Slow touch and ultrafast pain fibres: Revisiting peripheral nerve classification.

One hundred years ago, Erlanger and Gasser demonstrated that conduction velocity is correlated with the diameter of a peripheral nerve axon. Later, they also demonstrated that the functional role of the axon is related to its diameter: touch is signalled by large-diameter axons, whereas pain and temperature are signalled by small-diameter axons. Certain discoveries in recent decades prompt a modification of this canonical classification. Here, we review the evidence for unmyelinated (C) fibres signalling touch at a slow conduction velocity and likely contributing to affective aspects of tactile information. We also review the evidence for large-diameter Aß afferents signalling pain at ultrafast conduction velocity and likely contributing to the rapid nociceptive withdrawal reflex. These discoveries imply that conduction velocity is not as clear-cut an indication of the functional role of the axon as previously thought. We finally suggest that a future taxonomy of the peripheral afferent nervous system might be based on the combination of the axons molecular expression and electrophysiological response properties.

Disseminating Community-Engaged Research Involving People Experiencing Homelessness and Diabetes Using Participatory Theater.

People experiencing homelessness balance competing priorities resulting in reduced capacity to meet the care demands of chronic conditions, including Type 2 Diabetes Mellitus (T2DM). Arts-based performances present an avenue to expose others to these challenges. This article describes the process of incorporating qualitative research findings in a community-based participatory theater production to expose audiences to the day-to-day realities of living with T2DM while simultaneously experiencing homelessness. We conducted five focus groups and two individual interviews with people living with T2DM who had experienced homelessness with guidance from a community-engaged research team. We then collaborated with a local theater company to present common themes from these focus groups in a co-created play about the experience of managing T2DM while being homeless. We performed a staged reading of the play and assessed audience members' perceived stigma through a pre- and post-survey to determine if audience engagement within our theatrical production could reduce stigma toward individuals living with diabetes and/or people experiencing homelessness. This theatrical production is titled "Life Heist: Stealing Hope While Surviving Diabetes and Homelessness." Our work illustrates the feasibility and effectiveness of using participatory theater to disseminate qualitative research findings.

The role of clinical neurophysiology in the definition and assessment of fatigue and fatigability.

Though a common symptom, fatigue is difficult to define and investigate, occurs in a wide variety of neurological and systemic disorders, with differing pathological causes. It is also often accompanied by a psychological component. As a symptom of long-term COVID-19 it has gained more attention. In this review, we begin by differentiating fatigue, a perception, from fatigability, quantifiable through biomarkers. Central and peripheral nervous system and muscle disorders associated with these are summarised. We provide a comprehensive and objective framework to help identify potential causes of fatigue and fatigability in a given disease condition. It also considers the effectiveness of neurophysiological tests as objective biomarkers for its assessment. Among these, twitch interpolation, motor cortex stimulation, electroencephalography and magnetencephalography, and readiness potentials will be described for the assessment of central fatigability, and surface and needle electromyography (EMG), single fibre EMG and nerve conduction studies for the assessment of peripheral fatigability. The purpose of this review is to guide clinicians in how to approach fatigue, and fatigability, and to suggest that neurophysiological tests may allow an understanding of their origin and interactions. In this way, their differing types and origins, and hence their possible differing treatments, may also be defined more clearly.

Minimal impact of proprioceptive loss on implicit sensorimotor adaptation and perceived movement outcome.

Implicit sensorimotor adaptation keeps our movements well-calibrated amid changes in the body and environment. We have recently postulated that implicit adaptation is driven by a perceptual error: the difference between the desired and perceived movement outcome. According to this perceptual re-alignment model, implicit adaptation ceases when the perceived movement outcome - a multimodal percept determined by a prior belief conveying the intended action, the motor command, and feedback from proprioception and vision - is aligned with the desired movement outcome. Here, we examined the role of proprioception in implicit motor adaptation and perceived movement outcome by examining individuals who lack proprioception. We used a modified visuomotor rotation task designed to isolate implicit adaptation and probe perceived outcome throughout the experiment. Surprisingly, implicit adaptation and perceived outcome were minimally impacted by deafferentation, posing a challenge to the perceptual re-alignment model of implicit adaptation.

A proposal for harmonizing clinical neurophysiology training in the Europe, Middle East and Africa Chapter of the International Federation of Clinical Neurophysiology.

There are significant differences in duration and intensity of clinical neurophysiology specialty training within the countries of the Europe, Middle East and Africa Chapter of the International Federation of Clinical Neurophysiology. We address these differences by proposing recommendations which may facilitate harmonisation of training and education within the Chapter. They arose from two workshops whose recommendations were then circulated widely within national societies in the Chapter for feedback and for consensus. The recommendations are applicable to clinical neurophysiology as a medical monospecialty and/or as a subspecialty (usually of neurology). We make a number of recommendations on governance and regulation of training, on the requirements for competence and the numbers of various examinations and tests performed by trainees, some under supervision. We also recommend a modular approach considering primary and complementary modules. Primary modules are electroencephalography, electromyography, nerve conduction studies and evoked potentials, while complementary ones include sleep analysis, intraoperative monitoring, small fibre testing, peripheral nerve and muscle ultrasound, intracortical recordings, and analysis of movement disorders. It is recommended that national examinations should include a variety of techniques to assess knowledge and judgement, practical skills, teamwork, communication skills, as well as safety and quality. The aim of the suggested recommendations is to harmonize clinical neurophysiology training in the member societies throughout the Chapter. It is realised that this may mean that the numbers for competence are aspirational for some, though ways to mitigate this, for instance through supranational training centres, are also discussed.

PIEZO2-dependent rapid pain system in humans and mice.

The PIEZO2 ion channel is critical for transducing light touch into neural signals but is not considered necessary for transducing acute pain in humans. Here, we discovered an exception - a form of mechanical pain evoked by hair pulling. Based on observations in a rare group of individuals with PIEZO2 deficiency syndrome, we demonstrated that hair-pull pain is dependent on PIEZO2 transduction. Studies in control participants showed that hair-pull pain triggered a distinct nocifensive response, including a nociceptive reflex. Observations in rare Aß deafferented individuals and nerve conduction block studies in control participants revealed that hair-pull pain perception is dependent on Aß input. Single-unit axonal recordings revealed that a class of cooling-responsive myelinated nociceptors in human skin is selectively tuned to painful hair-pull stimuli. Further, we pharmacologically mapped these nociceptors to a specific transcriptomic class. Finally, using functional imaging in mice, we demonstrated that in a homologous nociceptor, Piezo2 is necessary for high-sensitivity, robust activation by hair-pull stimuli. Together, we have demonstrated that hair-pulling evokes a distinct type of pain with conserved behavioral, neural, and molecular features across humans and mice.

Dissociation between dreams and wakefulness: Insights from body and action representations of rare individuals with massive somatosensory deafferentation.

The realism of body and actions in dreams is thought to be induced by simulations based on internal representations used during wakefulness. As somatosensory signals contribute to the updating of body and action representations, these are impaired when somatosensory signals are lacking. Here, we tested the hypothesis that individuals with somatosensory deafferentation have impaired body and actions in their dreams, as in wakefulness. We questioned three individuals with a severe, acquired sensory neuropathy on their dreams. While deafferented participants were impaired in daily life, they could dream of themselves as able-bodied, with some sensations (touch, proprioception) and actions (such as running or jumping) which had not been experienced in physical life since deafferentation. We speculate that simulation in dreams could be based on former, "healthy" body and action representations. Our findings are consistent with the idea that distinct body and action representations may be used during dreams and wakefulness.

Training and education practice in the Europe, Middle East and Africa, Latin America and Asia Oceania chapters, IFCN; an international survey.

This paper presents results from the first survey of training and education undertaken by the Europe-Middle East-Africa (EMEAC), the Latin America (LAC) and the Asia-Oceania (AOC) Chapters of the International Federation of Clinical Neurophysiology (IFCN). The survey was conducted initially by the EMEAC in 2012 and updated in 2016, 2019, and 2020. It had the following categories: status of specialty and training in member country (21 questions), competency and accreditation (12 questions), practice and concerns (23 questions). An abbreviated version of the survey was conducted by the LAC and AOC in 2018-2019. Clinical neurophysiology (CN) was a single specialty in a minority of member societies' countries: 8/33 EMEAC, 2/12 AOC and 2/10 LAC. In others it was usually a subspecialty of neurology. Training periods in CN were split fairly evenly between 1, 2, 3, 4 and 5 years in EMEAC, while neurology takes 4 to 5 years. In the AOC, neurology training was for 3 to 4 years and CN for up to 2 years. In LAC a majority of countries trained for 2 to 3 years in both neurology and CN. An exit exam was performed in 16/30 EMEAC respondents, 8/12 in the AOC and 3/10 in the LAC. Competence was considered to require a wide range of numbers of tests performed under supervision, from <250 to >750 in EMEAC and AOC, with the EMEAC tending to require more. The main concerns were in recruitment and workload in EMEAC, training in AOC and the need for more recognition of the specialty in some countries within the LAC. This survey, the first across the three chapters, revealed considerable differences in training durations and numbers of tests performed for competence between national societies.

Academic freedom under fire.

Academic freedom is under fire across the world-from Hong Kong, where the Chinese government's crackdown on open discussion has spurred an exodus of scholars from universities, to the United States, where there is a rising tide of anti-intellectualism and assaults on free inquiry. The effort to undermine this cornerstone of American democracy has been driven by former President Trump and his administration, members of Congress, state governors, and legislators. Alas, it also comes from faculty and students on the ideological right and left, and even from some presidents of the country's research universities. These are powerful forces that must be overcome.

The role of somatosensation in automatic visuo-motor control: a comparison of congenital and acquired sensory loss.

Studies of chronically deafferented participants have illuminated how regaining some motor control after adult-onset loss of proprioceptive and touch input depends heavily on cognitive control. In this study we contrasted the performance of one such man, IW, with KS, a woman born without any somatosensory fibres. We postulated that her life-long absence of proprioception and touch might have allowed her to automate some simple visually-guided actions, something IW appears unable to achieve. We tested these two, and two age-matched control groups, on writing and drawing tasks performed with and without an audio-verbal echoing task that added a cognitive demand. In common with other studies of skilled action, the dual task was shown to affect visuo-motor performance in controls, with less well-controlled drawing and writing, evident as increases in path speed and reduction in curvature and trial duration. We found little evidence that IW was able to automate even the simplest drawing tasks and no evidence for automaticity in his writing. In contrast, KS showed a selective increase in speed of signature writing under the dual-task conditions, suggesting some ability to automate her most familiar writing. We also tested tracing of templates under mirror-reversed conditions, a task that imposes a powerful cognitive planning challenge. Both IW and KS showed evidence of a visuo-motor planning conflict, as did the controls, for shapes with sharp corners. Overall, IW was much faster than his controls to complete tracing shapes, consistent with an absence of visuo-proprioceptive conflict, whereas KS was slower than her controls, especially as the corners became sharper. She dramatically improved after a short period of practice while IW did not. We conclude that KS, who developed from birth without proprioception, may have some visually derived control of movement not under cognitive control, something not seen in IW. This allowed her to automate some writing and drawing actions, but impaired her initial attempts at mirror-tracing. In contrast, IW, who lost somatosensation as an adult, cannot automate these visually guided actions.

Perception of body shape and size without touch or proprioception: evidence from individuals with congenital and acquired neuropathy.

The degree to which mental representations of the body can be established and maintained without somatosensory input remains unclear. We contrast two "deafferented" adults, one who acquired large fibre sensory loss as an adult (IW) and another who was born without somatosensation (KS). We compared their responses to those of matched controls in three perceptual tasks: first accuracy of their mental image of their hands (assessed by testing recognition of correct hand length/width ratio in distorted photographs and by locating landmarks on the unseen hand); then accuracy of arm length judgements (assessed by judgement of reaching distance), and finally, we tested for an attentional bias towards peri-personal space (assessed by reaction times to visual target presentation). We hypothesised that IW would demonstrate responses consistent with him accessing conscious knowledge, whereas KS might show evidence of responses dependent on non-conscious mechanisms. In the first two experiments, both participants were able to give consistent responses about hand shape and arm length, but IW displayed a better awareness of hand shape than KS (and controls). KS demonstrated poorer spatial accuracy in reporting hand landmarks than both IW and controls, and appears to have less awareness of her hands. Reach distance was overestimated by both IW and KS, as it was for controls; the precision of their judgements was slightly lower than that of the controls. In the attentional task, IW showed no reaction time differences across conditions in the visual detection task, unlike controls, suggesting that he has no peri-personal bias of attention. In contrast, KS did show target location-dependent modulation of reaction times, when her hands were visible. We suggest that both IW and KS can access a conscious body image, although its accuracy may reflect their different experience of hand action. Acquired sensory loss has deprived IW of any subconscious body awareness, but the congenital absence of somatosensation may have led to its partial replacement by a form of visual proprioception in KS.

Innocuous pressure sensation requires A-type afferents but not functional ΡΙΕΖΟ2 channels in humans.

The sensation of pressure allows us to feel sustained compression and body strain. While our understanding of cutaneous touch has grown significantly in recent years, how deep tissue sensations are detected remains less clear. Here, we use quantitative sensory evaluations of patients with rare sensory disorders, as well as nerve blocks in typical individuals, to probe the neural and genetic mechanisms for detecting non-painful pressure. We show that the ability to perceive innocuous pressures is lost when myelinated fiber function is experimentally blocked in healthy volunteers and that two patients lacking Aß fibers are strikingly unable to feel innocuous pressures at all. We find that seven individuals with inherited mutations in the mechanoreceptor PIEZO2 gene, who have major deficits in touch and proprioception, are nearly as good at sensing pressure as healthy control subjects. Together, these data support a role for Aß afferents in pressure sensation and suggest the existence of an unknown molecular pathway for its detection.

Personality psychopathology: Longitudinal prediction of change in body mass index and weight post-bariatric surgery.

OBJECTIVE: Bariatric surgery is an effective treatment for obesity, which has been increasing worldwide. However, bariatric surgery causes dramatic physical changes that can cause significant stress. Prior research has found that psychological variables such as personality traits and levels of psychopathology can influence success after bariatric surgery (in terms of body mass index [BMI] reduction and weight loss). However, most prior studies have been limited by small sample sizes, inconsistent follow up, and categorical assessment of psychopathology. METHOD: The present study examines the predictive utility of the Personality Assessment Inventory (PAI) scales for three bariatric surgery outcomes (BMI reduction, weight loss, and percent excess weight loss [%EWL]) across 10 follow-up points 5 years after surgery. It also examines the largest sample of bariatric surgery-completing patients (N = 2,267) on the PAI to date. Latent growth modeling was used to examine change in the outcome variables. RESULTS: Results indicate that personality and psychopathology variables predicted less BMI reduction, weight loss, and %EWL 5 years after surgery and also affected the trajectories of change in the outcome variables across time. The PAI scales predicted more variance in the 5-year BMI outcomes than did age and gender. The most robust effects were for scales assessing phobias, traumatic stress, identity problems, and negative relationships. CONCLUSION: The PAI may be useful to clinical health psychologists who conduct recommended psychological evaluations with potential bariatric surgery candidates. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

An ultrafast system for signaling mechanical pain in human skin.

The canonical view is that touch is signaled by fast-conducting, thickly myelinated afferents, whereas pain is signaled by slow-conducting, thinly myelinated ("fast" pain) or unmyelinated ("slow" pain) afferents. While other mammals have thickly myelinated afferents signaling pain (ultrafast nociceptors), these have not been demonstrated in humans. Here, we performed single-unit axonal recordings (microneurography) from cutaneous mechanoreceptive afferents in healthy participants. We identified A-fiber high-threshold mechanoreceptors (A-HTMRs) that were insensitive to gentle touch, encoded noxious skin indentations, and displayed conduction velocities similar to A-fiber low-threshold mechanoreceptors. Intraneural electrical stimulation of single ultrafast A-HTMRs evoked painful percepts. Testing in patients with selective deafferentation revealed impaired pain judgments to graded mechanical stimuli only when thickly myelinated fibers were absent. This function was preserved in patients with a loss-of-function mutation in mechanotransduction channel PIEZO2. These findings demonstrate that human mechanical pain does not require PIEZO2 and can be signaled by fast-conducting, thickly myelinated afferents.

Cost-effectiveness of a combined classroom curriculum and parental intervention: economic evaluation of data from the Steps Towards Alcohol Misuse Prevention Programme cluster randomised controlled trial.

OBJECTIVES: This study aimed to assess the cost-effectiveness of the Steps Towards Alcohol Misuse Prevention Programme (STAMPP) compared with education as normal (EAN) in reducing self-reported heavy episodic drinking (HED) in adolescents. DESIGN: This is a cost-effectiveness analysis from a public sector perspective conducted as part of a cluster randomised trial. SETTING: This study was conducted in 105 high schools in Northern Ireland and in Scotland. PARTICIPANTS: Students in school year 8/S1 (aged 11-12) at baseline were included in the study. INTERVENTIONS: This is a classroom-based alcohol education curricula, combined with a brief alcohol intervention for parents/carers. OUTCOME MEASURES: The outcome of this study is the cost per young person experiencing HED avoided due to STAMPP at 33 months from baseline. RESULTS: The total cost of STAMPP was £85 900, equivalent to £818 per school and £15 per pupil. Due to very low uptake of the parental component, we calculated costs of £692 per school and £13 per pupil without this element. Costs per pupil were reduced further to £426 per school and £8 per pupil when it was assumed there were no additional costs of classroom delivery if STAMPP was delivered as part of activities such as personal, social, health and economic education. STAMPP was associated with a significantly greater proportion of pupils experiencing a heavy drinking episode avoided (0.08/8%) and slightly lower public sector costs (mean difference -£17.19). At a notional willingness-to-pay threshold of £15 (reflecting the cost of STAMPP), the probability of STAMPP being cost-effective was 56%. This level of uncertainty reflected the substantial variability in the cost differences between groups. CONCLUSIONS: STAMPP was relatively low cost and reduced HED. STAMPP was not associated with any clear public sector cost savings, but neither did it increase them or lead to any cost-shifting within the public sector categories. Further research is required to establish if the cost-effectiveness of STAMPP is sustained in the long term. TRIAL REGISTRATION NUMBER: ISRCTN47028486; Results.

Loss of haptic feedback impairs control of hand posture: a study in chronically deafferented individuals when grasping and lifting objects.

Previous work has highlighted the role of haptic feedback for manual dexterity, in particular for the control of precision grip forces between the index finger and thumb. It is unclear how fine motor skills involving more than just two digits might be affected, especially given that loss of sensation from the hand affects many neurological patients, and impacts on everyday actions. To assess the functional consequences of haptic deficits on multi-digit grasp of objects, we studied the ability of three rare individuals with permanent large-fibre sensory loss involving the entire upper limb. All three reported difficulties in everyday manual actions (ABILHAND questionnaire). Their performance in a reach-grasp-lift task was compared to that of healthy controls. Twenty objects of varying shape, mass, opacity and compliance were used. In the reach-to-grasp phase, we found slower movement, larger grip aperture and less dynamic modulation of grip aperture in deafferented participants compared to controls. Hand posture during the lift phase also differed; deafferented participants often adopted hand postures that may have facilitated visual guidance, and/or reduced control complexity. For example, they would extend fingers that were not in contact with the object, or fold these fingers into the palm of the hand. Variability in hand postures was increased in deafferented participants, particularly for smaller objects. Our findings provide new insights into how the complex control required for whole hand actions is compromised by loss of haptic feedback, whose contribution is, thus, highlighted.

Does Proprioception Influence Human Spatial Cognition? A Study on Individuals With Massive Deafferentation.

When navigating in a spatial environment or when hearing its description, we can develop a mental model which may be represented in the central nervous system in different coordinate systems such as an egocentric or allocentric reference frame. The way in which sensory experience influences the preferred reference frame has been studied with a particular interest for the role of vision. The present study investigated the influence of proprioception on human spatial cognition. To do so, we compared the abilities to form spatial models of two rare participants chronically deprived of proprioception (GL and IW) and healthy control participants. Participants listened to verbal descriptions of a spatial environment, and their ability to form and use a mental model was assessed with a distance-comparison task and a free-recall task. Given that the loss of proprioception has been suggested to specifically impair the egocentric reference frame, the deafferented individuals were expected to perform worse than controls when the spatial environment was described in an egocentric reference frame. Results revealed that in both tasks, one deafferented individual (GL) made more errors than controls while the other (IW) made less errors. On average, both GL and IW were slower to respond than controls, and reaction time was more variable for IW. Additionally, we found that GL but not IW was impaired compared to controls in visuo-spatial imagery, which was assessed with the Minnesota Paper Form Board Test. Overall, the main finding of this study is that proprioception can influence the time necessary to use spatial representations while other factors such as visuo-spatial abilities can influence the capacity to form accurate spatial representations.

Proprioceptive loss and the perception, control and learning of arm movements in humans: evidence from sensory neuronopathy.

It is uncertain how vision and proprioception contribute to adaptation of voluntary arm movements. In normal participants, adaptation to imposed forces is possible with or without vision, suggesting that proprioception is sufficient; in participants with proprioceptive loss (PL), adaptation is possible with visual feedback, suggesting that proprioception is unnecessary. In experiment 1 adaptation to, and retention of, perturbing forces were evaluated in three chronically deafferented participants. They made rapid reaching movements to move a cursor toward a visual target, and a planar robot arm applied orthogonal velocity-dependent forces. Trial-by-trial error correction was observed in all participants. Such adaptation has been characterized with a dual-rate model: a fast process that learns quickly, but retains poorly and a slow process that learns slowly and retains well. Experiment 2 showed that the PL participants had large individual differences in learning and retention rates compared to normal controls. Experiment 3 tested participants' perception of applied forces. With visual feedback, the PL participants could report the perturbation's direction as well as controls; without visual feedback, thresholds were elevated. Experiment 4 showed, in healthy participants, that force direction could be estimated from head motion, at levels close to the no-vision threshold for the PL participants. Our results show that proprioceptive loss influences perception, motor control and adaptation but that proprioception from the moving limb is not essential for adaptation to, or detection of, force fields. The differences in learning and retention seen between the three deafferented participants suggest that they achieve these tasks in idiosyncratic ways after proprioceptive loss, possibly integrating visual and vestibular information with individual cognitive strategies.

Steps Towards Alcohol Misuse Prevention Programme (STAMPP): a school-based and community-based cluster randomised controlled trial.

OBJECTIVES: To assess the effectiveness of a combined classroom curriculum and parental intervention (the Steps Towards Alcohol Misuse Prevention Programme (STAMPP)), compared with alcohol education as normal (EAN), in reducing self-reported heavy episodic drinking (HED) and alcohol-related harms (ARHs) in adolescents. SETTING: 105 high schools in Northern Ireland (NI) and in Scotland. PARTICIPANTS: Schools were stratified by free school meal provision. Schools in NI were also stratified by school type (male/female/coeducational). Eligible students were in school year 8/S1 (aged 11-12 years) at baseline (June 2012). INTERVENTION: A classroom-based alcohol education intervention, coupled with a brief alcohol intervention for parents/carers. PRIMARY OUTCOMES: (1) The prevalence of self-reported HED in the previous 30 days and (2) the number of self-reported ARHs in the previous 6 months. Outcomes were assessed using two-level random intercepts models (logistic regression for HED and negative binomial for number of ARHs). RESULTS: At 33 months, data were available for 5160 intervention and 5073 control students (HED outcome), and 5234 and 5146 students (ARH outcome), respectively. Of those who completed a questionnaire at either baseline or 12 months (n=12 738), 10 405 also completed the questionnaire at 33 months (81.7%). Fewer students in the intervention group reported HED compared with EAN (17%vs26%; OR=0.60, 95% CI 0.49 to 0.73), with no significant difference in the number of self-reported ARHs (incident rate ratio=0.92, 95% CI 0.78 to 1.05). Although the classroom component was largely delivered as intended, there was low uptake of the parental component. There were no reported adverse effects. CONCLUSIONS: Results suggest that STAMPP could be an effective programme to reduce HED prevalence. While there was no significant reduction in ARH, it is plausible that effects on harms would manifest later. TRIAL REGISTRATION NUMBER: ISRCTN47028486; Post-results.

Defining the Key Competencies in Radiation Protection for Endovascular Procedures: A Multispecialty Delphi Consensus Study.

OBJECTIVES: Radiation protection training courses currently focus on broad knowledge topics which may not always be relevant in daily practice. The goal of this study was to determine the key competencies in radiation protection that every endovascular team member should possess and apply routinely, through multispecialty clinical content expert consensus. METHODS: Consensus was obtained through a two round modified Delphi methodology. The expert panel consisted of European vascular surgeons, interventional radiologists, and interventional cardiologists/angiologists experienced in endovascular procedures. An initial list of statements, covering knowledge skills, technical skills and attitudes was created, based on a literature search. Additional statements could be suggested by the experts in the first Delphi round. Each of the statements had to be rated on a 5- point Likert scale. A statement was considered to be a key competency when the internal consistency was greater than alpha = 0.80 and at least 80% of the experts agreed (rating 4/5) or strongly agreed (rating 5/5) with the statement. Questionnaires were emailed to panel members using the Surveymonkey service. RESULTS: Forty-one of 65 (63.1%) invited experts agreed to participate in the study. The response rates were 36 out of 41 (87.8%): overall 38 out of 41(92.6%) in the first round and 36 out of 38 (94.7%) in the second round. The 71 primary statements were supplemented with nine items suggested by the panel. The results showed excellent consensus among responders (Cronbach's alpha = 0.937 first round; 0.958 s round). Experts achieved a consensus that 30 of 33 knowledge skills (90.9%), 23 of 27 technical skills (82.1%), and 15 of 20 attitudes (75.0%) should be considered as key competencies. CONCLUSIONS: A multispecialty European endovascular expert panel reached consensus about the key competencies in radiation protection. These results may serve to create practical and relevant radiation protection training courses in the future, enhancing radiation safety for both patients and the entire endovascular team.