Revisiting distinct nerve excitability patterns in patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease, characterized by loss of central and peripheral motor neurons. Although the disease is clinically and genetically heterogeneous, axonal hyperexcitability is a commonly observed feature that has been suggested to reflect an early pathophysiological step linked to the neurodegenerative cascade. Therefore, it is important to clarify the mechanisms causing axonal hyperexcitability and how these relate to the clinical characteristics of patients. Measures derived directly from a nerve excitability recording are frequently used as study end points, although their biophysical basis is difficult to deduce. Mathematical models can aid in the interpretation but are reliable only when applied to group-averaged recordings. Consequently, model estimates of membrane properties cannot be compared with clinical characteristics or treatment effects in individual patients, posing a considerable limitation in heterogeneous diseases, such as amyotrophic lateral sclerosis. To address these challenges, we revisited nerve excitability using a new pattern analysis-based approach (principal component analysis). We evaluated disease-specific patterns of excitability changes and established their biophysical origins. Based on the observed patterns, we developed new compound measures of excitability that facilitate the implementation of this approach in clinical settings. We found that excitability changes in amyotrophic lateral sclerosis patients (n = 161, median disease duration = 11 months) were characterized by four unique patterns compared with controls (n = 50, age and sex matched). These four patterns were best explained by changes in resting membrane potential (modulated by Na+/K+ currents), slow potassium and sodium currents (modulated by their gating kinetics) and refractory properties of the nerve. Consequently, we were able to show that altered gating of slow potassium channels was associated with, and predictive of, the rate of progression of the disease on the amyotrophic lateral sclerosis functional rating scale. Based on these findings, we designed four composite measures that capture these properties to facilitate implementation outside this study. Our findings demonstrate that changes in nerve excitability in patients with amyotrophic lateral sclerosis are dominated by four distinct patterns, each with a distinct biophysical origin. Based on this new approach, we provide evidence that altered slow potassium-channel function might play a role in the rate of disease progression. The magnitudes of these patterns, quantified using a similar approach or our new composite measures, have potential as efficient measures to study membrane properties directly in amyotrophic lateral sclerosis patients, and thus aid prognostic stratification and trial design.

Toward a Useful and Cost-Effective Workup in Chronic Polyneuropathy: The EXPRESS Study Protocol.

BACKGROUND: Knowledge gaps exist about the usefulness and extent of blood tests and nerve conduction studies in the workup of polyneuropathy. We hypothesize that a limited workup improves costs spent on diagnostics without loss of diagnostic reliability or disadvantageous effect on treatment choice in many patients with a clinical diagnosis of chronic polyneuropathy. We aim to determine which investigations are necessary in the workup of patients with suspected chronic polyneuropathy clinically diagnosed by neurologists in an outpatient clinic and will perform an early health technology assessment. METHODS: This is a prospective multicenter quality in healthcare evaluation. We compare two diagnostic strategies, both performed on all participants: the standard care by each patient's neurologist and the proposed (limited) workup by the study panel members consisting of neurologists with experience in neuromuscular diseases. RESULTS: The primary outcome is the effectiveness of a limited workup expressed as concordance between the patient's neurologist diagnosis and the panel diagnosis. This will be related to differences in costs and impact on treatment or patient management otherwise. Other outcomes are burden/gain for the patient in terms of number of investigations, time to diagnosis, hospital visits, sick leave, loss of productivity, expenses, experienced quality of care. CONCLUSION: This multicenter prospective observational study on quality in health care will provide improved evidence about the components of a cost-effective workup for patients with chronic polyneuropathy.

Scanxiety and quality of life around follow-up imaging in patients with unruptured intracranial aneurysms: a prospective cohort study.

OBJECTIVES: Patients with an unruptured intracranial aneurysm (UIA) may experience scanxiety around follow-up imaging. We studied the prevalence and temporal pattern of scanxiety, and compared quality of life (QoL) outcomes in patients with and without scanxiety. METHODS: We performed a prospective cohort study in a tertiary referral center in the Netherlands between October 2021 and November 2022. We sent questionnaires to patients ≥ 18 years old undergoing UIA follow-up imaging 4 weeks before (T1), immediately after (T2), and 6 weeks after the scan (T3) to assess health-related QoL (HRQoL) and emotional functioning. At T3, we also assessed scanxiety with a purpose-designed questionnaire. We compared differences in QoL outcomes between respondents with and without scanxiety using mixed models. RESULTS: Of 158 eligible patients, 106 (67%) participated (mean age 61 years ± 11 [standard deviation], 84 women). Sixty of the 91 respondents (66%) who completed the purpose-designed questionnaire experienced scanxiety. Of the 49 respondents who experienced scanxiety after the scan, it resolved in 22 (45%) within a day after receiving the radiology report. HRQoL did not differ between respondents with or without scanxiety. Emotional functioning was worse for respondents with scanxiety (mean Hospital Anxiety and Depression Scale sum score difference at T1, 3.6 [95% CI, 0.9-6.3]; T2, 4.1 [95% CI, 1.5-6.8]; and T3, 4.0 [95% CI, 1.5-6.5]). CONCLUSIONS: Two-thirds of the respondents experienced scanxiety around follow-up imaging, which often resolved within a day after receiving results. Patients with scanxiety had similar HRQoL but worse emotional functioning compared to patients without scanxiety. The time between the scan and receiving the results should be minimized to decrease the duration of scanxiety. CLINICAL RELEVANCE STATEMENT: We showed that scanxiety is common in UIA patients, and negatively associated with emotional functioning. Since scanxiety often disappears immediately after receiving the radiology report, it should be communicated to the patient as early as possible to alleviate patients' distress. KEY POINTS: • Many patients with an unruptured intracranial aneurysm experience emotional distress around follow-up imaging, termed "scanxiety." • Patients with scanxiety had worse emotional functioning compared to patients without scanxiety. • Scanxiety often resolved within a day after receiving the radiology report.

Amyotrophic lateral sclerosis established as a multistep process across phenotypes.

BACKGROUND AND PURPOSE: Given the accepted multistep process of disease causation in amyotrophic lateral sclerosis (ALS), the present study was undertaken to determine the number of steps required for disease onset across each of the ALS phenotypes. METHODS: Clinical and demographic data were prospectively accumulated using the Australian Motor Neurone Disease Registry (2005-2016), and age-specific incidence rates were calculated. Poisson regression was utilized to assess the relationship between log age-specific incidence and log age of onset, with McFadden's R2 used to assess the goodness of fit of the model. RESULTS: In total, 2647 ALS patients were included, with mean disease-onset age being 62.2 ± 12.1 years. A linear relationship between log incidence and log age was established across ALS phenotypes, with variable slope estimates: bulbar 5.1 (95% confidence interval [CI] 4.6-5.6); cervical 2.7 (95% CI 2.3-3.0); lumbar 3.5 (95% CI 3.2-3.9); flail arm 4.7 (95% CI 3.9-5.5); flail leg 3.6 (95% CI 2.6-4.5); primary lateral sclerosis 2.7 (95% CI 1.8-3.7). Slope estimates were significantly higher in the bulbar compared to the cervical, lumbar and primary lateral sclerosis phenotypes. McFadden's R2 values were >0.4 for all phenotypes indicating excellent model fit. DISCUSSION: A multistep process has been established across all ALS phenotypes with variable slope estimates, suggesting that the number of steps to develop disease is different across clinical presentations. Identification of mechanisms underlying slope estimate variability could exert pathophysiological significance.

A 21-bp deletion in the complement regulator CD55 promotor region is associated with multifocal motor neuropathy and its disease course.

BACKGROUND AND AIMS: To further substantiate the role of antibody-mediated complement activation in multifocal motor neuropathy (MMN) immunopathology, we investigated the distribution of promotor polymorphisms of genes encoding the membrane-bound complement regulators CD46, CD55, and CD59 in patients with MMN and controls, and evaluated their association with disease course. METHODS: We used Sanger sequencing to genotype five common polymorphisms in the promotor regions of CD46, CD55, and CD59 in 133 patients with MMN and 380 controls. We correlated each polymorphism to clinical parameters. RESULTS: The genotype frequencies of rs28371582, a 21-bp deletion in the CD55 promotor region, were altered in patients with MMN as compared to controls (p .009; Del/Del genotype 16.8% vs. 7.7%, p .005, odds ratio: 2.43 [1.27-4.58]), and patients carrying this deletion had a more favorable disease course (mean difference 0.26 Medical Research Council [MRC] points/year; 95% confidence interval [CI]: 0.040-0.490, p .019). The presence of CD59 rs141385724 was associated with less severe pre-diagnostic disease course (mean difference 0.940 MRC point/year; 95% CI: 0.083-1.80, p .032). INTERPRETATION: MMN susceptibility is associated with a 21-bp deletion in the CD55 promotor region (rs2871582), which is associated with lower CD55 expression. Patients carrying this deletion may have a more favorable long-term disease outcome. Taken together, these results point out the relevance of the pre-C5 level of the complement cascade in the inflammatory processes underlying MMN.

The Effects of a Blended Care Intervention in Partners of Patients With Acquired Brain Injury - Results of the CARE4Carer Randomized Controlled Trial.

OBJECTIVE: To assess effects of the CARE4Carer blended care intervention on caregiver mastery and psychosocial functioning compared with usual care in partners of patients with acquired brain injury (ABI). DESIGN: Multicenter randomized controlled trial. SETTING: Nine sites for rehabilitation medicine. PARTICIPANTS: 120 partners of outpatients with ABI were randomly allocated to blended care (N=59) or usual care (N=61). INTERVENTION: The blended care intervention (20 weeks) was aimed at improving caregiving skills and consisted of 9 online sessions, combined with 2 face-to-face consultations with a social worker. MAIN OUTCOME MEASURES: Mastery was assessed with the Caregiver Mastery Scale, secondary outcome measures were caregiver strain (Caregiver Strain Index), family functioning (Family Assessment Device), anxiety and depression (Hospital Anxiety and Depression Scale), burden (self-rated), and quality of life (CarerQol). Assessments were performed at baseline, 24, and 40 weeks. RESULTS: The adjusted mean difference in caregiver mastery between intervention and control group at week 24 was 1.31 (SD3.48, 95% confidence interval (CI) -0.12 to 2.74, P=.072) and at week 40 was 1.31 (SD3.69, 95% CI -0.26 to 2.88, P=.100). In the per protocol analysis, the adjusted mean difference in caregiver mastery at week 24 was 1.53 (SD3.38, 95% CI 0.10 to 2.96, P=.036) and at week 40 was 1.57 (SD3.63, 95% CI 0.01 to 3.14, P=.049). Regarding secondary outcomes, caregiver strain was lower in the intervention group in the per protocol analysis at week 40. Family functioning was higher in the intervention group in week 24, whereas anxiety was lower at both timepoints. CONCLUSIONS: In the subset of participants who were able to complete the intervention, caregiver mastery and psychosocial functioning improved. Future work should focus on improving adherence as this will optimize beneficial effects of blended care.

Continuous Theta-Burst Stimulation of the Contralesional Primary Motor Cortex for Promotion of Upper Limb Recovery After Stroke: A Randomized Controlled Trial.

BACKGROUND: Despite improvements in acute stroke therapies and rehabilitation strategies, many stroke patients are left with long-term upper limb motor impairment. We assessed whether an inhibitory repetitive transcranial magnetic stimulation treatment paradigm started within 3 weeks after stroke onset promotes upper limb motor recovery. METHODS: We performed a single-center randomized, sham-controlled clinical trial. Patients with ischemic stroke or intracerebral hemorrhage and unilateral upper limb motor impairment were randomized to 10 daily sessions of active or sham continuous theta-burst stimulation (cTBS) of the contralesional primary motor cortex combined with standard upper limb therapy, started within 3 weeks after stroke onset. The primary outcome was the change in the Action Research Arm Test score from baseline (pretreatment) at 3 months after stroke. Secondary outcomes included the score on the modified Rankin Scale at 3 months and the length of stay at the rehabilitation center. Statistical analyses were performed using mixed models for repeated measures. RESULTS: We enrolled 60 patients between April 2017 and February 2021, of whom 29 were randomized to active cTBS and 31 to sham cTBS. One patient randomized to active cTBS withdrew consent before the intervention and was excluded from the analyses. The mean difference in the change in Action Research Arm Test score from baseline at 3 months poststroke was 9.6 points ([95% CI, 1.2-17.9]; P=0.0244) in favor of active cTBS. Active cTBS was associated with better scores on the modified Rankin Scale at 3 months (OR, 0.2 [95% CI, 0.1-0.8]; P=0.0225) and with an 18 days shorter length of stay at the rehabilitation center than sham cTBS ([95% CI, 0.0-36.4]; P=0.0494). There were no serious adverse events. CONCLUSIONS: Ten daily sessions of cTBS of the contralesional primary motor cortex combined with upper limb training, started within 3 weeks after stroke onset, promote recovery of the upper limb, reduce disability and dependence and leads to earlier discharge from the rehabilitation center. REGISTRATION: URL: https://trialsearch.who.int/; Unique identifier: NTR6133.

UNC13A in amyotrophic lateral sclerosis: from genetic association to therapeutic target.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with limited treatment options and an incompletely understood pathophysiology. Although genomewide association studies (GWAS) have advanced our understanding of the disease, the precise manner in which risk polymorphisms contribute to disease pathogenesis remains unclear. Of relevance, GWAS have shown that a polymorphism (rs12608932) in the UNC13A gene is associated with risk for both ALS and frontotemporal dementia (FTD). Homozygosity for the C-allele at rs12608932 modifies the ALS phenotype, as these patients are more likely to have bulbar-onset disease, cognitive impairment and FTD at baseline as well as shorter survival. UNC13A is expressed in neuronal tissue and is involved in maintaining synaptic active zones, by enabling the priming and docking of synaptic vesicles. In the absence of functional TDP-43, risk variants in UNC13A lead to the inclusion of a cryptic exon in UNC13A messenger RNA, subsequently leading to nonsense mediated decay, with loss of functional protein. Depletion of UNC13A leads to impaired neurotransmission. Recent discoveries have identified UNC13A as a potential target for therapy development in ALS, with a confirmatory trial with lithium carbonate in UNC13A cases now underway and future approaches with antisense oligonucleotides currently under consideration. Considering UNC13A is a potent phenotypic modifier, it may also impact clinical trial outcomes. This present review describes the path from the initial discovery of UNC13A as a risk gene in ALS to the current therapeutic options being explored and how knowledge of its distinct phenotype needs to be taken into account in future trials.

A randomized, double-blind, placebo-controlled phase 2 study to assess safety, tolerability, and efficacy of RT001 in patients with amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: RT001 is a deuterated synthetic homologue of linoleic acid, which makes membrane polyunsaturated fatty acids resistant to lipid peroxidation, a process involved in motor neuron degeneration in amyotrophic lateral sclerosis (ALS). METHODS: We conducted a randomized, multicenter, placebo-controlled clinical trial. Patients with ALS were randomly allocated to receive either RT001 or placebo for 24 weeks. After the double-blind period, all patients received RT001 during an open-label phase for 24 weeks. The primary outcome measures were safety and tolerability. Key efficacy outcomes included the ALS Functional Rating Scale (ALSFRS-R), percent predicted slow vital capacity, and plasma neurofilament light chain concentration. RESULTS: In total, 43 patients (RT001 = 21; placebo = 22) were randomized. RT001 was well tolerated; one patient required dose reduction due to adverse events (AEs). Numerically, there were more AEs in the RT001 group compared to the placebo group (71% versus 55%, p = 0.35), with gastrointestinal symptoms being the most common (43% in RT001, 27% in placebo, p = 0.35). Two patients in the RT001 group experienced a serious AE, though unrelated to treatment. The least-squares mean difference in ALSFRS-R total score at week 24 of treatment was 1.90 (95% confidence interval = -1.39 to 5.19) in favor of RT001 (p = 0.25). The directions of other efficacy outcomes favored RT001 compared to placebo, although no inferential statistics were performed. CONCLUSIONS: Initial data indicate that RT001 is safe and well tolerated. Given the exploratory nature of the study, a larger clinical trial is required to evaluate its efficacy.

The RESISTANT study (Respiratory Muscle Training in Patients with Spinal Muscular Atrophy): study protocol for a randomized controlled trial.

BACKGROUND: Spinal Muscular Atrophy (SMA) is characterized by progressive and predominantly proximal and axial muscle atrophy and weakness. Respiratory muscle weakness results in impaired cough with recurrent respiratory tract infections, nocturnal hypoventilation, and may ultimately lead to fatal respiratory failure in the most severely affected patients. Treatment strategies to either slow down the decline or improve respiratory muscle function are wanting. OBJECTIVE: The aim of this study is to assess the feasibility and efficacy of respiratory muscle training (RMT) in patients with SMA and respiratory muscle weakness. METHODS: The effect of RMT in patients with SMA, aged ≥ 8 years with respiratory muscle weakness (maximum inspiratory mouth pressure [PImax] ≤ 80 Centimeters of Water Column [cmH2O]), will be investigated with a single blinded randomized sham-controlled trial consisting of a 4-month training period followed by an 8-month open label extension phase. INTERVENTION: The RMT program will consist of a home-based, individualized training program involving 30-breathing cycles through an inspiratory and expiratory muscle training device. Patients will be instructed to perform 10 training sessions over 5-7 days per week. In the active training group, the inspiratory and expiratory threshold will be adjusted to perceived exertion (measured on a Borg scale). The sham-control group will initially receive RMT at the same frequency but against a constant, non-therapeutic resistance. After four months the sham-control group will undergo the same intervention as the active training group (i.e., delayed intervention). Individual adherence to the RMT protocol will be reviewed every two weeks by telephone/video call with a physiotherapist. MAIN STUDY PARAMETERS/ENDPOINTS: We hypothesize that the RMT program will be feasible (good adherence and good acceptability) and improve inspiratory muscle strength (primary outcome measure) and expiratory muscle strength (key secondary outcome measure) as well as lung function, patient reported breathing difficulties, respiratory infections, and health related quality of life (additional secondary outcome measures, respectively) in patients with SMA. DISCUSSION: RMT is expected to have positive effects on respiratory muscle strength in patients with SMA. Integrating RMT with recently introduced genetic therapies for SMA may improve respiratory muscle strength in this patient population. TRIAL REGISTRATION: Retrospectively registered at clinicaltrial.gov: NCT05632666.

Longitudinal prospective cohort study to assess peripheral motor function with extensive electrophysiological techniques in patients with Spinal Muscular Atrophy (SMA): the SMA Motor Map protocol.

BACKGROUND: Hereditary spinal muscular atrophy (SMA) is a motor neuron disorder with a wide range in severity in children and adults. Two therapies that alter splicing of the Survival Motor Neuron 2 (SMN2) gene, i.e. nusinersen and risdiplam, improve motor function in SMA, but treatment effects vary. Experimental studies indicate that motor unit dysfunction encompasses multiple features, including abnormal function of the motor neuron, axon, neuromuscular junction and muscle fibres. The relative contributions of dysfunction of different parts of the motor unit to the clinical phenotype are unknown. Predictive biomarkers for clinical efficacy are currently lacking. The goals of this project are to study the association of electrophysiological abnormalities of the peripheral motor system in relation to 1) SMA clinical phenotypes and 2) treatment response in patients treated with SMN2-splicing modifiers (nusinersen or risdiplam). METHODS: We designed an investigator-initiated, monocentre, longitudinal cohort study using electrophysiological techniques ('the SMA Motor Map') in Dutch children (≥ 12 years) and adults with SMA types 1-4. The protocol includes the compound muscle action potential scan, nerve excitability testing and repetitive nerve stimulation test, executed unilaterally at the median nerve. Part one cross-sectionally assesses the association of electrophysiological abnormalities in relation to SMA clinical phenotypes in treatment-naïve patients. Part two investigates the predictive value of electrophysiological changes at two-months treatment for a positive clinical motor response after one-year treatment with SMN2-splicing modifiers. We will include 100 patients in each part of the study. DISCUSSION: This study will provide important information on the pathophysiology of the peripheral motor system of treatment-naïve patients with SMA through electrophysiological techniques. More importantly, the longitudinal analysis in patients on SMN2-splicing modifying therapies (i.e. nusinersen and risdiplam) intents to develop non-invasive electrophysiological biomarkers for treatment response in order to improve (individualized) treatment decisions. TRIAL REGISTRATION: NL72562.041.20 (registered at https://www.toetsingonline.nl . 26-03-2020).

Composite endpoint for ALS clinical trials based on patient preference: Patient-Ranked Order of Function (PROOF).

BACKGROUND: Patients with amyotrophic lateral sclerosis (ALS) show considerable variation in symptoms. Treatments targeting an overall improvement in symptomatology may not address what the majority of patients consider to be most important. Here, we propose a composite endpoint for ALS clinical trials that weighs the improvement in symptoms compared with what the patient population actually wants. METHODS: An online questionnaire was sent out to a population-based registry in The Netherlands. Patients with ALS were asked to score functional domains with a validated self-reported questionnaire, and rank the order of importance of each domain. This information was used to estimate variability in patient preferences and to develop the Patient-Ranked Order of Function (PROOF) endpoint. RESULTS: There was extensive variability in patient preferences among the 433 responders. The majority of the patients (62.1%) preferred to prioritise certain symptoms over others when evaluating treatments. The PROOF endpoint was established by comparing each patient in the treatment arm to each patient in the placebo arm, based on their preferred order of functional domains. PROOF averages all pairwise comparisons, and reflects the probability that a patient receiving treatment has a better outcome on domains that are most important to them, compared with a patient receiving placebo. By means of simulation we illustrate how incorporating patient preference may upgrade or downgrade trial results. CONCLUSIONS: The PROOF endpoint provides a balanced patient-focused analysis of the improvement in function and may help to refine the risk-benefit assessment of new treatments for ALS.

Characterising ALS disease progression according to El Escorial and Gold Coast criteria.

BACKGROUND: The Gold Coast criteria (GCC) have been proposed as a means of selecting patients for amyotrophic lateral sclerosis (ALS) clinical trials. We aimed to characterise disease progression according to the GCC. METHODS: Data from population-based ALS registries from the Netherlands and Belgium were analysed. The GCC additionally define ALS as lower motor neuron (LMN) dysfunction in ≥2 body regions without upper motor neuron dysfunction. Therefore, the revised El Escorial criteria (rEEC) were supplemented with a 'Gold Coast ALS' category for patients with only LMN dysfunction in ≥2 body regions. We assessed survival time, ALS Functional Rating Scale (ALSFRS-R) progression rates and between-patient variability per diagnostic category. RESULTS: We included 5957 ALS patients, of whom 600 (10.1%) fulfilled the GCC but not the rEEC, and 95 (1.6%) fulfilled only the rEEC. ALSFRS-R progression rates were similar for the rEEC (0.84 points/month) and GCC (0.81 points/month) with similar variability (standard deviation of 0.59 vs. 0.60) and median survival time (17.8 vs.18.7 months). Survival time and average progression rates varied (p<0.001) between categories. Per category, however, there was considerable between-patient variability with progression rates ranging from: -2.10 to -0.14 (definite), -1.94 to -0.06 (probable), -2.10 to -0.02 (probable laboratory supported), -1.79 to -0.02 (possible) and -1.31 to 0.08 (Gold Coast). CONCLUSIONS: The GCC broaden the definition of ALS, allowing more patients to participate in trials, while minimally impacting population heterogeneity. Given the large variability per diagnostic category, selecting only specific categories for trials may not result in a more homogeneous study population.

Clinical relevance of testing for metabolic vitamin B12 deficiency in patients with polyneuropathy.

OBJECTIVE: Determine vitamin B12 threshold levels below which additional testing of methylmalonic acid (MMA) and/or homocysteine (Hcy) is useful to diagnose metabolic vitamin B12 deficiency in patients with polyneuropathy, and how vitamin B12, MMA and Hcy levels relate to the effect of supplementation therapy. METHODS: In a retrospective cohort study of 331 patients with polyneuropathy, vitamin B12, MMA and Hcy were measured. Linear regression models with vitamin B12 as dependent and Hcy or MMA as covariate were compared, to assess which was best related to vitamin B12. Threshold vitamin B12 levels for metabolic deficiency (defined as elevatede metabolites) were determined using logistic regression with elevated metabolites as dependent and vitamin B12 as covariate. A structured interview was conducted in 42 patients to evaluate response to vitamin B12 supplementation. RESULTS: MMA was best related to vitamin B12. Using elevated MMA for metabolic deficiency, we found 90% sensitivity at a vitamin B12 threshold level <264 pmol/L (358 pg/mL) and 95% sensitivity at <304 pmol/L (412 pg/mL). Improvement after supplementation was reported by 19% patients and stabilization by 24%. 88% of patients with improvement and 90% with stabilization either had absolute deficiency (Vitamin B12 < 148 pmol/L) or metabolic deficiency (elevated MMA and vitamin B12 ≥ 148 pmol/L). There were no additional patients with improvement or stabilization with isolated elevated Hcy. CONCLUSION: Testing of MMA has additional value in identifying patients with clinically relevant metabolic deficiency when vitamin B12 is below 304 pmol/L (412 pg/mL). Supplementation can be effective in patients with absolute and metabolic deficiency.

The Distinct Traits of the UNC13A Polymorphism in Amyotrophic Lateral Sclerosis.

OBJECTIVE: The rs12608932 single nucleotide polymorphism in UNC13A is associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) susceptibility, and may underlie differences in treatment response. We aimed to characterize the clinical, cognitive, behavioral, and neuroimaging phenotype of UNC13A in patients with ALS. METHODS: We included 2,216 patients with ALS without a C9orf72 mutation to identify clinical characteristics associated with the UNC13A polymorphism. A subcohort of 428 patients with ALS was used to study cognitive and behavioral profiles, and 375 patients to study neuroimaging characteristics. Associations were analyzed under an additive genetic model. RESULTS: Genotyping rs12608932 resulted in 854 A/A, 988 A/C, and 374 C/C genotypes. The C allele was associated with a higher age at symptom onset (median years A/A 63.5, A/C 65.6, and C/C 65.5; p < 0.001), more frequent bulbar onset (A/A 29.6%, A/C 31.8%, and C/C 43.1%; p < 0.001), higher incidences of ALS-FTD (A/A 4.3%, A/C 5.2%, and C/C 9.5%; p = 0.003), lower forced vital capacity at diagnosis (median percentage A/A 92.0, A/C 90.0, and C/C 86.5; p < 0.001), and a shorter survival (median in months A/A 33.3, A.C 30.7, and C/C 26.6; p < 0.001). UNC13A was associated with lower scores on ALS-specific cognition tests (means A/A 79.5, A/C 78.1, and C/C 76.6; p = 0.037), and more frequent behavioral disturbances (A/A 16.7%, A/C 24.4%, and C/C 27.7%; p = 0.045). Thinner left inferior temporal and right fusiform cortex were associated with the UNC13A single nucleotide polymorphism (SNP; p = 0.045 and p = 0.036). INTERPRETATION: Phenotypical distinctions associated with UNC13A make it an important factor to take into account in clinical trial design, studies on cognition and behavior, and prognostic counseling. ANN NEUROL 2020;88:796-806.

Quantification of disease progression in spinal muscular atrophy with muscle MRI-a pilot study.

OBJECTIVES: Quantitative MRI (qMRI) of muscles is a promising tool to measure disease progression or to assess therapeutic effects in neuromuscular diseases. Longitudinal imaging studies are needed to show sensitivity of qMRI in detecting disease progression in spinal muscular atrophy (SMA). In this pilot study we therefore studied one-year changes in quantitative MR parameters in relation to clinical scores. METHODS: We repeated quantitative 3 T MR analysis of thigh muscles and clinical testing one year after baseline in 10 treatment-naïve patients with SMA, 5 with Type 2 (21.6 ± 7.0 years) and 5 with Type 3 (33.4 ± 11.9 years). MR protocol consisted of Dixon, T2 mapping and diffusion tensor imaging (DTI). The temporal relation of parameters was examined with a mixed model. RESULTS: We detected a significant increase in fat fraction (baseline, 38.2% SE 0.6; follow-up, 39.5% SE 0.6; +1.3%, p = 0.001) in all muscles. Muscles with moderate to high fat infiltration at baseline show a larger increase over time (+1.6%, p < 0.001). We did not find any changes in DTI parameters except for low fat-infiltration muscles (m. adductor longus and m. biceps femoris (short head)). The T2 of muscles decreased from 28.2 ms to 28.0 ms (p = 0.07). Muscle strength and motor function scores were not significantly different between follow-up and baseline. CONCLUSION: Longitudinal imaging data show slow disease progression in skeletal muscle of the thigh of (young-) adult patients with SMA despite stable strength and motor function scores. Quantitative muscle imaging demonstrates potential as a biomarker for disease activity and monitoring of therapy response.

Pattern of muscle strength improvement after intravenous immunoglobulin therapy in multifocal motor neuropathy.

INTRODUCTION: In multifocal motor neuropathy (MMN), knowledge about the pattern of treatment response in a wide spectrum of muscle groups, distal as well as proximal, after intravenous immunoglobulin (IVIg) initiation is lacking. METHODS: Hand-held dynamometry data of 11 upper and lower limb muscles, from 47 patients with MMN was reviewed. Linear mixed models were used to determine the treatment response after IVIg initiation and its relationship with initial muscle weakness. RESULTS: All muscle groups showed a positive treatment response after IVIg initiation. Changes in SD scores ranged from +0.1 to +0.95. A strong association between weakness at baseline and the magnitude of the treatment response was found. DISCUSSION: Improved muscle strength in response to IVIg appears not only in distal, but to a similar degree also in proximal muscle groups in MMN, with the largest response in muscle groups that show the greatest initial weakness.

Venous creatinine as a biomarker for loss of fat-free mass and disease progression in patients with amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To establish the utility of venous creatinine as a biomarker to monitor loss of fat-free mass in patients with amyotrophic lateral sclerosis (ALS). METHODS: In this multicenter natural history study, body composition and venous creatinine were assessed in 107 patients with ALS and 52 healthy controls. Longitudinal patterns of venous creatinine and its association with the risk of death during follow-up were determined in a cohort of patients with ALS from Australia (n = 69) and the Netherlands (n = 38). RESULTS: The mean levels of venous creatinine were 75.78 ± 11.15 µmol/L for controls, 70.25 ± 12.81 µmol/L for Australian patients, and 59.95 ± 14.62 µmol/L for Dutch patients with ALS. The relationship between measures of venous creatinine and fat-free mass was similar between all groups (r = 0.36, p < 0.001). Within patients, fat-free mass declined by 0.31 (95% confidence interval [CI]: 0.22-0.40) kg/month, and venous creatinine declined by 0.52 (95% CI: 0.38-0.66) µmol/L/month, with a longitudinal correlation of 0.57 (95% CI: 0.35-0.76, p < 0.001). Lower levels of venous creatinine were associated with increased risk for earlier death in patients with ALS (hazard ratio = 0.94, 95% CI: 0.90-0.98, p = 0.007). CONCLUSIONS: Venous creatinine is decreased in ALS and declines alongside a decline in fat-free mass over the course of the disease, and may serve as a practical marker to monitor the change of fat-free mass in patients with ALS. This could inform clinical care and provide an alternative endpoint for the evaluation of therapeutic interventions that focus on slowing the loss of fat-free mass and disease progression in ALS.

Prognostic value of nerve ultrasonography: A prospective multicenter study on the natural history of chronic inflammatory neuropathies.

BACKGROUND AND OBJECTIVE: Nerve ultrasound is a promising new tool in chronic inflammatory neuropathies. The aim of this study was to determine its prognostic value in a prospective multicenter cohort study including incident and prevalent patients with CIDP and MMN. METHODS: We enrolled 126 patients with CIDP, and 72 with MMN; 71 were treatment-naive. Patients with chronic idiopathic axonal polyneuropathy (CIAP; n = 35) were considered as disease controls. Standardized neurological examination, questionnaires, and nerve ultrasonography were obtained at time of inclusion and 1-year follow-up. Nerve size development over time and correlation between nerve size and clinical outcome measures were determined using linear mixed effects models. RESULTS: Nerve size development over time was heterogeneous. Only in MMN was there a correlation between C5 nerve root size and deterioration of grip strength (-1.3 kPa/mm2 (95% confidence interval [CI] -2.3 to -0.2). No other significant correlations between nerve size and clinical outcome measures were found. In MMN, presence of nerve enlargement at inclusion predicted deterioration of grip strength, and MMN patients with enlargement confined to the brachial plexus seemed to have more favorable outcomes. No other predictive effects of sonographic nerve size were found. CONCLUSIONS: The present study indicates that the natural course of nerve size development in CIDP and MMN is heterogeneous, and that the prognostic value of sonographic nerve enlargement is limited. It had some predictive effect in patients with MMN. Further research in specific subgroups of chronic inflammatory neuropathy is necessary to determine the usefulness of nerve ultrasonography after the diagnostic phase.

A Road Map for Remote Digital Health Technology for Motor Neuron Disease.

Despite recent and potent technological advances, the real-world implementation of remote digital health technology in the care and monitoring of patients with motor neuron disease has not yet been realized. Digital health technology may increase the accessibility to and personalization of care, whereas remote biosensors could optimize the collection of vital clinical parameters, irrespective of patients' ability to visit the clinic. To facilitate the wide-scale adoption of digital health care technology and to align current initiatives, we outline a road map that will identify clinically relevant digital parameters; mediate the development of benefit-to-burden criteria for innovative technology; and direct the validation, harmonization, and adoption of digital health care technology in real-world settings. We define two key end products of the road map: (1) a set of reliable digital parameters to capture data collected under free-living conditions that reflect patient-centric measures and facilitate clinical decision making and (2) an integrated, open-source system that provides personalized feedback to patients, health care providers, clinical researchers, and caregivers and is linked to a flexible and adaptable platform that integrates patient data in real time. Given the ever-changing care needs of patients and the relentless progression rate of motor neuron disease, the adoption of digital health care technology will significantly benefit the delivery of care and accelerate the development of effective treatments.