Preliminary evidence of transcutaneous vagus nerve stimulation effects on sleep in veterans with post-traumatic stress disorder

Sleep problems are common among veterans with post-traumatic stress disorder and closely associated with hyperarousal symptoms. Transcutaneous vagus nerve stimulation (tVNS) may have potential to improve sleep quality in veterans with PTSD through effects on brain systems relevant to hyperarousal and sleep-wake regulation. The current pilot study examines the effect of 1 h of tVNS administered at "lights out" on sleep architecture, microstructure, and autonomic activity. Thirteen veterans with PTSD completed two nights of laboratory-based polysomnography during which they received 1 h of either active tVNS (tragus) or sham stimulation (earlobe) at "lights out" with randomised order. Sleep staging and stability metrics were derived from polysomnography data. Autonomic activity during sleep was assessed using the Porges-Bohrer method for calculating respiratory sinus arrhythmia (RSAP-B ). Paired t-tests revealed a small decrease in the total sleep time (d = -0.31), increase in N3 sleep (d = 0.23), and a small-to-moderate decrease in REM sleep (d = -0.48) on nights of active tVNS relative to sham stimulation. tVNS was also associated with a moderate reduction in cyclic alternating pattern (CAP) rate (d = -0.65) and small-to-moderate increase in RSAP-B during NREM sleep. Greater NREM RSAP-B was associated with a reduced CAP rate and NREM alpha power. This pilot study provides preliminary evidence that tVNS may improve sleep depth and stability in veterans with PTSD, as well as increase parasympathetically mediated nocturnal autonomic activity. These results warrant continued investigation into tVNS as a potential tool for treating sleep disturbance in veterans with PTSD.

A Computable Phenotype for the Identification of Sexual and Gender Minorities in Electronic Health Records

Sexual gender minorities, including lesbian, gay, and bisexual (LGB) individuals face unique challenges due to discrimination, stigma, and marginalization, which negatively impact their well-being. Electronic health record (EHR) systems present an opportunity for LGB research, but accurately identifying LGB individuals in EHRs is challenging. Our study developed and validated a rule-based computable phenotype (CP) to identify LGB individuals and their subgroups using both structured data and unstructured clinical narratives from a large integrated health system. Validating against a sample of 537 chart-reviewed patients, our three best performing CP algorithms balancing different performance metrics, each achieved sensitivity of 1.000, PPV of 0.982, and F1-score of 0.875 in identifying LGB individuals, respectively. Applying the three best-performing CPs, our study also found that the LGB population is younger and experiences a disproportionate burden of adverse health outcomes, particularly mental health distress.

Effects of sleep disturbance on trauma-focused psychotherapy outcomes in posttraumatic stress disorder: A systematic review

This study aimed to synthesize existing research on the effects of sleep disturbances on trauma-focused psychotherapy outcomes in adults with posttraumatic stress disorder (PTSD). A systematic review using PubMed, PsycINFO, Embase, Web of Science, and PTSDpubs was performed up to April 2021. Two independent reviewers screened articles for inclusion, performed data extraction, and assessed risk of bias and certainty of the evidence. Narrative synthesis was conducted based on the type of sleep disorder symptom assessed. Sixteen primary studies were included in this review, the majority of which had a high overall risk of bias. Results suggested that sleep disorder symptoms were associated with higher overall PTSD severity across treatment; however, they did not interfere with treatment effectiveness, with the exception of sleep-disordered breathing. Improvements in insomnia, sleep duration, and sleep quality during treatment were associated with greater treatment gains. Certainty of the evidence ranged from low to very low. These results suggest that it may not be necessary to address sleep disorder symptoms prior to initiating trauma-focused psychotherapy. Instead, concurrent treatment of sleep- and trauma-related symptoms may be most beneficial. Continued research is needed to clarify the mechanistic relationship between sleep and treatment outcomes and to guide clinical decision-making.

Distinct cortical and subcortical predictors of Purdue Pegboard decline in Parkinson's disease and atypical parkinsonism

Objective measures of disease progression are critically needed in research on Parkinson's disease (PD) and atypical Parkinsonism but may be hindered by both practicality and cost. The Purdue Pegboard Test (PPT) is objective, has high test-retest reliability, and has a low cost. The goals of this study were to determine: (1) longitudinal changes in PPT in a multisite cohort of patients with PD, atypical Parkinsonism, and healthy controls; (2) whether PPT performance reflects brain pathology revealed by neuroimaging; (3) quantify kinematic deficits shown by PD patients during PPT. Parkinsonian patients showed a decline in PPT performance that correlated with motor symptom progression, which was not seen in controls. Neuroimaging measures from basal ganglia were significant predictors of PPT performance in PD, whereas cortical, basal ganglia, and cerebellar regions were predictors for atypical Parkinsonism. Accelerometry in a subset of PD patients showed a diminished range of acceleration and irregular patterns of acceleration, which correlated with PPT scores.

A consensus on optimization of care in patients with growth hormone deficiency and mild traumatic brain injury

OBJECTIVE/DESIGN

Approximately 2.9 million children and adults in the US experience traumatic brain injuries (TBIs) annually, most of which are considered mild. TBI can induce varying consequences on pituitary function, with growth hormone deficiency (GHD) among the more commonly reported conditions. Panels of pediatric and adult endocrinologists, neurologists, physical medicine and rehabilitation specialists, and neuropsychologists convened in February and October 2020 to discuss ongoing challenges and provide strategies for detection and optimal management of patients with mild TBI and GHD.

RESULTS

Difficulties include a low rate of seeking medical attention in the population, suboptimal screening tools, cost and complexity of GHD testing, and a lack of consensus regarding when to test or retest for GHD. Additionally, referrals to endocrinologists from other specialists are uncommon. Recommendations from the panels for managing such patients included multidisciplinary guidelines on the diagnosis and management of post-TBI GHD and additional education on long-term metabolic and probable cognitive benefits of GH replacement therapy.

CONCLUSION

As patients of all ages with mild TBI may develop GHD and/or other pituitary deficiencies, a multidisciplinary approach to provide education to endocrinologists, neurologists, neurosurgeons, traumatologists, and other providers and guidelines for the early identification and management of persistent mild TBI-related GHD are urgently needed.

Prevalence of Alzheimer's and Related Dementia Diseases and Risk Factors Among Transgender Adults, Florida, 2012‒2020

Objectives. To estimate the prevalence rates of Alzheimer's disease and related dementias (ADRD) and their risk factors in the transgender population and compare the rates to those in cisgender adults. Methods. We identified 1784 transgender adults in the linked electronic health records and claims data between 2012 and 2020 from the OneFlorida Clinical Research Consortium. We calculated the prevalence of ADRD and ADRD risk factors for the transgender and matched cisgender control adults. Results. The prevalence of ADRD was higher in the transgender adults compared with the cisgender control adults. Overall, the prevalence of ADRD risk factors was significantly higher in the transgender adults than the cisgender controls for 11 out of the 13 risk factors, with the only exceptions being traumatic brain injury and visual impairment. Conclusions. Transgender adults are at significantly higher risk for ADRD than cisgender adults. Our study highlights the urgent need for more research on the unique ADRD risks among the aging transgender and larger sexual- and gender-minority populations. (Am J Public Health. 2022;112(5):754-757. https://doi.org/10.2105/AJPH.2022.306720).

The Neurology Access Clinic: A Model to Improve Access to Neurologic Care in an Academic Medical Center

Background:

Delays in access to neurologic care is a major problem. In this pilot program, we aimed to evaluate the effectiveness of a novel staffing model for neurology outpatient clinic within an academic neurology center to increase access to neurological care, while incorporating such a model into a growing academic neurology department.

Methods:

We created a new model for provision of access to neurological care that could be introduced in an academic neurological department, the “access clinic”. One attending was assigned to staff the access clinic for one week at a time. This was introduced as rotation equal to conventional on-service inpatient rotations. Descriptive analyses were performed to characterize the access clinic’s performance characteristics. Comparisons were made to the previously established traditional faculty clinic model.

Results:

5,917 access clinic visits were compared to 6,000 traditional clinic visits. Lead time dropped from 142 to 18 days for new patients, and from 64 to 0 days for return visits. While total readmission rates were similar during both clinic periods, readmission through the emergency room was less for access clinic patients. Access clinic resulted in significant improvement in patient satisfaction ratings. The access clinic model was financially profitable.

Conclusions:

Our findings suggest that introducing an access clinic as service rotation for neurology faculty is both effective in offering enhanced access for patients to neurological care and for patient satisfaction. Future studies may test this model in other centers, and should address effect on provider satisfaction.

Impacts of Eligibility Criteria on Trial Participants' Age in Alzheimer's Disease Clinical Trials

Overly restricted and poorly designed eligibility criteria reduce the generalizability of the results from clinical trials. We conducted a study to identify and quantify the impacts of study traits extracted from eligibility criteria on the age of study populations in Alzheimer's Disease (AD) clinical trials. Using machine learning methods and SHapley Additive exPlanation (SHAP) values, we identified 30 and 34 study traits that excluded older patients from AD trials in our 2 generated target populations respectively. We also found that study traits had different magnitudes of impacts on the age distributions of the generated study populations across racial-ethnic groups. To our best knowledge, this was the first study that quantified the impact of eligibility criteria on the age of AD trial participants. Our research is a first step in addressing the overly restrictive eligibility criteria in AD clinical trials.

Posttraumatic Stress Disorder and Anxiety-Related Conditions

PURPOSE OF REVIEW

This article provides a synopsis of current assessment and treatment considerations for posttraumatic stress disorder (PTSD) and related anxiety disorder characteristics. Epidemiologic and neurobiological data are reviewed as well as common associated symptoms, including sleep disruption, and treatment approaches to these conditions.

RECENT FINDINGS

PTSD is no longer considered an anxiety-related disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition classification and instead is associated with trauma/stressor-related disorders. PTSD symptoms are clustered into four domains including intrusive experiences, avoidance, mood, and arousal symptoms. Despite this reclassification, similarities exist in consideration of diagnosis, treatment, and comorbidities with anxiety disorders. PTSD and anxiety-related disorders are heterogeneous, which is reflected by the neural circuits involved in the genesis of symptoms that may vary across symptom domains. Treatment is likely to benefit from consideration of this heterogeneity.Research in animal models of fear and anxiety, as well as in humans, suggests that patients with PTSD and generalized anxiety disorder have difficulty accurately determining safety from danger and struggle to suppress fear in the presence of safety cues.Empirically supported psychotherapies commonly involved exposure (fear extinction learning) and are recommended for PTSD. Cognitive-behavioral therapy has been shown to be effective in other anxiety-related disorders. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) are commonly used in the treatment of PTSD and anxiety disorders in which pharmacologic intervention is supported. Treating sleep disruption including sleep apnea (continuous positive airway pressure [CPAP]), nightmares, and insomnia (preferably via psychotherapy) may improve symptoms of PTSD, as well as improve mood in anxiety disorders.

SUMMARY

PTSD has a lifetime prevalence that is close to 10% and shares neurobiological features with anxiety disorders. Anxiety disorders are the most common class of mental conditions and are highly comorbid with other disorders; treatment considerations typically include cognitive-behavioral therapy and pharmacologic intervention. Developing technologies show some promise as treatment alternatives in the future.

Behavioral and Cognitive Aspects of Concussion

PURPOSE OF REVIEW

This review provides the reader with an overview of concussion and mild traumatic brain injury (TBI). Key aspects of the pathophysiology, signs, and symptoms, treatment and rehabilitation, and recovery from concussion/mild TBI are reviewed with an emphasis on the variety of factors that may contribute to cognitive concerns following injury.

RECENT FINDINGS

Concussion remains a clinical diagnosis based on symptoms that occur in the immediate aftermath of an applied force and in the hours, days, and weeks thereafter. Although advances have been made in advanced diagnostics, including neuroimaging and fluid biomarkers in hopes of developing objective indicators of injury, such markers currently lack sufficient specificity to be used in clinical diagnostics. The symptoms of concussion are heterogeneous and may be seen to form subtypes, each of which suggests a targeted rehabilitation by the interdisciplinary team. Although the majority of patients with concussion recover within the first 30 to 90 days after injury, some have persistent disabling symptoms. The concept of postconcussion syndrome, implying a chronic syndrome of injury-specific symptoms, is replaced by a broader concept of persistent symptoms after concussion. This concept emphasizes the fact that most persistent symptoms have their basis in complex somatic, cognitive, psychiatric, and psychosocial factors related to risk and resilience. This framework leads to the important conclusion that concussion is a treatable injury from which nearly all patients can be expected to recover.

SUMMARY

Concussion/mild TBI is a significant public health problem in civilian, military, and organized athletic settings. Recent advances have led to a better understanding of underlying pathophysiology and symptom presentation and efficacious treatment and rehabilitation of the resulting symptoms. An interdisciplinary team is well-positioned to provide problem-oriented, integrated care to facilitate recovery and to advance the evidence base supporting effective practice in diagnosis, treatment, and prevention.

Making a Difference: Affective Distress Explains Discrepancy Between Objective and Subjective Cognitive Functioning After Mild Traumatic Brain Injury

OBJECTIVE

To assess the relationship between subjective cognitive symptoms and objective cognitive test scores in patients after concussion. We additionally examined factors associated with subjective and objective cognitive dysfunction, as well as their discrepancy.

PARTICIPANTS

Eighty-six individuals (65.1% female; 74.4% adult) from an interdisciplinary concussion clinic.

METHODS

Subjective and objective cognitive functioning was measured via the SCAT-Symptom Evaluation and the CNS Vital Signs Neurocognition Index (NCI), respectively. Cognitive discrepancy scores were derived by calculating standardized residuals (via linear regression) using subjective symptoms as the outcome and NCI score as the predictor. Hierarchical regression assessed predictors (age, education, time postinjury, attention-deficit/hyperactivity disorder, affective distress, and sleep disturbance) of cognitive discrepancy scores. Nonparametric analyses evaluated relationships between predictor variables, subjective symptoms, and NCI.

RESULTS

More severe affective and sleep symptoms (large and medium effects), less time postinjury (small effect), and older age (small effect) were associated with higher subjective cognitive symptoms. Higher levels of affective distress and less time since injury were associated with higher cognitive discrepancy scores (β = .723, P < .001; β = -.204, P < .05, respectively).

CONCLUSION

Clinical interpretation of subjective cognitive dysfunction should consider these additional variables. Evaluation of affective distress is warranted in the context of higher subjective cognitive complaints than objective test performance.

Exploratory study of sport-related concussion effects on peripheral micro-RNA expression

OBJECTIVE

Explore changes in micro-RNA (miRNA) expression in blood after sport-related concussion (SRC) in collegiate athletes.

METHODS

Twenty-seven collegiate athletes (~41% male, ~75% white, age 18.8 ± 0.8 years) provided both baseline and post-SRC blood samples. Serum was analyzed for expression of miR-153-3p (n = 27), miR-223-3p (n = 23), miR-26a-5p (n = 26), miR-423-3p (n = 23), and miR-let-7a-5p (n = 23) at both time points via quantitative polymerase chain reaction (qPCR). Nonparametric analyses were used to compare miRNA expression changes between baseline and SRC and to evaluate associations with clinical outcomes (symptom severity, cognition, balance, and oculomotor function, and clinical recovery time).

RESULTS

Participants manifested a significant increase in miRNA expression following SRC for miR153-3p (Z = -2.180, p = .029, 59% of the participants increased post-SRC), miR223-3p (Z = -1.998, p = .046, 70% increased), and miR-let-7a-5p (Z = -2.190, p = .029, 65% increased). There were no statistically significant associations between changes in miRNA expression and clinical test scores, acute symptom severity, or clinical recovery time.

CONCLUSION

MiR-153-3p, miR-223-3p, and miR-let-7a-5p were significantly upregulated acutely following SRC in male and female collegiate athletes compared to baseline levels, though several athletes demonstrated no change or a decrease in expression. The biological mechanisms and functional implications of the increased expression of these circulating miRNA are unclear and require more research, as does their relevance to clinical outcomes.

Concussion Biomarkers Assessed in Collegiate Student-Athletes (BASICS) I: Normative study

OBJECTIVE

To describe variability in concussion biomarker concentrations collected from serum in a sample of healthy collegiate athletes, as well as report reliability metrics in a subsample of female athletes.

METHODS

In this observational cohort study, β-amyloid peptide 42 (Aβ₄₂), total tau, S100 calcium binding protein B (S100B), ubiquitin carboxy-terminal hydrolyzing enzyme L1 (UCH-L1), glial fibrillary acidic protein, microtubule associated protein 2, and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase) serum concentrations were measured in 415 (61% male, 40% white, aged 19.0 ± 1.2 years) nonconcussed collegiate athletes without recent exposure to head impacts. Standardized normative distributions are reported for each biomarker. We evaluated main effects (analyses of variance) of sex and race, reporting demographic-specific normative metrics when appropriate. In a subset of 31 female participants, test-retest reliability (Pearson r) and reliable change indices (80%, 90%, and 95% confidence intervals) across a 6- to 12-month interval are reported for Aβ₄₂, total tau, S100B, and UCH-L1.

RESULTS

Males exhibited higher UCH-L1 (p < 0.001, Cohen d = 0.75) and S100B (p < 0.001, d = 0.56) than females, while females had higher CNPase (p < 0.001, d = 0.43). Regarding race, black participants had higher baseline levels of UCH-L1 (p < 0.001, d = 0.61) and S100B (p < 0.001, d = 1.1) than white participants. Conversely, white participants had higher baseline levels of Aβ₄₂ (p = 0.005, d = 0.28) and CNPase (p < 0.001, d = 0.46). Test-retest reliability was generally poor, ranging from -0.02 to 0.40, and Aβ₄₂ significantly increased from time 1 to time 2.

CONCLUSION

Healthy collegiate athletes express concussion-related serum biomarkers in variable concentrations. Accounting for demographic factors such as sex and race is essential. Evidence suggested poor reliability for serum biomarkers; however, understanding how other factors influence biomarker expression, as well as knowledge of reliable change metrics, may improve clinical interpretation and future study designs.

Concussion BASICS II: Baseline serum biomarkers, head impact exposure, and clinical measures

OBJECTIVE

To examine the effect of concussion history and cumulative exposure to collision sports on baseline serum biomarker concentrations, as well as associations between biomarker concentrations and clinical assessments.

METHODS

In this observational cohort study, β-amyloid peptide 42 (Aβ₄₂), total tau, S100 calcium binding protein B (S100B), ubiquitin carboxy-terminal hydrolyzing enzyme L1 (UCH-L1), glial fibrillary acidic protein, microtubule associated protein 2, and 2',3'-cyclic-nucleotide 3'-phosphodiesterase serum concentrations were measured in 415 (61% male, 40% white, aged 19.0 ± 1.2 years) nonconcussed collegiate athletes without recent exposure to head impacts. Regression analyses were used to evaluate the relationship between self-reported history of concussion(s), cumulative years playing collision sports, clinical assessments, and baseline biomarker concentrations. Football-specific analyses were performed using a modified Cumulative Head Impact Index. Clinical assessments included symptom, cognitive, balance, and oculomotor tests.

RESULTS

Athletes with a greater number of concussions had a higher baseline Aβ₄₂ concentration only (ρ = 0.140, p = 0.005, small effect size). No biomarker concentrations correlated with cumulative exposure to collision sports. Race status fully mediated the correlations of S100B, UCH-L1, and Aβ₄₂ with cognitive scores. Football exposure, specifically, was not associated with serum biomarker concentrations or clinical assessment scores based on the modified Cumulative Head Impact Index.

CONCLUSION

Concussion-related serum biomarkers showed no consistent association with concussion history, cumulative exposure to collision sports, or clinical assessments in a sample of healthy collegiate athletes. Serum Aβ₄₂ concentrations could increase following multiple previous concussions. Considering race status is essential when investigating links between biomarkers and cognition. The biomarkers studied may not detect residual effects of concussion or repetitive head impact exposure in otherwise asymptomatic collegiate athletes without recent exposure to head impacts. Much more research is needed for identifying reliable and valid blood biomarkers of brain trauma history.

Research Gaps and Controversies in Chronic Traumatic Encephalopathy: A Review

Importance

Scientific and lay interest in negative outcomes associated with exposure to repetitive brain trauma (RBT) continues to strengthen. Concerns about the association between RBT and dementia began more than a century ago, but have resurfaced in the last decade with the more recently described chronic traumatic encephalopathy (CTE). Chronic traumatic encephalopathy is a tauopathy associated with RBT that has become inextricably linked to conversations about sport-related concussion and mild traumatic brain injury. Accordingly, specific populations such as collision sport athletes and certain military personnel are of particular interest owing to their unique exposure to RBT. The gaps and controversies in our understanding of the epidemiologic factors, mechanism, and clinicopathological correlates of CTE reflect the current reliance on postmortem case series investigations. This review discusses the state of the science of CTE and raises considerations for researching and interpreting cognitive changes in members of at-risk populations.

Observations

The recent development of pathological diagnostic criteria for CTE represented an important step for differentiating CTE from other neurodegenerative diseases. By comparison, defining the clinical syndrome(s) associated with CTE and the necessary and sufficient symptoms needed for its diagnosis lags behind. The absence of validated in vivo biomarkers of pathological characteristics of CTE and longitudinal tracking with neuropsychological evaluation remains a significant hurdle. Attribution of candidate symptoms in retired athletes to CTE is complicated by the presence of multiple premorbid and comorbid factors affecting cognitive reserve that influence normal or expected cognitive functioning. This is a critical issue in appropriately defining reference groups for normative comparisons.

Conclusions and Relevance

Available data, while limited and complicated by selection bias, indicate that exposure to RBT represents the greatest risk factor for CTE pathological features, although clinicopathological correlates and the nature of onset and progression of symptoms are largely unknown. Considering aspects of cognitive reserve is likely essential for both interpreting cognitive outcomes associated with CTE and for developing preventive treatment programs. Research on CTE would benefit greatly from incorporating principles established within other areas of neurodegenerative disease and the nuances of clinicopathological considerations.

Glymphatic system disruption as a mediator of brain trauma and chronic traumatic encephalopathy

Traumatic brain injury (TBI) is an increasingly important issue among veterans, athletes and the general public. Difficulties with sleep onset and maintenance are among the most commonly reported symptoms following injury, and sleep debt is associated with increased accumulation of beta amyloid (Aβ) and phosphorylated tau (p-tau) in the interstitial space. Recent research into the glymphatic system, a lymphatic-like metabolic clearance mechanism in the central nervous system (CNS) which relies on cerebrospinal fluid (CSF), interstitial fluid (ISF), and astrocytic processes, shows that clearance is potentiated during sleep. This system is damaged in the acute phase following mTBI, in part due to re-localization of aquaporin-4 channels away from astrocytic end feet, resulting in reduced potential for waste removal. Long-term consequences of chronic dysfunction within this system in the context of repetitive brain trauma and insomnia have not been established, but potentially provide one link in the explanatory chain connecting repetitive TBI with later neurodegeneration. Current research has shown p-tau deposition in perivascular spaces and along interstitial pathways in chronic traumatic encephalopathy (CTE), pathways related to glymphatic flow; these are the main channels by which metabolic waste is cleared. This review addresses possible links between mTBI-related damage to glymphatic functioning and physiological changes found in CTE, and proposes a model for the mediating role of sleep disruption in increasing the risk for developing CTE-related pathology and subsequent clinical symptoms following repetitive brain trauma.

Factors Influencing Clinical Correlates of Chronic Traumatic Encephalopathy (CTE): a Review

Chronic traumatic encephalopathy (CTE) is a neuropathologically defined disease reportedly linked to a history of repetitive brain trauma. As such, retired collision sport athletes are likely at heightened risk for developing CTE. Researchers have described distinct pathological features of CTE as well a wide range of clinical symptom presentations, recently termed traumatic encephalopathy syndrome (TES). These clinical symptoms are highly variable, non-specific to individuals described as having CTE pathology in case reports, and are often associated with many other factors. This review describes the cognitive, emotional, and behavioral changes associated with 1) developmental and demographic factors, 2) neurodevelopmental disorders, 3) normal aging, 4) adjusting to retirement, 5) drug and alcohol abuse, 6) surgeries and anesthesia, and 7) sleep difficulties, as well as the relationship between these factors and risk for developing dementia-related neurodegenerative disease. We discuss why some professional athletes may be particularly susceptible to many of these effects and the importance of choosing appropriate controls groups when designing research protocols. We conclude that these factors should be considered as modifiers predominantly of the clinical outcomes associated with repetitive brain trauma within a broader biopsychosocial framework when interpreting and attributing symptom development, though also note potential effects on neuropathological outcomes. Importantly, this could have significant treatment implications for improving quality of life.

Parkinson's disease psychosis: therapy tips and the importance of communication between neurologists and psychiatrists

Parkinson's disease (PD) is a chronic and complex neurodegenerative disorder resulting in a mixture of motor and nonmotor symptoms. Psychosis develops in around 60% of PD patients during and can be one of the most challenging nonmotor symptoms. PD psychosis is considered the single greatest precipitant for nursing home placement. PD psychosis is an independent predictor of increased mortality, and there is no 'ideal' or universal treatment strategy. The treatment approach to PD psychosis should be tailored and individualized for each patient. In this review, we will discuss PD psychosis and provide practical treatment considerations for neurologists, psychiatrists and other healthcare professionals. We stress the importance of real-time communication between members of the healthcare team.

Combat-related traumatic brain injury and its implications to military healthcare

Traumatic brain injury (TBI) is a known injury in today's combat arena. Improved screening and surveillance methods have diagnosed TBI with increasing frequency. Current treatment plans are based largely on information gleaned from sports injuries. However, these management paradigms fail to address the effect of physiologic stress (fatigue, dehydration) and psychological stress at the time of injury as well as the number of previous concussions that may affect recovery from combat-related TBI. This article presents current evaluation and management of combat-related injury and discusses other psychological conditions that may coexist with TBI.

Military traumatic brain injury and blast

The effects of blast on biological tissue are documented for some organ systems such as the lung. In the central nervous system (CNS) the mechanism of CNS injury following blast wave is unclear. For example is there a selective effect of blast on varying brain region or white matter bundles. The effect of blast on traumatic brain injury (TBI) has come into particular focus with the Global War on Terror and Operation Iraqi Freedom and Operation Enduring Freedom where TBI has become known as the signature injury of these conflicts. The reason for the prominence of TBI in these particular conflicts as opposed to others is unclear but may result from the increased survivability of blast due to improvements in body armor. In the current series of articles in the Journal some developments of current research concepts in relation to military traumatic brain injury (TBI) are highlighted together with many remaining unsolved questions.

Acute clinical care and care coordination for traumatic brain injury within Department of Defense

The nature of current combat situations that U.S. military forces encounter and the use of unconventional weaponry have dramatically increased service personnel's risks of sustaining a traumatic brain injury (TBI). Although the true incidence and prevalence of combat-related TBI are unknown, service personnel returning from deployment have reported rates of concussion between 10% and 20%. The Department of Defense has recently released statistics on TBI dating back to before the wars in Iraq and Afghanistan to better elucidate the impact and burden of TBI on America's warriors and veterans. Patients with severe TBI move through a well-established trauma system of care, beginning with triage of initial injury by first-responders in the war zone to acute care to rehabilitation and then returning home and to the community. Mild and moderate TBIs may pose different clinical challenges, especially when initially undetected or if treatment is delayed because more serious injuries are present. To ensure identification and prompt treatment of mild and moderate TBI, the U.S. Congress has mandated that military and Department of Veterans Affairs hospitals screen all service personnel returning from combat. Military health professionals must evaluate them for concussion and then treat the physical, emotional, and cognitive problems that may surface. A new approach to health management and care coordination is needed that will allow medical transitions between networks of care to become more centralized and allow for optimal recovery at all severity levels. This article summarizes the care systems available for the acute management of TBI from point of injury to stateside military treatment facilities. We describe TBI assessment, treatment, and overall coordination of care, including innovative clinical initiatives now used.

A brief overview of traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) within the Department of Defense

The current conflicts in the Middle East have yielded increasing awareness of the acute and chronic effect of traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). The increasing frequency of exposure to blast and multiple deployments potentially impact the probability that a service member may sustain one of these injuries. The 2008 International Conference on Behavioral Health and Traumatic Brain Injury united experts in the fields of behavioral health and traumatic brain injury to address these significant health concerns. This article summarizes current Department of Defense (DOD) initiatives related to TBI and PTSD.

Computational biology - modeling of primary blast effects on the central nervous system

OBJECTIVES

Recent military conflicts in Iraq and Afghanistan have highlighted the wartime effect of traumatic brain injury (TBI). The reason for the prominence of TBI in these particular conflicts as opposed to others is unclear but may result from the increased survivability of blast due to improvements in body armor. In the military context blunt, ballistic and blast effects may all contribute to CNS injury, however blast in particular, has been suggested as a primary cause of military TBI. While blast effects on some biological tissues, such as the lung, are documented in terms of injury thresholds, this is not the case for the CNS. We hypothesized that using bio-fidelic models, allowing for fluid-solid interaction and basic material properties available in the literature, a blast wave would interact with CNS tissue and cause a possible concussive effect.

METHODS

The modeling approach employed for this investigation consisted of a computational framework suitable for simulating coupled fluid-solid dynamic interactions. The model included a complex finite element mesh of the head and intra-cranial contents. The effects of threshold and 50% lethal blast lung injury were compared with concussive impact injury using the full head model allowing upper and lower bounds of tissue injury to be applied using pulmonary injury as the reference tissue.

RESULTS

The effects of a 50% lethal dose blast lung injury (LD(50)) were comparable with concussive impact injury using the DVBIC-MIT full head model.

INTERPRETATION

CNS blast concussive effects were found to be similar between impact mild TBI and the blast field associated with LD(50) lung blast injury sustained without personal protective equipment. With the ubiquitous use of personal protective equipment this suggests that blast concussive effects may more readily ascertained in personnel due to enhanced survivability in the current conflicts.

Case report of a soldier with primary blast brain injury

Primary blast injury of the central nervous system is described in a service-member exposed to a large ordinance explosion. Neuroimaging abnormalities are described together with normalization of the fractional anisotrophy on diffusion tensor imaging after follow-up imaging studies.

Blast physics and central nervous system injury

The effect of blast on biological tissue is well documented for particular organ systems such as the lung. This is not the case for the CNS, where the mechanism of CNS injury following a detonation and blast wave is unclear. The effect of blast on traumatic brain injury (TBI) has come into particular focus with the Global War on Terror and Operation Iraqi Freedom, and Operation Enduring Freedom where TBI has become known as the signature injury of these conflicts. The reason for the prominence of TBI in these particular conflicts as opposed to others is unclear, but may result from the increased survivability of blast due to improvements in body armor. In this review, we trace the historical context of blast injury and develop current concepts from this framework, in addition to highlighting many remaining unsolved questions.

The Neurology of Aviation, Underwater, and Space Environments

It can be seen that aspects of different environments can have adverse effects on normal, healthy nervous systems. Aerospace and underwater neurology consultants are often required to evaluate aviators, divers, or astronauts who have neurologic problem to determine whether they should be granted a waiver. In general, these considerations include course of the disorder (static, progressive, or paroxysmal), potential for sudden incapacitation that may compromise safety, predictability of course of the disorder, ability to monitor disease, and potential adverse effects of medications. A background in the toxic effects of an abnormal environment on the nervous system can be used to make better clinical judgements when considering effects of exposing someone with an abnormal nervous system to such environmental stressors.

Buspirone as an antidote to SSRI-induced bruxism in 4 cases

BACKGROUND

One hypothesis to explain selective serotonin reuptake inhibitor (SSRI)-induced bruxism states that SSRIs increase extrapyramidal serotonin levels, thereby inhibiting dopaminergic pathways controlling movement. Previous reports have emphasized buspirone's postsynaptic dopaminergic effect as a partial antidote to the suppressed dopamine levels.

CASE REPORTS

Four patients, recently started on treatment with the SSRI sertraline, presented with new-onset complaints attributable to SSRI-induced bruxism. All 4 responded to adjunctive buspirone, a serotonin-1A (5-HT1A) receptor agonist, with relief of bruxism and associated symptoms.

DISCUSSION

We expand the hypothesis put forth in previous reports by proposing that buspirone is not only acting postsynaptically in the extrapyramidal system, but also presynaptically on serotonergic neurons that influence masticatory modulation in the mesocortical tract. Our 4 cases support the concept of buspirone acting as a full agonist at the presynaptic 5-HT1A somatodendritic receptors located on the cell bodies of raphe serotonergic neurons that project to the ventral tegmental area (VTA) of the midbrain. These serotonergic neurons modulate the firing of the mesocortical tract, which itself projects from the VTA to the prefrontal cortex and acts on masticatory muscle activity through inhibiting spontaneous movements such as bruxism. While the literature is confusing and contradictory on definitions of bruxism and etiologies of incompletely understood movement disorders, we believe SSRI-induced bruxism is best conceptualized as a form of akathisia.