Optimal stimulation settings for CMAP scan registrations

Background: The CMAP (Compound Muscle Action Potential) scan is a non-invasive electrodiagnostic tool, which provides a quick and visual assessment of motor unit potentials as electrophysiological components that together constitute the CMAP. The CMAP scan records the electrical activity of the muscle (CMAP) in response to transcutaneous stimulation of the motor nerve with gradual changes in stimulus intensity. Large MUs, including those that result from collateral reinnervation, appear in the CMAP scan as so-called steps, i.e., clearly visible jumps in CMAP amplitude. The CMAP scan also provides information on nerve excitability. This study aims to evaluate the influence of the stimulation protocol used on the CMAP scan and its quantification. Methods: The stimulus frequency (1, 2 and 3 Hz), duration (0.05, 0.1 and 0.3 ms), or number (300, 500 and 1000 stimuli) in CMAP scans of 23 subjects was systematically varied while the other two parameters were kept constant. Pain was measured by means of a visual analogue scale (VAS). Non-parametric paired tests were used to assess significant differences in excitability and step variables and VAS scores between the different stimulus parameter settings. Results: We found no effect of stimulus frequency on CMAP scan variables or VAS scores. Stimulus duration affected excitability variables significantly, with higher stimulus intensity values for shorter stimulus durations. Step variables showed a clear trend towards increasing values with decreasing stimulus number. Conclusions: A protocol delivering 500 stimuli at a frequency of 2 Hz with a 0.1 ms pulse duration optimized CMAP scan quantification with a minimum of subject discomfort, artefact and duration of the recording. CMAP scan variables were influenced by stimulus duration and number; hence, these need to be standardized in future studies

Genetic evidence for the most common risk factors for chronic axonal polyneuropathy in the general population

BACKGROUND AND PURPOSE: Chronic axonal polyneuropathy is a common disease, but the etiology remains only partially understood. Previous etiologic studies have identified clinical risk factors, but genetic evidence supporting causality between these factors and polyneuropathy are largely lacking. In this study, we investigate whether there is a genetic association of clinically established important risk factors (diabetes, body mass index [BMI], vitamin B12 levels, and alcohol intake) with chronic axonal polyneuropathy. METHODS: This study was performed within the population‐based Rotterdam Study and included 1565 participants (median age = 73.6 years, interquartile range = 64.6–78.8, 53.5% female), of whom 215 participants (13.7%) had polyneuropathy. Polygenic scores (PGSs) for diabetes, BMI, vitamin B12 levels, and alcohol intake were calculated at multiple significance thresholds based on published genome‐wide association studies. RESULTS: Higher PGSs of diabetes, BMI, and alcohol intake were associated with higher prevalence of chronic axonal polyneuropathy, whereas higher PGS of vitamin B12 levels was associated with lower prevalence of polyneuropathy. These effects were most pronounced for PGSs with lenient significance thresholds for diabetes and BMI (odds ratio [OR](diabetes, p < 1.0) = 1.21, 95% confidence interval [CI] = 1.05–1.39 and OR(BMI, p < 1.0) = 1.21, 95% CI = 1.04–1.41) and for the strictest significance thresholds for vitamin B12 level and alcohol intake (OR (vitamin B12, p < 5e‐6) = 0.79, 95% CI = 0.68–0.92 and OR(alcohol, p < 5e‐8) = 1.17, 95% CI = 1.02–1.35). We did not find an association between different PGSs and sural sensory nerve action potential amplitude, nor between individual lead variants of PGS (p ) (< 5e‐8) and polyneuropathy. CONCLUSIONS: This study provides evidence for polygenic associations of diabetes, BMI, vitamin B12 level, and alcohol intake with chronic axonal polyneuropathy. This supports the hypothesis of causal associations between well‐known clinical risk factors and polyneuropathy

The Web-Based Advance Care Planning Program "Explore Your Preferences for Treatment and Care":Development, Pilot Study, and Before-and-After Evaluation

BACKGROUND: Web-based advance care planning (ACP) programs may support patients in thinking about and discussing their preferences for future treatment and care. However, they are not widely available, and only a limited number of programs are evidence based. OBJECTIVE: We aimed to develop and evaluate an evidence-based, interactive web-based ACP program that guides users through the process of thinking about, discussing, and recording of preferences for treatment and care. METHODS: The program "Explore your preferences for treatment and care" was developed, pilot-tested on feasibility, and subsequently evaluated; engagement in ACP was assessed before program completion and 2 months after program completion using the ACP Engagement Survey (score 1-5) among 147 persons with chronic disease. Usability (score 0-100) and user satisfaction (score 1-5) were also assessed. RESULTS: ACP engagement increased from 2.8 before program completion to 3.0 two months after program completion (P&lt;.001); contemplation about ACP increased from 2.6 to 2.8 (P=.003), and readiness for ACP increased from 2.2 to 2.5 (P&lt;.001). No changes were found for knowledge about ACP (3.0-3.2; P=.07) and self-efficacy for ACP (3.8-3.8; P=.25). The program was perceived as usable (mean 70, SD 13), attractive (mean 3.8, SD 0.7), and comprehensible (mean 4.2, SD 0.6). CONCLUSIONS: We developed an evidence-based, interactive web-based ACP program in cocreation with patients, relatives, and health care professionals. Before-and-after evaluation showed that the program can support people in taking first steps in ACP and in reflecting on preferences for treatment and care, by guiding them through the process of ACP using a stepwise approach. Participants perceived the program as usable and understandable, and they were satisfied with the program and with the amount of information. Health care professionals may use the program as a tool to start ACP discussions with their patients. The program may increase awareness of ACP.</p

Diagnosis of Guillain–Barré syndrome in children and validation of the Brighton criteria

To describe the key diagnostic features of pediatric Guillain–Barré syndrome (GBS) and validate the Brighton criteria. Retrospective cohort study of all children (<18 years) diagnosed with GBS between 1987 and 2013 at Sophia Children’s Hospital, Erasmus MC, Rotterdam. Clinical information was collected and the sensitivity of the Brighton criteria was calculated. 67 children (35 boys) were included, with a median age of 5.0 years [interquartile range (IQR) 3.0–10.0 years]. Bilateral limb weakness was present at hospital admission in 93% of children, and at nadir in all patients. Children presented with tetraparesis in 70% or with paraparesis in 23%. Reduced reflexes in paretic limbs were observed at hospital admission in 82% and during follow-up in all children. The progressive phase lasted median 6 days (IQR 3–8 days) and less than 4 weeks in all children. A monophasic disease course was seen in 97%, including 5 children with a treatment-related fluctuation. Two children had a later relapse at 9 weeks and 19 weeks after onset. 77% of the children showed an elevated protein level in CSF. Nerve conduction studies showed evidence for a poly(radiculo)neuropathy in 91% of the children. 46 children had a complete data set, the sensitivity of the Brighton criteria level 1 was 72% (95% CI 57–84) and 96% (95% CI 85–99) for level 2 and 98% (95% CI 88–100) for level 3. The majority of the pediatric GBS patients presented in this cohort fulfilled the current diagnostic criteria

The Dorsal Root Ganglion as a Novel Neuromodulatory Target to Evoke Strong and Reproducible Motor Responses in Chronic Motor Complete Spinal Cord Injury: A Case Series of Five Patients

Objectives: Current strategies for motor recovery after spinal cord injury (SCI) aim to facilitate motor performance through modulation of afferent input to the spinal cord using epidural electrical stimulation (EES). The dorsal root ganglion (DRG) itself, the first relay station of these afferent inputs, has not yet been targeted for this purpose. The current study aimed to determine whether DRG stimulation can facilitate clinically relevant motor response in motor complete SCI. Materials and Methods: Five patients with chronic motor complete SCI were implanted with DRG leads placed bilaterally on level L4 during five days. Based on personalized stimulation protocols, we aimed to evoke dynamic (phase 1) and isotonic (phase 2) motor responses in the bilateral

Diet quality and chronic axonal polyneuropathy: a population-based study

Objective: To investigate the association between diet quality and chronic axonal polyneuropathy. Methods: Between June 2013 and January 2017, among 1650 participants of the Rotterdam Study (median age 69.1 years, 54.2% women), diet quality was quantified based on food frequency questionnaires as a sum score of adherence (yes/no) to 14 components of the Dutch dietary guidelines. Presence of polyneuropathy was determined based on a questionnaire, neurological examination of the legs, and nerve conduction studies. We used logistic regression to associate diet quality with the presence of chronic axonal polyneuropathy and linear regression to associate with sural sensory nerve action potential (SNAP) amplitude in participants without polyneuropathy. Results were adjusted for age, sex, time between measurement

Changes in motor nerve excitability in acute phase Guillain-Barré syndrome

Background: The most common subtypes of Guillain-Barré syndrome (GBS) are acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). In the first days after the onset of weakness, standard nerve conduction studies (NCS) may not distinguish GBS subtypes. Reduced nerve excitability may be an early symptom of nerve dysfunction, which can be determined with the compound muscle action potential (CMAP) scan. The aim of this study was to explore whether early changes in motor nerve excitability in GBS patients are related to various subtypes. Methods: Prospective case–control study in 19 GBS patients from The Netherlands and 22 from Bangladesh. CMAP scans were performed within 2 days of hospital admission and NCS 7–14 days after onset of weakness. CMAP scans were also performed in age- and country-matched controls. Results: CMAP scan patterns of patients who were classified as AMAN were distinctly different compared to the CMAP scan patterns of the patients who were classified as AIDP. The most pronounced differences were found in the stimulus intensity parameters. Conclusions: CMAP scans made at hospital admission demonstrate several characteristics that can be used as an early indicator of GBS subtype