Faculty Bibliography

In memory, our continuous experiences are broken up into discrete events. Boundaries between events are known to influence the temporal organization of memory. However, how and through which mechanism event boundaries shape temporal order memory (TOM) remains unknown. Across four experiments, we show that event boundaries exert a dual role: improving TOM for items within an event and impairing TOM for items across events. Decreasing event length in a list enhances TOM, but only for items at earlier local event positions, an effect we term the local primacy effect. A computational model, in which items are associated to a temporal context signal that drifts over time but resets at boundaries captures all behavioural results. Our findings provide a unified algorithmic mechanism for understanding how and why event boundaries affect TOM, reconciling a long-standing paradox of why both contextual similarity and dissimilarity promote TOM.

OBJECTIVE:Chronic subdural hematoma (CSDH) is a serious problem with an incidence of 20.6/100,000/year in North America and is posited to grow as the population ages. Middle Meningeal Artery (MMA) embolization is an upcoming therapy for treatment of CSDH. Among patients with CSDH who undergo MMA embolization outcomes are no different in patients who resume the antithrombotic (AT) after MMA embolization as compared to patients who don't resume AT. METHODS:We did retrospective review of all cases of MMA embolization in the setting of CSDH done over 2.5 years in 2 centers. Comparison of cases in which AT was resumed vs controls with no AT was performed. A successful outcome was defined as reduction of at least 50% volume in CSDH. Univariate analysis regarding all outcome measures for baseline variables was performed using Fisher exact test or t-test. Multivariate logistic regression with controlling for age, surgical evacuation of the hematoma. RESULTS:There were a total of 56 MMA embolization cases, 33 of them had no AT started and 23 of them had AT resumption at a mean of 2.4 days. About 40% of patients had surgical evacuation done prior to MMA embolization. There was no significant difference in hematoma reduction or volume even after adjusting for surgical evacuation (OR 1.00 95%CI 0.60- 1.67). Patients who had AT resumption had more CAD (71%vs 21% p= 0.001) and Afib (58% vs 18% p=0.002) necessitating AT. CONCLUSION/CONCLUSIONS:AT therapy can be safely resumed in CSDH after MMA embolization as there is no significant difference in CSDH volume reduction and recurrence.

Gait and balance abnormalities develop commonly in Parkinson's disease and are among the motor symptoms most disabling and refractory to dopaminergic or other treatments, including deep brain stimulation. Efforts to develop effective therapies are challenged by limited understanding of these complex disorders. There is a major need for novel and appropriately targeted research to expedite progress in this area. The Scientific Issues Committee of the International Parkinson and Movement Disorder Society has charged a panel of experts in the field to consider the current knowledge gaps and determine the research routes with highest potential to generate groundbreaking data. © 2021 International Parkinson and Movement Disorder Society.

Cytomegalovirus (CMV) disease is usually a mild and self-limiting disease in immunocompetent patients. Recent evidence shows that CMV infection may also develop in the setting of critical illness, burn and sepsis and is usually associated with increased mortality rate and prolonged ICU stay. This paper describes an 83-year-old female who was initially admitted as a case of community-acquired pneumonia-high risk but remained febrile with paucity of verbal output despite correction of pneumonia and other electrolyte derangements. MRI showed the presence of peculiar-appearing signal abnormalities in the interhemispheric region and the anterior frontal convexities which were suspected to represent secondarily infected fluid collections. On lumbar tap, viral cerebrospinal fluid (CSF) panel showed a positive result for CMV infection. The patient was then given ganciclovir for 14 days followed by valganciclovir for three months. The most notable improvement was noted with the lysis of fever several days after starting anti-viral treatment. Verbal output remained limited, yet, on repeat tap after completion of treatment, CMV viral panel is now negative.

Hearing one's own voice is critical for fluent speech production as it allows for the detection and correction of vocalization errors in real time. This behavior known as the auditory feedback control of speech is impaired in various neurological disorders ranging from stuttering to aphasia; however, the underlying neural mechanisms are still poorly understood. Computational models of speech motor control suggest that, during speech production, the brain uses an efference copy of the motor command to generate an internal estimate of the speech output. When actual feedback differs from this internal estimate, an error signal is generated to correct the internal estimate and update necessary motor commands to produce intended speech. We were able to localize the auditory error signal using electrocorticographic recordings from neurosurgical participants during a delayed auditory feedback (DAF) paradigm. In this task, participants hear their voice with a time delay as they produced words and sentences (similar to an echo on a conference call), which is well known to disrupt fluency by causing slow and stutter-like speech in humans. We observed a significant response enhancement in auditory cortex that scaled with the duration of feedback delay, indicating an auditory speech error signal. Immediately following auditory cortex, dorsal precentral gyrus (dPreCG), a region that has not been implicated in auditory feedback processing before, exhibited a markedly similar response enhancement, suggesting a tight coupling between the 2 regions. Critically, response enhancement in dPreCG occurred only during articulation of long utterances due to a continuous mismatch between produced speech and reafferent feedback. These results suggest that dPreCG plays an essential role in processing auditory error signals during speech production to maintain fluency.

OBJECTIVES/OBJECTIVE:To assess whether MR fingerprinting (MRF)-based relaxation properties exhibit cross-sectional and prospective correlations with patient outcome and compare the results with those from DTI. METHODS:from MRF were compared in 12 gray and white matter regions with Mann-Whitney tests. Bivariate associations between MR measures and outcome were assessed using the Spearman correlation and logistic regression. RESULTS:, accounted for five of the six MR measures with the highest utility for identification of non-recovered patients at timepoint 2 (AUC > 0.80). CONCLUSION/CONCLUSIONS:, FA, and ADC for predicting 3-month outcome after mTBI. KEY POINTS/CONCLUSIONS:, and FA.

BACKGROUND:Levetiracetam is commonly used for seizure prophylaxis in patients with intracerebral hemorrhage (ICH), traumatic brain injury (TBI), supratentorial neurosurgery, and spontaneous subarachnoid hemorrhage (SAH). However, its efficacy, optimal dosing, and the adverse events associated with levetiracetam prophylaxis remain unclear. METHODS:A systematic search of PubMed, Embase, and Cochrane central register of controlled trials (CENTRAL) database was conducted from January 1, 2000, to October 30, 2020, including articles addressing treatment with levetiracetam for seizure prophylaxis after SAH, ICH, TBI, and supratentorial neurosurgery. Non-English, pediatric (aged < 18 years), preclinical, reviews, case reports, and articles that included patients with a preexisting seizure condition or epilepsy were excluded. The coprimary meta-analyses examined first seizure events in (1) levetiracetam versus no antiseizure medication and (2) levetiracetam versus other antiseizure medications in all ICH, TBI, SAH, and supratentorial neurosurgery populations. Secondary meta-analyses evaluated the same comparator groups in individual disease populations. Risk of bias in non-randomised studies - of interventions (ROBINS-I) and risk-of-bias tool for randomized trials (RoB-2) tools were used to assess risk of bias. RESULTS: = 39%, P = 0.13 for heterogeneity). There were no significant differences in meta-analyses of patients with ICH, SAH, or TBI. Adverse events of any severity were reported in a median of 8% of patients given levetiracetam compared with 21% of patients in comparator groups. CONCLUSIONS:Based on the current moderately to seriously biased heterogeneous data, which frequently used low and possibly subtherapeutic doses of levetiracetam, our meta-analyses did not demonstrate significant reductions in seizure incidence and neither supports nor refutes the use of levetiracetam prophylaxis in TBI, SAH, or ICH. Levetiracetam may be preferred post supratentorial neurosurgery. More high-quality randomized trials of prophylactic levetiracetam are warranted.

A roundtable convened in July 2020 examined issues concerning respiratory support in amyotrophic lateral sclerosis (ALS), with reference to the potential for an early-phase orally administered medication that might either postpone the introduction of noninvasive ventilation (NIV) and/or enhance the benefits to be gained from it. Attention was also given to the impact of the COVID-19 pandemic on usual practice in the assessment and management of ALS-related respiratory difficulties. Implementation of NIV marks a step-change in clinical status for patients and a major increase in burden for caregivers. All means to ease this transition should be explored: an oral therapy that supported respiratory function and patients' independence and sense of well-being would aid discussions to facilitate the eventual successful introduction of NIV. Assessment of a candidate oral therapy that might support respiratory function in ALS patients would be aided by the development of improved patient-reported outcome measures for robust quantification of treatment effect and quality of life. Such instruments could also be used to monitor patients' status during the COVID-19 pandemic, averting some of the risks of face-to-face assessment plus the patient burden and costs of traditional methods. Several oral candidate therapies have recently failed to meet their primary endpoints in clinical trials. However, understanding of the underlying physiology and appropriate trial design have grown and will inform future developments in this field.

Current therapeutic development in amyotrophic lateral sclerosis (ALS) relies on individual randomized clinical trials to test a specific investigational product in a single patient population. This approach has intrinsic limitations, including cost, time, and lack of flexibility. Adaptive platform trials represent a novel approach to investigate several interventions for a single disease in a continuous manner. Already in use in oncology, this approach is now being employed more often in neurology. Here, we describe a newly launched platform trial for ALS. The Healey ALS Platform Trial is testing multiple investigational products concurrently in people with ALS, with the goal of rapidly identifying novel treatments, biomarkers, and trial endpoints. ANN NEUROL 2022;91:165-175.