Psychophysiology, Cognitive Function, and Musculoskeletal Status Holistically Explain Tactical Performance Readiness and Resilience.

ABSTRACT: Thompson, AG, Ramadan, JH, Alexander, JS, and Galster, SM. Psychophysiology, cognitive function, and musculoskeletal status holistically explain tactical performance readiness and resilience. J Strength Cond Res 37(12): 2443-2456, 2023-This study aimed to advance the techniques used in quantifying holistic readiness and resilience within military personnel. Tactical performers, instructors, and applied human performance scientists designed a weeklong competition to reflect realistic operational demands, test specific underlying performance constructs, and elucidate how modernized assessments could drive programmatic action. By placing first in their installation's local preliminary competition, 34 active-duty Marines earned the opportunity to compete in a series of 7 intense events for the title of champion. All inferential statistics were set to a p ≤ 0.05 level of significance. Morning heart rate variability identified top from bottom quartile finishers before a single competition event. By day 3, morning countermovement jump force production (normalized reactive strength index-modified) and cognitive psychomotor vigilance were significant indicators of performance resilience and final competition group rank. Heart rate variability also tracked performer readiness across time, identifying within-group and between-group differences among top, bottom, and field. Collectively, these holistic assessments proved significant markers of acute and chronic tactical performance capabilities. In summary, the incorporation of psychophysiological monitoring, cognitive performance testing, and musculoskeletal force plate evaluations could help inform selection and support needs, drive workload or recovery modulation, and provide critical metrics for evaluating training efficacy and operational readiness. Defense organizations should consider routinely incorporating and actioning similar holistic status monitoring strategies in training and operational settings. Moreover, leveraging other tactical competitions may provide key opportunities for advancing the standard of practice through additional scientific investigation.

Not according to plan: Cognitive failures in marksmanship due to effects of expertise, unknown environments, and the likelihood of shooting unintended targets.

Shooting errors have multi-faceted causes with contributing factors that include sensorimotor activity and cognitive failures. Empirical investigations often assess mental errors through threat identification, yet other cognitive failures could contribute to poor outcomes. The current study explored several possible sources of cognitive failures unrelated to threat identification with live fire exercises. Experiment 1 examined a national shooting competition to compare marksmanship accuracy, expertise, and planning in the likelihood of hitting no-shoot or unintended targets. Experts demonstrated an inverse speed/accuracy trade-off and fired upon fewer no-shoot targets than lesser skilled shooters, yet overall, greater opportunity to plan produced more no-shoot errors, thereby demonstrating an increase in cognitive errors. Experiment 2 replicated and extended this finding under conditions accounting for target type, location, and number. These findings further dissociate the roles of marksmanship and cognition in shooting errors while suggesting that marksmanship evaluations should be re-designed to better incorporate cognitive variables.

Ultra-brief training in cognitive reappraisal or mindfulness reduces anxiety and improves motor performance efficiency under stress.

BACKGROUND AND OBJECTIVES: We examined the effects of ultra-brief training in mindfulness and cognitive reappraisal on affective response and performance under stress. We hypothesized that one or both types of training would decrease affective responding and improve performance, and that these effects might be moderated by acute stress induction. DESIGN: We manipulated training (mindfulness, cognitive reappraisal, control) between subjects and level of stress (low, high) within subjects in a 3 × 2 mixed factorial design. Method: Participants (N = 112, ages 18-35) completed two sessions on different days. In each session, they received mindfulness or cognitive reappraisal training or listened to a control script prior to a low- or high-stress simulated hostage situation. We measured motor performance efficiency (proportion of shots that hit hostile and hostage targets), affective responding (self-reported anxiety, salivary cortisol and alpha amylase, and autonomic physiology), and physical activity. RESULTS: Compared to control instructions, ultra-brief training in cognitive reappraisal or mindfulness reduced subjective anxiety and increased performance efficiency. There were few effects of training on other measures. CONCLUSION: Ultra-brief training in cognitive reappraisal or mindfulness prior to a stressful task may be both helpful and harmful; effects are preliminary and subject to boundary conditions.

Applying Heart Rate Variability to Monitor Health and Performance in Tactical Personnel: A Narrative Review.

Human performance optimization of tactical personnel requires accurate, meticulous, and effective monitoring of biological adaptations and systemic recovery. Due to an increased understanding of its importance and the commercial availability of assessment tools, the use of heart rate variability (HRV) to address this need is becoming more common in the tactical community. Measuring HRV is a non-invasive, practical method for objectively assessing a performer's readiness, workload, and recovery status; when combined with additional data sources and practitioner input, it provides an affordable and scalable solution for gaining actionable information to support the facilitation and maintenance of operational performance. This narrative review discusses the non-clinical use of HRV for assessing, monitoring, and interpreting autonomic nervous system resource availability, modulation, effectiveness, and efficiency in tactical populations. Broadly, HRV metrics represent a complex series of interactions resulting from internal and external stimuli; therefore, a general overview of HRV applications in tactical personnel is discussed, including the influence of occupational specific demands, interactions between cognitive and physical domains, and recommendations on implementing HRV for training and recovery insights into critical health and performance outcomes.

Evaluation of plasma tau and neurofilament light chain biomarkers in a 12-year clinical cohort of human prion diseases.

Prion diseases are fatal neurodegenerative conditions with highly accurate CSF and imaging diagnostic tests, but major unmet needs for blood biomarkers. Using ultrasensitive immuno-assays, we measured tau and neurofilament light chain (NfL) protein concentrations in 709 plasma samples taken from 377 individuals with prion disease during a 12 year prospective clinical study, alongside healthy and neurological control groups. This provides an unprecedented opportunity to evaluate their potential as biomarkers. Plasma tau and NfL were increased across all prion disease types. For distinguishing sCJD from control groups including clinically-relevant "CJD mimics", both show considerable diagnostic value. In sCJD, NfL was substantially elevated in every sample tested, including during early disease with minimal functional impairment and in all follow-up samples. Plasma tau was independently associated with rate of clinical progression in sCJD, while plasma NfL showed independent association with severity of functional impairment. In asymptomatic PRNP mutation carriers, plasma NfL was higher on average in samples taken within 2 years of symptom onset than in samples taken earlier. We present biomarker trajectories for nine mutation carriers healthy at enrolment who developed symptoms during follow-up. NfL started to rise as early as 2 years before onset in those with mutations typically associated with more slowly progressive clinical disease. This shows potential for plasma NfL as a "proximity marker", but further work is needed to establish predictive value on an individual basis, and how this varies across different PRNP mutations. We conclude that plasma tau and NfL have potential to fill key unmet needs for biomarkers in prion disease: as a secondary outcome for clinical trials (NfL and tau); for predicting onset in at-risk individuals (NfL); and as an accessible test for earlier identification of patients that may have CJD and require more definitive tests (NfL). Further studies should evaluate their performance directly in these specific roles.

Assessing the Accuracy of Popular Commercial Technologies That Measure Resting Heart Rate and Heart Rate Variability.

Commercial off-the shelf (COTS) wearable devices continue development at unprecedented rates. An unfortunate consequence of their rapid commercialization is the lack of independent, third-party accuracy verification for reported physiological metrics of interest, such as heart rate (HR) and heart rate variability (HRV). To address these shortcomings, the present study examined the accuracy of seven COTS devices in assessing resting-state HR and root mean square of successive differences (rMSSD). Five healthy young adults generated 148 total trials, each of which compared COTS devices against a validation standard, multi-lead electrocardiogram (mECG). All devices accurately reported mean HR, according to absolute percent error summary statistics, although the highest mean absolute percent error (MAPE) was observed for CameraHRV (17.26%). The next highest MAPE for HR was nearly 15% less (HRV4Training, 2.34%). When measuring rMSSD, MAPE was again the highest for CameraHRV [112.36%, concordance correlation coefficient (CCC): 0.04], while the lowest MAPEs observed were from HRV4Training (4.10%; CCC: 0.98) and OURA (6.84%; CCC: 0.91). Our findings support extant literature that exposes varying degrees of veracity among COTS devices. To thoroughly address questionable claims from manufacturers, elucidate the accuracy of data parameters, and maximize the real-world applicative value of emerging devices, future research must continually evaluate COTS devices.

Monitoring Neuromuscular Performance in Military Personnel.

A necessarily high standard for physical readiness in tactical environments is often accompanied by high incidences of injury due to overaccumulations of neuromuscular fatigue (NMF). To account for instances of overtraining stimulated by NMF, close monitoring of neuromuscular performance is warranted. Previously validated tests, such as the countermovement jump, are useful means for monitoring performance adaptations, resiliency to fatigue, and risk for injury. Performing such tests on force plates provides an understanding of the movement strategy used to obtain the resulting outcome (e.g., jump height). Further, force plates afford numerous objective tests that are valid and reliable for monitoring upper and lower extremity muscular strength and power (thus sensitive to NMF) with less fatiguing and safer methods than traditional one-repetition maximum assessments. Force plates provide numerous software and testing application options that can be applied to military's training but, to be effective, requires the practitioners to have sufficient knowledge of their functions. Therefore, this review aims to explain the functions of force plate testing as well as current best practices for utilizing force plates in military settings and disseminate protocols for valid and reliable testing to collect key variables that translate to physical performance capacities.

A blood miRNA signature associates with sporadic Creutzfeldt-Jakob disease diagnosis.

Sporadic Creutzfeldt-Jakob disease (sCJD) presents as a rapidly progressive dementia which is usually fatal within six months. No clinical blood tests are available for diagnosis or disease monitoring. Here, we profile blood microRNA (miRNA) expression in sCJD. Sequencing of 57 sCJD patients, and healthy controls reveals differential expression of hsa-let-7i-5p, hsa-miR-16-5p, hsa-miR-93-5p and hsa-miR-106b-3p. Downregulation of hsa-let-7i-5p, hsa-miR-16-5p and hsa-miR-93-5p replicates in an independent cohort using quantitative PCR, with concomitant upregulation of four mRNA targets. Absence of correlation in cross-sectional analysis with clinical phenotypes parallels the lack of association between rate of decline in miRNA expression, and rate of disease progression in a longitudinal cohort of samples from 21 patients. Finally, the miRNA signature shows a high level of accuracy in discriminating sCJD from Alzheimer's disease. These findings highlight molecular alterations in the periphery in sCJD which provide information about differential diagnosis and improve mechanistic understanding of human prion diseases.

A new way of rapidly screening for depression in multiple sclerosis using Emotional Thermometers.

OBJECTIVE: Depression is a common, serious, but under-recognised problem in multiple sclerosis (MS). The primary objective of this study was to assess whether a rapid visual analogue screening tool for depression could operate as a quick and reliable screening method for depression, in patients with MS. METHOD: Patients attending a regional MS outpatient clinic completed the Emotional Thermometer 7 tool (ET7), the Hospital Anxiety and Depression Scale - Depression Subscale (HADS-D) and the Major Depression Inventory (MDI) to establish a Diagnostic and Statistical Manual, 4th edition (DSM-IV) diagnosis of Major Depression. Full ET7, briefer subset ET4 version and depression and distress thermometers alone were compared with HADS-D and MDI. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and receiver operating characteristic (ROC) curve were calculated to compare the performance of all the screening tools. RESULTS: In total, 190 patients were included. ET4 performed well as a 'rule-out' screening step (sensitivity 0.91, specificity 0.72, NPV 0.98, PPV 0.32). ET4 performance was comparable to HADS-D (sensitivity 0.96, specificity 0.77, NPV 0.99, PPV 0.37) without need for clinician scoring. The briefer ET4 performed as well as the full ET7. CONCLUSION: ET are quick, sensitive and useful screening tools for depression in this MS population, to be complemented by further questioning or more detailed psychiatric assessment where indicated. Given that ET4 and ET7 perform equally well, we recommend the use of ET4 as it is briefer. It has the potential to be widely implemented across busy neurology clinics to assist in depression screening in this under diagnosed group.

Review: Fluid biomarkers in the human prion diseases.

The human prion diseases are a diverse set of often rapidly progressive neurodegenerative conditions associated with abnormal forms of the prion protein. We review work to establish diagnostic biomarkers and assays that might fill other important roles, particularly those that could assist the planning and interpretation of clinical trials. The field now benefits from highly sensitive and specific diagnostic biomarkers using cerebrospinal fluid: detecting by-products of rapid neurodegeneration or specific functional properties of abnormal prion protein, with the second generation real time quaking induced conversion (RT-QuIC) assay being particularly promising. Blood has been a more challenging analyte, but has now also yielded valuable biomarkers. Blood-based assays have been developed with the potential to screen for variant Creutzfeldt-Jakob disease, although it remains uncertain whether these will ever be used in practice. The very rapid neurodegeneration of prion disease results in strong signals from surrogate protein markers in the blood that reflect neuronal, axonal, synaptic or glial pathology in the brain: notably the tau and neurofilament light chain proteins. We discuss early evidence that such tests, applied alongside robust diagnostic biomarkers, may have potential to add value as clinical trial outcome measures, predictors of future disease course (including for asymptomatic individuals at high risk of prion disease), and as rapidly accessible and sensitive markers to aid early diagnosis.

Why self-controlled feedback enhances motor learning: Answers from electroencephalography and indices of motivation.

It was tested whether learners who choose when to receive augmented feedback while practicing a motor skill exhibit enhanced augmented feedback processing and intrinsic motivation, along with superior learning, relative to learners who do not control their feedback. Accordingly, participants were assigned to either self-control (Self) or yoked groups and asked to practice a non-dominant arm beanbag toss. Self participants received augmented feedback at their discretion, whereas Yoked participants were given feedback schedules matched to Self counterparts. Participants' visual feedback was occluded, and when they received augmented feedback, their processing of it was indexed with the electroencephalography-derived feedback-related negativity (FRN). Participants self-reported intrinsic motivation via the Intrinsic Motivation Inventory (IMI) after practice, and completed a retention and transfer test the next day to index learning. Results partially support the hypothesis. Specifically, Self participants reported higher IMI scores, exhibited larger FRNs, and demonstrated better accuracy on the transfer test, but not on the retention test, nor did they exhibit greater consistency on the retention or transfer tests. Additionally, post-hoc multiple regression analysis indicated FRN amplitude predicted transfer test accuracy (accounting for IMI score). Results suggest self-controlled feedback schedules enhance feedback processing, which enhances the transfer of a newly acquired motor skill.

The efficacy of auditory probes in indexing cognitive workload is dependent on stimulus complexity.

We examined whether the utility of a recently developed auditory probe technique for indexing cognitive workload was dependent on the stimulus properties of the probes. EEG was recorded while participants played a videogame under various levels of cognitive workload. At each level of workload, participants were probed with one of four different types of auditory stimuli: novel complex, repeated complex, novel simple, or repeated simple sounds. Probe efficacy at indexing cognitive workload was assessed by determining which probes elicited ERP components that decreased monotonically as a function of workload. Results suggest that complex auditory stimuli were significantly more effective in indexing cognitive workload than simple stimuli. The efficacy of complex stimuli was due to their ability to elicit a robust orienting response, indexed by the early P3a component of the ERP, which decreased monotonically as a function of cognitive workload.

Autonomic response to tactical pistol performance measured by heart rate variability.

This study evaluated changes in autonomic tone during a tactical pistol competition. At rest and during a match, heart rate variability (HRV) was examined in 28 healthy subjects. Heart rate variability time-domain variables (including interbeat interval [IBI]) and frequency-domain variables (low frequency [LF], high frequency [HF], total power [TP]) measured during shooting were subtracted from those measured during rest to produce Δs. The shooting task involved several, rapid tactical maneuvers. Raw time to completion and inaccurate shots (points down [PDs]) were recorded and combined to form a match score where lower values indicated superior shooting performance. Mean (±SD) raw time was 135.9 ± 34.1 seconds, PDs were 78 ± 34, and match score was 175.3 ± 39.8. Shooting decreased IBI (i.e., increased heart rate) and LF. ΔLF, ΔHF, and ΔTP were independent of ΔIBI. Raw time was significantly (p ≤ 0.05) correlated to shooting IBI (r = 0.404) and ΔIBI (r = -0.426). Points down were significantly correlated to ΔTP (r = 0.416) and ΔLF (r = 0.376). Match score was significantly correlated to ΔIBI (r = -0.458), ΔHF (r = 0.467), ΔLF (r = 0.377), and ΔTP (r = 0.451). In conclusion, individuals with a greater decrease in IBI (and thus heart rate) performed better by accomplishing the match faster. Individuals with less change in stress-related HRV measures (LF, HF, and TP) performed better through improved accuracy. Thus, HRV-derived sympathetic response is significantly related to shooting performance and should be used to assess marksmanship effectiveness under duress.

Acute effect of breathing exercises on heart rate variability in type 2 diabetes: a pilot study.

BACKGROUND: Type 2 diabetes (T2D) is associated with autonomic nervous system damage resulting in reduced heart rate variability (HRV). Limited evidence suggests yogic breathing exercises may improve indices of HRV. PURPOSE: The purpose of this study was to evaluate the effect of two commonly used yogic breathing exercises on HRV in T2D versus an age-matched, normoglycemic (CON) population. METHODS: Twelve (12) subjects with T2D (7 female, 5 male; 54.9±7.4 years) and 14 CON subjects (12 female, 2 male; 54.7±6.8 years) participated in a breathing protocol consisting of two 10-min bouts of randomly assigned uni-nostril breathing (UNB). UNB bouts were preceded and followed by 5-min periods of dual-nostril paced breathing (PB). HRV was measured by standard deviation of normal-to-normal consecutive heartbeats (SDNN), square root of the mean squared differences in successive normal heartbeats (RMSSD), and total spectral power (TP). All data (except instantaneous heart rate) were log transformed to improve normality. Within-group comparisons were analyzed using analysis of variance with repeated measures, whereas between-group comparisons were analyzed using independent-samples t-test. RESULTS: Between-groups comparisons revealed significant reductions in all measures of HRV at nearly all time points in T2D compared to CON. Within-group comparison demonstrated no significant effect of UNB or PB on HRV in CON. In the T2D group, however, left UNB significantly reduced mean HR (-1.2 bpm, p<0.05) as well as TP (p<0.05). CONCLUSIONS: In summary, neither UNB nor PB had an impact upon HRV in a healthy older population and had a minimal impact in T2D.

The Medical Research Council prion disease rating scale: a new outcome measure for prion disease therapeutic trials developed and validated using systematic observational studies.

Progress in therapeutics for rare disorders like prion disease is impeded by the lack of validated outcome measures and a paucity of natural history data derived from prospective observational studies. The first analysis of the U.K. National Prion Monitoring Cohort involved 1337 scheduled clinical assessments and 479 telephone assessments in 437 participants over 373 patient-years of follow-up. Scale development has included semi-quantitative and qualitative carer interviews, item response modelling (Rasch analysis), inter-rater reliability testing, construct analysis and correlation with several existing scales. The proposed 20-point Medical Research Council prion disease rating scale assesses domains of cognitive function, speech, mobility, personal care/feeding and continence, according to their relative importance documented by carer interviews. It is quick and simple to administer, and has been validated for use by doctors and nurses and for use over the telephone, allowing for frequent assessments that capture the rapid change typical of these diseases. The Medical Research Council Scale correlates highly with widely used cognitive and single item scales, but has substantial advantages over these including minimal floor effects. Three clear patterns of decline were observed using the scale: fast linear decline, slow linear decline (usually inherited prion disease) and in some patients, decline followed by a prolonged preterminal plateau at very low functional levels. Rates of decline and progress through milestones measured using the scale vary between sporadic, acquired and inherited prion diseases following clinical expectations. We have developed and validated a new functionally-oriented outcome measure and propose that future clinical trials in prion disease should collect data compatible with this scale, to allow for combined and comparative analyses. Such approaches may be advantageous in orphan conditions, where single studies of feasible duration will often struggle to achieve statistical power.

One stop or full stop? The continuing challenges for researchers despite the new streamlined NHS research governance process.

BACKGROUND: Obtaining the necessary approvals and permission for clinical research requires successful negotiation of the ethical and R&D layers of the NHS. Differences in structure and governance frameworks feature between the constituent nations of the UK (England, Scotland, Wales and Northern Ireland), which adds complexity to cross-national studies. Difficulties in carrying out research in the NHS in the UK due to bureaucratic and time-consuming governance processes have led to the development of a new system of application and co-ordination from 2009. This paper illustrates how this new system fails to be consistent and streamlined and is unlikely to become so unless changes are made to the implementation and management of the governance processes. METHODS: We present a case study of the research governance process at the survey stage of an investigation into the use, preferences and need for information by people making choices or decisions about health care. The method involved home-based, face-to-face interviewing in a questionnaire survey in relation to decisions about lymphoma treatment, Down's syndrome screening in pregnancy, and caring for people with dementia. RESULTS: Our experience of the ethics stage was very positive, noting an efficient process of application and a speedy decision, both in relation to the initial application and to subsequent substantial amendments. By contrast, the R&D stages were very slow, most with unexplained delays, but some offering contradictory advice and exhibiting a lack of clear guidance and training for NHS staff. The R&D arrangements in Scotland were far quicker and more likely to be successful than in England. Overall, the delays were so severe that substantial parts of the research could not be delivered as planned within the funding timescale. CONCLUSIONS: If high-quality research in the NHS, particularly in England, is to be delivered in a timely and cost-effective way, R&D processes for gaining research governance approval need improvement. Attention is needed in process implementation and management, particularly in relation to staff training, as well as clarity in guidance and communication within and between organisations.

The meaning of patient involvement and participation in health care consultations: a taxonomy.

A number of trends, pressures and policy shifts can be identified that are promoting greater patient involvement in health care delivery through consultations, treatments and continuing care. However, while the literature is growing fast on different methods of involvement, little attention has been given so far to the role which patients themselves wish to play, nor even of the conceptual meanings behind involvement or participation. This article reviews the current models of involvement in health care delivery as derived from studies of professional views of current and potential practice, prior to examining the empirical evidence from a large-scale qualitative study of the views and preferences of citizens, as patients, members of voluntary groups, or neither. Individual domiciliary interviews were carried out with 44 people recruited from GP practices in northern England. These respondents were then included in a second phase of 34 focus groups in 6 different localities in northern and southern England, of which 22 were with individuals unaffiliated to any voluntary/community groups, 6 related to local voluntary/community groups with specific interests in health or health care, and 6 related to groups without such specific interests. A final set of 12 workshops with the same samples helped to confirm emergent themes. The qualitative data enabled a taxonomy of patient-desired involvement to be derived, which is contrasted with professional-determined levels of involvement identified from the literature. Participation is seen as being co-determined by patients and professionals, and occurring only through the reciprocal relationships of dialogue and shared decision-making. Not everyone wanted to be involved and the extent to which involvement was desired depended on the contexts of type and seriousness of illness, various personal characteristics and patients' relationships with professionals. These levels are seen to provide basic building blocks for a more sophisticated understanding of involvement within and between these contexts for use by professionals, managers, policy-makers and researchers.

Predicting and comparing patient satisfaction in four different modes of health care across a nation.

This study aims to inform strategic policy makers and managers about the value of general population surveys by determining and comparing dimensions of satisfaction in four different health services in Scotland: general practice, domiciliary care, outpatients and inpatients (including day cases). The research design involved secondary data analysis of a national telephone survey conducted to inform the development of a national health plan. The database was created using a stratified quota sample of 3052 people of 16 years and above resident in Scotland in 2000. The main outcome measures investigated were overall measures of patient satisfaction with each type of service. Principal components analysis was used to determine the dimensions. Interest was in the extent to which patients, many of whom were the same (having used more than one service), evaluated different services in similar ways, as well as those factors specific to each service. Using logistic regression, the results demonstrate that interpersonal care and information, and desired improvements in service were universal and key explanatory dimensions in all services, followed by a combination of access, physical facilities, time and quality of food, depending on relevance to the service. These factors, particularly interpersonal care and information, distinguished well the highly satisfied from the others, with age providing further discrimination between non-hospital patients, while gender added to discrimination between inpatients. In conclusion, despite the limitations of telephone interviews, it is feasible to ask about several services at the same time and for the answers to reflect common underlying dimensions of evaluation found in more exhaustive research within each service. These factors offer a set of summary measures by which services can be easily evaluated at a strategic level and point to where efforts to increase patient satisfaction can be maximised.