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  • Journal article
    Yu X, Ghajari M, 2019,

    An assessment of blast modelling techniques for injury biomechanics research

    , International Journal for Numerical Methods in Biomedical Engineering, Vol: 35, Pages: 1-15, ISSN: 1069-8299

    Blast-induced Traumatic Brain Injury (TBI) has been affecting combatants and civilians. The blast pressure wave is thought to have a significant contribution to blast related TBI. Due to the limitations and difficulties of conducting blast tests on surrogates, computational modelling has been used as a key method for exploring this field. However, the blast wave modelling methods reported in current literature have drawbacks. They either cannot generate the desirable blast pressure wave history, or they are unable to accurately simulate the blast wave/structure interaction. In addition, boundary conditions, which can have significant effects on model predictions, have not been described adequately. Here, we critically assess the commonly used methods for simulating blast wave propagation in air (open-field blast) and its interaction with the human body. We investigate the predicted blast wave time history, blast wave transmission and the effects of various boundary conditions in 3 dimensional (3D) models of blast prediction. We propose a suitable meshing topology, which enables accurate prediction of blast wave propagation and interaction with the human head and significantly decreases the computational cost in 3D simulations. Finally, we predict strain and strain rate in the human brain during blast wave exposure and show the influence of the blast wave modelling methods on the brain response. The findings presented here can serve as guidelines for accurately modelling blast wave generation and interaction with the human body for injury biomechanics studies and design of prevention systems.

  • Journal article
    Rankin IA, Thuy-Tien N, Carpanen D, Clasper JC, Masouros SDet al., 2019,

    Restricting Lower Limb Flail is Key to Preventing Fatal Pelvic Blast Injury

    , ANNALS OF BIOMEDICAL ENGINEERING, Vol: 47, Pages: 2232-2240, ISSN: 0090-6964
  • Journal article
    Koziakova M, Harris K, Edge C, Franks N, White I, Dickinson Ret al., 2019,

    Noble gas neuroprotection: Xenon and argon protect against hypoxic-ischaemic injury in rat hippocampus in vitro via distinct mechanisms

    , British Journal of Anaesthesia, Vol: 123, Pages: 601-609, ISSN: 1471-6771

    BackgroundNoble gases may provide novel treatments for neurological injuries such as ischaemic and traumatic brain injury. Few studies have evaluated the complete series of noble gases under identical conditions in the same model.MethodsWe used an in vitro model of hypoxia–ischaemia to evaluate the neuroprotective properties of the series of noble gases, helium, neon, argon, krypton, and xenon. Organotypic hippocampal brain slices from mice were subjected to oxygen-glucose deprivation, and injury was quantified using propidium iodide fluorescence.ResultsBoth xenon and argon were equally effective neuroprotectants, with 0.5 atm of xenon or argon reducing injury by 96% (P<0.0001), whereas helium, neon, and krypton were devoid of any protective effect. Neuroprotection by xenon, but not argon, was reversed by elevated glycine.ConclusionsXenon and argon are equally effective as neuroprotectants against hypoxia–ischaemia in vitro, with both gases preventing injury development. Although xenon's neuroprotective effect may be mediated by inhibition of the N-methyl-d-aspartate receptor at the glycine site, argon acts via a different mechanism. These findings may have important implications for their clinical use as neuroprotectants.

  • Journal article
    Etard O, Kegler M, Braiman C, Forte AE, Reichenbach Tet al., 2019,

    Decoding of selective attention to continuous speech from the human auditory brainstem response

    , NeuroImage, Vol: 200, Pages: 1-11, ISSN: 1053-8119

    Humans are highly skilled at analysing complex acoustic scenes. The segregation of different acoustic streams and the formation of corresponding neural representations is mostly attributed to the auditory cortex. Decoding of selective attention from neuroimaging has therefore focussed on cortical responses to sound. However, the auditory brainstem response to speech is modulated by selective attention as well, as recently shown through measuring the brainstem's response to running speech. Although the response of the auditory brainstem has a smaller magnitude than that of the auditory cortex, it occurs at much higher frequencies and therefore has a higher information rate. Here we develop statistical models for extracting the brainstem response from multi-channel scalp recordings and for analysing the attentional modulation according to the focus of attention. We demonstrate that the attentional modulation of the brainstem response to speech can be employed to decode the attentional focus of a listener from short measurements of 10 s or less in duration. The decoding remains accurate when obtained from three EEG channels only. We further show how out-of-the-box decoding that employs subject-independent models, as well as decoding that is independent of the specific attended speaker is capable of achieving similar accuracy. These results open up new avenues for investigating the neural mechanisms for selective attention in the brainstem and for developing efficient auditory brain-computer interfaces.

  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge C, Franks N, Dickinson Ret al., 2019,

    Xenon prevents early neuronal loss and neuroinflammation in a rat model of traumatic brain injury

    , BJA Research Forum / Anaesthetic Research Society, Publisher: Elsevier, Pages: e508-e509, ISSN: 0007-0912
  • Journal article
    Etard O, Reichenbach J, 2019,

    Neural speech tracking in the theta and in the delta frequency band differentially encode clarity and comprehension of speech in noise

    , Journal of Neuroscience, Vol: 39, Pages: 5750-5759, ISSN: 0270-6474

    Humans excel at understanding speech even in adverse conditions such as background noise. Speech processing may be aided by cortical activity in the delta and theta frequency bands that has been found to track the speech envelope. However, the rhythm of non-speech sounds is tracked by cortical activity as well. It therefore remains unclear which aspects of neural speech tracking represent the processing of acoustic features, related to the clarity of speech, and which aspects reflect higher-level linguistic processing related to speech comprehension. Here we disambiguate the roles of cortical tracking for speech clarity and comprehension through recording EEG responses to native and foreign language in different levels of background noise, for which clarity and comprehension vary independently. We then use a both a decoding and an encoding approach to relate clarity and comprehension to the neural responses. We find that cortical tracking in the theta frequency band is mainly correlated to clarity, while the delta band contributes most to speech comprehension. Moreover, we uncover an early neural component in the delta band that informs on comprehension and that may reflect a predictive mechanism for language processing. Our results disentangle the functional contributions of cortical speech tracking in the delta and theta bands to speech processing. They also show that both speech clarity and comprehension can be accurately decoded from relatively short segments of EEG recordings, which may have applications in future mind-controlled auditory prosthesis.

  • Conference paper
    Campos-Pires R, Yonis A, Pau A, Macdonald W, Harris K, Franks N, Edge C, Dickinson Ret al., 2019,

    Delayed xenon treatment prevents injury development following blast-neurotrauma in vitro

    , 37th Annual National Neurotrauma Symposium, Publisher: Mary Ann Liebert, Pages: A40-A41, ISSN: 0897-7151
  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge CJ, Franks NP, Dickinson Ret al., 2019,

    XENON REDUCES SECONDARY INJURY, PREVENTS NEURONAL LOSS AND NEUROINFLAMMATION IN A RAT MODEL OF TRAUMATIC BRAIN INJURY

    , 37th Annual National Neurotrauma Symposium, Publisher: MARY ANN LIEBERT, INC, Pages: A116-A116, ISSN: 0897-7151
  • Conference paper
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Radyushkin K, Aldhoun J, Saville J, Edge CJ, Franks NP, Thal SC, Dickinson Ret al., 2019,

    XENON PREVENTS NEURODEGENERATION AND LATE-ONSET COGNITIVE IMPAIRMENT, AND IMPROVES SURVIVAL AFTER TRAUMATIC BRAIN INJURY IN MICE

    , 37th Annual National Neurotrauma Symposium, Publisher: MARY ANN LIEBERT, INC, Pages: A47-A47, ISSN: 0897-7151
  • Journal article
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Radyushkin K, Aldhoun J, Saville J, Edge CJ, Franks NP, Thal SC, Dickinson Ret al., 2019,

    Xenon improves long-term cognitive function, reduces neuronal loss and chronic neuroinflammation, and improves survival after traumatic brain injury in mice

    , British Journal of Anaesthesia, Vol: 123, Pages: 60-73, ISSN: 0007-0912
  • Conference paper
    Nguyen TT, Masouros S, 2019,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury
  • Conference paper
    Nguyen TT, Masouros S, 2019,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury 2019
  • Conference paper
    Nguyen TT, Meek G, Masouros S, 2019,

    Blast Fragment Protection for The Extremities

    , Light Weight Armour for Defense & Security 2019
  • Conference paper
    Campos-Pires R, Hirnet T, Valeo F, Ong BE, Saville J, Radyushkin K, Edge C, Franks N, Thal S, Dickinson Ret al., 2019,

    Xenon Treatment Prevents Late Onset Cognitive Impairment and Improves Survival Following Traumatic Brain Injury in Mice

    , 13th World Conference on Brain Injury, Pages: 220-220, ISSN: 0269-9052
  • Conference paper
    Campos-Pires R, Mohamed-Ali N, Balaet M, Aldhoun J, Abelleira-Hervas L, Aitken P, Edge C, Franks N, Dickinson Ret al., 2019,

    Xenon Treatment Reduces Secondary Injury Development and Prevents Neuronal Loss and Microglial Proliferation in a Rat Model of Traumatic Brain Injury

    , 13th World Conference on Brain injury, Pages: 222-222, ISSN: 0269-9052
  • Conference paper
    Campos-Pires R, Yonis A, Pau A, Macdonald W, Harris K, Edge C, Franks N, Dickinson Ret al., 2019,

    The Noble Gas Xenon Prevents Injury Development Following Blast-Traumatic Brain Injury In Vitro

    , 13th World Conference on Brain Injury, Pages: 218-218, ISSN: 0269-9052
  • Journal article
    Webster CE, Clasper J, Gibb I, Masouros SDet al., 2019,

    Environment at the time of injury determines injury patterns in pelvic blast

    , JOURNAL OF THE ROYAL ARMY MEDICAL CORPS, Vol: 165, Pages: 15-17, ISSN: 0035-8665
  • Journal article
    Nguyen T-T, Pearce AP, Carpanen D, Sory D, Grigoriadis G, Newell N, Clasper J, Bull A, Proud WG, Masouros SDet al., 2019,

    Experimental platforms to study blast injury

    , Journal of the Royal Army Medical Corps, Vol: 165, Pages: 33-37, ISSN: 2052-0468

    Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.

  • Journal article
    Stewart SK, Pearce AP, Clasper JC, 2019,

    Fatal head and neck injuries in military underbody blast casualties

    , Journal of the Royal Army Medical Corps, Vol: 165, Pages: 18-21, ISSN: 2052-0468

    INTRODUCTION: Death as a consequence of underbody blast (UBB) can most commonly be attributed to central nervous system injury. UBB may be considered a form of tertiary blast injury but is at a higher rate and somewhat more predictable than injury caused by more classical forms of tertiary injury. Recent studies have focused on the transmission of axial load through the cervical spine with clinically relevant injury caused by resultant compression and flexion. This paper seeks to clarify the pattern of head and neck injuries in fatal UBB incidents using a pragmatic anatomical classification. METHODS: This retrospective study investigated fatal UBB incidents in UK triservice members during recent operations in Afghanistan and Iraq. Head and neck injuries were classified by anatomical site into: skull vault fractures, parenchymal brain injuries, base of skull fractures, brain stem injuries and cervical spine fractures. Incidence of all injuries and of each injury type in isolation was compared. RESULTS: 129 fatalities as a consequence of UBB were identified of whom 94 sustained head or neck injuries. 87 casualties had injuries amenable to analysis. Parenchymal brain injuries (75%) occurred most commonly followed by skull vault (55%) and base of skull fractures (32%). Cervical spine fractures occurred in only 18% of casualties. 62% of casualties had multiple sites of injury with only one casualty sustaining an isolated cervical spine fracture. CONCLUSION: Improvement of UBB survivability requires the understanding of fatal injury mechanisms. Although previous biomechanical studies have concentrated on the effect of axial load transmission and resultant injury to the cervical spine, our work demonstrates that cervical spine injuries are of limited clinical relevance for UBB survivability and that research should focus on severe brain injury secondary to direct head impact.

  • Journal article
    Grigoriadis G, Carpanen D, Webster CE, Ramasamy A, Newell N, Masouros SDet al., 2019,

    Lower limb posture affects the mechanism of injury in under-body blast

    , Annals of Biomedical Engineering, Vol: 47, Pages: 306-316, ISSN: 0090-6964

    Over 80% of wounded Service Members sustain at least one extremity injury. The 'deck-slap' foot, a product of the vehicle's floor rising rapidly when attacked by a mine to injure the limb, has been a signature injury in recent conflicts. Given the frequency and severity of these combat-related extremity injuries, they require the greatest utilisation of resources for treatment, and have caused the greatest number of disabled soldiers during recent conflicts. Most research efforts focus on occupants seated with both tibia-to-femur and tibia-to-foot angles set at 90°; it is unknown whether results obtained from these tests are applicable when alternative seated postures are adopted. To investigate this, lower limbs from anthropometric testing devices (ATDs) and post mortem human subjects (PMHSs) were loaded in three different seated postures using an under-body blast injury simulator. Using metrics that are commonly used for assessing injury, such as the axial force and the revised tibia index, the lower limb of ATDs were found to be insensitive to posture variations while the injuries sustained by the PMHS lower limbs differed in type and severity between postures. This suggests that the mechanism of injury depends on the posture and that this cannot be captured by the current injury criteria. Therefore, great care should be taken when interpreting and extrapolating results, especially in vehicle qualification tests, when postures other than the 90°-90° are of interest.

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