METHODS: Seven epilepsy centers enrolled 373 patients and completed a comprehensive diagnostic workup and psychiatric and follow-up QOL evaluation. Subjects were evaluated before surgery and then at 3, 6, 12, 24, 48, and 60 months after surgery. Standardized assessments included the Quality of Life in Epilepsy Inventory-89, Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI). A mixed-model repeated-measures analysis was used to analyze associations of depression, anxiety, seizure outcome, and seizure history with overall QOL score and QOL subscores (cognitive distress, physical health, mental health, epilepsy-targeted) prospectively. RESULTS: The groups with excellent and good seizure control showed a significant positive effect on the overall QOL compared to the groups with fair and poor seizure control. The BDI and BAI scores were both highly and negatively associated with overall QOL; increases in BDI and BAI scores were associated with decreased overall QOL score. CONCLUSIONS: Depression and anxiety are strongly and independently associated with worse QOL after epilepsy surgery. Interestingly, even partial seizure control, controlling for depression and anxiety levels, improved QOL. Management of mood and anxiety is a critical component to postsurgical care.

OBJECTIVE: Seizures are common in individuals with duplications of chromosome 15q11.2-q13 (Dup15q). The goal of this study was to examine the phenotypes and treatments of seizures in Dup15q in a large population. METHODS: A detailed electronic survey was conducted through the Dup15q Alliance containing comprehensive questions regarding seizures and their treatments in Dup15q. RESULTS: There were 95 responses from Dup15q families. For the 83 with idic(15), 63% were reported to have seizures, of which 81% had multiple seizure types and 42% had infantile spasms. Other common seizure types were tonic-clonic, atonic, myoclonic, and focal. Only 3 of 12 individuals with int dup(15) had seizures. Broad spectrum antiepileptic drugs (AEDs) were the most effective medications, but carbamazepine and oxcarbazepine were also effective, although typical benzodiazepines were relatively ineffective. There was a 24% response rate (>90% seizure reduction) to the first AED tried. For those with infantile spasms, adrenocorticotropic hormone (ACTH) was more effective than vigabatrin. SIGNIFICANCE: This is the largest study assessing seizures in Duplication 15q syndrome, but because this was a questionnaire-based study with a low return rate, it is susceptible to bias. Seizures are common in idic(15) and typically difficult to control, often presenting with infantile spasms and progressing to a Lennox-Gastaut-type syndrome. Seizures in those with int dup(15) are less common, with a frequency similar to the general autism population. In addition to broad spectrum AED, medications such as carbamazepine and oxcarbazepine are also relatively effective in controlling seizures in this population, suggesting a possible multifocal etiology, which may also explain the high rate of infantile spasms. Our small sample suggests a relative lack of efficacy of vigabatrin and other gamma-aminobutyric acid (GABA)ergic medications, such as typical benzodiazepines, which may be attributable to abnormal GABAergic transmission resulting from the duplication of a cluster of GABAbeta3 receptor genes in the 15q11.2-13 region.

OBJECTIVE: Genetic loss of Tsc1/Tsc2 function in tuberous sclerosis complex (TSC) results in altered mammalian target of rapamycin (mTOR) signaling and abnormal brain development. Although earlier studies have focused on characterization of cortical tubers, in this study we sought to examine the unique cellular and molecular features of the perituberal cortex in order to better understand its contribution to epileptogenesis, cognitive dysfunction, and autism. METHODS: Standard histologic and immunohistochemical labeling was used to assess structural abnormalities and cell-specific pattern of mTORC1 activation in surgically resected cortical tubers and perituberal cortex. Western blotting was performed to quantify the expression of the mTORC1 and mTORC2 biomarkers phospho-S6 (Ser235/236), phospho-S6 (Ser240/244), and phospho-Akt (Ser473), in addition to evaluating the differential expression levels of several neuronal and glial-specific proteins in tubers and peritubers, as compared to non-TSC epilepsy specimens. RESULTS: Tubers demonstrated mild to severe disruption of cortical lamination, the presence of pS6-positive dysplastic neurons and giant cells, an overall increase in mTORC1 and a decrease in mTORC2 activity, increased axonal connectivity and growth, and hypomyelination. Perituberal cortex presented similar histologic, immunohistochemical, and molecular features; however, they were overall milder. Axonal growth was specific for TSC and was negatively correlated with deficient myelination. SIGNIFICANCE: Our results show an extension of cellular dysplasia and dysregulated mTOR signaling in the perituberal tissue, and demonstrate for the first time aberrant connectivity in human TSC brain. This study provides new insights into the pathophysiology of neurologic dysfunction associated with TSC and supports the intrinsic epileptogenicity of normal-appearing perituberal cortex.

Historically, the study of speech processing has emphasized a strong link between auditory perceptual input and motor production output. A kind of 'parity' is essential, as both perception- and production-based representations must form a unified interface to facilitate access to higher-order language processes such as syntax and semantics, believed to be computed in the dominant, typically left hemisphere. Although various theories have been proposed to unite perception and production, the underlying neural mechanisms are unclear. Early models of speech and language processing proposed that perceptual processing occurred in the left posterior superior temporal gyrus (Wernicke's area) and motor production processes occurred in the left inferior frontal gyrus (Broca's area). Sensory activity was proposed to link to production activity through connecting fibre tracts, forming the left lateralized speech sensory-motor system. Although recent evidence indicates that speech perception occurs bilaterally, prevailing models maintain that the speech sensory-motor system is left lateralized and facilitates the transformation from sensory-based auditory representations to motor-based production representations. However, evidence for the lateralized computation of sensory-motor speech transformations is indirect and primarily comes from stroke patients that have speech repetition deficits (conduction aphasia) and studies using covert speech and haemodynamic functional imaging. Whether the speech sensory-motor system is lateralized, like higher-order language processes, or bilateral, like speech perception, is controversial. Here we use direct neural recordings in subjects performing sensory-motor tasks involving overt speech production to show that sensory-motor transformations occur bilaterally. We demonstrate that electrodes over bilateral inferior frontal, inferior parietal, superior temporal, premotor and somatosensory cortices exhibit robust sensory-motor neural responses during both perception and production in an overt word-repetition task. Using a non-word transformation task, we show that bilateral sensory-motor responses can perform transformations between speech-perception- and speech-production-based representations. These results establish a bilateral sublexical speech sensory-motor system.

Sensory integration of touch and sight is crucial to perceiving and navigating the environment. While recent evidence from other sensory modality combinations suggests that low-level sensory areas integrate multisensory information at early processing stages, little is known about how the brain combines visual and tactile information. We investigated the dynamics of multisensory integration between vision and touch using the high spatial and temporal resolution of intracranial electrocorticography in humans. We present a novel, two-step metric for defining multisensory integration. The first step compares the sum of the unisensory responses to the bimodal response as multisensory responses. The second step eliminates the possibility that double addition of sensory responses could be misinterpreted as interactions. Using these criteria, averaged local field potentials and high-gamma-band power demonstrate a functional processing cascade whereby sensory integration occurs late, both anatomically and temporally, in the temporo-parieto-occipital junction (TPOJ) and dorsolateral prefrontal cortex. Results further suggest two neurophysiologically distinct and temporally separated integration mechanisms in TPOJ, while providing direct evidence for local suppression as a dominant mechanism for synthesizing visual and tactile input. These results tend to support earlier concepts of multisensory integration as relatively late and centered in tertiary multimodal association cortices.

BACKGROUND:: Surgical resection of epileptic foci relies on accurate localization of the epileptogenic zone, often achieved by subdural and depth electrodes. Our epilepsy center has treated selected children with poorly localized medically refractory epilepsy with a staged surgical protocol, with at least one phase of invasive monitoring for localization and resection of epileptic foci. OBJECTIVE:: To evaluate the safety of staged surgical treatments for refractory epilepsy among children. METHODS:: Data were retrospectively collected, including surgical details and complications of all patients who underwent invasive monitoring. RESULTS:: 161 children underwent 200 admissions including staged procedures (>1 surgery during one hospital admission), and 496 total surgeries. Average age at surgery was 7y (8m-16.5y). 250 surgeries included resections (and invasive monitoring), and 189 involved electrode placement only. Cumulative total number of surgeries per patient was 2-10 (average 3). Average duration of monitoring was 10 days (1-30). There were no deaths. Follow-up ranged from 1m to 10y. Major complications included unexpected new permanent mild neurological deficits (2%/admission), CNS or bone flap infections (1.5%/admission), intracranial hemorrhage, CSF leak, and a retained strip (each 0.5%/admission). Minor complications included bone absorption (5%/admission), positive surveillance sub/epidural cultures in asymptomatic patients (5.5%/admission), non-infectious fever (5%/admission), and wound complications (3%/admission). 30 complications necessitated additional surgical treatment. CONCLUSION:: Staged epilepsy surgery, with invasive electrode monitoring, is safe in children with poorly localized medically refractory epilepsy. The rate of major complications is low, and appears comparable to that associated with other elective neurosurgical procedures.

Object Subependymal giant cell astrocytomas (SEGAs) are benign tumors, most commonly associated with tuberous sclerosis complex (TSC). The vast majority of these tumors arise from the lateral ependymal surface adjacent to the foramen of Monro, therefore potentially encroaching on one or both foramina, and resulting in obstructive hydrocephalus that necessitates surgical decompression. The indications for surgery, intraoperative considerations, and evolution of the authors' management paradigm are presented. Methods Patients with TSC who underwent craniotomy for SEGA resection at New York University Langone Medical Center between January 1997 and March 2011 were identified. Preoperative imaging, clinical characteristics, management decisions, operative procedures, and outcomes were reviewed. Results Eighteen patients with TSC underwent 22 primary tumor resections for SEGAs. The indication for surgery was meaningful radiographic tumor progression in 16 of 21 cases. The average age at the time of operation was 10.3 years. Average follow-up duration was 52 months (range 12-124 months). The operative approach was intrahemispheric-transcallosal in 16 cases, transcortical-transventricular in 5, and neuroendoscopic in 1. Nine tumors were on the right, 9 on the left, and 3 were bilateral. Gross-total resection was documented in 16 of 22 cases in our series, with radical subtotal resection achieved in 4 cases, and subtotal resection (STR) in 2 cases. Two patients had undergone ventriculoperitoneal shunt placement preoperatively and 7 patients required shunt placement after surgery for moderate to severe ventriculomegaly. Two patients experienced tumor progression requiring reoperation; both of these patients had initially undergone STR. Conclusions The authors present their management strategy for TSC patients with SEGAs. Select patients underwent microsurgical resection of SEGAs with acceptable morbidity. Gross-total resection or radical STR was achieved in 90.9% of our series (20 of 22 primary tumor resections), with no recurrences in this group. Approximately half of our patient series required CSF diversionary procedures. There were no instances of permanent neurological morbidity associated with surgery.