Amyotrophic lateral sclerosis: a comparison of two staging systems in a population-based study

Advances in molecular pathology, diagnosis, and treatment of amyotrophic lateral sclerosis

Although the past two decades have produced exciting discoveries in the genetics and pathology of amyotrophic lateral sclerosis (ALS), progress in developing an effective therapy remains slow. This review summarizes the critical discoveries and outlines the advances in disease characterization, diagnosis, imaging, and biomarkers, along with the current status of approaches to ALS care and treatment. Additional knowledge of the factors driving disease progression and heterogeneity will hopefully soon transform the care for patients with ALS into an individualized, multi-prong approach able to prevent disease progression sufficiently to allow for a dignified life with limited disability.

Healthcare resource utilization at different stages of amyotrophic lateral sclerosis: Results from a real-world survey

People with amyotrophic lateral sclerosis (pALS) require complex, multi-disciplinary care, resulting in extensive healthcare resource utilization (HCRU). To investigate the relationship between HCRU and ALS progression, the study objectives were (i) to characterize HCRU in pALS and (ii) to establish whether this varied according to disease stage, as defined using three different methodologies: neurologist-defined early/mid/late stage, the King's clinical staging system for ALS, and the Milan Torino Staging system for ALS (MiToS). Real-world data were drawn from the Adelphi ALS Disease-Specific Programme™, a point-in-time survey of neurologists in France, Germany, Italy, Spain, the UK, and the USA conducted July 2020-March 2021. The analysis included survey responses from 142 physicians with respect to 880 pALS. With advancing ALS stage, significant differences were observed in the number of healthcare professional consultations and X-rays per person (both p < 0.05 for all staging systems), and the proportion of pALS with emergency room admissions, intensive care unit admissions, and assisted ventilation (all p < 0.05 for all staging systems). Across stages, >55% of pALS received care from a general neurologist and a general/primary care practitioner. With increasing stage, there was a significant difference in the proportion receiving care from a physical therapist, pulmonologist/respiratory care practitioner, respiratory therapist, speech/language therapist, and palliative care team, and in the proportion receiving care only from professional caregivers (all p < 0.05 for all staging systems). This study confirmed the substantial HCRU required to support pALS through all stages of ALS and highlighted an increasing need for healthcare resources as the disease progresses.

Quantitative Brain MRI Metrics Distinguish Four Different ALS Phenotypes: A Machine Learning Based Study

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease whose diagnosis depends on the presence of combined lower motor neuron (LMN) and upper motor neuron (UMN) degeneration. LMN degeneration assessment is aided by electromyography, whereas no equivalent exists to assess UMN dysfunction. Magnetic resonance imaging (MRI) is primarily used to exclude conditions that mimic ALS. We have identified four different clinical/radiological phenotypes of ALS patients. We hypothesize that these ALS phenotypes arise from distinct pathologic processes that result in unique MRI signatures. To our knowledge, no machine learning (ML)-based data analyses have been performed to stratify different ALS phenotypes using MRI measures. During routine clinical evaluation, we obtained T1-, T2-, PD-weighted, diffusion tensor (DT) brain MRI of 15 neurological controls and 91 ALS patients (UMN-predominant ALS with corticospinal tract CST) hyperintensity, n = 21; UMN-predominant ALS without CST hyperintensity, n = 26; classic ALS, n = 23; and ALS patients with frontotemporal dementia, n = 21). From these images, we obtained 101 white matter (WM) attributes (including DT measures, graph theory measures from DT and fractal dimension (FD) measures using T1-weighted), 10 grey matter (GM) attributes (including FD based measures from T1-weighted), and 10 non-imaging attributes (2 demographic and 8 clinical measures of ALS). We employed classification and regression tree, Random Forest (RF) and also artificial neural network for the classifications. RF algorithm provided the best accuracy (70-94%) in classifying four different phenotypes of ALS patients. WM metrics played a dominant role in classifying different phenotypes when compared to GM or clinical measures. Although WM measures from both right and left hemispheres need to be considered to identify ALS phenotypes, they appear to be differentially affected by the degenerative process. Longitudinal studies can confirm and extend our findings.

Exercise Physiology Impairments of Patients With Amyotrophic Lateral Sclerosis: Cardiopulmonary Exercise Testing Findings

Background and Objective

In amyotrophic lateral sclerosis (ALS), progressive weakness significantly limits the ability to exercise. However, measurements of the impaired exercise function and their practical value to assess disease progression in ALS are scarce. Cardiopulmonary exercise testing (CPET) is a non-invasive accurate method used to comprehensively quantify exercise physiology in a variety of diseases. This study aimed to evaluate the clinical value of CPET and to explore its association with disease severity and prognosis prediction in ALS.

Methods

A total of 319 participants were enrolled in this 3-year prospective study. After strict quality control, 109 patients with ALS and 150 age- and sex-matched healthy controls were included with comprehensive clinical assessment and follow-ups. The incremental ramp protocol for symptom-limited CPET was applied in both groups. The exercise physiology during peak effort exercise was systematically measured, including the overall aerobic capacity of exercise (VO₂ peak) and the respective capacity of the exercise-involved organs [cardiac response (heart rate peak—HR peak), ventilatory efficiency (VE/VCO₂ slope), breathing economy (VE/VO₂ peak), and other relevant parameters]. Disease severity and progression were evaluated using recognized scales. Survival was monitored with regular follow-ups every 6 months.

Results

Decreased exercise capacity (VO₂ peak < 16 ml/kg/min) occurred more frequently in patients with ALS than in controls (44.95% vs. 9.33%, p < 0.01). In patients with ALS, the average VO₂ peak (16.16 ± 5.43 ml/kg/min) and HR peak [135 (112–153) bpm] were significantly lower (p < 0.01) than in controls [22.26 ± 7.09 ml/kg/min; 148 (135–164) bpm], but the VE/VCO₂ slope was significantly higher [28.05 (25.03–32.16) vs. 26.72 (24.37–29.58); p = 0.03]. In patients with ALS, the VO₂ peak and HR peak were significantly correlated with disease severity and progression scores (p < 0.05). Survival analyses revealed the VO₂ peak and HR peak as protective indicators while the VE/VO₂ peak as a detrimental indicator for the prognostic prediction in ALS (HR = 0.839, p = 0.001; HR = 0.967, p < 0.001; HR = 1.137, p = 0.028, respectively).

Conclusion

Our prospective study quantified the significantly decreased exercise capacity in ALS through non-invasive CPET. The impaired VO₂ peak and HR peak closely correlated with disease severity and independently predicted a worse prognosis. Our findings identified the clinical value of CPET as an objective indicator of disease progression in ALS.

King's college progression rate at first clinical evaluation: A new measure of disease progression in amyotrophic lateral sclerosis

BACKGROUND

To estimate King's college clinical stage progression rate (ΔKC) at first clinical evaluation in order to define its predictive and prognostic role on survival in a large cohort of Amyotrophic Lateral Sclerosis (ALS) patients.

METHODS

The ΔKC was calculated with the following formula: 0 - KC clinical stage at first clinical evaluation/disease duration from onset to first evaluation, and each result was reported as absolute value. All the evaluations were performed in two cohorts: one from our tertiary centre for motor neuron disease and the other one from a pooled resource open-access ALS clinical trials (PRO-ACT) database. C-statistic was used to evaluate the model discrimination of survival at different time points (1-3 years). Cox proportional hazard model was used to identify factors associated with survival.

RESULTS

ΔKC predicted survival at three years in our centre and in the PRO-ACT cohort (C-statistic 0.83, 95% CI 0.8-0.86, p < 0.0001; 0.7, 95% CI 0.68-0.73, p < 0.0001, respectively). At multivariate analysis, ΔKC was independently associated with survival both in our cohort (HR 3.62 95% CI 2.71-4.83 p = 0.001) and in the PRO-ACT cohort (HR 2.75 95% CI 2.1-3.6 p = 0.001).

CONCLUSIONS

Based on our results, ΔKC could be used as a novel measure of disease progression, hence as an accurate predictor of survival in ALS patients. Indeed, greater values of ΔKC were associated with a 3.5-fold higher risk to experience the event, confirming its robust prognostic value.

Milano-Torino Staging and Long-Term Survival in Chinese Patients with Amyotrophic Lateral Sclerosis

(1) Background: The aim of this longitudinal study was to evaluate the association between disease progression according to the Milano–Torino staging (MITOS) system and long-term survival in Chinese patients with amyotrophic lateral sclerosis (ALS). We also examined factors affecting MITOS progression. (2) Methods: Patients were enrolled and underwent follow-up at 6, 12, 18, and 24 months, and their demographic and clinical data, including the Milano–Torino stage, Amyotrophic Lateral Sclerosis Functional Rating Scale—Revised (ALSFRS-R) score and neuropsychiatric data, were evaluated. The sensitivity and specificity of predicting survival outcomes based on MITOS progression and ALSFRS-R score decline from baseline to 6 months were compared. The associations between MITOS progression from baseline to 6 months and survival outcome at 12, 18 and 24 months were examined, and factors associated with disease progression were evaluated with subgroup analyses. (3) Results: Among the 100 patients included, 74% were in stage 0 at baseline, and approximately 95% progressed to a higher stage of the MITOS system at 24 months. MITOS progression from baseline to 6 months and ALSFRS-R decline showed comparable value for predicting survival at 12, 18, and 24 months. MITOS progression from baseline to 6 months is strongly associated with death outcomes. Older age at onset and increased depression and anxiety scores may be related to disease progression. (4) Conclusions: MITOS progression during the early disease course could serve as a prognostic marker of long-term survival and may have utility in clinical trials. Age at onset and diagnosis and neuropsychiatric factors might be associated with disease progression.

Comparison of the ability of the King's and MiToS staging systems to predict disease progression and survival in amyotrophic lateral sclerosis

Background: Assessing clinical progression in amyotrophic lateral sclerosis (ALS) remains a challenge. We evaluated the validity and predictive capabilities of the King's and Milano-Torino Staging (MiToS) systems in a cohort of patients with ALS to demonstrate their benefit in clinical practice.Methodology: A cohort study was performed by including ALS incident cases in a referral center from 2007 to 2016. The staging systems were determined at time of diagnosis and follow-up. The standardized median times to reach each stage were computed. A multi-state model in the framework of the Cox model evaluated the predictive value of measurements. The survival C-statistic was reported as a measure of prediction ability.Results: Overall, 298 incident cases were included. The King's and MiToS systems described a progressive increase in the risk of dying with each elapsed stage. However, a lower resolution for late disease description for the King's system was observed, and late stages overlapped for the MiToS system. Slight variations in the staging systems appeared to improve performance based on validity and prediction abilities: (i) in the King's (C-statistic = 0.783), by adding a new stage involving the need for both gastrostomy and NIV: (ii) in the MiToS (C-statistic = 0.792), by merging stage 3 and stage 4 into a single stage 3.Conclusion: Both King's and MiToS are valid systems but have certain limitations. Variations in the staging systems may provide a more suitable framework for describing progression and survival. Further research is needed to evaluate the variations in the staging systems.

Intuitive Staging Correlates With King's Clinical Stage

Background: Clinical stage in amyotrophic lateral sclerosis (ALS) can be assigned using King's staging with a simple protocol based on the number of CNS regions involved and the presence of significant nutritional or respiratory failure. It is important that the assigned clinical stage matches expectations, and generally corresponds with how a health care professional would intuitively stage the patient. We therefore investigated the relationship between King's clinical ALS stage and ALS stage as intuitively assigned by health care professionals. Methods: We wrote 17 case vignettes describing people with ALS at different disease stages from very early limited disease involvement through to severe, multi-domain disease. During two workshops, we asked health care professionals to intuitively stage the vignettes and compared the answers with the actual King's clinical ALS stage. Results: There was a good correlation between King's clinical ALS stage and intuitively assigned stage, with a Spearman's Rank correlation coefficient of 0.64 (p < 0.001). There was no difference in the intuitive stages assigned by practitioners of different types or at different levels of experience. Conclusions: Across a spectrum of ALS scenarios, King's clinical ALS stage corresponds to intuitive ALS stage as assigned by a range of health care professionals.

The utility of ALS staging systems in a multi-ethnic patient cohort

Objective: To compare two ALS staging systems, King's clinical staging and Milano-Torino (MiToS) functional staging, using prospective data from a multi-ethnic cohort of ALS patients. Methods: The stages of disease were determined prospectively based on existing definitions. The two systems were compared for timing of stages using box plots, correspondence using chi-square tests and association using Spearman's rank correlation. Results: The distribution of stages differed between the two systems. The proportions of disease stages of the King's staging system were more evenly distributed whereas in MiToS, there was greater weight seen at the later stages of disease. At the early stages, patients moved consecutively in the MiToS staging system but not in the King's staging system where patients tended to skip stages to reach later stages. Both systems had good correlation (Spearman's rho = 0.869) and the King's stage 4 most frequently corresponded to MiToS stage 2. Conclusion: We found the King's staging was helpful in determining the stages of disease burden, whereas both were helpful in determining the time to functional dependence with MiToS further refining the levels of dependence.

Applying the D50 disease progression model to gray and white matter pathology in amyotrophic lateral sclerosis

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The D50 disease progression model well characterized a cross-sectional ALS cohort.

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VBM reveled ALS-related widespread gray and white matter density decreases.

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A spread of structural alterations occurs along with D50 model derived disease phases.

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White-matter alterations were associated with higher disease aggressiveness.

Therapeutic management and research in Amyotrophic Laterals Sclerosis (ALS) have been limited by the substantial heterogeneity in progression and anatomical spread that are endemic of the disease. Neuroimaging biomarkers represent powerful additions to the current monitoring repertoire but have yielded inconsistent associations with clinical scores like the ALS functional rating scale. The D50 disease progression model was developed to address limitations with clinical indices and the difficulty obtaining longitudinal data in ALS. It yields overall disease aggressiveness as time taken to reach halved functionality (D50); individual disease covered in distinct phases; and calculated functional state and calculated functional loss as acute descriptors of local disease activity. It greatly reduces the noise of the ALS functional rating scale and allows the comparison of highly heterogeneous disease and progression subtypes. In this study, we performed Voxel-Based Morphometry for 85 patients with ALS (60.1 ± 11.5 years, 36 female) and 62 healthy controls. Group-wise comparisons were performed separately for gray matter and white matter using ANCOVA testing with threshold-free cluster enhancement. ALS-related widespread gray and white matter density decreases were observed in the bilateral frontal and temporal lobes (p < 0.001, family-wise error corrected). We observed a progressive spread of structural alterations along the D50-derived phases, that were primarily located in frontal, temporal and occipital gray matter areas, as well as in supratentorial neuronal projections (p < 0.001 family-wise error corrected). ALS patients with higher overall disease aggressiveness (D50 < 30 months) showed a distinct pattern of supratentorial white matter density decreases relative to patients with lower aggressiveness; no significant differences were observed for gray matter density (p < 0.001 family-wise error corrected).

The application of the D50 disease progression model separates measures of disease aggressiveness from disease accumulation. It revealed a strong correlation between disease phases and in-vivo measures of cerebral structural integrity. This study underscores the proposed corticofugal spread of cerebral pathology in ALS. We recommend application of the D50 model in studies linking clinical data with neuroimaging correlates.

Machine Learning in Amyotrophic Lateral Sclerosis: Achievements, Pitfalls, and Future Directions

Background: Amyotrophic Lateral Sclerosis (ALS) is a relentlessly progressive neurodegenerative condition with limited therapeutic options at present. Survival from symptom onset ranges from 3 to 5 years depending on genetic, demographic, and phenotypic factors. Despite tireless research efforts, the core etiology of the disease remains elusive and drug development efforts are confounded by the lack of accurate monitoring markers. Disease heterogeneity, late-stage recruitment into pharmaceutical trials, and inclusion of phenotypically admixed patient cohorts are some of the key barriers to successful clinical trials. Machine Learning (ML) models and large international data sets offer unprecedented opportunities to appraise candidate diagnostic, monitoring, and prognostic markers. Accurate patient stratification into well-defined prognostic categories is another aspiration of emerging classification and staging systems. Methods: The objective of this paper is the comprehensive, systematic, and critical review of ML initiatives in ALS to date and their potential in research, clinical, and pharmacological applications. The focus of this review is to provide a dual, clinical-mathematical perspective on recent advances and future directions of the field. Another objective of the paper is the frank discussion of the pitfalls and drawbacks of specific models, highlighting the shortcomings of existing studies and to provide methodological recommendations for future study designs. Results: Despite considerable sample size limitations, ML techniques have already been successfully applied to ALS data sets and a number of promising diagnosis models have been proposed. Prognostic models have been tested using core clinical variables, biological, and neuroimaging data. These models also offer patient stratification opportunities for future clinical trials. Despite the enormous potential of ML in ALS research, statistical assumptions are often violated, the choice of specific statistical models is seldom justified, and the constraints of ML models are rarely enunciated. Conclusions: From a mathematical perspective, the main barrier to the development of validated diagnostic, prognostic, and monitoring indicators stem from limited sample sizes. The combination of multiple clinical, biofluid, and imaging biomarkers is likely to increase the accuracy of mathematical modeling and contribute to optimized clinical trial designs.

Clinical disease stage related changes of serological factors in amyotrophic lateral sclerosis

OBJECTIVE

Little is known whether disease clinical stage would influence the serological values in Amyotrophic lateral sclerosis (ALS). We aimed to explore the association between the levels of serological factors with clinical progression determined by the King's College staging system.

METHODS

ALS Patients were registered from May 2008 to December 2016. The differences of serological values between patients and healthy controls, and the correlation of these serological values with disease stage were examined.

RESULTS

A total of 571 patients and 571 age-/gender-/BMI-matched healthy controls were included. The levels of creatinine, uric acid (UA), albumin, total protein, total cholesterol, and high-density lipoprotein (HDL) were significantly lower, and the low-density lipoprotein/HDL ratio was higher in ALS patients than those in healthy controls. The levels of UA, albumin, and total protein were significantly reversely correlated with diseases stages. The longitudinal observation of 81 ALS patients also showed that the levels of UA, creatinine, albumin, total protein, and HDL were significantly decreased in the second hematological examinations.

CONCLUSIONS

In the present study, ALS patients and control subjects were evenly matched with regard to sex, age, and BMI value, this finding could be considered as a metabolite signature in ALS. The changes of metabolite-based serological factors with progression of disease stage might be related to the pathophysiology of disease, and might have clinical utility in clinical practice.

A standard operating procedure for King's ALS clinical staging

Objective: Clinical stages in amyotrophic lateral sclerosis (ALS) can be measured using a simple system based on the number of CNS regions involved and requirement for gastrostomy or noninvasive ventilation (NIV). We aimed to design a standard operating procedure (SOP) to define the standardized use and application of the King’s staging system. Methods: We designed a SOP for the King’s staging system. We wrote case vignettes representative of ALS patients at different disease stages. During two workshops, we taught health care professionals how to use the SOP, then asked them to stage the vignettes using the SOP. We measured the extent to which SOP staging corresponded with correct clinical stage. Results: The reliability of staging using the SOP was excellent, with a Spearman’s Rank coefficient of 0.95 (p < 0.001), and was high for different groups of health care professionals, and for those with different levels of experience in ALS. The limits of agreement between SOP staging and actual clinical stage lie within a single stage, confirming that there is a clinically acceptable level of agreement between staging using the SOP and actual King’s clinical stage. There were also no systematic biases of the SOP over the range of stages, either for over-staging or under-staging. Conclusions: We have demonstrated that the staging SOP provides a reliable method of calculating clinical stages in ALS patients and can be used prospectively by a range of health care professionals with different levels of experience, as for example may be the case in multicentre clinical trials.

Staging amyotrophic lateral sclerosis: A new focus on progression

Amyotrophic lateral sclerosis (ALS) is a heterogenous motoneuronal neurodegenerative condition with a panel of phenotypes exhibiting different clinical patterns. Two compounds are currently available for the treatment of ALS but the majority of trials have failed to show a positive effect on prognosis. One of the explanations which could be put forward involves the way efficacy is evaluated: clinicians agree that the ALSFRS-revised scale used in all trials does not fit with highlighting a positive effect. So, the development and validation of new tools allowing a reliable assessment of ALS has become a key issue in clinical research. Over the last three years, two functional scales (the King's College and MiToS staging systems) have been proposed. These scales rely on two different approaches to ALS: an anatomical and prognostic concept, and loss of autonomy. Both scales propose five stages. We will discuss below the contribution of these two scales to clinical evaluation and the questions which remain to be resolved in the future.

Clinical Staging of Amyotrophic Lateral Sclerosis in Chinese Patients

Objective: It is important to explore the utility of clinical staging systems in the management of amyotrophic lateral sclerosis (ALS). Our aim was to assess the validity of King's College in a Chinese ALS cohort, by evaluating the duration and informativeness of each stage and examining the association between stage and prognosis.

Methods: From May 2008 to December 2016, patients with a likely diagnosis of ALS were registered. We prospectively assessed the progression of the patients through the stages and calculated the duration of each stage.

Results: The median duration in Stage 1 was 12.00 months, Stage 2 7.50 months, Stage 3 6.50 months, and Stage 4 4.10 months. Subset analysis revealed that the spinal-onset and early-onset patients had a longer median time in Stage 1 compared to bulbar-onset and late-onset patients, respectively. Riluzole treatment extended the durations of Stages 1 and 2, and the effect was maintained in patients with long-term use of riluzole (>6 months). Patients who initiated long-term riluzole therapy early, in Stage 1 or 2, had a longer Stage 2. Patients who received percutaneous gastrostomy endoscopy (PEG) or non-invasive positive-pressure ventilation (NIPPV) showed longer durations of Stage 4. The differences in survival time measured from each stage to death or censor date were significant.

Conclusions: We validated the King's College staging system in a Chinese population, and showed this system to be useful in clinical practice. Patients with bulbar-onset or an age of onset>45 years tended to have rapidly progressing ALS. Riluzole may be more effective when initiated in an early disease stage and continued long-term. PEG and NIPPV treatments can extend disease duration of Stage 4.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is characterized by the degeneration of both upper and lower motor neurons, which leads to muscle weakness and eventual paralysis. Until recently, ALS was classified primarily within the neuromuscular domain, although new imaging and neuropathological data have indicated the involvement of the non-motor neuraxis in disease pathology. In most patients, the mechanisms underlying the development of ALS are poorly understood, although a subset of patients have familial disease and harbour mutations in genes that have various roles in neuronal function. Two possible disease-modifying therapies that can slow disease progression are available for ALS, but patient management is largely mediated by symptomatic therapies, such as the use of muscle relaxants for spasticity and speech therapy for dysarthria.

What causes amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis is a neurodegenerative disease predominantly affecting upper and lower motor neurons, resulting in progressive paralysis and death from respiratory failure within 2 to 3 years. The peak age of onset is 55 to 70 years, with a male predominance. The causes of amyotrophic lateral sclerosis are only partly known, but they include some environmental risk factors as well as several genes that have been identified as harbouring disease-associated variation. Here we review the nature, epidemiology, genetic associations, and environmental exposures associated with amyotrophic lateral sclerosis.

Comparison of the King's and MiToS staging systems for ALS

Objective: To investigate and compare two ALS staging systems, King’s clinical staging and Milano-Torino (MiToS) functional staging, using data from the LiCALS phase III clinical trial (EudraCT 2008-006891-31). Methods: Disease stage was derived retrospectively for each system from the ALS Functional Rating Scale-Revised subscores using standard methods. The two staging methods were then compared for timing of stages using box plots, correspondence using chi-square tests, agreement using a linearly weighted kappa coefficient and concordance using Spearman’s rank correlation. Results: For both systems, progressively higher stages occurred at progressively later proportions of the disease course, but the distribution differed between the two methods. King’s stage 3 corresponded to MiToS stage 1 most frequently, with earlier King’s stages 1 and 2 largely corresponding to MiToS stage 0 or 1. The Spearman correlation was 0.54. There was fair agreement between the two systems with kappa coefficient of 0.21. Conclusion: The distribution of timings shows that the two systems are complementary, with King’s staging showing greatest resolution in early to mid-disease corresponding to clinical or disease burden, and MiToS staging having higher resolution for late disease, corresponding to functional involvement. We therefore propose using both staging systems when describing ALS.