Faculty Bibliography

PURPOSE:While there is strong evidence supporting the importance of telemedicine in stroke, its role in other areas of neurology is not as clear. The goal of this review is to provide an overview of evidence-based data on the role of teleneurology in the care of patients with neurologic disorders other than stroke. RECENT FINDINGS:Studies across multiple specialties report noninferiority of evaluations by telemedicine compared with traditional, in-person evaluations in terms of patient and caregiver satisfaction. Evidence reports benefits in expediting care, increasing access, reducing cost, and improving diagnostic accuracy and health outcomes. However, many studies are limited, and gaps in knowledge remain. SUMMARY:Telemedicine use is expanding across the vast array of neurologic disorders. More studies are needed to validate and support its use.

Mild traumatic brain injury (mTBI, also known as a concussion) as a consequence of battlefield blast exposure or blunt force trauma has been of increasing concern to militaries during recent conflicts. This concern is due to the frequency of exposure to improvised explosive devices for forces engaged in operations both in Iraq and Afghanistan coupled with the recognition that mTBI may go unreported or undetected. Blasts can lead to mTBI through a variety of mechanisms. Debate continues as to whether exposure to a primary blast wave alone is sufficient to create brain injury in humans, and if so, exactly how this occurs with an intact skull. Resources dedicated to research in this area have also varied substantially among contributing NATO countries. Most of the research has been conducted in the US, focused on addressing uncertainties in management practices. Development of objective diagnostic tests should be a top priority to facilitate both diagnosis and prognosis, thereby improving management. It is expected that blast exposure and blunt force trauma to the head will continue to be a potential source of injury during future conflicts. An improved understanding of the effects of blast exposure will better enable military medical providers to manage mTBI cases and develop optimal protective measures. Without the immediate pressures that come with a high operational tempo, the time is right to look back at lessons learned, make full use of available data, and modify mitigation strategies with both available evidence and new evidence as it comes to light. Toward that end, leveraging our cooperation with the civilian medical community is critical because the military experience over the past 10 years has led to a renewed interest in many similar issues pertaining to mTBI in the civilian world. Such cross-fertilization of knowledge will undoubtedly benefit all. This paper highlights similarities and differences in approach to mTBI patient care in NATO and partner countries and provides a summary of and lessons learned from a NATO lecture series on the topic of mTBI, demonstrating utility of having patients present their experiences to a medical audience, linking practical clinical care to policy approaches.

Nearly 380,000 U.S. service members between 2000 and 2017 were, and at least 300,000 athletes annually are, diagnosed with concussion. It is imperative to establish a gold-standard diagnostic test to quickly and accurately diagnose concussion. In this non-randomized, prospective study, we examined the reliability and validity of a novel neurocognitive assessment tool, the Defense Automated Neurobehavioral Assessment (DANA), designed to be a more sensitive, yet efficient, measure of concussion symptomatology. In this study, the DANA Brief version was compared to an established measure of concussion screening, the Military Acute Concussion Evaluation (MACE), in a group of non-concussed service members. DANA Brief subtests demonstrated low to moderate reliability, as measured by intra-class correlation coefficient (ICC; values range: 0.28-0.58), which is comparable to other computerized neurocognitive tests that are widely-implemented to diagnose concussion. Statistically significant associations were found between learning and memory components of the DANA Brief and the diagnostic MACE cognitive test score (DANA Brief subtests: CDD: R ² = 0.05, p = 0.023; CDS: R ² = 0.10, p = 0.010). However, a more robust relationship was found between DANA Brief components involving attention and working memory, including immediate memory, and the MACE cognitive test score (DANA Brief subtests: GNG: R ² = 0.08, p = 0.003; PRO: R ² = 0.08, p = 0.002). These results provide evidence that the DANA Rapid version, a 5-min assessment self-administered on a hand-held portable device, based on the DANA Brief version, may serve as a clinically useful and improved neurocognitive concussion screen to minimize the time between injury and diagnosis in settings where professional medical evaluation may be unavailable or delayed. The DANA's portability, durability, shorter test time and lack of need for a medical professional to diagnose concussion overcome these critical limitations of the MACE.

A common complaint after concussion is the development of new or worsening headaches which can make it difficult or even impossible for patients to work or function in their day-to-day lives. Uncertainties associated with the complaints and a wide variety of approaches exist regarding the appropriate work-up and management of these patients. Areas of ongoing debate include the need for neuroimaging; optimal, acute, and preventative treatment; and proper counseling and expectation management. Given the wide variety of potential approaches and the lack of consensus, we sought expert opinion from around the globe on how to evaluate and manage patients with headache following concussion. Similar questions were posed to the rest of our readership in an online survey (links.lww.com/CPJ/A96), the results of which are also presented.

Rare pain-insensitive individuals offer unique insights into how pain circuits function and have led to the development of new strategies for pain control. We investigated pain sensitivity in humans with WAGR (Wilms tumor, aniridia, genitourinary anomaly, and range of intellectual disabilities) syndrome, who have variably sized heterozygous deletion of the 11p13 region. The deletion region can be inclusive or exclusive of the brain-derived neurotrophic factor (BDNF) gene, a crucial trophic factor for nociceptive afferents. Nociceptive responses assessed by quantitative sensory testing demonstrated reduced pain sensitivity only in the WAGR subjects whose deletion boundaries included the BDNF gene. Corresponding behavioral assessments were made in heterozygous Bdnf knockout rats to examine the specific role of Bdnf. These analogous experiments revealed impairment of Aδ- and C-fiber-mediated heat nociception, determined by acute nociceptive thermal stimuli, and in aversive behaviors evoked when the rats were placed on a hot plate. Similar results were obtained for C-fiber-mediated cold responses and cold avoidance on a cold-plate device. Together, these results suggested a blunted responsiveness to aversive stimuli. Our parallel observations in humans and rats show that hemizygous deletion of the BDNF gene reduces pain sensitivity and establishes BDNF as a determinant of nociceptive sensitivity.

Facial recognition is widely thought to involve a holistic perceptual process, and optimal recognition performance can be rapidly achieved within two fixations. However, is facial identity encoding likewise holistic and rapid, and how do gaze dynamics during encoding relate to recognition? While having eye movements tracked, participants completed an encoding ("study") phase and subsequent recognition ("test") phase, each divided into blocks of one- or five-second stimulus presentation time conditions to distinguish the influences of experimental phase (encoding/recognition) and stimulus presentation time (short/long). Within the first two fixations, several differences between encoding and recognition were evident in the temporal and spatial dynamics of the eye-movements. Most importantly, in behavior, the long study phase presentation time alone caused improved recognition performance (i.e., longer time at recognition did not improve performance), revealing that encoding is not as rapid as recognition, since longer sequences of eye-movements are functionally required to achieve optimal encoding than to achieve optimal recognition. Together, these results are inconsistent with a scan path replay hypothesis. Rather, feature information seems to have been gradually integrated over many fixations during encoding, enabling recognition that could subsequently occur rapidly and holistically within a small number of fixations.

Objective:Traditional neurology teaching states that when mean arterial pressure dips below a 60 mm Hg threshold, there is an increase in stroke risk due to cerebral hypoperfusion. The aim of this study was to determine whether intensive lowering of systolic blood pressure increases adverse cardiovascular outcomes by examining the association between achieved blood pressure values, specifically mean arterial pressure and pulse pressure, and risk of stroke. Methods:Data from participants in the Systolic Blood Pressure Intervention Trial (SPRINT) and the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Blood Pressure (BP) trial were examined, using survival analysis to model minimal arterial pressure and average pulse pressure during the study period against risk of stroke, hypotension, and syncope, with death as a competing risk. Results:In both SPRINT and ACCORD participants, there was no increase in stroke risk with achieved mean arterial pressure values below 60 mm Hg. In SPRINT participants, achieved mean arterial pressure values greater than 90 mm Hg were associated with a 247% (HR: 3.47, 95% CI: 2.06-5.85) higher risk of stroke compared with participants in the 80-89 mmHg reference group. No association was found between low achieved pulse pressure values and greater stroke risk in either the SPRINT or ACCORD participants, as well as no association between mean arterial pressure and pulse pressure values and risk of syncope. Interpretation:Intensive lowering of systolic blood pressure does not increase risk of stroke in hypertensive patients, despite extremely low mean arterial pressure or pulse pressure values.