Faculty Bibliography

Deep brain stimulation of the subthalamic nucleus is an effective and established therapy for patients with advanced Parkinson's disease improving quality of life, motor symptoms and non-motor symptoms. However, there is a considerable degree of interindividual variability for these outcomes, likely due to variability in electrode placement and stimulation settings. Here, we present probabilistic mapping data from a prospective, open-label, multicentre, international study to investigate the influence of the location of subthalamic nucleus deep brain stimulation on non-motor symptoms in patients with Parkinson's disease. A total of 91 Parkinson's disease patients undergoing bilateral deep brain stimulation of the subthalamic nucleus were included, and we investigated NMSScale, NMSQuestionnaire, Scales for Outcomes in Parkinson's disease-motor examination, -activities of daily living, and -motor complications, and Parkinson's disease Questionnaire-8 preoperatively and at 6-month follow-up after surgery. Leads were localized in standard space using the Lead-DBS toolbox and individual volumes of tissue activated were calculated based on clinical stimulation settings. Probabilistic stimulation maps and non-parametric permutation statistics were applied to identify voxels with significant above or below average improvement for each scale and analysed using the DISTAL atlas. All outcomes improved significantly at follow-up. Significant spatial distribution patterns of neurostimulation were observed for NMSScale total score and its mood/apathy and attention/memory domains. For both domains, voxels associated with below average improvement were mainly located dorsal to the subthalamic nucleus. In contrast, above average improvement for mood/apathy was observed in the ventral border region of the subthalamic nucleus and in its sensorimotor subregion and for attention/memory in the associative subregion. A trend was observed for NMSScale sleep domain showing voxels with above average improvement located ventral to the subthalamic nucleus. Our study provides evidence that the interindividual variability of mood/apathy, attention/memory, and sleep outcomes after subthalamic nucleus deep brain stimulation depends on the location of neurostimulation. This study highlights the importance of holistic assessments of motor and non-motor aspects of Parkinson's disease to tailor surgical targeting and stimulation parameter settings to patients' personal profiles.

OBJECTIVE:To estimate the prevalence of having at least one or two or more chronic health conditions among US adults with self-reported migraine or severe headaches. DESIGN/METHODS:Cross-sectional study. METHODS:Using data collected from the 2013-2015 National Health Interview Survey, we examined adults with and without migraine or severe headache and associations with chronic obstructive pulmonary disease, cancer, heart disease, stroke, diabetes, and hypertension. We calculated point estimates, variances, and 95% confidence intervals and conducted bivariate and multivariable logistic regression modeling to examine the relationships between migraine or severe headache and each of the chronic health conditions, as well as multinomial modeling, to examine the relationship between migraine or severe headache and having one or more chronic health conditions. RESULTS:A total of 104,926 people were in the study. Adults aged 18 to 44 years (18.2%), women (20.1%), and those with some college education (17.6%) had the greatest proportion with migraine or severe headache (P < 0.0001). Using multinomial modeling with the number of chronic health conditions as the dependent variable, adults reporting migraine had an increased odds of reporting a single chronic health condition (adjusted odds ratio [aOR] = 1.7, 95% confidence interval [CI] = 1.6-1.8) and more than double the odds of reporting two or more chronic health conditions (aOR = 2.5, 95% CI = 2.3-2.8) compared with adults who did not have migraine or severe headache. CONCLUSIONS:Our study confirms observed relationships between migraine or severe headache and chronic health conditions and supports the need for further research to uncover the shared biological pathways.

We analyze the role of inhibition in sustaining focal epileptic seizure activity. We review ongoing seizure activity at the mesoscopic scale that can be observed with microelectrode arrays as well as at the macroscale of standard clinical EEG. We provide clinical, experimental, and modeling data to support the hypothesis that paroxysmal depolarization (PD) is a critical component of the ictal machinery. We present dual-patch recordings in cortical cultures showing reduced synaptic transmission associated with presynaptic occurrence of PD, and we find that the PD threshold is cell size related. We further find evidence that optically evoked PD activity in parvalbumin neurons can promote propagation of neuronal excitation in neocortical networks in vitro. Spike sorting results from microelectrode array measurements around ictal wave propagation in human focal seizures demonstrate a strong increase in putative inhibitory firing with an approaching excitatory wave, followed by a sudden reduction of firing at passage. At the macroscopic level, we summarize evidence that this excitatory ictal wave activity is strongly correlated with oscillatory activity across a centimeter-sized cortical network. We summarize Wilson-Cowan-type modeling showing how inhibitory function is crucial for this behavior. Our findings motivated us to develop a network motif of neurons in silico, governed by a reduced version of the Hodgkin-Huxley formalism, to show how feedforward, feedback, PD, and local failure of inhibition contribute to observed dynamics across network scales. The presented multidisciplinary evidence suggests that the PD not only is a cellular marker or epiphenomenon but actively contributes to seizure activity.NEW & NOTEWORTHY We present mechanisms of ongoing focal seizures across meso- and macroscales of microelectrode array and standard clinical recordings, respectively. We find modeling, experimental, and clinical evidence for a dual role of inhibition across these scales: local failure of inhibition allows propagation of a mesoscopic ictal wave, whereas inhibition elsewhere remains intact and sustains macroscopic oscillatory activity. We present evidence for paroxysmal depolarization as a mechanism behind this dual role of inhibition in shaping ictal activity.

OBJECTIVE: Traumatic brain injury (TBI) is the most common cause of death and disability in persons between 15 and 30 years of age. Although various pharmacological agents have been reported to enhance consciousness recovery, few trials have studied these medications in patients with acute TBI. The objective of this study was to determine the effect of modafinil, methylphenidate, amantadine, and zolpidem in improving wakefulness in patients with TBI in an intensive care unit (ICU) setting and to identify any adverse drug reactions. METHODS: Retrospective chart review identified all patients prescribed modafinil, methylphenidate, amantadine, or zolpidem; only patients older than 18 years with TBI in an ICU setting were further analyzed. The electronic medical record was used to retrieve clinical data including patient demographics, mechanism of TBI, drug dosage, treatment duration, Glasgow Coma Scale (GCS) score, length of time to improve GCS score, hospital length of stay, reported adverse drug reactions associated with above medications, and mortality. The primary outcome was the rate of positive response in the clinical neurological exam. Secondary outcomes included change in baseline and final GCS score, time to response, duration of treatment, change in GCS score over time, length of hospital stay, and in-hospital mortality. Descriptive statistics were used to analyze the data. RESULTS: The final analysis included a total of 53 patients. Median ages ranged from 44.0 to 61.5 years; 85% of patients were male. Baseline median GCS score was 8.0 in the amantadine group; 6.5, modafinil; 7.5, methylphenidate; and 7.0, zolpidem. The highest positive response rate was 90% in the amantadine group, followed by modafinil, 77%; methylphenidate, 50%; and zolpidem, 36%. The change in baseline GCS score and median final GCS score for amantadine, modafinil, methylphenidate, and zolpidem was 2.5, 3.0, 1.0, and 0, respectively (P = 0.20). The median time to response in days was 1.5, 1.0, 0.5, and 1.0, respectively. Change in GCS score over time for amantadine, modafinil, methylphenidate, and zolpidem was 0.16, 0.38, 0.12, and 0, respectively. Though rare, the most common adverse events were agitation, hypertension, and posturing. CONCLUSION: It remains to be determined if these medications have a role in reducing ICU and hospital length of stay, length of mechanical ventilation, tracheostomies, and overall medical costs in managing TBI patients. In our study amantadine was associated with the highest overall positive response rate when used as an awakening agent in TBI. Modafinil was associated with the largest change in GCS score over time.

Application of molecular neuroimaging using positron emission tomographic techniques to assess pediatric neurodegenerative disorders has been limited, unlike in adults where positron emission tomography has contributed to clinical diagnosis, monitoring of neurodegenerative disease progression, and assessment of novel therapeutic approaches. Yet, there is a huge unexplored potential of molecular imaging to improve our understanding of the pathophysiology of neurodegenerative disorders in children and provide radiological biomarkers that can be applied clinically. The obstacles in performing PET scans on children include sedation, radiation exposure, and access but, as will be illustrated, these barriers can be easily overcome. In this review, we summarize findings from PET studies that have been performed over the past three decades on children with various neurodegenerative disorders, including the neuronal ceroid lipofuscinoses, juvenile Huntington disease, Wilson disease, Niemann-Pick disease type C, Dravet syndrome, dystonia, mitochondrial disorders, inborn errors of metabolism, lysosomal storage diseases, dysmyelinating disorders, Rett syndrome, neurotransmitter disorders, glucose transporter Glut 1 deficiency, and Lesch-Nyhan disease. Because positron emission tomographic scans have often been clinically useful and have contributed to the management of these disorders, we suggest that the time has come for glucose metabolism positron emission tomographic scans to be reimbursed by insurance carriers for children with neurodegenerative disorders, and not restricted only to epilepsy surgery evaluation.

Myelin has traditionally been considered a static structure that is produced and assembled during early developmental stages. While this characterization is accurate in some contexts, recent studies have revealed that oligodendrocyte generation and patterns of myelination are dynamic and potentially modifiable throughout life. Unique structural and biochemical properties of the myelin sheath provide opportunities for the development and implementation of multimodal label-free and fluorescence optical imaging approaches. When combined with genetically encoded fluorescent tags targeted to distinct cells and subcellular structures, these techniques offer a powerful methodological toolbox for uncovering mechanisms of myelin generation and plasticity in the live brain. Here, we discuss recent advances in these approaches that have allowed the discovery of several forms of myelin plasticity in developing and adult nervous systems. Using these techniques, long-standing questions related to myelin generation, remodeling, and degeneration can now be addressed.

OBJECTIVE:Review the effect of orthostatic hypotension (OH) and rapid-eye-movement sleep behavioural disorder (RBD) on survival, cognitive impairment and postural stability, and discuss pathogenic mechanisms involved in the association of these two common non-motor features with relevant clinical outcomes in α-synucleinopathies. METHODS:We searched PubMed (January 2007-February 2019) for human studies of OH and RBD evaluating cognitive impairment, postural instability, and survival in Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA) and pure autonomic failure (PAF). Included studies were analysed for design, key results and limitations as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS:OH and RBD showed a positive association with cognitive impairment in PD and DLB, conflicting association in PAF, and no association in MSA. OH was correlated with incident falls and postural instability in PD and DLB but not in MSA. The association between RBD and postural instability was inconclusive; positive in five studies, negative in seven. OH, but not RBD, correlated with reduced survival in PD, DLB and MSA. The combination of OH and RBD was associated with cognitive impairment and more rapid progression of postural instability. CONCLUSIONS:OH and RBD yielded individual and combined negative effects on disability in α-synucleinopathies, reflecting a 'malignant' phenotype of PD with early cognitive impairment and postural instability. Underlying mechanisms may include involvement of selected brainstem cholinergic and noradrenergic nuclei.

H3 K27M-mutant gliomas often manifest as midline gliomas, have a dismal prognosis, and have no established or effective treatments at recurrence. ONC201 is the first clinical bitopic DRD2 antagonist/ClpP agonist and is under evaluation in Phase II trials for gliomas and other cancers. We previously reported in vitro studies suggesting dysregulated dopamine receptor expression and enhanced ONC201 sensitivity among H3 K27Mmutant gliomas. Following these observations, adults with midline H3 K27M-mutant glioma patients were enrolled to a dedicated Phase II clinical trial (NCT03295396), a multi-arm Phase II trial (NCT0252569), and expanded access protocols under the Sponsor's IND. An integrated radiographic analysis with an objective response rate primary endpoint in patients who received ONC201 monotherapy with confirmed H3 K27M-mutant glioma (not primarily in the pons or spinal cord and without leptomeningeal spread) that was progressive and measurable disease by RANO criteria, >90 days from completion of prior radiation, and had KPS >60. As of December 15, 2018, 15 patients have received single agent ONC201 who meet these criteria (n=9 NCT03295396; n=5 NCT0252569; n=1 expanded access). ONC201 was orally administered at 625 mg weekly, except for one patient dosed once every 3 weeks. As midline gliomas can exhibit a mixture of contrast-enhancing and non-contrast-enhancing disease, objective response was assessed by blinded independent central review using RANO-HGG and RANO-LGG criteria for each patient. Best response to date by RANO-HGG criteria is at least 27%: 1 CR, 3 PR, 7 SD, and 4 PD; by RANO-LGG is at least 36%: 1 CR, 1 PR, 3 minor response (MR), 4 SD, 5 PD, 1 unevaluable. By RANO-HGG, median onset of response is 2.6 months (range 1.3-3.4); median duration of response has not been reached with a median follow-up of 7.7 months (range 1.8-29.8). Updated radiographic response, pharmacodynamics, safety, and other clinical outcomes will be reported

AIM/OBJECTIVE:To assess the accuracy of consumer available wrist-based and hip-based activity trackers in quantitatively measuring ambulation in children with cerebral palsy (CP). METHOD/METHODS:Thirty-nine children (23 males, 16 females; mean age [SD] 9y 7mo [3y 5mo]; range 4-15y) with CP were fitted with trackers both on their wrist and hip. Each participant stood for 3 minutes, ambulated in a hallway, and sat for 3 minutes. The number of steps and distance were recorded on trackers and compared to manually counted steps and distance. Pearson correlation coefficients were determined for the number of steps during ambulation from each tracker and a manual count. Mean absolute error (MAE) and range of errors were calculated for steps during ambulation for each tracker and a manual count and for distance for each tracker and hallway distance. RESULTS:For the number of steps, a weak inverse relationship (r=-0.033) was found for the wrist-based tracker and a strong positive relationship (r=0.991) for the hip-based tracker. The MAE was 88 steps for the wrist-based and seven steps for the hip-based tracker. The MAE for distance was 0.06 miles for the wrist-based and 0.07 miles for the hip-based tracker. INTERPRETATION/CONCLUSIONS:Only the hip-based tracker provided an accurate step count; neither tracker was accurate for distance. Thus, ambulation of children with CP can be accurately quantified with readily available trackers.