The role of the brainstem in sleep disturbances and chronic pain of Gulf War and Iraq/Afghanistan veterans.

Introduction: Gulf War Illness is a type of chronic multisymptom illness, that affects about 30% of veterans deployed to the 1990-91 Persian Gulf War. Veterans deployed to Iraq/Afghanistan after 2000 are reported to have a similar prevalence of chronic multisymptom illness. More than 30 years after the Persian Gulf War, Gulf War Illness still has an unexplained symptom complex, unknown etiology and lacks definitive diagnostic criteria and effective treatments.

Brainstem Diffusion Tensor Tractography and Clinical Applications in Pain.

The brainstem is one of the most vulnerable brain structures in many neurological conditions, such as pain, sleep problems, autonomic dysfunctions, and neurodegenerative disorders. Diffusion tensor imaging and tractography provide structural details and quantitative measures of brainstem fiber pathways. Until recently, diffusion tensor tractographic studies have mainly focused on whole-brain MRI acquisition.

Distant histories of mild traumatic brain injury exacerbate age-related differences in white matter properties.

We examined associations of distant histories of mild traumatic brain injury (mTBI) with non-linear and linear trajectories of white matter (WM) properties across a wide age range (23-77). Diffusion tensor imaging (DTI) data obtained from 171 Veterans with histories of clinically diagnosed mTBIs and 115 controls were subjected to tractography, isolating 20 major WM tracts. Non-linear and linear effects of age on each tract's diffusion properties were examined in terms of their interactions with group (mTBI and control).

Brainstem damage is associated with poorer sleep quality and increased pain in gulf war illness veterans.

Aims: Gulf War Illness (GWI) is manifested as multiple chronic symptoms, including chronic pain, chronic fatigue, sleep problems, neuropsychiatric disorders, respiratory, gastrointestinal, and skin problems. No single target tissue or unifying pathogenic process has been identified that accounts for this variety of symptoms. The brainstem has been suspected to contribute to this multiple symptomatology.

Perspective: Cognitive Behavioral Therapy for Insomnia Is a Promising Intervention for Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI) is a significant public health problem. Insomnia is one of the most common symptoms of TBI, occurring in 30-50% of patients with TBI, and is more frequently reported in patients with mild as opposed to moderate or severe TBI. Although insomnia may be precipitated by mTBI, it is unlikely to subside on its own without specific treatment even after symptoms of mTBI reduce or remit.

Brainstem atrophy in Gulf War Illness.

Background: Gulf War Illness (GWI) is a condition that affects about 30 % of veterans who served in the 1990-91 Persian Gulf War. Given its broad symptomatic manifestation, including chronic pain, fatigue, neurological, gastrointestinal, respiratory, and skin problems, it is of interest to examine whether GWI is associated with changes in the brain. Existing neuroimaging studies, however, have been limited by small sample sizes, inconsistent GWI diagnosis criteria, and potential comorbidity confounds.

Cortical Thickness and Diffusion Properties in the Injured Brain: The Influence of Chronic Health Complaints.

Introduction: Cortical thickness and diffusion properties can be served as an indicator of aging and other brain changes such as those related to brain injury. It can additionally provide another platform by which we can characterize the injury and its associated symptoms, especially in the chronic condition.

Methods: We examined the changes in cortical thickness and diffusion properties in white matter tracts in 51 patients with and without traumatic brain injury (TBI) and/or self-report chronic symptoms.

Diffusion tensor tractography of brainstem fibers and its application in pain.

Evaluation of brainstem pathways with diffusion tensor imaging (DTI) and tractography may provide insights into pathophysiologies associated with dysfunction of key brainstem circuits. However, identification of these tracts has been elusive, with relatively few in vivo human studies to date. In this paper we proposed an automated approach for reconstructing nine brainstem fiber trajectories of pathways that might be involved in pain modulation.

Military Environmental Exposure Concerns, Posttraumatic Stress Disorder, and Somatic Symptoms: Their Interrelation Among Treatment-Seeking Veterans.

Objective: Research suggests military environmental exposure concerns are associated with negative health outcomes. This study investigated the relationship among exposure concerns, Posttraumatic Stress Disorder (PTSD), and somatic symptoms to enhance post-deployment health care programs for veterans.

Methods: We analyzed intake health data from a heterogeneous sample of predominantly Operation Desert Storm/Shield and Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) veterans (N = 247).

White Matter Asymmetry: A Reflection of Pathology in Traumatic Brain Injury.

Comparisons of white matter (WM) fractional anisotropy (FA) values between mild traumatic brain injury (mTBI) patients and controls have revealed inconsistencies in the directions of the resulting FA changes. To address these discrepancies, we examined hemispheric FA symmetry levels across WM tracts in 150 mTBI patients relative to 96 military controls. Automated fiber quantification was used to extract 18 WM tracts with 100 FA values, which were used to compute correlation strengths between the nine bilateral tract pairs.

Altered Microstructural Caudate Integrity in Posttraumatic Stress Disorder but Not Traumatic Brain Injury.

Objective: Given the high prevalence and comorbidity of combat-related PTSD and TBI in Veterans, it is often difficult to disentangle the contributions of each disorder. Examining these pathologies separately may help to understand the neurobiological basis of memory impairment in PTSD and TBI independently of each other. Thus, we investigated whether a) PTSD and TBI are characterized by subcortical structural abnormalities by examining diffusion tensor imaging (DTI) metrics and volume and b) if these abnormalities were specific to PTSD versus TBI.

Patterns of Cortical and Subcortical Amyloid Burden across Stages of Preclinical Alzheimer's Disease.

Objectives: We examined florbetapir positron emission tomography (PET) amyloid scans across stages of preclinical Alzheimer's disease (AD) in cortical, allocortical, and subcortical regions. Stages were characterized using empirically defined methods.

Methods: A total of 312 cognitively normal Alzheimer's Disease Neuroimaging Initiative participants completed a neuropsychological assessment and florbetapir PET scan.

Associations between Neuropsychiatric Symptoms and Cerebral Amyloid Deposition in Cognitively Impaired Elderly People.

Background: Neuropsychiatric symptoms, also known as behavioral and psychological symptoms of dementia (BPSD), affect the majority of patients with dementia, and result in a greater cognitive and functional impairment.

Objective: To investigate associations between BPSD and amyloid cerebral deposition as measured by 18F-Florbetapir-PET quantitative uptake in elderly subjects with and without cognitive impairment.

Methods: Participants with cognitive impairment [mild cognitive impairment (MCI) or Alzheimer's disease (AD)] and healthy controls (HC) from the ADNI cohort (Alzheimer Disease Neuroimaging Initiative) who underwent an 18F-florbetapir PET scan between May 2010 and March 2014 were included.

The impact of depression on Veterans with PTSD and traumatic brain injury: a diffusion tensor imaging study.

A significant proportion of military personnel deployed in support of Operation Enduring Freedom and Operation Iraqi Freedom were exposed to war-zone events associated with traumatic brain injury (TBI), depression (DEP) and posttraumatic stress disorder (PTSD). The co-occurrence of TBI, PTSD and DEP in returning Veterans has recently increased research and clinical interest. This study tested the hypothesis that white matter abnormalities are further impacted by depression.

Amyloid-β and glucose metabolism in Alzheimer's disease.

This study used PET with the amyloid-β (Aβ) imaging agent 11 C Pittsburgh Compound-B (PIB) and the glucose metabolic tracer 18F-fluorodeoxyglucose (FDG) to map the relationship of Aβ deposition to regional glucose metabolism in Alzheimer's disease (AD). Comparison of 13 AD patients' FDG scans with 11 healthy controls confirmed a typical temporo-parietal hypometabolic pattern in AD. In contrast, PIB distribution-volume-ratios showed a distinct pattern of specific tracer retention in fronto-temporo-parietal regions and striatum in AD with peaks in left frontal cortex, precuneus, temporal cortex, striatum and right posterior cingulate.

Cognition, glucose metabolism and amyloid burden in Alzheimer's disease.

The authors investigated relationships between glucose metabolism, amyloid load, and measures of cognitive and functional impairment in Alzheimer's disease (AD). Patients meeting criteria for probable AD underwent (11)C-labeled Pittsburgh Compound-B ([(11)C]PIB) and 18F-fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) imaging and were assessed on a set of clinical measures. The Pittsburgh Compound-B (PIB) Distribution volume ratios and fluorodeoxyglucose (FDG) scans were spatially normalized and average PIB counts from regions-of-interest (ROI) were used to compute a measure of global PIB uptake.

Increased metabolic vulnerability in early-onset Alzheimer's disease is not related to amyloid burden.

Patients with early age-of-onset Alzheimer's disease show more rapid progression, more generalized cognitive deficits and greater cortical atrophy and hypometabolism compared to late-onset patients at a similar disease stage. The biological mechanisms that underlie these differences are not well understood. The purpose of this study was to examine in vivo whether metabolic differences between early-onset and late-onset Alzheimer's disease are associated with differences in the distribution and burden of fibrillar amyloid-beta.

Abeta amyloid and glucose metabolism in three variants of primary progressive aphasia.

Objective: Alzheimer's disease (AD) is found at autopsy in up to one third of patients with primary progressive aphasia (PPA), but clinical features that predict AD pathology in PPA are not well defined. We studied the relationships between language presentation, Abeta amyloidosis, and glucose metabolism in three PPA variants using [11C]-Pittsburgh compound B ([11C]PIB) and [18F]-labeled fluorodeoxyglucose positron emission tomography ([18F]FDG-PET).

Methods: Patients meeting PPA criteria (N = 15) were classified as logopenic aphasia (LPA), progressive nonfluent aphasia (PNFA), or semantic dementia (SD) based on language testing.