Faculty Bibliography

Frequency and outcomes of mechanical thrombectomy (MT) in clinical practice for patients with severe pre-stroke disability are largely unknown. In this case series, we aim to describe the disability make-up and outcomes of 33 patients with severe pre-stroke disability undergoing MT. Patients with a permanent, severe, pre-stroke disability (modified Rankin Score, mRS, 4-5) were identified from a prospectively-maintained database of consecutive, MT-treated, anterior circulation acute ischemic stroke patients at two comprehensive stroke centers in the United States. We present details on the cause of disability and socio-demographic status as well as procedural and functional outcomes. This study, despite the lack of inferential testing due to limited sample size, provides insight into demographics and outcomes of MT-treated patients with severe pre-stroke disability. Rate of return to functional baseline as well as rates of procedural success and complications were comparable to that reported in the literature for patients without any pre-existing disability.

Background/UNASSIGNED:care could improve our understanding of disease progression, treatment options, and unmet needs in this vulnerable population, and whether such a model could mitigate decline in QoL. Methods/UNASSIGNED:Patients with PD meeting Medicare homebound criteria were eligible for quarterly interdisciplinary home visits over 12 months. Each visit entailed an evaluation by a movement disorders neurologist, social worker, and nurse, including history, examination, medication reconciliation, psychosocial evaluation, pharmacologic and nonpharmacologic management, and service referrals. Disease severity, as measured by the Unified Parkinson's Disease Rating Scale (UPDRS), and QoL using the Neuro-QoL were measured at visits 1 and 4. Results/UNASSIGNED:= 0.19-0.95). Conclusions/UNASSIGNED:Homebound individuals with advanced PD receiving interdisciplinary home visits experienced no significant decline in QoL over 1 year, despite disease progression. Our findings highlight the disease severity and impaired QoL of the advanced, homebound PD population, and the potential for novel approaches to foster continuity of care.

Patients, clinicians, and hospitals have undergone monumental changes during the COVID-19 pandemic. This time of troubles has forced us to consider the fundamental obligations that neurologists have to our own individual patients as well as the greater community. By returning to our fundamental understanding of these duties we can ensure that we are providing the most ethically appropriate contingency and crisis care possible. We recommend specific adaptations to both the inpatient and outpatient settings, as well as changes to medical and trainee education. Furthermore, we explore the daunting but potentially necessary implementation of scare resource allocation protocols. As the pandemic evolves, we will need to adapt continuously to these rapidly changing circumstances and consider both national and regional standards and variation.

BACKGROUND:In Parkinson's disease (PD), impulsive-compulsive behaviors (ICBs) may develop as side-effect of dopaminergic medications. Abnormal incentive-driven decision-making, which is supported by the cognitive control and motivation interaction, may represent an ICBs signature. This systematic review explored whether structural and/or functional brain differences between PD patients with vs without ICBs encompass incentive-driven decision-making networks. METHODS:Structural and functional neuroimaging studies comparing PD patients with and without ICBs, either de novo or medicated, were included. RESULTS:Thirty articles were identified. No consistent evidence of structural alteration both in de novo and medicated PD patients were found. Differences in connectivity within the default mode, the salience and the central executive networks predate ICBs development and remain stable once ICBs are fully developed. Medicated PD patients with ICBs show increased metabolism and cerebral blood flow in orbitofrontal and cingulate cortices, ventral striatum, amygdala, insula, temporal and supramarginal gyri. Abnormal ventral striatum connectivity with anterior cingulate cortex and limbic structures was reported in PD patients with ICBs. DISCUSSION/CONCLUSIONS:Functional brain signatures of ICBs in PD encompass areas involved in cognitive control and motivational encoding networks of the incentive-driven decision-making. Functional alterations predating ICBs may be related to abnormal synaptic plasticity in these networks.

OBJECTIVE:Understanding barriers and facilitators to engaging with implementation science (IS) research can provide insight into how to improve efforts to encourage more researchers to participate in IS research. STUDY DESIGN/METHODS:The study design used is a grounded theory qualitative study. METHODS:We conducted semistructured telephone interviews with 20 health researchers familiar with IS that both report engaging in IS research and those that do not. We explored perceptions of barriers and facilitators to engaging in IS research. Themes surrounding difficulties defining IS, lack of training availability, and obstacles to forming research partnerships were discussed as barriers to engaging IS research. Interview topics were informed by the result of an online survey of health researchers in the US. RESULTS:Themes surrounding difficulties defining IS, lack of training availability, and obstacles to forming research partnerships were discussed as barriers to engaging IS research. While accessible mentorship, exposure to formative experiences that develop interest in IS research and an increasing IS visibility were described as motivators for engaging in IS research. CONCLUSIONS:These results highlight the importance of mentorship and exposure to IS ideas in motivating engagement in IS research and the presence of training and methodological barriers to engagement. Future research should expand this line of inquiry to include the perspectives of more junior researchers and students to better reflect the current IS environment.

The paranodal junctions flank mature nodes of Ranvier and provide a barrier between ion channels at the nodes and juxtaparanodes. These junctions also promote node assembly and maintenance by mechanisms that are poorly understood. Here, we examine their role in the accumulation of NF186, a key adhesion molecule of PNS and CNS nodes. We previously showed NF186 is initially targeted/accumulates via its ectodomain to forming PNS (hemi)nodes by diffusion trapping whereas it is later targeted to mature nodes by a transport-dependent mechanism mediated by its cytoplasmic segment. To address the role of the paranodes in this switch, we compared accumulation of NF186 ectodomain and cytoplasmic domain constructs in wild type vs. paranode defective, i.e. Caspr-null mice. Both pathways are affected in the paranodal mutants. In the PNS of Caspr-null mice, diffusion trapping mediated by the NF186 ectodomain aberrantly persists into adulthood whereas the cytoplasmic domain/transport-dependent targeting is impaired. In contrast, accumulation of NF186 at CNS nodes does not undergo a switch - it is predominantly targeted to both forming and mature CNS nodes via its cytoplasmic domain and requires intact paranodes. FRAP analysis indicates the paranodes provide a membrane diffusion barrier that normally precludes diffusion of NF186 to nodes. Linkage of paranodal proteins to the underlying cytoskeleton likely contributes to this diffusion barrier based on 4.1B and βII spectrin expression in Caspr-null mice. Together, these results implicate the paranodes as membrane diffusion barriers that regulate targeting to nodes and highlight differences in the assembly of PNS and CNS nodes.SIGNIFICANCE STATEMENTNodes of Ranvier are essential for effective saltatory conduction along myelinated axons. A major question is how the various axonal proteins that comprise the multimeric nodal complex accumulate at this site. Here we examine how targeting of NF186, a key nodal adhesion molecule, is regulated by the flanking paranodal junctions. We show the transition from diffusion-trapping to transport-dependent accumulation of NF186 requires the paranodal junctions. We also demonstrate that these junctions are a barrier to diffusion of axonal proteins into the node and highlight differences in PNS and CNS node assembly. These results provide new insights into the mechanism of node assembly and the pathophysiology of neurological disorders in which impaired paranodal function contributes to clinical disability.

OBJECTIVE:To identify similarities and differences in protocols on determination of brain death/death by neurologic criteria (BD/DNC) around the world. METHODS:We collected and reviewed official national BD/DNC protocols from contacts around the world between January 2018 and April 2019. RESULTS:We communicated with contacts in 136 countries and found that 83 (61% of countries with contacts identified, 42% of the world) had BD/DNC protocols, 78 of which were unique. Protocols addressed the following prerequisites and provided differing instructions: drug clearance (64, 82%), temperature (61, 78%), laboratory values (56, 72%), observation period (37, 47%), and blood pressure (34, 44%). Protocols did not consistently identify the same components for the clinical examination of brain death; 70 (90%) included coma, 70 (90%) included the pupillary reflex, 68 (87%) included the corneal reflex, 67 (86%) included the oculovestibular reflex, 64 (82%) included the gag reflex, 62 (79%) included the cough reflex, 58 (74%) included the oculocephalic reflex, 37 (47%) included noxious stimulation to the face, and 22 (28%) included noxious stimulation to the limbs. Apnea testing was mentioned in 71 (91%) protocols; there was variability in the technique and target across protocols. Ancillary testing was included as a requirement for all determinations of BD/DNC in 22 (28%) protocols. CONCLUSIONS:There is considerable variability in BD/DNC determination protocols around the world. Medical standards for death should be the same everywhere. We recommend that a worldwide consensus be reached on the minimum standards for BD/DNC.