Faculty Bibliography

Responsive neurostimulation is increasingly required to probe neural circuit function and treat neuropsychiatric disorders. We introduce a multiplex-then-amplify (MTA) scheme that, in contrast to current approaches (which necessitate an equal number of amplifiers as number of channels), only requires one amplifier per multiplexer, significantly reducing the number of components and the size of electronics in multichannel acquisition systems. It also enables simultaneous stimulation of arbitrary waveforms on multiple independent channels. We validated the function of MTA by developing a fully implantable, responsive embedded system that merges the ability to acquire individual neural action potentials using conformable conducting polymer-based electrodes with real-time onboard processing, low-latency arbitrary waveform stimulation, and local data storage within a miniaturized physical footprint. We verified established responsive neurostimulation protocols and developed a network intervention to suppress pathological coupling between the hippocampus and cortex during interictal epileptiform discharges. The MTA design enables effective, self-contained, chronic neural network manipulation with translational relevance to the treatment of neuropsychiatric disease.

Despite being cognitively intact, patients with Guillain Barre Syndrome are often unable to communicate. Because of this, goals-of-care decisions may need to be made by family members/surrogates. Here, I describe a patient with Guillain Barre Syndrome whose voice was initially stifled by dysarthria, then hypophonia, then intubation, but who ultimately managed to express herself and convey her wishes regarding goals-of-care.

The hippocampus is one of the most challenging brain regions for proton MR spectroscopy (MRS) applications. Moreover, quantification of J-coupled species such as myo-inositol (m-Ins) and glutamate + glutamine (Glx) is affected by the presence of macromolecular background. While long echo time (TE) MRS eliminates the macromolecules, it also decreases the m-Ins and Glx signal and, as a result, these metabolites are studied mainly with short TE. Here, we investigate the feasibility of reproducibly measuring their concentrations at a long TE of 120 ms, using a semi-adiabatic localization by adiabatic selective refocusing (sLASER) sequence, as this sequence was recently recommended as a standard for clinical MRS. Gradient offset-independent adiabatic refocusing pulses were implemented, and an optimal long TE for the detection of m-Ins and Glx was determined using the T₂ relaxation times of macromolecules. Metabolite concentrations and their coefficients of variation (CVs) were obtained for a 3.4-mL voxel centered on the left hippocampus on 3-T MR systems at two different sites with three healthy subjects (aged 32.5 ± 10.2 years [mean ± standard deviation]) per site, with each subject scanned over two sessions, and with each session comprising three scans. Concentrations of m-Ins, choline, creatine, Glx and N-acetyl-aspartate were 5.4 ± 1.5, 1.7 ± 0.2, 5.8 ± 0.3, 11.6 ± 1.2 and 5.9 ± 0.4 mM (mean ± standard deviation), respectively. Their respective mean within-session CVs were 14.5% ± 5.9%, 6.5% ± 5.3%, 6.0% ± 3.4%, 10.6% ± 6.2% and 3.5% ± 1.4%, and their mean within-subject CVs were 17.8% ± 18.2%, 7.5% ± 6.3%, 7.4% ± 6.4%, 12.4% ± 5.3% and 4.8% ± 3.0%. The between-subject CVs were 25.0%, 12.3%, 5.3%, 10.7% and 6.4%, respectively. Hippocampal long-TE sLASER single voxel spectroscopy can provide macromolecule-independent assessment of all major metabolites including Glx and m-Ins.

PURPOSE OF REVIEW:Central and peripheral nervous system manifestations of coronavirus disease 2019 (COVID-19) have been frequently reported and may cause significant morbidity and mortality. This review details the latest evidence on the neuropathogenesis and neurologic complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. RECENT FINDINGS:Commonly reported neurologic complications include toxic-metabolic encephalopathy, acute cerebrovascular disorders, seizures, and anoxic-brain injury. These complications represent secondary injury due to COVID-19 related hypoxia, sepsis, hypercoagulability, or hyperinflammation. Postinfectious complications, such as encephalitis, postinfectious demyelination, and Guillain-Barré syndrome have been reported, but are rare. Recent reports of persistent neurocognitive symptoms highlight the possibility of lasting impairment. SUMMARY:Although some neurologic complications should be treated with standard practices, further investigations are still needed to determine the optimal treatment of COVID-related neurologic complications, such as ischemic stroke. Entering into the next phase of the pandemic, investigations into the long-term neurologic and cognitive impacts of SARS-CoV-2 infection will be needed. Clinicians must have a high clinical suspicion for both acute and chronic neurologic complications among COVID-19 patients.

There are varying medical, legal, social, religious and philosophical perspectives about the distinction between life and death. Death can be declared using cardiopulmonary or neurologic criteria throughout much of the world. After solicitation of brain death/death by neurologic criteria (BD/DNC) protocols from contacts around the world, we found that the percentage of countries with BD/DNC protocols is much lower in Africa than other developing regions. We performed an informal review of the literature to identify barriers to declaration of BD/DNC in Africa. We found that there are numerous medical, legal, social and religious barriers to the creation of BD/DNC protocols in Africa including 1) limited number of healthcare facilities, critical care resources and clinicians with relevant expertise; 2) absence of a political and legal framework codifying death; and 3) cultural and religious perspectives that present ideological conflict with the idea of BD/DNC, in particular, and between traditional and Western medicine, in general. Because there are a number of unique barriers to the creation of BD/DNC protocols in Africa, it remains to be seen how the World Brain Death Project, which is intended to create minimum standards for BD/DNC around the world, will impact BD/DNC determination in Africa.

Although it is self-evident that education in neurology is important and necessary, how to fund the educational mission is a frequent challenge for neurology departments and clinicians. Department chairs often resort to a piecemeal approach, cobbling together funding for educators from various sources, but frequently falling short. Here, we review the various sources available to fund the educational mission in neurology, understanding that not every department will have access to every source. We describe the multiple different teaching models and formats used by the modern student and educator and their associated costs, some of which are exorbitant. We discuss possible nonfinancial incentives, including pathways to promotion, educational research, and other awards and recognition. Neurological education is commonly underfunded, and departments and institutions must be nimble and creative in finding ways to fund the time and effort of educators.