Evaluation of Neuromuscular Diseases and Complaints by Quantitative Muscle MRI

Background: Quantitative muscle MRI (qMRI) is a promising tool for evaluating and monitoring neuromuscular disorders (NMD). However, the application of different imaging protocols and processing pipelines restricts comparison between patient cohorts and disorders. In this qMRI study, we aim to compare dystrophic (limb-girdle muscular dystrophy), inflammatory (inclusion body myositis), and metabolic myopathy (Pompe disease) as well as patients with post-COVID-19 conditions suffering from myalgia to healthy controls. Methods: Ten subjects of each group underwent a 3T lower extremity muscle MRI, including a multi-echo, gradient-echo, Dixon-based sequence, a multi-echo, spin-echo (MESE) T2 mapping sequence, and a spin-echo EPI diffusion-weighted sequence. Furthermore, the following clinical assessments were performed: Quick Motor Function Measure, patient questionnaires for daily life activities, and 6-min walking distance. Results: Different involvement patterns of conspicuous qMRI parameters for different NMDs were observed. qMRI metrics correlated significantly with clinical assessments. Conclusions: qMRI metrics are suitable for evaluating patients with NMD since they show differences in muscular involvement in different NMDs and correlate with clinical assessments. Still, standardisation of acquisition and processing is needed for broad clinical use

Stratifying patients with peripheral neuropathic pain based on sensory profiles : algorithm and sample size recommendations

In a recent cluster analysis, it has been shown that patients with peripheral neuropathic pain can be grouped into 3 sensory phenotypes based on quantitative sensory testing profiles, which are mainly characterized by either sensory loss, intact sensory function and mild thermal hyperalgesia and/or allodynia, or loss of thermal detection and mild mechanical hyperalgesia and/or allodynia. Here, we present an algorithm for allocation of individual patients to these subgroups. The algorithm is nondeterministic-ie, a patient can be sorted to more than one phenotype-and can separate patients with neuropathic pain from healthy subjects (sensitivity: 78%, specificity: 94%). We evaluated the frequency of each phenotype in a population of patients with painful diabetic polyneuropathy (n = 151), painful peripheral nerve injury (n = 335), and postherpetic neuralgia (n = 97) and propose sample sizes of study populations that need to be screened to reach a subpopulation large enough to conduct a phenotype-stratified study. The most common phenotype in diabetic polyneuropathy was sensory loss (83%), followed by mechanical hyperalgesia (75%) and thermal hyperalgesia (34%, note that percentages are overlapping and not additive). In peripheral nerve injury, frequencies were 37%, 59%, and 50%, and in postherpetic neuralgia, frequencies were 31%, 63%, and 46%. For parallel study design, either the estimated effect size of the treatment needs to be high (> 0.7) or only phenotypes that are frequent in the clinical entity under study can realistically be performed. For crossover design, populations under 200 patients screened are sufficient for all phenotypes and clinical entities with a minimum estimated treatment effect size of 0.5.Peer reviewe

Evoked potentials after painful cutaneous electrical stimulation depict pain relief during a conditioned pain modulation

Abstract Background Conditioned pain modulation (CPM) evaluates the pain modulating effect of a noxious conditioning stimulus (CS) on another noxious test stimulus (TS), mostly based solely on subjective pain ratings. We used painful cutaneous electrical stimulation (PCES) to induce TS in a novel CPM-model. Additionally, to evaluate a more objective parameter, we recorded the corresponding changes of cortical evoked potentials (PCES-EP). Methods We examined the CPM-effect in 17 healthy subjects in a randomized controlled cross-over design during immersion of the non-dominant hand into 10 °C or 24 °C cold water (CS). Using three custom-built concentric surface electrodes, electrical stimuli were applied on the dominant hand, inducing pain of 40–60 on NRS 0–100 (TS). At baseline, during and after CS we assessed the electrically induced pain intensity and electrically evoked potentials recorded over the central electrode (Cz). Results Only in the 10 °C-condition, both pain (52.6 ± 4.4 (baseline) vs. 30.3 ± 12.5 (during CS)) and amplitudes of PCES-EP (42.1 ± 13.4 μV (baseline) vs. 28.7 ± 10.5 μV (during CS)) attenuated during CS and recovered there after (all p < 0.001). In the 10 °C-condition changes of subjective pain ratings during electrical stimulation and amplitudes of PCES-EP correlated significantly with each other (r = 0.5) and with CS pain intensity (r = 0.5). Conclusions PCES-EPs are a quantitative measure of pain relief, as changes in the electrophysiological response are paralleled by a consistent decrease in subjective pain ratings. This novel CPM paradigm is a feasible method, which could help to evaluate the function of the endogenous pain modulation processes. Trial registration German Clinical Trials Register DRKS-ID: DRKS00012779 , retrospectively registered on 24 July 2017

Additional file 1: Table S1. A. of Ipsilateral and contralateral sensory changes in healthy subjects after experimentally induced concomitant sensitization and hypoesthesia

QST data after single substance application (site of application; data are presented as median (range)). B. QST data after combined substance application (site of application; data are presented as median (range)). (DOCX 35 kb

Additional file 3: Figure S1. of Ipsilateral and contralateral sensory changes in healthy subjects after experimentally induced concomitant sensitization and hypoesthesia

(A) Contralateral changes in the cold detection threshold of all subjects before and after application of a combination of capsaicin and local anesthetics as well as 7-14 days later. (B) Contralateral changes in the mechanical detection threshold of all subjects before and after application of capsaicin and local anesthetics as well as 7–14 days later. Gray circuits show the calculated group means. Red borders indicate significant changes. (TIF 1022 kb

Generation and validation of a PREP sample response

PREP are typical signal courses in the EEG, which are used to investigate the influence of neuropathologies or, for example, post-traumatic headaches on pain processing. The medically meaningful peaks are detected manually for further analysis. To develop a more time-efficient method, an automatic, latency-independent way of detection was created using the cross-correlation function, which generates a sample response for each data set. The comparison of automatic and manual methods shows advantages and disadvantages of both methods, but no significant deviation of the automatic method can be found

Distraction by a cognitive task has a higher impact on electrophysiological measures compared with conditioned pain modulation

Background!#!Conditioned pain modulation (CPM) evaluates the effect of a painful conditioning stimulus (CS) on a painful test stimulus (TS). Using painful cutaneous electrical stimulation (PCES) as TS and painful cold water as CS, the pain relief was paralleled by a decrease in evoked potentials (PCES-EPs). We now aimed to compare the effect of CPM with cognitive distraction on PCES-induced pain and PCES-EP amplitudes.!##!Methods!#!PCES was performed using surface electrodes inducing a painful sensation of 60 (NRS 0-100) on one hand. In a crossover design healthy subjects (included: n = 38, analyzed: n = 23) immersed the contralateral hand into 10 °C cold water (CS) for CPM evaluation and performed the 1-back task for cognitive distraction. Before and during the CS and 1-back task, respectively, subjects rated the pain intensity of PCES and simultaneously cortical evoked potentials were recorded.!##!Results!#!Both CPM and cognitive distraction significantly reduced PCES-EP amplitudes (CPM: 27.6 ± 12.0 μV to 20.2 ± 9.5 μV, cognitive distraction: 30.3 ± 14.2 µV to 13.6 ± 5.2 μV, p &amp;lt; 0.001) and PCES-induced pain (on a 0-100 numerical rating scale: CPM: 58 ± 4 to 41.1 ± 12.3, cognitive distraction: 58.3 ± 4.4 to 38.0 ± 13.0, p &amp;lt; 0.001), though the changes in pain intensity and PCES-amplitude did not correlate. The changes of the PCES-EP amplitudes during cognitive distraction were more pronounced than during CPM (p = 0.001).!##!Conclusions!#!CPM and cognitive distraction reduced the PCES-induced pain to a similar extent. The more pronounced decrease of PCES-EP amplitudes after distraction by a cognitive task implies that both conditions might not represent the general pain modulatory capacity of individuals, but may underlie different neuronal mechanisms with the final common pathway of perceived pain reduction

Career and life planning in the context of the postgraduate medical training – current challenges and opportunities

Introduction: The possibility of balancing career and family is meanwhile a central concern for most physicians when choosing a job. The aim of this study was to identify current barriers and opportunities for physician education and career planning.Methods: This cross-sectional study was conducted as an online survey between 11/2021 and 02/2022 and targeted physicians at all career levels in Germany who were members of a clinical professional association. Alternative and consent questions were used to assess experiences/attitudes toward various aspects of life and career planning, as well as alternative work and parental leave models, depending on gender, specialty, and hierarchical level.Results: The majority of the 2060 participants were female (69%) and had children (66%). Many childless residents reported that they felt they had to choose between children and a career. The majority of female residents, specialists and attending physicians (Ø 55.5%) stated that they had experienced career losses as a result of taking parental leave, while most men did not share this experience (Ø 53.7%). 92% of all participants agreed with the statement that men and women have different career opportunities. Job-sharing models were considered feasible at all levels of the hierarchy by an average of 55.6% of all medical executives. Conclusion: Parenthood and the use of parental leave and part-time work appear to have a significant impact on the career paths of those surveyed. Although the majority of directors of medical training programs are open to job-sharing models, further measures are needed in order to equalize career opportunities for men and women