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Clancy U, Cheng Y, Brara A, Doubal FN, Wardlaw JM. Occupational and domestic exposure associations with cerebral small vessel disease and vascular dementia: A systematic review and meta-analysis. Alzheimers Dement 2024; 20:3021-3033. [PMID: 38270898 PMCID: PMC11032565 DOI: 10.1002/alz.13647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 01/26/2024]
Abstract
INTRODUCTION The prevalence of cerebral smallvessel disease (SVD) and vascular dementia according to workplace or domestic exposure to hazardous substances is unclear. METHODS We included studies assessing occupational and domestic hazards/at-risk occupations and SVD features. We pooled prevalence estimates using random-effects models where possible, or presented a narrative synthesis. RESULTS We included 85 studies (n = 47,743, mean age = 44·5 years). 52/85 reported poolable estimates. SVD prevalence in populations exposed to carbon monoxide was 81%(95% CI = 60-93%; n = 1373; results unchanged in meta-regression), carbon disulfide73% (95% CI = 54-87%; n = 131), 1,2-dichloroethane 88% (95% CI = 4-100%, n = 40), toluene 82% (95% CI = 3-100%, n = 64), high altitude 49% (95% CI = 38-60%; n = 164),and diving 24% (95% CI = 5-67%, n = 172). We narratively reviewed vascular dementia studies and contact sport, lead, military, pesticide, and solvent exposures as estimates were too few/varied to pool. DISCUSSION SVD and vascular dementia may be associated with occupational/domestic exposure to hazardous substances. CRD42021297800.
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Affiliation(s)
- Una Clancy
- Centre for Clinical Brain Sciences and the UK Dementia Research InstituteChancellor's BuildingUniversity of EdinburghEdinburghUK
| | - Yajun Cheng
- Center of Cerebrovascular DiseasesDepartment of NeurologyWest China HospitalSichuan UniversityChengduSichuanChina
| | - Amrita Brara
- Centre for Clinical Brain Sciences and the UK Dementia Research InstituteChancellor's BuildingUniversity of EdinburghEdinburghUK
| | - Fergus N. Doubal
- Centre for Clinical Brain Sciences and the UK Dementia Research InstituteChancellor's BuildingUniversity of EdinburghEdinburghUK
| | - Joanna M. Wardlaw
- Centre for Clinical Brain Sciences and the UK Dementia Research InstituteChancellor's BuildingUniversity of EdinburghEdinburghUK
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Botz J, Lohner V, Schirmer MD. Spatial patterns of white matter hyperintensities: a systematic review. Front Aging Neurosci 2023; 15:1165324. [PMID: 37251801 PMCID: PMC10214839 DOI: 10.3389/fnagi.2023.1165324] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023] Open
Abstract
Background White matter hyperintensities are an important marker of cerebral small vessel disease. This disease burden is commonly described as hyperintense areas in the cerebral white matter, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging data. Studies have demonstrated associations with various cognitive impairments, neurological diseases, and neuropathologies, as well as clinical and risk factors, such as age, sex, and hypertension. Due to their heterogeneous appearance in location and size, studies have started to investigate spatial distributions and patterns, beyond summarizing this cerebrovascular disease burden in a single metric-its volume. Here, we review the evidence of association of white matter hyperintensity spatial patterns with its risk factors and clinical diagnoses. Design/methods We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We used the standards for reporting vascular changes on neuroimaging criteria to construct a search string for literature search on PubMed. Studies written in English from the earliest records available until January 31st, 2023, were eligible for inclusion if they reported on spatial patterns of white matter hyperintensities of presumed vascular origin. Results A total of 380 studies were identified by the initial literature search, of which 41 studies satisfied the inclusion criteria. These studies included cohorts based on mild cognitive impairment (15/41), Alzheimer's disease (14/41), Dementia (5/41), Parkinson's disease (3/41), and subjective cognitive decline (2/41). Additionally, 6 of 41 studies investigated cognitively normal, older cohorts, two of which were population-based, or other clinical findings such as acute ischemic stroke or reduced cardiac output. Cohorts ranged from 32 to 882 patients/participants [median cohort size 191.5 and 51.6% female (range: 17.9-81.3%)]. The studies included in this review have identified spatial heterogeneity of WMHs with various impairments, diseases, and pathologies as well as with sex and (cerebro)vascular risk factors. Conclusion The results show that studying white matter hyperintensities on a more granular level might give a deeper understanding of the underlying neuropathology and their effects. This motivates further studies examining the spatial patterns of white matter hyperintensities.
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Affiliation(s)
- Jonas Botz
- Computational Neuroradiology, Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Sankt Augustin, Germany
| | - Valerie Lohner
- Cardiovascular Epidemiology of Aging, Department of Cardiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Markus D. Schirmer
- Computational Neuroradiology, Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
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Shu J, Fei W, Zhang J, Li F, Hao Y, Ding Z, Tseyang, Drolma, Ji S, Zhao W, Hu Y, Sun W, Huang Y, Zhao Y, Zhang W. Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain. Front Neurol 2023; 14:1086476. [PMID: 36970535 PMCID: PMC10034167 DOI: 10.3389/fneur.2023.1086476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Background and purpose Cerebral small-vessel disease (CSVD) is prevalent worldwide and one of the major causes of stroke and dementia. For patients with CSVD at high altitude, a special environmental status, limited information is known about their clinical phenotype and specific neuroimaging change. We investigated the clinical and neuroimaging features of patients residing at high altitude by comparing with those in the plain, trying to explore the impact of high altitude environment on CSVD. Methods Two cohorts of CSVD patients from the Tibet Autonomous Region and Beijing were recruited retrospectively. In addition to the collection of clinical diagnoses, demographic information and traditional vascular risk factors, the presence, location, and severity of lacunes and white matter hyperintensities were assessed by manual counting and using age-related white matter changes (ARWMC) rating scale. Differences between the two groups and influence of long-term residing in the plateau were analyzed. Results A total of 169 patients in Tibet (high altitude) and 310 patients in Beijing (low altitude) were enrolled. Fewer patients in high altitude group were found with acute cerebrovascular events and concomitant traditional vascular risk factors. The median (quartiles) ARWMC score was 10 (4, 15) in high altitude group and 6 (3, 12) in low altitude group. Less lacunes were detected in high altitude group [0 (0, 4)] than in low altitude group [2 (0, 5)]. In both groups, most lesions located in the subcortical (especially frontal) and basal ganglia regions. Logistic regressions showed that age, hypertension, family history of stroke, and plateau resident were independently associated with severe white matter hyperintensities, while plateau resident was negatively correlated with lacunes. Conclusion Patients of CSVD residing at high altitude showed more severe WMH but less acute cerebrovascular events and lacunes in neuroimaging, comparing to patients residing at low altitude. Our findings suggest potential biphasic effect of high altitude on the occurrence and progression of CSVD.
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Affiliation(s)
- Junlong Shu
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Wen Fei
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Jing Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Fan Li
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yu Hao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Zhijie Ding
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Tseyang
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Drolma
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Shiyong Ji
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Weiwei Zhao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Yaxiong Hu
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
| | - Wei Sun
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Yuhua Zhao
- Department of Neurology, People's Hospital of Tibet Autonomous Region, Lhasa, China
- Yuhua Zhao
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
- Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
- *Correspondence: Wei Zhang
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Zhang X, Zhang J. The human brain in a high altitude natural environment: A review. Front Hum Neurosci 2022; 16:915995. [PMID: 36188182 PMCID: PMC9520777 DOI: 10.3389/fnhum.2022.915995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/25/2022] [Indexed: 12/04/2022] Open
Abstract
With the advancement of in vivo magnetic resonance imaging (MRI) technique, more detailed information about the human brain at high altitude (HA) has been revealed. The present review aimed to draw a conclusion regarding changes in the human brain in both unacclimatized and acclimatized states in a natural HA environment. Using multiple advanced analysis methods that based on MRI as well as electroencephalography, the modulations of brain gray and white matter morphology and the electrophysiological mechanisms underlying processing of cognitive activity have been explored in certain extent. The visual, motor and insular cortices are brain regions seen to be consistently affected in both HA immigrants and natives. Current findings regarding cortical electrophysiological and blood dynamic signals may be related to cardiovascular and respiratory regulations, and may clarify the mechanisms underlying some behaviors at HA. In general, in the past 10 years, researches on the brain at HA have gone beyond cognitive tests. Due to the sample size is not large enough, the current findings in HA brain are not very reliable, and thus much more researches are needed. Moreover, the histological and genetic bases of brain structures at HA are also needed to be elucidated.
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Affiliation(s)
- Xinjuan Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
- *Correspondence: Jiaxing Zhang,
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High altitude is associated with pTau deposition, neuroinflammation, and myelin loss. Sci Rep 2022; 12:6839. [PMID: 35477957 PMCID: PMC9046305 DOI: 10.1038/s41598-022-10881-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 04/14/2022] [Indexed: 11/30/2022] Open
Abstract
Mammals are able to adapt to high altitude (HA) if appropriate acclimation occurs. However, specific occupations (professional climbers, pilots, astronauts and other) can be exposed to HA without acclimation and be at a higher risk of brain consequences. In particular, US Air Force U2-pilots have been shown to develop white matter hyperintensities (WMH) on MRI. Whether WMH are due to hypoxia or hypobaria effects is not understood. We compared swine brains exposed to 5000 feet (1524 m) above sea level (SL) with 21% fraction inspired O2 (FiO2) (Control group [C]; n = 5) vs. 30,000 feet (9144 m) above SL with 100% FiO2 group (hypobaric group [HYPOBAR]; n = 6). We performed neuropathologic assessments, molecular analyses, immunohistochemistry (IHC), Western Blotting (WB), and stereology analyses to detect differences between HYPOBAR vs. Controls. Increased neuronal insoluble hyperphosphorylated-Tau (pTau) accumulation was observed across different brain regions, at histological level, in the HYPOBAR vs. Controls. Stereology-based cell counting demonstrated a significant difference (p < 0.01) in pTau positive neurons between HYPOBAR and C in the Hippocampus. Higher levels of soluble pTau in the Hippocampus of HYPOBAR vs. Controls were also detected by WB analyses. Additionally, WB demonstrated an increase of IBA-1 in the Cerebellum and a decrease of myelin basic protein (MBP) in the Hippocampus and Cerebellum of HYPOBAR vs. Controls. These findings illustrate, for the first time, changes occurring in large mammalian brains after exposure to nonhypoxic-hypobaria and open new pathophysiological views on the interaction among hypobaria, pTau accumulation, neuroinflammation, and myelination in large mammals exposed to HA.
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Pristipino C, Germonpré P, Toni D, Sievert H, Meier B, D'Ascenzo F, Berti S, Onorato E, Bedogni F, Mas JL, Scacciatella P, Hildick-Smith D, Gaita F, Kyrle P, Thomson J, Derumeaux G, Sibbing D, Chessa M, Hornung M, Zamorano J, Dudek D. European position paper on the management of patients with patent foramen ovale. Part II - Decompression sickness, migraine, arterial deoxygenation syndromes and select high-risk clinical conditions. EUROINTERVENTION 2021; 17:e367-e375. [PMID: 33506796 PMCID: PMC9724983 DOI: 10.4244/eij-d-20-00785] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions but to date only one official position paper related to left circulation thromboembolism has been published. This interdisciplinary paper, prepared with the involvement of eight European scientific societies, reviews the available evidence and proposes a rationale for decision making for other PFO-related clinical conditions. In order to guarantee a strict evidence-based process, we used a modified grading of recommendations, assessment, development, and evaluation (GRADE) methodology. A critical qualitative and quantitative evaluation of diagnostic and therapeutic procedures was performed, including assessment of the risk/benefit ratio. The level of evidence and the strength of the position statements were weighed and graded according to predefined scales. Despite being based on limited and observational or low-certainty randomised data, a number of position statements were made to frame PFO management in different clinical settings, along with suggestions for new research avenues. This interdisciplinary position paper, recognising the low or very low certainty of existing evidence, provides the first approach to several PFO-related clinical scenarios beyond left circulation thromboembolism and strongly stresses the need for fresh high-quality evidence on these topics.
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Affiliation(s)
- Christian Pristipino
- San Filippo Neri - ASL Roma 1 Hospital, Via Alessandro Poerio 140, 00152 Rome, Italy
| | | | - Danilo Toni
- Hospital Policlinico Umberto I, Sapienza University, Rome, Italy
| | - Horst Sievert
- CardioVascular Center Frankfurt (CVC Frankfurt), Frankfurt, Germany,Anglia Ruskin University, Chelmsford, United Kingdom,University California San Francisco (UCSF), San Francisco, CA, USA
| | | | - Fabrizio D'Ascenzo
- Città della Salute e della Scienza Hospital, University of Turin, Turin, Italy
| | | | | | | | - Jean-Louis Mas
- Hôpital Sainte-Anne, Université Paris Descartes, Paris, France
| | | | - David Hildick-Smith
- Sussex Cardiac Centre, Brighton and Sussex University Hospitals, Brighton, United Kingdom
| | - Fiorenzo Gaita
- Città della Salute e della Scienza Hospital, University of Turin, Turin, Italy
| | | | | | | | - Dirk Sibbing
- Privatklinik Lauterbacher Mühle am Ostersee, Iffeldorf and Ludwig-Maximilians-Universität (LMU) München, Munich, Germany
| | - Massimo Chessa
- IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Marius Hornung
- CardioVascular Center Frankfurt (CVC Frankfurt), Frankfurt, Germany
| | | | - Dariusz Dudek
- Jagiellonian University Medical College, Krakow, Poland,Maria Cecilia Hospital, GVM Care & Research, Cotignola (RA), Italy
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Burtscher J, Mallet RT, Burtscher M, Millet GP. Hypoxia and brain aging: Neurodegeneration or neuroprotection? Ageing Res Rev 2021; 68:101343. [PMID: 33862277 DOI: 10.1016/j.arr.2021.101343] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/12/2022]
Abstract
The absolute reliance of the mammalian brain on oxygen to generate ATP renders it acutely vulnerable to hypoxia, whether at high altitude or in clinical settings of anemia or pulmonary disease. Hypoxia is pivotal to the pathogeneses of myriad neurological disorders, including Alzheimer's, Parkinson's and other age-related neurodegenerative diseases. Conversely, reduced environmental oxygen, e.g. sojourns or residing at high altitudes, may impart favorable effects on aging and mortality. Moreover, controlled hypoxia exposure may represent a treatment strategy for age-related neurological disorders. This review discusses evidence of hypoxia's beneficial vs. detrimental impacts on the aging brain and the molecular mechanisms that mediate these divergent effects. It draws upon an extensive literature search on the effects of hypoxia/altitude on brain aging, and detailed analysis of all identified studies directly comparing brain responses to hypoxia in young vs. aged humans or rodents. Special attention is directed toward the risks vs. benefits of hypoxia exposure to the elderly, and potential therapeutic applications of hypoxia for neurodegenerative diseases. Finally, important questions for future research are discussed.
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Affiliation(s)
- Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland; Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Robert T Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland
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Connolly DM, Lupa HT. Prospective Study of White Matter Health for an Altitude Chamber Research Program. Aerosp Med Hum Perform 2021; 92:215-222. [PMID: 33752784 DOI: 10.3357/amhp.5730.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: Hypobaric decompression has been associated with brain white matter injury. Relevant exposure limits are unknown, raising ethical concerns over safety of volunteers for altitude chamber research. To inform this, a prospective study of white matter status using brain Magnetic Resonance Imaging (MRI) was conducted before and after a 9-mo program of hypobaric research.METHODS: Volunteers underwent 3-D, volumetric, fluid attenuated inversion recovery (FLAIR) MRI at the University of Nottingham, UK, on study entry and again after their final exposure. MRI data were analyzed and reported independently at the University of Maryland, Baltimore, MD, USA. Entry criteria were 5 subcortical white matter hyperintensities (WMH) of total volume 0.08 mL.RESULTS: One volunteer failed screening with 63 WMH (total volume 2.38 mL). Eleven individuals completed 160 short-duration (< 1h) exposures (range 3 to 26) to 18,000 ft pressure altitude (maximum 40,000 ft), no more often than twice weekly. The cohort exhibited eight total WMH on study entry (total volume 0.166 mL) and five (mostly different) total WMH on exit (0.184 mL). Just one WMH (frontal lobe) was present on both entry and exit scans. Excess background WMH on MRI screening were associated with past mild traumatic brain injury (MTBI).CONCLUSIONS: One hypoxia familiarization plus multiple, brief, infrequent, nonhypoxic hypobaric exposures (with denitrogenation) have not promoted WMH in this small cohort. Less intensive programs of decompression stress do not warrant MRI screening. A negative past history of MTBI has strong negative predictive value for excess WMH in young healthy subjects (N 33).Connolly DM, Lupa HT. Prospective study of white matter health for an altitude chamber research program. Aerosp Med Hum Perform. 2021; 92(4):215222.
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Harrison MF, Butler WP, Murad MH, Toups GN. Decompression Sickness Risk Assessment and Awareness in General Aviation. Aerosp Med Hum Perform 2021; 92:138-145. [PMID: 33754970 DOI: 10.3357/amhp.5623.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: Decompression sickness (DCS) can occur during unpressurized flight to altitudes >18,000 ft (FL180; 5486 m). To our knowledge, this has not been studied in general aviation (GA). This knowledge gap may have public health and safety implications because the most popular models of GA aircraft by sales volume are capable of flying >FL180.METHODS: Data from a 1-yr period in a commercial flight tracking database were analyzed to identify flights >FL180 in unpressurized, piston aircraft in the United States. Peak altitude and duration at that altitude were used to calculate DCS risk employing the U.S. Air Force (USAF) Altitude Decompression Sickness Risk Assessment Computer (ADRAC). Registration numbers were cross referenced in publicly available federal databases to identify any events that might be attributable to impairment due to DCS. A web-based survey of practices and associated symptoms was also made available to GA pilots through an online discussion forum.RESULTS: During the data collection period, 1696 flights occurred. The DCS risk was calculated to be 1.9 4.2%. There were 42 responses to the survey. Of these, 25 (59.5%) pilots reported having flown at altitudes >FL180 and 21 (84%) of them reported symptoms possibly attributable to DCS. None sought medical attention. No safety events were identified for any of the aircraft during the study period.CONCLUSION: The risk of DCS in the GA community is not zero. As GA aircraft performance profiles advance and sales increase, this may have significant implications from a public health and safety perspective. Further study is warranted.Harrison MF, Butler WP, Murad MH, Toups GN. Decompression sickness risk assessment and awareness in general aviation. Aerosp Med Hum Perform. 2021; 92(3):138145.
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Ottestad W, Hansen TA, Ksin JI. Hypobaric Decompression and White Matter Hyperintensities: An Evaluation of the NATO Standard. Aerosp Med Hum Perform 2021; 92:39-42. [PMID: 33357271 DOI: 10.3357/amhp.5710.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: In their seminal work, McGuire and colleagues reported an increased incidence of white matter hyperintensities (WMH) in a cohort of U2 pilots and hypobaric chamber personnel. WMH burden was higher in U2 pilots with previous reports of decompression sickness (DCS), and McGuire's reports have raised concerns regarding adverse outcomes in the aftermath of hypobaric exposures. Accordingly, a NATO working group has recently revised its standard recommendations regarding hypobaric exposures, including measures to mitigate the risk of WMH. Mandatory recovery time for up to 72 h between repeated exposures has been suggested on the basis of experimental evidence. However, we argue that the evidence is scarce which supports restricting repeated exposures to mitigate WMH. It is plausible that WMH is correlated with DCS and emphasis should be made on limiting the duration of exposures rather than restricting short and repeated exposures. The profiles in the NATO recommendations are meant to mitigate the risk of DCS. Still, they will potentially expose NATO Air Force and Special Operations personnel to flight profiles that can give rise to DCS incidence above 35%. Awaiting reliable data, we recommend limiting the duration of exposures and allowing for short repeated exposures.Ottestad W, Hansen TA, Ksin JI. Hypobaric decompression and white matter hyperintensities: an evaluation of the NATO standard. Aerosp Med Hum Perform. 2021; 92(1):3942.
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Moore BA, Hale WJ, Nabity PS, Koehn TR, McGeary D, Peterson AL. A Retrospective, Epidemiological Review of Hemiplegic Migraines in a Military Population. Mil Med 2020; 184:781-787. [PMID: 30877794 DOI: 10.1093/milmed/usz040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/28/2019] [Accepted: 02/20/2019] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Headaches are one of the world's most common disabling conditions. They are also both highly prevalent and debilitating among military personnel and can have a significant impact on fitness for duty. Hemiplegic migraines are an uncommon, yet severely incapacitating, subtype of migraine with aura for which there has been a significant increase amongst US military personnel over the past decade. To date, there has not been a scientific report on hemiplegic migraine in United States military personnel. MATERIALS AND METHODS The aim of this study was to provide an overview of hemiplegic migraine, to analyze data on the incidence of hemiplegic migraine in US military service members, and to evaluate demographic factors associated with hemiplegic migraine diagnoses. First time diagnoses of hemiplegic migraine were extracted from the Defense Medical Epidemiological Database according to ICD-9 and ICD-10 codes for hemiplegic migraine. One sample Chi-Square goodness of fit tests were conducted on weighted demographic samples to determine whether significant proportional differences existed between gender, age, military grade, service component, race, and marital status. RESULTS From 1997 to 2007 there were no cases of hemiplegic migraine recorded in the Defense Medical Epidemiological Database. However, from 2008 to 2017 there was a significant increase in the number of initial diagnoses of hemiplegic migraine, from 4 in 2008 to a high of 101 in 2016. From 2008 to 2017, 597 new cases of hemiplegic migraine were reported among US military service members. Disproportional incidence of hemiplegic migraine was observed for gender, X2 (1, 597) = 297.37, p <.001, age, X2 (5, 597) = 62.60, p <.001, service component, X2 (3, 597) = 31.48, p <.001, pay grade X2 (3, 597) = 57.96, p <.001, and race, X2 (2, 597) = 37.32, p <.001, but not for marital status X2 (1, 597) = 2.57, p >.05. CONCLUSION Over the past decade, there has been a significant increase in the number of initial diagnoses of hemiplegic migraine in Active Duty United States military personnel. Based on these diagnosis rates, there is evidence to suggest that hemiplegic migraine has a higher incidence and prevalence rate among post 9/11 service members of the United States military as compared to the general population. Given the sudden increase in new patients diagnosed with hemiplegic migraine in the past decade, the global prevalence estimates of hemiplegic migraine should be reconsidered. Additionally, the impact of hemiplegic migraine on service member's duties and responsibilities deserves further consideration.
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Affiliation(s)
- Brian A Moore
- University of Texas at San Antonio, One UTSA Circle, San Antonio, TX.,University of Texas Health Science Center at San Antonio, 7550 Interstate Highway 10 West, Suite 1325, San Antonio, TX
| | - Willie J Hale
- University of Texas at San Antonio, One UTSA Circle, San Antonio, TX
| | - Paul S Nabity
- University of Texas Health Science Center at San Antonio, 7550 Interstate Highway 10 West, Suite 1325, San Antonio, TX
| | - Tyler R Koehn
- Brooke Army Medical Center, Department of Neurology, 3551 Roger Brooke Drive, Fort Sam Houston JBSA, TX
| | - Donald McGeary
- University of Texas Health Science Center at San Antonio, 7550 Interstate Highway 10 West, Suite 1325, San Antonio, TX
| | - Alan L Peterson
- University of Texas at San Antonio, One UTSA Circle, San Antonio, TX.,University of Texas Health Science Center at San Antonio, 7550 Interstate Highway 10 West, Suite 1325, San Antonio, TX.,South Texas Veterans Health Care System, 7400 Merton Minter Boulevard, San Antonio, TX
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Deora H, Moscote-Salazar LR, Agrawal A, Deora A. Letter: Brain Physiological Response and Adaptation During Spaceflight. Neurosurgery 2019; 85:E1136-E1137. [PMID: 31541239 DOI: 10.1093/neuros/nyz369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Harsh Deora
- Department of Neurosurgery NIMHANS, Bangalore, India
| | - Luis Rafael Moscote-Salazar
- Center for Biomedical Research (CIB) Cartagena Neurotrauma Research Group Faculty of Medicine University of Cartagena Cartagena de Indias, Colombia
| | - Amit Agrawal
- Department of Neurosurgery Narayana Medical College and Hospital Nellore, India
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Andicochea CT, Henriques ME, Fulkerson J, Jay S, Chen H, Deaton T. Elevated Environmental Carbon Dioxide Exposure Confounding Physiologic Events in Aviators? Mil Med 2019; 184:e863-e867. [PMID: 31038172 DOI: 10.1093/milmed/usz092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/24/2019] [Accepted: 03/29/2019] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Physiological events (PEs) are a growing problem for US military aviation with detrimental risks to safety and mission readiness. Seeking causative factors is, therefore, of high importance. There is no evidence to date associating carbon dioxide (CO2) pre-flight exposure and decompression sickness (DCS) in aviators. MATERIALS AND METHODS This study is a case series of six aviators with PE after being exposed to a rapid decompression event (RDE) with symptoms consistent with type II DCS. The analysis includes retrospective review of flight and environmental data to further assess a possible link between CO2 levels and altitude physiologic events (PEs). IRB approval was obtained for this study. RESULTS This case series presents six aviators with PE after being exposed to a rapid decompression event (RDE) with symptoms consistent with type II DCS. Another three aviators were also exposed to a RDE, but remained asymptomatic. All events involved tactical jet aircraft flying at an average of 35,600' Mean Sea Level (MSL) when a RDE occurred, Retrospective reviews led to the discovery that the affected individuals were exposed, pre-flight, to poor indoor air quality demonstrated by elevated levels of measured CO2. CONCLUSION PEs are a growing safety concern for the aviation community in the military. As such, increasing measures are taken to ensure safety of flight and completion of the mission. To date, there is no correlation of CO2 exposure and altitude DCS. While elevated CO2 levels cannot be conclusively implicated as causative, this case series suggests a potential role of CO2 in altitude DCS through CO2 direct involvement with emboli gas composition, as well as pro-inflammatory cascade. Aviators exposed to elevated CO2 in poorly ventilated rooms developed PE symptoms consistent with DCS, while at the same command, aviators that were exposed to a well ventilated room did not. This report is far from an answer, but does demonstrate an interesting case series that draws some questions about CO2's role in these aviator's DCS experience. Other explanations are plausible, including the accurate diagnosis of DCS, health variables amongst the aviators, and differences in aircraft and On-Board Oxygen Generation Systems (OBOGS). For a better understanding, the role of environmental CO2 and pre-flight exposure as a risk of DCS should be reviewed.
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Affiliation(s)
- Chad T Andicochea
- Naval Medical Center, Department of Emergency Medicine, 34800 Bob Wilson Dr., San Diego, CA 92134
| | - Matthew E Henriques
- Uniformed Services University of the Health Sciences, School of Medicine, 4301 Jones Bridge Rd, Bethesda, MD 20814
| | - Joel Fulkerson
- Navy Medicine Operational Training Center, Dept 33 Aerospace Medicine Residency, 340 Hulse Road, Pensacola, FL 32508-1092
| | - Susan Jay
- Commander, Naval Air Force, Pacific Force Health Services Bldg. 8C, FL 2, Rm. 200, P. O. Box 357051 NASNI, San Diego, CA 92135-7051
| | - Howard Chen
- Renown Hyperbaric Oxygen Therapy, 1500 E 2nd St #104, Reno, NV 89502
| | - Travis Deaton
- Naval Medical Center, Department of Emergency Medicine, 34800 Bob Wilson Dr., San Diego, CA 92134
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14
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Chronic Exposure to High Altitude: Synaptic, Astroglial and Memory Changes. Sci Rep 2019; 9:16406. [PMID: 31712561 PMCID: PMC6848138 DOI: 10.1038/s41598-019-52563-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/11/2019] [Indexed: 11/18/2022] Open
Abstract
Long-term operations carried out at high altitude (HA) by military personnel, pilots, and astronauts may trigger health complications. In particular, chronic exposure to high altitude (CEHA) has been associated with deficits in cognitive function. In this study, we found that mice exposed to chronic HA (5000 m for 12 weeks) exhibited deficits in learning and memory associated with hippocampal function and were linked with changes in the expression of synaptic proteins across various regions of the brain. Specifically, we found decreased levels of synaptophysin (SYP) (p < 0.05) and spinophilin (SPH) (p < 0.05) in the olfactory cortex, post synaptic density−95 (PSD-95) (p < 0.05), growth associated protein 43 (GAP43) (p < 0.05), glial fibrillary acidic protein (GFAP) (p < 0.05) in the cerebellum, and SYP (p < 0.05) and PSD-95 (p < 0.05) in the brainstem. Ultrastructural analyses of synaptic density and morphology in the hippocampus did not reveal any differences in CEHA mice compared to SL mice. Our data are novel and suggest that CEHA exposure leads to cognitive impairment in conjunction with neuroanatomically-based molecular changes in synaptic protein levels and astroglial cell marker in a region specific manner. We hypothesize that these new findings are part of highly complex molecular and neuroplasticity mechanisms underlying neuroadaptation response that occurs in brains when chronically exposed to HA.
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15
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Chapleau RR, Martin CA, Hughes SR, Baldwin JC, Sladky J, Sherman PM, Grinkemeyer M. Apolipoprotein E promoter genotypes are not associated with white matter hyperintensity development in high-altitude careers. BMC Res Notes 2019; 12:630. [PMID: 31551090 PMCID: PMC6760100 DOI: 10.1186/s13104-019-4654-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/17/2019] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE This study sought to determine if there is an association between variants in the apolipoprotein E (ApoE) promoter regions and development of white matter hyperintensities (WMH) in military subjects who have been exposed to high altitude. In an earlier study, we found that ApoE status did not correlate with WMH development, and here we hypothesized that regulation of APOE protein expression may be protective. RESULTS Our cohort of 92 subjects encountered altitude exposures above 25,000 feet mean sea level through their occupations as pilots or altitude chamber technicians. Using Taqman-style polymerase chain reaction genotyping and t-tests and two-way analyses of variance we found no significant association between ApoE promoter genotypes and the presence, volume, or quantity of WMHs after high altitude exposure. Taken together, the observations that neither ApoE genotype status nor promoter status are associated with WMH properties, we believe that the mechanism of action for developing WMH does not derive from ApoE, nor would therapies for ApoE-mediated neurodegeneration likely benefit high altitude operators.
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Affiliation(s)
- Richard R Chapleau
- Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA.
| | - CharLee A Martin
- Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA
| | - Summer R Hughes
- Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA
| | - James C Baldwin
- Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA
| | - John Sladky
- Aeromedical Research Department, Operational Health and Performance Research Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA.,59th Medical Wing, Department of Neurology, Joint Base San Antonio-Lackland, San Antonio, TX, USA
| | - Paul M Sherman
- Aeromedical Research Department, Operational Health and Performance Research Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA.,59th Medical Wing, Department of Neuroradiology, Joint Base San Antonio-Lackland, San Antonio, TX, USA
| | - Michael Grinkemeyer
- Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, U.S. Air Force School of Aerospace Medicine, Dayton, OH, USA
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16
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McGuire SA, Ryan MC, Sherman PM, Sladky JH, Rowland LM, Wijtenburg SA, Hong LE, Kochunov PV. White matter and hypoxic hypobaria in humans. Hum Brain Mapp 2019; 40:3165-3173. [PMID: 30927318 DOI: 10.1002/hbm.24587] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/05/2019] [Accepted: 03/18/2019] [Indexed: 12/18/2022] Open
Abstract
Occupational exposure to hypobaria (low atmospheric pressure) is a risk factor for reduced white matter integrity, increased white matter hyperintensive burden, and decline in cognitive function. We tested the hypothesis that a discrete hypobaric exposure will have a transient impact on cerebral physiology. Cerebral blood flow, fractional anisotropy of water diffusion in cerebral white matter, white matter hyperintensity volume, and concentrations of neurochemicals were measured at baseline and 24 hr and 72 hr postexposure in N = 64 healthy aircrew undergoing standard US Air Force altitude chamber training and compared to N = 60 controls not exposed to hypobaria. We observed that hypobaric exposure led to a significant rise in white matter cerebral blood flow (CBF) 24 hr postexposure that remained elevated, albeit not significantly, at 72 hr. No significant changes were observed in structural measurements or gray matter CBF. Subjects with higher baseline concentrations of neurochemicals associated with neuroprotection and maintenance of normal white matter physiology (glutathione, N-acetylaspartate, glutamate/glutamine) showed proportionally less white matter CBF changes. Our findings suggest that discrete hypobaric exposure may provide a model to study white matter injury associated with occupational hypobaric exposure.
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Affiliation(s)
- Stephen A McGuire
- Department of Neurology, University of Texas Health Science Center, San Antonio, Texas
| | - Meghann C Ryan
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Paul M Sherman
- U.S. Air Force School of Aerospace Medicine, 59MDW-USAFSAM/FHOH, San Antonio, Texas
| | - John H Sladky
- U.S. Air Force School of Aerospace Medicine, 59MDW-USAFSAM/FHOH, San Antonio, Texas
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Peter V Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
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Weaver LK, Wilson SH, Lindblad AS, Churchill S, Deru K, Price R, Williams CS, Orrison WW, Patel JB, Walker JM, Meehan A, Mirow S. Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study. Front Neurol 2018; 9:1030. [PMID: 30631299 PMCID: PMC6315163 DOI: 10.3389/fneur.2018.01030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/15/2018] [Indexed: 12/25/2022] Open
Abstract
Introduction: Even though mild traumatic brain injury is common and can result in persistent symptoms, traditional measurement tools can be insensitive in detecting functional deficits after injury. Some newer assessments do not have well-established norms, and little is known about how these measures perform over time or how cross-domain assessments correlate with one another. We conducted an exploratory study to measure the distribution, stability, and correlation of results from assessments used in mild traumatic brain injury in healthy, community-dwelling adults. Materials and Methods: In this prospective cohort study, healthy adult men and women without a history of brain injury underwent a comprehensive brain injury evaluation that included self-report questionnaires and neurological, electroencephalography, sleep, audiology/vestibular, autonomic, visual, neuroimaging, and laboratory testing. Most testing was performed at 3 intervals over 6 months. Results: The study enrolled 83 participants, and 75 were included in the primary analysis. Mean age was 38 years, 58 were male, and 53 were civilians. Participants did not endorse symptoms of post-concussive syndrome, PTSD, or depression. Abnormal neurological examination findings were rare, and 6 had generalized slowing on electroencephalography. Actigraphy and sleep diary showed good sleep maintenance efficiency, but 21 reported poor sleep quality. Heart rate variability was most stable over time in the sleep segment. Dynavision performance was normal, but 41 participants had abnormal ocular torsion. On eye tracking, circular, horizontal ramp, and reading tasks were more likely to be abnormal than other tasks. Most participants had normal hearing, videonystagmography, and rotational chair testing, but computerized dynamic posturography was abnormal in up to 21% of participants. Twenty-two participants had greater than expected white matter changes for age by MRI. Most abnormal findings were dispersed across the population, though a few participants had clusters of abnormalities. Conclusions: Despite our efforts to enroll normal, healthy volunteers, abnormalities on some measures were surprisingly common. Trial Registration: This study was registered at www.clinicaltrials.gov, trial identifier NCT01925963.
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Affiliation(s)
- Lindell K. Weaver
- Division of Hyperbaric Medicine Intermountain Medical Center, Murray, UT, United States
- Intermountain LDS Hospital, Salt Lake City, UT, United States
- Department of Internal Medicine, School of Medicine, University of Utah, Salt Lake City, UT, United States
| | | | | | - Susan Churchill
- Division of Hyperbaric Medicine Intermountain Medical Center, Murray, UT, United States
- Intermountain LDS Hospital, Salt Lake City, UT, United States
| | - Kayla Deru
- Division of Hyperbaric Medicine Intermountain Medical Center, Murray, UT, United States
- Intermountain LDS Hospital, Salt Lake City, UT, United States
| | - Robert Price
- Evans Army Community Hospital, Fort Carson, CO, United States
| | | | | | - Jigar B. Patel
- Lovelace Biomedical Research, Albuquerque, NM, United States
| | - James M. Walker
- Lovelace Biomedical Research, Albuquerque, NM, United States
| | - Anna Meehan
- Lovelace Biomedical Research, Albuquerque, NM, United States
| | - Susan Mirow
- Department of Internal Medicine, School of Medicine, University of Utah, Salt Lake City, UT, United States
- Lovelace Biomedical Research, Albuquerque, NM, United States
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18
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Seyithanoğlu MH, Abdallah A, Dündar TT, Kitiş S, Aralaşmak A, Gündağ Papaker M, Sasani H. Investigation of Brain Impairment Using Diffusion-Weighted and Diffusion Tensor Magnetic Resonance Imaging in Experienced Healthy Divers. Med Sci Monit 2018; 24:8279-8289. [PMID: 30447152 PMCID: PMC6252049 DOI: 10.12659/msm.911475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background The aim of this study was to understand the changes of decompression illness in healthy divers by comparing diffusion-weighted (DWI) and diffusion tensor MRI findings among healthy professional divers and healthy non-divers with no history of diving. Material/Methods A total of 26 people were recruited in this prospective study: 11 experienced divers with no history of neurological decompression disease (cohort) and 15 healthy non-divers (control). In all study subjects, we evaluated apparent diffusion coefficient (ADC) and type of diffusion tensor metric fractional anisotropy (FA) values of different brain locations (e.g., frontal and parieto-occipital white matter, hippocampus, globus pallidus, putamen, internal capsule, thalamus, cerebral peduncle, pons, cerebellum, and corpus callosum). Results ADC values of hippocampus were high in divers but low in the control group; FA values of globus pallidus and putamen were lower in divers compared to the control group. DWI depicted possible changes due to hypoxia in different regions of the brain. Statistically significant differences in ADC values were found in hypoxia, particularly in the hippocampus (p=0.0002), while FA values in the globus pallidus and putamen were statistically significant (p=0.015 and p=0.031, respectively). We detected forgetfulness in 6 divers and deterioration in fine-motor skills in 2 divers (p=0.002 and p=0.17, respectively). All of them were examined using neuro-psychometric tests. Conclusions Repeated hyperbaric exposure increases the risk of white matter damage in experienced healthy divers without neurological decompression illness. The hippocampus, globus pallidus, and putamen are the brain areas responsible for memory, learning, navigation, and fine-motor skills and are sensitive to repeated hyperbaric exposure.
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Affiliation(s)
| | - Anas Abdallah
- Department of Neurosurgery, Bezmialem Vakif University, Istanbul, Turkey
| | - Tolga Turan Dündar
- Department of Neurosurgery, Bezmialem Vakif University, Istanbul, Turkey
| | - Serkan Kitiş
- Department of Neurosurgery, Bezmialem Vakif University, Istanbul, Turkey
| | - Ayşe Aralaşmak
- Department of Radiology, Bezmialem Vakif University, Istanbul, Turkey
| | | | - Hadi Sasani
- Department of Radiology, Faculty of Medicine, Namik Kemal University, Tekirdag, Turkey
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19
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Chapleau RR, Martin CA, Hughes SR, Baldwin JC, Sladky J, Sherman PM, Grinkemeyer M. Evaluating apolipoprotein E genotype status and neuroprotective effects against white matter hyperintensity development in high-altitude careers. BMC Res Notes 2018; 11:764. [PMID: 30359295 PMCID: PMC6203269 DOI: 10.1186/s13104-018-3867-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 10/17/2018] [Indexed: 11/25/2022] Open
Abstract
Objective This study considers the use of a rapid molecular assay to evaluate apolipoprotein E (ApoE) status in military subjects who have been exposed to high altitude. We hypothesize that ApoE status may be protective against developing brain white matter hyperintensities (WMHs) after high altitude exposure. Results We tested 92 subjects who had been exposed to altitudes above 25,000 ft mean sea level, either as pilots or as altitude chamber technicians. We determined subject genetic status using rapid Taqman-style polymerase chain reaction genotyping and evaluated the association of ApoE subtype versus brain lesions using t-tests and two-way analyses of variance. Our results indicate that there is no significant association between ApoE genotype status and the presence of WMHs after high altitude exposure. We did observe a significantly higher number of hours spent at altitude for subjects with the ApoE E2 allele; however, the mechanism by which this may occur is not determined in this study. To more fully elucidate this effect, larger populations would be required to observe greater numbers of subjects with the E2 and E4 alleles.
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Affiliation(s)
- Richard R Chapleau
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, Dayton, OH, US.
| | - CharLee A Martin
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, Dayton, OH, US
| | - Summer R Hughes
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, Dayton, OH, US
| | - James C Baldwin
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, Dayton, OH, US
| | - John Sladky
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Operational Health and Performance Research Division, Wright-Patterson AFB, Dayton, OH, US.,59th Medical Wing, Department of Neurology, Joint Base San Antonio-Lackland, Houston, TX, US
| | - Paul M Sherman
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Operational Health and Performance Research Division, Wright-Patterson AFB, Dayton, OH, US.,59th Medical Wing, Department of Neuroradiology, Joint Base San Antonio-Lackland, Houston, TX, US
| | - Michael Grinkemeyer
- US Air Force School of Aerospace Medicine, Aeromedical Research Department, Applied Technology and Genomics Division, Wright-Patterson AFB, Dayton, OH, US
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20
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Cramer NP, Korotcov A, Bosomtwi A, Xu X, Holman DR, Whiting K, Jones S, Hoy A, Dardzinski BJ, Galdzicki Z. Neuronal and vascular deficits following chronic adaptation to high altitude. Exp Neurol 2018; 311:293-304. [PMID: 30321497 DOI: 10.1016/j.expneurol.2018.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/20/2018] [Accepted: 10/10/2018] [Indexed: 02/03/2023]
Abstract
We sought to understand the mechanisms underlying cognitive deficits that are reported to affect non-native subjects following their prolonged stay and/or work at high altitude (HA). We found that mice exposed to a simulated environment of 5000 m exhibit deficits in hippocampal learning and memory accompanied by abnormalities in brain MR imaging. Exposure (1-8 months) to HA led to an increase in brain ventricular volume, a reduction in relative cerebral blood flow and changes in diffusion tensor imaging (DTI) derived parameters within the hippocampus and corpus callosum. Furthermore, neuropathological examination revealed significant expansion of the neurovascular network, microglia activation and demyelination within the corpus callosum. Electrophysiological recordings from the corpus callosum indicated that axonal excitabilities are increased while refractory periods are longer despite a lack of change in action potential conduction velocities of both myelinated and unmyelinated fibers. Next generation RNA-sequencing identified alterations in hippocampal and amygdala transcriptome signaling pathways linked to angiogenesis, neuroinflammation and myelination. Our findings reveal that exposure to hypobaric-hypoxia triggers maladaptive responses inducing cognitive deficits and suggest potential mechanisms underlying the adverse impacts of staying or traveling at high altitude.
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Affiliation(s)
- Nathan P Cramer
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Alexandru Korotcov
- Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Department of Radiology and Radiological Sciences, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Asamoah Bosomtwi
- Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Department of Radiology and Radiological Sciences, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Xiufen Xu
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Derek R Holman
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Molecular & Cell Biology Graduate Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, MD, United States
| | - Kathleen Whiting
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Neuroscience Graduate Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Scott Jones
- Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Department of Radiology and Radiological Sciences, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Andrew Hoy
- Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Department of Radiology and Radiological Sciences, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Bernard J Dardzinski
- Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Department of Radiology and Radiological Sciences, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Center for Neuroscience and Regenerative Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States; Molecular & Cell Biology Graduate Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, MD, United States; Neuroscience Graduate Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
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McGuire JA, Sherman PM, Dean E, Bernot JM, Rowland LM, McGuire SA, Kochunov PV. Utilization of MRI for Cerebral White Matter Injury in a Hypobaric Swine Model-Validation of Technique. Mil Med 2018; 182:e1757-e1764. [PMID: 29087921 DOI: 10.7205/milmed-d-16-00188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Repetitive hypobaric exposure in humans induces subcortical white matter change, observable on magnetic resonance imaging (MRI) and associated with cognitive impairment. Similar findings occur in traumatic brain injury (TBI). We are developing a swine MRI-driven model to understand the pathophysiology and to develop treatment interventions. METHODS Five miniature pigs (Sus scrofa domestica) were repetitively exposed to nonhypoxic hypobaria (30,000 feet/FIO2 100%/transcutaneous PO2 >90%) while under general anesthesia. Three pigs served as controls. Pre-exposure and postexposure MRIs were obtained that included structural sequences, dynamic contrast perfusion, and diffusion tensor quantification. Statistical comparison of individual subject and group change was performed utilizing a two-tailed t test. FINDINGS No structural imaging change was noted on T2-weighted or three-dimensional fluid-attenuated inversion recovery imaging between MRI 1 and MRI 2. No absolute difference in dynamic contrast perfusion was observed. A trend (p = 0.084) toward increase in interstitial extra-axonal fluid was noted. When individual subjects were examined, this trend toward increased extra-axonal fluid paralleled a decrease in contrast perfusion rate. DISCUSSION/IMPACT/RECOMMENDATIONS This study demonstrates high reproducibility of quantitative noninvasive MRI, suggesting MRI is an appropriate assessment tool for TBI and hypobaric-induced injury research in swine. The lack of fluid-attenuated inversion recovery change may be multifactorial and requires further investigation. A trend toward increased extra-axonal water content that negatively correlates with dynamic contrast perfusion implies generalized axonal injury was induced. This study suggests this is a potential model for hypobaric-induced injury as well as potentially other axonal injuries such as TBI in which similar subcortical white matter change occurs. Further development of this model is necessary.
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Affiliation(s)
- Jennifer A McGuire
- Conte Center, Maryland Psychiatric Research Center, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228
| | - Paul M Sherman
- U.S. Air Force School of Aerospace Medicine, Aeromedical Research Department, 2510 5th Street, Building 840, Wright-Patterson AFB, OH 45433-7913
| | - Erica Dean
- U.S. Air Force School of Aerospace Medicine, Aeromedical Research Department, 2510 5th Street, Building 840, Wright-Patterson AFB, OH 45433-7913
| | - Jeremy M Bernot
- Department of Neuroradiology, 59th Medical Wing, 2200 Bergquist Drive, Suite 1, Room 7A45, Joint Base San Antonio-Lackland AFB, TX 78236
| | - Laura M Rowland
- Conte Center, Maryland Psychiatric Research Center, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228
| | - Stephen A McGuire
- U.S. Air Force School of Aerospace Medicine, Aeromedical Research Department, 2510 5th Street, Building 840, Wright-Patterson AFB, OH 45433-7913
| | - Peter V Kochunov
- Conte Center, Maryland Psychiatric Research Center, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228
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Alperin N, Bagci AM, Lee SH. Spaceflight-induced changes in white matter hyperintensity burden in astronauts. Neurology 2017; 89:2187-2191. [DOI: 10.1212/wnl.0000000000004475] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/19/2017] [Indexed: 11/15/2022] Open
Abstract
Objective:To assess the effect of weightlessness and the respective roles of CSF and vascular fluid on changes in white matter hyperintensity (WMH) burden in astronauts.Methods:We analyzed prespaceflight and postspaceflight brain MRI scans from 17 astronauts, 10 who flew a long-duration mission on the International Space Station (ISS) and 7 who flew a short-duration mission on the Space Shuttle. Automated analysis methods were used to determine preflight to postflight changes in periventricular and deep WMH, CSF, and brain tissue volumes in fluid-attenuated inversion recovery and high-resolution 3-dimensional T1-weighted imaging. Differences between cohorts and associations between individual measures were assessed. The short-term reversibility of the identified preflight to postflight changes was tested in a subcohort of 5 long-duration astronauts who had a second postflight MRI scan 1 month after the first postflight scan.Results:Significant preflight to postflight changes were measured only in the long-duration cohort and included only the periventricular WMH and ventricular CSF volumes. Changes in deep WMH and brain tissue volumes were not significant in either cohort. The increase in periventricular WMH volume was significantly associated with an increase in ventricular CSF volume (ρ = 0.63, p = 0.008). A partial reversal of these increases was observed in the long-duration subcohort with a 1-month follow-up scan.Conclusions:Long-duration exposure to microgravity is associated with an increase in periventricular WMH in astronauts. This increase was linked to an increase in ventricular CSF volume documented in ISS astronauts. There was no associated change in or abnormal levels of WMH volumes in deep white matter as reported in U-2 high-altitude pilots.
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Savica R. Environmental Neurologic Injuries. Continuum (Minneap Minn) 2017; 23:862-871. [PMID: 28570332 DOI: 10.1212/con.0000000000000470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE OF REVIEW This article discusses neurologic complications resulting from environmental injuries and the treatment modalities for these conditions. RECENT FINDINGS Recent advances include improved management of altitude sickness. Relatively uncommon conditions, such as keraunoparalysis (lightning-induced paralysis) and high-pressure neurologic syndrome, are areas of ongoing study. SUMMARY Environmental injuries may be associated with serious neurologic sequelae. This article reviews thermal and electrical injuries as well as injuries related to aviation, altitude, and diving. Recognition of signs and symptoms of such complex injuries and exposures will permit accurate diagnoses and improved outcomes.
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Wei W, Wang X, Gong Q, Fan M, Zhang J. Cortical Thickness of Native Tibetans in the Qinghai-Tibetan Plateau. AJNR Am J Neuroradiol 2017; 38:553-560. [PMID: 28104637 DOI: 10.3174/ajnr.a5050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/24/2016] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE High-altitude environmental factors and genetic variants together could have exerted their effects on the human brain. The present study was designed to investigate the cerebral morphology in high-altitude native Tibetans. MATERIALS AND METHODS T1-weighted brain images were obtained from 77 Tibetan adolescents on the Qinghai-Tibetan Plateau (altitude, 2300-5300 m) and 80 matched Han controls living at sea level. Cortical thickness, curvature, and sulcus were analyzed by using FreeSurfer. RESULTS Cortical thickness was significantly decreased in the left posterior cingulate cortex, lingual gyrus, superior parietal cortex, precuneus, and rostral middle frontal cortex and the right medial orbitofrontal cortex, lateral occipital cortex, precuneus, and paracentral lobule. Curvature was significantly decreased in the left superior parietal cortex and right superior marginal gyrus; the depth of the sulcus was significantly increased in the left inferior temporal gyrus and significantly decreased in the right superior marginal gyrus, superior temporal gyrus, and insular cortex. Moreover, cortical thickness was negatively correlated with altitude in the left superior and middle temporal gyri, rostral middle frontal cortex, insular cortex, posterior cingulate cortex, precuneus, lingual gyrus, and the right superior temporal gyrus. Curvature was positively correlated with altitude in the left rostral middle frontal cortex, insular cortex, and middle temporal gyrus. The depth of the sulcus was negatively correlated with altitude in the left lingual gyrus and right medial orbitofrontal cortex. CONCLUSIONS Differences in cortical morphometry in native Tibetans may reflect adaptations related to high altitude.
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Affiliation(s)
- W Wei
- From the MRI Center (W.W.), First Affiliated Hospital of Xiamen University, Xiamen, China.,Institute of Brain Disease and Cognition (W.W., J.Z.), Medical College of Xiamen University, Xiamen, China
| | - X Wang
- Department of Neurology (X.W.), Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
| | - Q Gong
- Huaxi Magnetic Resonance Research Center (Q.G.), West China Hospital, Sichuan University, Chengdu, China
| | - M Fan
- Department of Cognitive Sciences (M.F.), Institute of Basic Medical Sciences, Beijing, China
| | - J Zhang
- Institute of Brain Disease and Cognition (W.W., J.Z.), Medical College of Xiamen University, Xiamen, China
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McGuire SA, Boone GR, Sherman PM, Tate DF, Wood JD, Patel B, Eskandar G, Wijtenburg SA, Rowland LM, Clarke GD, Grogan PM, Sladky JH, Kochunov PV. White Matter Integrity in High-Altitude Pilots Exposed to Hypobaria. Aerosp Med Hum Perform 2016; 87:983-988. [PMID: 28323582 DOI: 10.3357/amhp.4585.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Nonhypoxic hypobaric (low atmospheric pressure) occupational exposure, such as experienced by U.S. Air Force U-2 pilots and safety personnel operating inside altitude chambers, is associated with increased subcortical white matter hyperintensity (WMH) burden. The pathophysiological mechanisms underlying this discrete WMH change remain unknown. The objectives of this study were to demonstrate that occupational exposure to nonhypoxic hypobaria is associated with altered white matter integrity as quantified by fractional anisotropy (FA) measured using diffusion tensor imaging and relate these findings to WMH burden and neurocognitive ability. METHODS There were 102 U-2 pilots and 114 age- and gender-controlled, health-matched controls who underwent magnetic resonance imaging. All pilots performed neurocognitive assessment. Whole-brain and tract-wise average FA values were compared between pilots and controls, followed by comparison within pilots separated into high and low WMH burden groups. Neurocognitive measurements were used to help interpret group difference in FA values. RESULTS Pilots had significantly lower average FA values than controls (0.489/0.500, respectively). Regionally, pilots had higher FA values in the fronto-occipital tract where FA values positively correlated with visual-spatial performance scores (0.603/0.586, respectively). There was a trend for high burden pilots to have lower FA values than low burden pilots. DISCUSSION Nonhypoxic hypobaric exposure is associated with significantly lower average FA in young, healthy U-2 pilots. This suggests that recurrent hypobaric exposure causes diffuse axonal injury in addition to focal white matter changes.McGuire SA, Boone GRE, Sherman PM, Tate DF, Wood JD, Patel B, Eskandar G, Wijtenburg SA, Rowland LM, Clarke GD, Grogan PM, Sladky JH, Kochunov PV. White matter integrity in high-altitude pilots exposed to hypobaria. Aerosp Med Hum Perform. 2016; 87(12):983-988.
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Affiliation(s)
- Stephen A. McGuire
- Department of Neurology, 59th Medical Wing, Joint Base San Antonio-Lackland, TX, USA
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Foster GE, Davies-Thompson J, Dominelli PB, Heran MKS, Donnelly J, duManoir GR, Ainslie PN, Rauscher A, Sheel AW. Changes in cerebral vascular reactivity and structure following prolonged exposure to high altitude in humans. Physiol Rep 2015; 3:3/12/e12647. [PMID: 26660556 PMCID: PMC4760444 DOI: 10.14814/phy2.12647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Although high‐altitude exposure can lead to neurocognitive impairment, even upon return to sea level, it remains unclear the extent to which brain volume and regional cerebral vascular reactivity (CVR) are altered following high‐altitude exposure. The purpose of this study was to simultaneously determine the effect of 3 weeks at 5050 m on: (1) structural brain alterations; and (2) regional CVR after returning to sea level for 1 week. Healthy human volunteers (n = 6) underwent baseline and follow‐up structural and functional magnetic resonance imaging (MRI) at rest and during a CVR protocol (end‐tidal PCO2 reduced by −10, −5 and increased by +5, +10, and +15 mmHg from baseline). CVR maps (% mmHg−1) were generated using BOLD MRI and brain volumes were estimated. Following return to sea level, whole‐brain volume and gray matter volume was reduced by 0.4 ± 0.3% (P < 0.01) and 2.6 ± 1.0% (P < 0.001), respectively; white matter was unchanged. Global gray matter CVR and white matter CVR were unchanged following return to sea level, but CVR was selectively increased (P < 0.05) in the brainstem (+30 ± 12%), hippocampus (+12 ± 3%), and thalamus (+10 ± 3%). These changes were the result of improvement and/or reversal of negative CVR to positive CVR in these regions. Three weeks of high‐altitude exposure is reflected in loss of gray matter volume and improvements in negative CVR.
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Affiliation(s)
- Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Jodie Davies-Thompson
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Manraj K S Heran
- Diagnostic and Therapeutic Neuroradiology, Vancouver General Hospital University of British Columbia, Vancouver, Canada
| | - Joseph Donnelly
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Gregory R duManoir
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Alexander Rauscher
- Department of Radiology, UBC MRI Research Centre University of British Columbia, Vancouver, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, Canada
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27
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Occupation and the risk of chronic toxic leukoencephalopathy. HANDBOOK OF CLINICAL NEUROLOGY 2015; 131:73-91. [PMID: 26563784 DOI: 10.1016/b978-0-444-62627-1.00006-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Among the hundreds of environmental insults capable of inducing nervous system injury, a small number can produce clinically significant damage to the brain white matter. The use of magnetic resonance imaging (MRI) in affected individuals has greatly illuminated this previously obscure area of neurotoxicology. Toxic leukoencephalopathy has acute and chronic forms, in both of which cognitive dysfunction is the major clinical manifestation. Chronic toxic leukoencephalopathy (CTL) has been most thoroughly described in individuals with intense and prolonged exposure to leukotoxins, but the consequences of lesser degrees of exposure are not well understood. Rare cases of CTL have been reported in workers exposed to culpable leukotoxins, but study of this syndrome is hindered by many confounds such as uncertain level of toxin exposure, the presence of multiple toxins, vague dose-response relationship, comorbid medical or neurologic disorders, psychiatric illness, and legal issues. The risk of CTL in workers is low, although it is not possible to determine quantitative risk estimates. More knowledge can be expected with the application of advanced MRI techniques to the assessment of workers who may have been exposed to known or potential leukotoxins. Preventive measures for avoiding workplace CTL will be informed by clinical assessment involving the use of advanced neuroimaging and neuropsychologic evaluation in combination with accurate measurement of leukotoxin exposure.
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Kochunov P, Fu M, Nugent K, Wright SN, Du X, Muellerklein F, Morrissey M, Eskandar G, Shukla DK, Jahanshad N, Thompson PM, Patel B, Postolache TT, Strauss KA, Shuldiner AR, Mitchell BD, Hong LE. Heritability of complex white matter diffusion traits assessed in a population isolate. Hum Brain Mapp 2015; 37:525-35. [PMID: 26538488 DOI: 10.1002/hbm.23047] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/07/2015] [Accepted: 10/22/2015] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Diffusion weighted imaging (DWI) methods can noninvasively ascertain cerebral microstructure by examining pattern and directions of water diffusion in the brain. We calculated heritability for DWI parameters in cerebral white (WM) and gray matter (GM) to study the genetic contribution to the diffusion signals across tissue boundaries. METHODS Using Old Order Amish (OOA) population isolate with large family pedigrees and high environmental homogeneity, we compared the heritability of measures derived from three representative DWI methods targeting the corpus callosum WM and cingulate gyrus GM: diffusion tensor imaging (DTI), the permeability-diffusivity (PD) model, and the neurite orientation dispersion and density imaging (NODDI) model. These successively more complex models represent the diffusion signal modeling using one, two, and three diffusion compartments, respectively. RESULTS We replicated the high heritability of the DTI-based fractional anisotropy (h(2) = 0.67) and radial diffusivity (h(2) = 0.72) in WM. High heritability in both WM and GM tissues were observed for the permeability-diffusivity index from the PD model (h(2) = 0.64 and 0.84), and the neurite density from the NODDI model (h(2) = 0.70 and 0.55). The orientation dispersion index from the NODDI model was only significantly heritable in GM (h(2) = 0.68). CONCLUSION DWI measures from multicompartmental models were significantly heritable in WM and GM. DWI can offer valuable phenotypes for genetic research; and genes thus identified may reveal mechanisms contributing to mental and neurological disorders in which diffusion imaging anomalies are consistently found. Hum Brain Mapp 37:525-535, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Peter Kochunov
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mao Fu
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Katie Nugent
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Susan N Wright
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Xiaoming Du
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Florian Muellerklein
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mary Morrissey
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - George Eskandar
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Dinesh K Shukla
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Neda Jahanshad
- Keck School of Medicine of USC, Imaging Genetics Center, Marina Del Rey, California
| | - Paul M Thompson
- Keck School of Medicine of USC, Imaging Genetics Center, Marina Del Rey, California
| | - Binish Patel
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Teodor T Postolache
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Alan R Shuldiner
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Braxton D Mitchell
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland.,Veterans Affairs Maryland Health Care System, Geriatric Research and Education Clinical Center, Baltimore, Maryland
| | - L Elliot Hong
- Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, Maryland
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McGuire SA, Sherman PM, Wijtenburg SA, Rowland LM, Grogan PM, Sladky JH, Robinson AY, Kochunov PV. White matter hyperintensities and hypobaric exposure. Ann Neurol 2014; 76:719-26. [PMID: 25164539 DOI: 10.1002/ana.24264] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/11/2014] [Accepted: 08/22/2014] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Demonstrate that occupational exposure to nonhypoxic hypobaria is associated with subcortical white matter hyperintensities (WMHs) on fluid-attenuated inversion recovery magnetic resonance imaging (MRI). METHODS Eighty-three altitude chamber personnel (PHY), 105 U-2 pilots (U2P), and 148 age- controlled and health-matched doctorate degree controls (DOC) underwent high-resolution MRI. Subcortical WMH burden was quantified as count and volume of subcortical WMH lesions after transformation of images to the Talairach atlas-based stereotactic frame. RESULTS Subcortical WMHs were more prevalent in PHY (volume p = 0.011/count p = 0.019) and U2P (volume p < 0.001/count p < 0.001) when compared to DOC, whereas PHY were not significantly different than U2P. INTERPRETATION This study provides strong evidence that nonhypoxic hypobaric exposure may induce subcortical WMHs in a young, healthy population lacking other risk factors for WMHs and adds this occupational exposure to other environmentally related potential causes of WMHs. Ann Neurol 2014;76:719-726.
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Affiliation(s)
- Stephen A McGuire
- US Air Force School of Aerospace Medicine, Aerospace Medicine Consultation Division, Wright-Patterson Air Force Base, OH; Department of Neurology, University of Texas Health Sciences Center, San Antonio, TX; Department of Neurology, 59th Medical Wing, Lackland Air Force Base, TX
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Kochunov P, Chiappelli J, Wright SN, Rowland LM, Patel B, Wijtenburg SA, Nugent K, McMahon RP, Carpenter WT, Muellerklein F, Sampath H, Hong LE. Multimodal white matter imaging to investigate reduced fractional anisotropy and its age-related decline in schizophrenia. Psychiatry Res 2014; 223:148-56. [PMID: 24909602 PMCID: PMC4100065 DOI: 10.1016/j.pscychresns.2014.05.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 04/18/2014] [Accepted: 05/08/2014] [Indexed: 01/14/2023]
Abstract
We hypothesized that reduced fractional anisotropy (FA) of water diffusion and its elevated aging-related decline in schizophrenia patients may be caused by elevated hyperintensive white matter (HWM) lesions, by reduced permeability-diffusivity index (PDI), or both. We tested this hypothesis in 40/30 control/patient participants. FA values for the corpus callosum were calculated from high angular resolution diffusion tensor imaging (DTI). Whole-brain volume of HWM lesions was quantified by 3D-T2w-fluid-attenuated inversion recovery (FLAIR) imaging. PDI for corpus callosum was ascertained using multi b-value diffusion imaging (15 b-shells with 30 directions per shell). Patients had significantly lower corpus callosum FA values, and there was a significant age-by-diagnosis interaction. Patients also had significantly reduced PDI but no difference in HWM volume. PDI and HWM volume were significant predictors of FA and captured the diagnosis-related variance. Separately, PDI robustly explained FA variance in schizophrenia patients, but not in controls. Conversely, HWM volume made equally significant contributions to variability in FA in both groups. The diagnosis-by-age effect of FA was explained by a PDI-by-diagnosis interaction. Post hoc testing showed a similar trend for PDI of gray mater. Our study demonstrated that reduced FA and its accelerated decline with age in schizophrenia were explained by pathophysiology indexed by PDI, rather than HWM volume.
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Affiliation(s)
- Peter Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA; Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250, USA.
| | - Joshua Chiappelli
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Susan N. Wright
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Laura M. Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Benish Patel
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - S. Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Katie Nugent
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Robert P. McMahon
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - William T. Carpenter
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Florian Muellerklein
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Hemalatha Sampath
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - L. Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD 21228, USA
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McGuire SA, Tate DF, Wood J, Sladky JH, McDonald K, Sherman PM, Kawano ES, Rowland LM, Patel B, Wright SN, Hong E, Rasmussen J, Willis AM, Kochunov PV. Lower neurocognitive function in U-2 pilots: Relationship to white matter hyperintensities. Neurology 2014; 83:638-45. [PMID: 25008397 DOI: 10.1212/wnl.0000000000000694] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Determine whether United States Air Force (USAF) U-2 pilots (U2Ps) with occupational exposure to repeated hypobaria had lower neurocognitive performance compared to pilots without repeated hypobaric exposure and whether U2P neurocognitive performance correlated with white matter hyperintensity (WMH) burden. METHODS We collected Multidimensional Aptitude Battery-II (MAB-II) and MicroCog: Assessment of Cognitive Functioning (MicroCog) neurocognitive data on USAF U2Ps with a history of repeated occupational exposure to hypobaria and compared these with control data collected from USAF pilots (AFPs) without repeated hypobaric exposure (U2Ps/AFPs MAB-II 87/83; MicroCog 93/80). Additional comparisons were performed between U2Ps with high vs low WMH burden. RESULTS U2Ps with repeated hypobaric exposure had significantly lower scores than control pilots on reasoning/calculation (U2Ps/AFPs 99.4/106.5), memory (105.5/110.9), information processing accuracy (102.1/105.8), and general cognitive functioning (103.5/108.5). In addition, U2Ps with high whole-brain WMH count showed significantly lower scores on reasoning/calculation (high/low 96.8/104.1), memory (102.9/110.2), general cognitive functioning (101.5/107.2), and general cognitive proficiency (103.6/108.8) than U2Ps with low WMH burden (high/low WMH mean volume 0.213/0.003 cm(3) and mean count 14.2/0.4). CONCLUSION In these otherwise healthy, highly functioning individuals, pilots with occupational exposure to repeated hypobaria demonstrated lower neurocognitive performance, albeit demonstrable on only some tests, than pilots without repeated exposure. Furthermore, within the U2P population, higher WMH burden was associated with lower neurocognitive test performance. Hypobaric exposure may be a risk factor for subtle changes in neurocognition.
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Affiliation(s)
- Stephen A McGuire
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore.
| | - David F Tate
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Joe Wood
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - John H Sladky
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Kent McDonald
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Paul M Sherman
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Elaine S Kawano
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Laura M Rowland
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Beenish Patel
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Susan N Wright
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Elliot Hong
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Jennifer Rasmussen
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Adam M Willis
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
| | - Peter V Kochunov
- From the US Air Force School of Aerospace Medicine (S.A.M., J.W., K.M., E.S.K.), Aerospace Medicine Consultation Division, Wright-Patterson AFB, OH; Department of Neurology (S.A.M., J.R.), University of Texas Health Sciences Center, San Antonio; Departments of Neuroradiology (P.M.S.) and Neurology (S.A.M., J.H.S., A.M.W.), 59th Medical Wing, Lackland AFB; Henry Jackson Foundation for the Advancement of Military Medicine (D.F.T.), San Antonio, TX; and Maryland Psychiatric Research Center (L.M.R., B.P., S.N.W., E.H., P.V.K.), University of Maryland School of Medicine, Baltimore
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Matsuo R, Kamouchi M, Arakawa S, Furuta Y, Kanazawa Y, Kitazono T. Magnetic resonance imaging in breath-hold divers with cerebral decompression sickness. Case Rep Neurol 2014; 6:23-7. [PMID: 24575029 PMCID: PMC3934779 DOI: 10.1159/000357169] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The mechanism of cerebral decompression sickness (DCS) is still unclear. We report 2 cases of breath-hold divers with cerebral DCS in whom magnetic resonance imaging (MRI) demonstrated distinctive characteristics. One case presented right hemiparesthesia, diplopia, and gait disturbance after breath-hold diving into the sea at a depth of 20 m. Brain MRI with fluid-attenuated inversion recovery (FLAIR) sequence revealed multiple hyperintense lesions in the right frontal lobe, bilateral thalamus, pons, and right cerebellar hemisphere. The second case presented visual and gait disturbance after repetitive breath-hold diving into the sea. FLAIR imaging showed hyperintense areas in the bilateral occipito-parietal lobes. In both cases, diffusion-weighted imaging and apparent diffusion coefficient mapping revealed hyperintense areas in the lesions identified by FLAIR. Moreover, follow-up MRI showed attenuation of the FLAIR signal abnormalities. These findings are suggestive of transient hyperpermeability in the microvasculature as a possible cause of cerebral DCS.
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Affiliation(s)
- Ryu Matsuo
- Department of Medicine and Clinical Science, Fukuoka, Japan
| | - Masahiro Kamouchi
- Department of Health Care Administration and Management, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shuji Arakawa
- Department of Cerebrovascular Medicine, Japan Labour Health and Welfare Organization, Kyushu Rosai Hospital, Kitakyushu, Japan
| | - Yoshihiko Furuta
- Department of Cerebrovascular Medicine, Japan Labour Health and Welfare Organization, Kyushu Rosai Hospital, Kitakyushu, Japan
| | - Yuka Kanazawa
- Department of Cerebrovascular Medicine, Japan Labour Health and Welfare Organization, Kyushu Rosai Hospital, Kitakyushu, Japan
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