Remote monitoring of amyotrophic lateral sclerosis using wearable sensors detects differences in disease progression and survival: a prospective cohort study.

BACKGROUND: There is an urgent need for objective and sensitive measures to quantify clinical disease progression and gauge the response to treatment in clinical trials for amyotrophic lateral sclerosis (ALS). Here, we evaluate the ability of an accelerometer-derived outcome to detect differential clinical disease progression and assess its longitudinal associations with overall survival in patients with ALS. METHODS: Patients with ALS wore an accelerometer on the hip for 3-7 days, every 2-3 months during a multi-year observation period. An accelerometer-derived outcome, the Vertical Movement Index (VMI), was calculated, together with predicted disease progression rates, and jointly analysed with overall survival. The clinical utility of VMI was evaluated using comparisons to patient-reported functionality, while the impact of various monitoring schemes on empirical power was explored through simulations. FINDINGS: In total, 97 patients (70.1% male) wore the accelerometer for 1995 days, for a total of 27,701 h. The VMI was highly discriminatory for predicted disease progression rates, revealing faster rates of decline in patients with a worse predicted prognosis compared to those with a better predicted prognosis (p < 0.0001). The VMI was strongly associated with the hazard for death (HR 0.20, 95% CI: 0.09-0.44, p < 0.0001), where a decrease of 0.19-0.41 unit was associated with reduced ambulatory status. Recommendations for future studies using accelerometery are provided. INTERPRETATION: The results serve as motivation to incorporate accelerometer-derived outcomes in clinical trials, which is essential for further validation of these markers to meaningful endpoints. FUNDING: Stichting ALS Nederland (TRICALS-Reactive-II).

Portable fixed dynamometry enables home-based, reliable assessment of muscle strength in patients with amyotrophic lateral sclerosis: a pilot study.

OBJECTIVE: To determine the feasibility, reliability, and sensitivity of remotely monitoring muscle strength loss of knee extensors using a novel portable fixed dynamometer (PFD) in patients with amyotrophic lateral sclerosis (ALS). METHODS: We conducted a pilot study with a newly developed device to measure knee extension strength. Patients performed unsupervised PFD measurements, biweekly, for 6 months at home. We evaluated feasibility using adherence and a device-specific questionnaire. Reliability was assessed by (1) comparing unsupervised and supervised measurements to identify systematic bias, and (2) comparing consecutive unsupervised measurements to determine test-retest reliability expressed as intraclass correlation coefficient (ICC) and standard error of measurement (SEM). Sensitivity to detect longitudinal change was described using linear mixed-effects models. RESULTS: We enrolled 18 patients with ALS. Adherence was 86%, where all patients found that the device suitable to measure muscle strength at home; 4 patients (24%) found the measurements burdensome. The correlation between (un)supervised measurements was excellent (Pearson's r 0.97, 95%CI; 0.94 - 0.99) and no systematic bias was present (mean difference 0.13, 95%CI; -2.22 - 2.48, p = 0.91). Unsupervised measurements had excellent test-retest reliability with an average ICC of 0.97 (95%CI: 0.94 - 0.99) and SEM of 5.8% (95%CI: 4.8 - 7.0). Muscle strength declined monthly by 1.9 %predicted points (95%CI; -3.0 to -0.9, p = 0.001). CONCLUSIONS: Using the PFD, it proved feasible to perform knee extension strength measurements at home which were reliable and sensitive for detecting muscle strength loss. Larger studies are warranted to compare the device with conventional outcomes.

Development and Evaluation of a Simulation-Based Algorithm to Optimize the Planning of Interim Analyses for Clinical Trials in ALS.

BACKGROUND AND OBJECTIVES: Late-phase clinical trials for neurodegenerative diseases have a low probability of success. In this study, we introduce an algorithm that optimizes the planning of interim analyses for clinical trials in amyotrophic lateral sclerosis (ALS) to better use the time and resources available and minimize the exposure of patients to ineffective or harmful drugs. METHODS: A simulation-based algorithm was developed to determine the optimal interim analysis scheme by integrating prior knowledge about the success rate of ALS clinical trials with drug-specific information obtained in early-phase studies. Interim analysis schemes were optimized by varying the number and timing of interim analyses, together with their decision rules about when to stop a trial. The algorithm was applied retrospectively to 3 clinical trials that investigated the efficacy of diaphragm pacing or ceftriaxone on survival in patients with ALS. Outcomes were additionally compared with conventional interim designs. RESULTS: We evaluated 183-1,351 unique interim analysis schemes for each trial. Application of the optimal designs correctly established lack of efficacy, would have concluded all studies 1.2-19.4 months earlier (reduction of 4.6%-57.7% in trial duration), and could have reduced the number of randomized patients by 1.7%-58.1%. By means of simulation, we illustrate the efficiency for other treatment scenarios. The optimized interim analysis schemes outperformed conventional interim designs in most scenarios. DISCUSSION: Our algorithm uses prior knowledge to determine the uncertainty of the expected treatment effect in ALS clinical trials and optimizes the planning of interim analyses. Improving futility monitoring in ALS could minimize the exposure of patients to ineffective or harmful treatments and result in significant ethical and efficiency gains.

Use of hip- versus wrist-based actigraphy for assessing functional decline and disease progression in patients with motor neuron disease.

BACKGROUND: Actigraphy has been proposed as a measure for tracking functional decline and disease progression in patients with Motor Neuron Disease (MND). There is, however, little evidence to show that wrist-based actigraphy measures correlate with functional decline, and no consensus on how best to implement actigraphy. We report on the use of wrist actigraphy to show decreased activity in patients compared to controls, and compared the utility of wrist- and hip-based actigraphy for assessing functional decline in patients with MND. METHODS: In this multi-cohort, multi-centre, natural history study, wrist- and hip-based actigraphy were assessed in 139 patients with MND (wrist, n = 97; hip, n = 42) and 56 non-neurological control participants (wrist, n = 56). For patients with MND, longitudinal measures were contrasted with clinical outcomes commonly used to define functional decline. RESULTS: Patients with MND have reduced wrist-based actigraphy scores when compared to controls (median differences: prop. active = - 0.053 [- 0.075, - 0.026], variation axis 1 = - 0.073 [- 0.112, - 0.021]). When comparing wrist- and hip-based measures, hip-based accelerometery had stronger correlations with disease progression (prop. active: τ = 0.20 vs 0.12; variation axis 1: τ = 0.33 vs 0.23), whereas baseline wrist-based accelerometery was better related with future decline in fine-motor function (τ = 0.14-0.23 vs 0.06-0.16). CONCLUSIONS: Actigraphy outcomes measured from the wrist are more variable than from the hip and present differing sensitivity to specific functional outcomes. Outcomes and analysis should be carefully constructed to maximise benefit, should wrist-worn devices be used for at-home monitoring of disease progression in patients with MND.