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1.
J Int Neuropsychol Soc ; 29(4): 415-420, 2023 05.
Article in English | MEDLINE | ID: mdl-28889832

ABSTRACT

Objectives: The Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM4) is a computerized cognitive test often used in post-concussion assessments with U.S. service members (SMs). Existing evidence, however, remains mixed regarding ANAM4's ability to identify cognitive issues following mild traumatic brain injury (mTBI). Studies typically examine ANAM4 by comparing mean scores to baseline or normative scores. A more fine-grained approach involves examining inconsistency within an individual's performance. Methods: Data from a sample of 231 were healthy control SMs and 100 SMs within 7 days of mTBI who took the ANAM4 were included in analyses. We examine each individual's performance on a simple reaction time (SRT) subtest that is administered at the beginning (SRT1) and end (SRT2) of the ANAM4 battery, and calculate the standard deviation of difference scores by trial across administrations. Results: Multivariate analysis of variance and univariate analyses revealed group differences across all comparisons (p<.001) with pairwise comparisons revealing higher intra-individual variability and slower raw reaction time for the mTBI group compared with controls. Effect sizes were small though exceeded the recommended minimum practical effect size (ES>0.41). Conclusions: While inconsistencies in performance are often viewed as noise or test error, the results suggest intra-individual cognitive variability may be more sensitive than central tendency measures (i.e., comparison of means) in detecting changes in cognitive function in mTBI. Additionally, the findings highlight the utility of ANAM4's repeating a subtest at two points in a battery to explore within-subject differences in performance. (JINS, 2017, 23, 1-6).


Subject(s)
Brain Concussion , Military Personnel , Humans , Brain Concussion/complications , Brain Concussion/diagnosis , Reaction Time , Cognition , Multivariate Analysis , Neuropsychological Tests
2.
J Head Trauma Rehabil ; 36(6): 456-465, 2021.
Article in English | MEDLINE | ID: mdl-34145155

ABSTRACT

OBJECTIVE: To evaluate the potential impact of timing between the current and the most recent previous concussions on symptom severity among acutely concussed active duty military Service members (SMs). SETTING: Three military installations. PARTICIPANTS: Eighty-four SMs aged 18 to 44 years who sustained a concussion within 72 hours of enrollment. No previous concussion within 1 year preenrollment. DESIGN: Longitudinal study with enrollment within 72 hours of injury, and follow-up at 1 week and 1 month postinjury. MAIN MEASURES: Lifetime concussion history (yes/no) and recency of the latest concussion (no history, relatively more recent [1 to <6 years ago], and more remote [6+ years ago]) from the current concussion using the Ohio State University Traumatic Brain Injury Identification Method-Interview Form. Symptom severity (total and by categories: cognitive, affective, somatosensory, vestibular) at all time points using the Neurobehavioral Symptoms Inventory. RESULTS: Concussion history assessed as having any previous concussion was not found significantly related to symptom severity (total or by categories) following a current concussion. However, when timing between concussion was taken into account, time since previous concussion was significantly related to symptomatology, whereby those with relatively more recent previous concussion had greater total symptoms within 72 hours of injury and at 1 week postinjury (though not at 1 month) than those with more remote previous concussion (≤72 hours: difference = 15.4, 95% CI = 1.8 to 29.1; 1 week: difference = 15.2, 95% CI = 1.2 to 29.2) or no history (≤72 hours: difference = 11.6, 95% CI = 0.4 to 22.8; 1 week: difference = 13.9, 95% CI = 2.4 to 25.4). When evaluated by symptom category, this relationship was particularly important on affective and somatosensory symptoms. CONCLUSION: In recently concussed active duty SMs, the timing between the current and previous concussions may be an important factor in determining prognosis. Clinical assessment of concussion history that accounts for the timing of the most recent event may be necessary to identify patients who may require a more conservative plan of care and more gradual return to activity in the acute recovery stage.


Subject(s)
Brain Injuries , Military Personnel , Humans , Longitudinal Studies , Ohio , Universities
3.
Arch Phys Med Rehabil ; 101(7): 1204-1211, 2020 07.
Article in English | MEDLINE | ID: mdl-32234413

ABSTRACT

OBJECTIVES: To evaluate relationships between beliefs about the impact of rest and the level of activities and symptoms over time among active duty Service members sustaining concussion, and whether these relationships vary by provision of concussion education. DESIGN: Longitudinal study using multilevel modeling to assess the relationship between beliefs about rest within 72 hours of concussion and change in activity and symptom level over time, as well as interaction by concussion education at the initial clinic visit. SETTING: Three military treatment facilities. PARTICIPANTS: Study participants included active duty Service members diagnosed with a concussion (N=111; median age, 24 y). Individuals with previous history of concussion within 12 months of study enrollment were excluded. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Activity questionnaire and the Neurobehavioral Symptom Inventory assessed within 72 hours of concussion; at 1 week; and at 1, 3, and 6 month(s) postinjury. RESULTS: Receipt of concussion education from providers was significantly associated with greater belief that rest influences concussion recovery. Greater belief that rest influences symptom recovery at the acute stage of concussion was associated with a greater increase in activities over time, but only among those who received education from their provider. Additionally, greater belief about the influence of rest was related to a more rapid decrease in symptoms over time. CONCLUSIONS: Concussed Service members who underestimate the influence of rest during acute recovery may be at risk for poorer recovery. Treatment of Service members with postconcussive symptoms should consider patient knowledge and/or beliefs about rest and recovery, which may influence prognosis. Our results support the provider's use of concussion education to correct potential misconceptions that may negatively impact symptom recovery.


Subject(s)
Brain Concussion/rehabilitation , Health Knowledge, Attitudes, Practice , Military Personnel/statistics & numerical data , Post-Concussion Syndrome/prevention & control , Recovery of Function/physiology , Rest , Adult , Attitude to Health , Brain Concussion/diagnosis , Cohort Studies , Culture , Female , Follow-Up Studies , Humans , Injury Severity Score , Longitudinal Studies , Male , Neuropsychological Tests , Patient Education as Topic/methods , Risk Assessment , Time Factors , United States , Young Adult
4.
J Head Trauma Rehabil ; 35(2): 92-103, 2020.
Article in English | MEDLINE | ID: mdl-31246876

ABSTRACT

OBJECTIVE: To evaluate the impact on symptom resolution of activity acutely following a concussion and the role of acute-phase symptoms on this relationship among active duty service members (SMs). SETTING: Three military installations. PARTICIPANTS: Sixty-two SMs aged 18 to 44 years who sustained a concussion within 72 hours of enrollment. DESIGN: Longitudinal design with data collected within 72 hours of injury (baseline, n = 62) and at 1 week (n = 57), 1 month (n = 50), 3 months (n = 41), and 6 months (n = 40) postinjury. MAIN MEASURES: Baseline activity level using a 60-item Activity Questionnaire. Symptom level at baseline and during follow-up using Neurobehavioral Symptoms Inventory. RESULTS: Significant interaction (Pi < .05) was found, with significant main effects (P < .05) limited to SMs with elevated baseline symptomatology. Among these participants, greater baseline total activity was significantly related to greater vestibular symptoms at 1, 3, and 6 months (ß = .61, .63, and .59, respectively). Significant associations were also found for particular types of baseline activity (eg, physical; vestibular/balance; military-specific) and symptoms at 1, 3, and/or 6 months postinjury. CONCLUSION: These results provide support for clinical guidance that symptomatic SMs, particularly those with high levels of acute symptoms, may need to avoid excessive activity acutely following concussion.


Subject(s)
Brain Concussion , Exercise , Military Personnel , Brain Concussion/diagnosis , Humans
5.
J Int Neuropsychol Soc ; 24(2): 156-162, 2018 02.
Article in English | MEDLINE | ID: mdl-29168451

ABSTRACT

OBJECTIVES: The Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM4) is a computerized cognitive test often used in post-concussion assessments with U.S. service members (SMs). However, existing evidence remains mixed regarding ANAM4's ability to identify cognitive issues following mild traumatic brain injury (mTBI). Studies typically examine ANAM4 using standardized scores and/ or comparisons to a baseline. A more fine-grained approach involves examining inconsistency within an individual's performance (i.e., intraindividual variability). METHODS: Data from 237 healthy control SMs and 105 SMs within seven days of mTBI who took the ANAM4 were included in analyses. Using each individual's raw scores on a simple reaction time (RT) subtest (SRT1) that is repeated at the end of the battery (SRT2), we calculated mean raw RT and the intraindividual standard deviation (ISD) of trial-by-trial RT. Analyses investigated differences between groups in mean RT, RT variability (i.e., ISD), and change in ISD from SRT1 and SRT2. RESULTS: Using regression residuals to control for demographic variables, analysis of variance, and pairwise comparisons revealed the control group had faster mean RT and smaller ISD compared to the mTBI group. Furthermore, the mTBI group had a significant increase in ISD from SRT1 to SRT2, with effect sizes exceeding the minimum practical effect for comparisons of ISD in SRT2 and change in ISD from SRT1 to SRT2. CONCLUSIONS: While inconsistencies in performance are often viewed as test error, the results suggest intraindividual cognitive variability may be more sensitive than traditional metrics in detecting changes in cognitive function after mTBI. Additionally, the findings highlight the utility of the ANAM4's repeating a RT subtest at two points in the same session for exploring within-subject differences in performance variability. (JINS, 2018, 24, 156-162).


Subject(s)
Biological Variation, Individual , Brain Concussion/physiopathology , Military Personnel , Neuropsychological Tests/statistics & numerical data , Reaction Time/physiology , Adult , Female , Humans , Male , Middle Aged , United States , Young Adult
6.
Neurosurg Focus ; 45(6): E15, 2018 12 01.
Article in English | MEDLINE | ID: mdl-30544329

ABSTRACT

Over the past 8 years, advances in the US Military Health System (MHS) have led to extensive changes in the way combat casualty care is provided to deployed service members with a traumatic brain injury (TBI). Changes include the application of cutting-edge Clinical Practice Guidelines, use of pioneering technologies, and advances in evacuation procedures. Compared with previous engagements, current operations occur on a much smaller scale, and more frequently in austere environments, such that effective medical support is increasingly challenging. In this paper, the authors describe key aspects of the current continuum of TBI care in the US military, from the point of injury through rehabilitation, with an emphasis on how emerging technologies and evidence-based Clinical Practice Guidelines assist MHS clinicians with providing the best clinical care possible in the changing battlefield.


Subject(s)
Brain Injuries, Traumatic/rehabilitation , Brain Injuries, Traumatic/therapy , Military Personnel , Patient Care , Brain Injuries/rehabilitation , Brain Injuries/surgery , Humans , Treatment Outcome , United States
7.
Cogn Neuropsychol ; 33(3-4): 220-40, 2016.
Article in English | MEDLINE | ID: mdl-27315433

ABSTRACT

Theoretical and empirical studies of memory have long been framed by a distinction between declarative and non-declarative memory. We question the sharpness of the distinction by reporting evidence from amnesic L.S.J., who despite retrograde memory losses in declarative knowledge domains, shows sparing of declarative knowledge related to premorbid skill (e.g., playing an instrument). We previously showed that L.S.J. had severe losses of retrograde declarative knowledge across areas of premorbid expertise (e.g., artists of famous works) and everyday knowledge (e.g., company names for logos). Here we present evidence that L.S.J. has sparing of what we call skill-related declarative knowledge, in four domains in which she had premorbid skill (art, music, aviation, driving). L.S.J.'s pattern of loss and sparing raises questions about the strict separation between classically-defined memory types and aligns with a recent proposal by Stanley and Krakauer [2013. Motor skill depends on knowledge of facts. Frontiers in Human Neuroscience, 7,1-11].


Subject(s)
Amnesia , Memory , Humans , Knowledge , Music
8.
J Cogn Neurosci ; 26(8): 1736-47, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24456393

ABSTRACT

The sensory input that we experience is highly patterned, and we are experts at detecting these regularities. Although the extraction of such regularities, or statistical learning (SL), is typically viewed as a cortical process, recent studies have implicated the medial temporal lobe (MTL), including the hippocampus. These studies have employed fMRI, leaving open the possibility that the MTL is involved but not necessary for SL. Here, we examined this issue in a case study of LSJ, a patient with complete bilateral hippocampal loss and broader MTL damage. In Experiments 1 and 2, LSJ and matched control participants were passively exposed to a continuous sequence of shapes, syllables, scenes, or tones containing temporal regularities in the co-occurrence of items. In a subsequent test phase, the control groups exhibited reliable SL in all conditions, successfully discriminating regularities from recombinations of the same items into novel foil sequences. LSJ, however, exhibited no SL, failing to discriminate regularities from foils. Experiment 3 ruled out more general explanations for this failure, such as inattention during exposure or difficulty following test instructions, by showing that LSJ could discriminate which individual items had been exposed. These findings provide converging support for the importance of the MTL in extracting temporal regularities.


Subject(s)
Brain Damage, Chronic , Hippocampus/physiopathology , Learning/physiology , Pattern Recognition, Physiological/physiology , Temporal Lobe/physiopathology , Aged , Brain Damage, Chronic/etiology , Brain Damage, Chronic/pathology , Brain Damage, Chronic/physiopathology , Encephalitis, Herpes Simplex/complications , Female , Hippocampus/pathology , Humans , Magnetic Resonance Imaging , Middle Aged , Random Allocation , Temporal Lobe/pathology
10.
Int J Lang Commun Disord ; 49(2): 162-73, 2014.
Article in English | MEDLINE | ID: mdl-24741697

ABSTRACT

BACKGROUND: Previous studies of therapy for acquired anomia have treated nouns in isolation. The effect on nouns in connected speech remains unclear. In a recent study in 2012, we used a novel noun syntax therapy and found an increase in the number of determiner plus noun constructions in narrative after therapy. AIMS: Two aims arose from the previous study: to identify the critical ingredient in the noun syntax therapy,specifically whether this is lexical production, or the syntactic context; and to extend the analysis of the effects beyond narrative into conversation. METHODS & PROCEDURES: We compared the effects of lexical therapy with those of noun syntax therapy in one individual with aphasia, in a sequential intervention design. We analysed the effects on conversation and on narrative. OUTCOMES & RESULTS: There was improved picture naming of treated words after both therapies. Lexical therapy had no impact on narrative and conversation, whereas noun syntax therapy led to more noun production, primarily in the context of determiner plus noun combinations. CONCLUSIONS & IMPLICATIONS: The results support the claim that greater impact on narrative and conversation can be achieved for some people with aphasia by treating nouns in syntactic contexts.


Subject(s)
Anomia/therapy , Aphasia/therapy , Language Therapy/methods , Semantics , Stroke/therapy , Vocabulary , Aged , Aphasia, Broca/therapy , Communication , Female , Humans , Narration , Speech , Treatment Outcome
11.
J Psycholinguist Res ; 41(6): 439-53, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22411592

ABSTRACT

Gender priming studies have demonstrated facilitation of noun production following pre-activation of a target noun's grammatical gender. Findings provide support for models in which syntactic information relating to words is stored within the lexicon and activated during lexical retrieval. Priming effects are observed in the context of determiner plus noun phrase production. Few studies demonstrate gender priming effects in bare noun production (i.e., nouns in isolation). We investigated the effects of English determiner primes on bare mass and count noun production. In two experiments, participants named pictures after exposure to primes involving congruent, incongruent and neutral determiners. Facilitation of noun production by congruent and neutral determiner primes was found in both experiments. The results suggest that noun phrase syntax is activated in lexical retrieval, even when not explicitly required for production. Post hoc analysis of the relative frequency of congruent and incongruent prime-target pairs provides support for a frequency-based interpretation of the data.


Subject(s)
Association , Cues , Mental Recall , Pattern Recognition, Visual , Semantics , Speech Perception , Verbal Behavior , Verbal Learning , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Problem Solving , Reaction Time , Young Adult
12.
Front Neurol ; 13: 835752, 2022.
Article in English | MEDLINE | ID: mdl-35463137

ABSTRACT

The Department of Defense (DOD) has recently prioritized the investigation of the acute and chronic adverse brain health and performance effects of low-level blast (LLB) generated by the use of weapons systems. While acute exposure can be quantified by sensor technology, career exposure has no widely accepted and validated measure for characterization. Currently, distinct research groups are developing and validating four promising measures to estimate career blast exposure history: the Salisbury Blast Interview, Blast Exposure Threshold Survey, Blast Ordnance and Occupational Exposure Measure, and the Blast Frequency and Symptom Severity. Each measure offers an assessment of blast history that is uniquely beneficial to addressing specific research questions. However, use of divergent strategies is not efficient to accelerate the field's understanding of the impact of career exposure and Service-connected health outcomes. As a DOD-wide solution, collaboration across these groups is required to develop a tool(s) that can be standardized across research studies and, ultimately, pared down to be implemented in clinical settings. Here, we overview the current four measures and provide a perspective on the way forward for optimization and/or combination in support of this solution.

13.
Nat Geosci ; 15: 741-746, 2022 Sep 01.
Article in English | MEDLINE | ID: mdl-36246038

ABSTRACT

Transform faults accommodate the lateral motions between lithospheric plates, producing large earthquakes. Away from active transform boundaries, former oceanic transform faults also form the fracture zones that cover the ocean floor. However, the deep structure of these faults remains enigmatic. Here we present ultra-long offset seismic data from the Romanche transform fault in the equatorial Atlantic Ocean that indicates the presence of a low-velocity anomaly extending down to ~60 km depth below sea level. We performed 3D thermal modelling that suggests the anomaly is likely to be due to extensive serpentinization down to ~16 km depth, overlying a hydrated, shear mylonite zone down to 32 km depth. The water is considered to be sourced from seawater-derived fluids that infiltrate deep into the fault. Below 32 km is interpreted to be a low-temperature, water-induced melting zone that elevates the lithosphere-asthenosphere boundary, causing significant thinning of the lithosphere at the transform fault. The presence of a thinned lithosphere at transform faults could explain observations of volcanism, thickened crust and intra-transform spreading centres at transform faults. It also suggests that migration and mixing of water-induced melt with the high temperature melt may occur beneath the ridge axis.

14.
Sci Adv ; 7(15)2021 Apr.
Article in English | MEDLINE | ID: mdl-33837085

ABSTRACT

Oceanic transform faults, a key element of plate tectonics, represent the first-order discontinuities along mid-ocean ridges, host large earthquakes, and induce extreme thermal gradients in lithosphere. However, the thermal structure along transform faults and its effects on earthquake generation are poorly understood. Here we report the presence of a 10- to 15-kilometer-thick in-depth band of microseismicity in 10 to 34 kilometer depth range associated with a high-temperature (700° to 900°C) mantle below the brittle lithosphere along the Romanche mega transform fault in the equatorial Atlantic Ocean. The occurrence of the shallow 2016 moment magnitude 7.1 supershear rupture earthquake and these deep microearthquakes indicate that although large earthquakes occur in the upper brittle lithosphere, a substantial amount of deformation is accommodated in the semibrittle mylonitic mantle that resides at depths below the 600°C isotherm. We also observe a rapid westward deepening of this band of seismicity indicating a strong lateral heterogeneity.

15.
Can Med Educ J ; 11(6): e188-e190, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33349777

ABSTRACT

There is already considerable evidence of how this novel corona virus (COVID-19) has had a major impact on our mental health and wellbeing. We are reminded of the mental health consequences of previous infectious disease outbreaks, not only for the public, but for frontline healthcare workers. Yet the lived experiences of resident physicians are missing from this discussion despite them being essential to the COVID-19 response and continuing to provide care during this time. The author asserts that considering what is known about the mental health effects of frontline healthcare work during previous outbreaks, residents are at risk given their role as physicians. In addition to baseline systemic stressors that put residents at risk of mental distress, they also face COVID-19 related stressors that exacerbate the risk given their role as trainees too. The author acknowledges and welcomes several rapid responses to residents' developing mental health needs from medical leaders across Canadian hospitals, programs, and resident bodies. Ultimately, however, medical leaders need to advocate for and implement changes that will support residents' mental health now and in the long-term well after COVID-19 has left its mark.


À partir d'une recherche sur l'actualité qui a émergé de la Chine et des autres pays qui ont été touchés les premiers par la maladie à coronavirus 2019 (COVID-19), il existait déjà des données relativement à son incidence majeure sur notre santé et notre bien-être. On nous rappelle les conséquences des épidémies antérieures de maladies infectieuses sur la santé mentale, non seulement pour le public, mais également pour les travailleurs de la santé de première ligne. Pourtant, les expériences vécues par des médecins résidents sont absentes de cette discussion, même si elles sont essentielles à la réponse au COVID-19 et à la continuité des soins offerts au cours de cette période. L'auteur affirme qu'en tenant compte de ce qui est connu des effets sur la santé mentale du travail de la santé de première ligne au cours des éclosions antérieures, les résidents sont à risque étant donné leur rôle de médecins. En plus des agents stressants systémiques réguliers qui mettent les résidents à risque de détresse mentale, ils sont également confrontés aux agents stressants liés à la COVID-19 qui aggravent également le risque alors qu'ils sont stagiaires. L'auteur reconnaît de nombreuses initiatives des dirigeants médicaux dans les hôpitaux, les programmes et les organismes de résidence au Canada qui sont accueillies comme des réponses rapides à l'évolution des besoins en matière de santé mentale des résidents. En dépit de ces actions positives l'auteur demande aux responsables médicaux de continuer à promouvoir et à mettre en œuvre des modifications au soutien en matière de santé mentale maintenant et au cours des années à venir, après la COVID-19.

16.
Neurotrauma Rep ; 1(1): 137-145, 2020.
Article in English | MEDLINE | ID: mdl-33274343

ABSTRACT

Primary care providers can play a crucial role in the clinical management of concussion. However, many providers lack up-to-date information about best practices for rest and return to activity after these injuries. Most research on this topic has been conducted in athletes, and so less is known about how to assist patients with returning to activity in other settings and populations. This article provides a review of best practices for management of progressive return to activity after concussion, with an emphasis on "lessons learned" from the Defense and Veterans Brain Injury Center (DVBIC) Progressive Return to Activity (PRA) study, a multi-site longitudinal research project conducted to evaluate concussion management practices and the effectiveness of provider training on DVBIC clinical recommendations (CRs). Provider clinical practices and patient outcomes were examined at three U.S. military treatment facilities before and after providers completed a standardized training on DVBIC PRA CRs. In summary, research findings provide additional support that concussion recovery can be influenced by patients' activity levels after injury. Patients with concussion may experience poorer outcomes if they return to pre-injury levels of activity too rapidly, but they may also be at risk for prolonged symptoms if they fail to increase activity levels over time after an initial period of rest. Additionally, training primary care providers in return to activity guidelines can result in more effective patient education and better clinical outcomes. This knowledge can be used to inform best practices for progressive return to activity in both civilian and military settings.

17.
Prog Neurobiol ; 191: 101819, 2020 08.
Article in English | MEDLINE | ID: mdl-32380224

ABSTRACT

Repeated stimuli elicit attenuated responses in visual cortex relative to novel stimuli. This adaptation can be considered as a form of rapid learning and a signature of perceptual memory. Adaptation occurs not only when a stimulus is repeated immediately, but also when there is a lag in terms of time and other intervening stimuli before the repetition. But how does the visual system keep track of which stimuli are repeated, especially after long delays and many intervening stimuli? We hypothesized that the hippocampus and medial temporal lobe (MTL) support long-lag adaptation, given that this memory system can learn from single experiences, maintain information over delays, and send feedback to visual cortex. We tested this hypothesis with fMRI in an amnesic patient, LSJ, who has encephalitic damage to the MTL resulting in extensive bilateral lesions including complete hippocampal loss. We measured adaptation at varying time lags between repetitions in functionally localized visual areas that were intact in LSJ. We observed that these areas track information over a few minutes even when the hippocampus and extended parts of the MTL are unavailable. LSJ and controls were identical when attention was directed away from the repeating stimuli: adaptation occurred for lags up to three minutes, but not six minutes. However, when attention was directed toward stimuli, controls now showed an adaptation effect at six minutes but LSJ did not. These findings suggest that visual cortex can support one-shot perceptual memories lasting for several minutes but that the hippocampus and surrounding MTL structures are necessary for adaptation in visual cortex after longer delays when stimuli are task-relevant.


Subject(s)
Adaptation, Physiological/physiology , Amnesia/physiopathology , Feedback, Physiological/physiology , Hippocampus/physiology , Pattern Recognition, Visual/physiology , Temporal Lobe/physiology , Visual Cortex/physiology , Aged , Attention , Female , Hippocampus/pathology , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Temporal Lobe/pathology , Time Factors
18.
Clin Neuropsychol ; 34(6): 1156-1174, 2020 08.
Article in English | MEDLINE | ID: mdl-31985338

ABSTRACT

OBJECTIVE: "Return to duty" (RTD) is often used as an outcome metric in military concussion research, but is inconsistently defined across studies and presents several key problems to researchers. Using results from the Defense and Veterans Brain Injury Center's (DVBIC) Progressive Return to Activity (PRA) study, we highlight problems with RTD, and suggest solutions to inform future efforts. METHOD: 116 service members (SMs) were enrolled in one of two groups (pre-implementation and post-implementation of the PRA Clinical Recommendation [CR]). Data, including the Neurobehavioral Symptom Inventory (NSI-22), was collected within 72-hours of injury (baseline), and at 1-week, 1-month, 3-months, and 6-months post-injury. Our analyses focused on three time points: baseline, approximate RTD date, and post-RTD follow-up, with RTD data captured via self-report and electronic medical record (EMR). Secondary analyses included comparisons across PRA-CR implementation groups. RESULTS: Of those SMs (<50% of the sample) with both self-reported and EMR RTD dates, dates largely did not match (range 1 to 36 days). RTD (either date) also did not indicate symptom recovery, with >50% of SMs reporting "abnormally high" symptom levels (i.e., NSI-22 total ≥75th percentile) at RTD, and over 50% of SMs reporting at least one significant symptom (i.e., any NSI-22 item ≥ 2) after RTD. CONCLUSIONS: Our data demonstrate challenges encountered with a RTD outcome metric. Military concussion researchers should strive to use a well-defined RTD outcome metric. We propose defining RTD as a return to deployment readiness. Further, researchers should utilize Department of Defense definitions of Individual Medical Readiness and Deployment Limiting conditions to increase specificity of a RTD outcome metric. Improving the way RTD is captured will improve confidence that tools used after a SM sustains concussion are adequately informing RTD decisions.


Subject(s)
Brain Concussion/diagnosis , Military Personnel/psychology , Neuropsychological Tests/standards , Return to Work/psychology , Veterans/psychology , Adult , Female , Humans , Male
19.
J Geophys Res Solid Earth ; 125(10): e2020JB020275, 2020 Oct.
Article in English | MEDLINE | ID: mdl-33282617

ABSTRACT

Oceanic transform faults and fracture zones (FZs) represent major bathymetric features that keep the records of past and present strike-slip motion along conservative plate boundaries. Although they play an important role in ridge segmentation and evolution of the lithosphere, their structural characteristics, and their variation in space and time, are poorly understood. To address some of the unknowns, we conducted interdisciplinary geophysical studies in the equatorial Atlantic Ocean, the region where some of the most prominent transform discontinuities have been developing. Here we present the results of the data analysis in the vicinity of the Chain FZ, on the South American Plate. The crustal structure across the Chain FZ, at the contact between ∼10 and 24 Ma oceanic lithosphere, is sampled along seismic reflection and refraction profiles. We observe that the crustal thickness within and across the Chain FZ ranges from ∼4.6-5.9 km, which compares with the observations reported for slow-slipping transform discontinuities globally. We attribute this presence of close to normal oceanic crustal thickness within FZs to the mechanism of lateral dike propagation, previously considered to be valid only in fast-slipping environments. Furthermore, the combination of our results with other data sets enabled us to extend the observations to morphotectonic characteristics on a regional scale. Our broader view suggests that the formation of the transverse ridge is closely associated with a global plate reorientation that was also responsible for the propagation and for shaping lower-order Mid-Atlantic Ridge segmentation around the equator.

20.
Front Neurol ; 11: 559311, 2020.
Article in English | MEDLINE | ID: mdl-33178105

ABSTRACT

Background: Headache is a common symptom reported following concussion/mild traumatic brain injury. The Department of Defense's clinical recommendation (CR) describes guidance for primary care providers for the management of post-traumatic headache (PTH) in Service members. Objective: The objective of this study is to examine the association between training on the CR with provider clinical practice, patient behaviors, and symptom recovery. Methods: Participants were healthcare providers and two patient groups (one receiving care as usual [CAU] and another receiving care after provider training on PTH CR [CR+]). Providers were interviewed at three time points: (1) prior to CAU enrollment; (2) after CAU enrollment, but prior to training; and (3) after CR+ follow-up. Data from the second and third provider interview were used to evaluate a potential difference between provider practices pre- and post-training (n = 13). Patients were enrolled within 6 months of concussion. Patient outcomes (including neurobehavioral and headache symptoms) were assessed at three time-points: within 72 h (n = 35), at 1-week (n = 34) and at 1-month post-enrollment (n = 27). Results: Most follow-up care reported by providers were recommended within 72 h of initial visit post-training vs. >1 week pre-training. Additionally, providers reported a greater number of visits based on patient symptoms after training than before. Post-training, most providers reported referring patients to higher level of care "as needed," if not "very rarely," compared to 25% reported referrals prior to training. At 1-week post-enrollment the CR+ patient group reported more frequent medical provider visits compared to the CAU group. This trend was reversed at the 1-month follow-up whereby more CAU reported seeing a medical provider compared to CR+. By 1-week post-enrollment, fewer patients in the CR+ group reported being referred to any other providers or specialists compared to the CAU group. No differences in patient outcomes by provider training was found. Conclusion: The study results demonstrate the feasibility of training on the Management of Headache Following Concussion CR in order to change provider practices by promoting timely care, and promoting patient compliance as shown through improvement in follow-up visits and more monitoring within the primary care clinic.

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