Motor neuron disease in the province of Turin, Italy, 1966-1980. Survival analysis in an unselected population

Five-Year Incidence of Amyotrophic Lateral Sclerosis in British Columbia (2010-2015)

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal degenerative neurological disease with significant effects on quality of life. International studies continue to provide consistent incidence values, though complete case ascertainment remains a challenge. The Canadian population has been understudied, and there are currently no quantitative data on the incidence of ALS in British Columbia (BC). The objectives of this study were to determine the five-year incidence rates of ALS in BC and to characterize the demographic patterns of the disease.

METHODS

The capture-recapture method was employed to estimate ALS incidence over a five-year period (2010-2015). Two sources were used to identify ALS cases: one database from an ALS medical centre and another from a not-for-profit ALS organization.

RESULTS

During this time period, there were 690 incident cases within the two sources. The capture-recapture method estimated 57 unobserved cases, corresponding to a crude five-year incidence rate of 3.29 cases per 100,000 (CI 95%=3.05-3.53). The mean age of diagnosis was 64.6 (CI 95%=59.7-69.4), with 63.5 (CI 95%=56.9-70.1) for men and 65.7 (CI 95%=58.6-72.7) for women. There was a slight male preponderance in incidence, with a 1.05:1 ratio to females. Peak numbers in incidence occurred between the ages of 70 and 79.

CONCLUSIONS

The incidence of ALS in BC was found to be consistent with international findings though nominally higher than that in other Canadian provinces to date.

A fruitful endeavor: modeling ALS in the fruit fly

For over a century Drosophila melanogaster, commonly known as the fruit fly, has been instrumental in genetics research and disease modeling. In more recent years, it has been a powerful tool for modeling and studying neurodegenerative diseases, including the devastating and fatal amyotrophic lateral sclerosis (ALS). The success of this model organism in ALS research comes from the availability of tools to manipulate gene/protein expression in a number of desired cell-types, and the subsequent recapitulation of cellular and molecular phenotypic features of the disease. Several Drosophila models have now been developed for studying the roles of ALS-associated genes in disease pathogenesis that allowed us to understand the molecular pathways that lead to motor neuron degeneration in ALS patients. Our primary goal in this review is to highlight the lessons we have learned using Drosophila models pertaining to ALS research. This article is part of a Special Issue entitled ALS complex pathogenesis.

The epidemiology of ALS: a conspiracy of genes, environment and time

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease of motor neurons, resulting in worsening weakness of voluntary muscles until death from respiratory failure occurs after about 3 years. Although great advances have been made in our understanding of the genetic causes of ALS, the contribution of environmental factors has been more difficult to assess. Large-scale studies of the clinical patterns of ALS, individual histories preceding the onset of ALS, and the rates of ALS in different populations and groups have led to improved patient care, but have not yet revealed a replicable, definitive environmental risk factor. In this Review, we outline what is currently known of the environmental and genetic epidemiology of ALS, describe the current state of the art with respect to the different types of ALS, and explore whether ALS should be considered a single disease or a syndrome. We examine the relationship between genetic and environmental risk factors, and propose a disease model in which ALS is considered to be the result of environmental risks and time acting on a pre-existing genetic load, followed by an automatic, self-perpetuating decline to death.

A proposed staging system for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a neurodegenerative disorder characterized by progressive loss of upper and lower motor neurons, with a median survival of 2-3 years. Although various phenotypic and research diagnostic classification systems exist and several prognostic models have been generated, there is no staging system. Staging criteria for amyotrophic lateral sclerosis would help to provide a universal and objective measure of disease progression with benefits for patient care, resource allocation, research classifications and clinical trial design. We therefore sought to define easily identified clinical milestones that could be shown to occur at specific points in the disease course, reflect disease progression and impact prognosis and treatment. A tertiary referral centre clinical database was analysed, consisting of 1471 patients with amyotrophic lateral sclerosis seen between 1993 and 2007. Milestones were defined as symptom onset (functional involvement by weakness, wasting, spasticity, dysarthria or dysphagia of one central nervous system region defined as bulbar, upper limb, lower limb or diaphragmatic), diagnosis, functional involvement of a second region, functional involvement of a third region, needing gastrostomy and non-invasive ventilation. Milestone timings were standardized as proportions of time elapsed through the disease course using information from patients who had died by dividing time to a milestone by disease duration. Milestones occurred at predictable proportions of the disease course. Diagnosis occurred at 35% through the disease course, involvement of a second region at 38%, a third region at 61%, need for gastrostomy at 77% and need for non-invasive ventilation at 80%. We therefore propose a simple staging system for amyotrophic lateral sclerosis. Stage 1: symptom onset (involvement of first region); Stage 2A: diagnosis; Stage 2B: involvement of second region; Stage 3: involvement of third region; Stage 4A: need for gastrostomy; and Stage 4B: need for non-invasive ventilation. Validation of this staging system will require further studies in other populations, in population registers and in other clinic databases. The standardized times to milestones may well vary between different studies and populations, although the stages themselves and their meanings are likely to remain unchanged.

Patients who survive 5 years or more with ALS in Olmsted County, 1925-2004

BACKGROUND

A small proportion of patients with amyotrophic lateral sclerosis (ALS) survive more than 5 years. The frequency of 5-year or longer survival with ALS in a USA population is unknown but may provide a baseline for studies that employ survival as a primary endpoint of analysis.

METHODS

All persons diagnosed as having ALS in Olmsted County between 1925 and 2004 were studied for demographic and clinical features. Longer-term survivors were defined as patients who lived 5 years or longer, tracheostomy-free, following symptomatic onset.

RESULTS

94 patients (mean survival from symptomatic onset 2.95 years (95% CI 2.54 to 3.35), mean survival from diagnosis 1.89 years (95% CI 1.54 to 2.24)) were diagnosed as having ALS. Five-year or longer survivors accounted for 14% of the population of patients (95% CI 7.9% to 22.8%). The frequency of 5 year or longer survivors did not change over time. The mean survival of these individuals was 7.04 years (95% CI 6.14 to 7.94 years; range 5.11-9.35 years). They had a significantly longer mean time to diagnosis (1.77 years, 95% CI 0.95 to 2.58 years) as compared with survivors of less than 5 years (0.94 years, 95% CI 0.75 to 1.13 years) (p=0.02) but could not be reliably identified at the time of diagnosis by age, sex, clinical presentation or El Escorial category.

CONCLUSION

Patients surviving more than 5 years following the symptomatic onset of ALS account for 14% of the total ALS population. This frequency has not changed over time. Patients with a survival of 5 years or longer are clinically similar to the total population ALS population in terms of age, gender, presentation and site of onset but have a longer time from symptomatic onset to diagnosis. GRANT NUMBER: NIH AR30582.

Prognostic factors in ALS: A critical review

We have performed a systematic review to summarize current knowledge concerning factors related to survival in ALS and to evaluate the implications of these data for clinical trials design. The median survival time from onset to death ranges from 20 to 48 months, but 10-20% of ALS patients have a survival longer than 10 years. Older age and bulbar onset are consistently reported to have a worse outcome. There are conflicting data on gender, diagnostic delay and El Escorial criteria. The rate of symptom progression was revealed to be an independent prognostic factor. Psychosocial factors, FTD, nutritional status, and respiratory function are also related to ALS outcome. The effect of enteral nutrition on survival is still unclear, while NIPPV has been found to improve survival. There are no well established biological markers of progression, although some are likely to emerge in the near future. These findings have relevant implications for the design of future trials. Randomization, besides the type of onset, should take into account age, respiratory status at entry, and a measure of disease progression pre-entry. Alternative trial designs can include the use of natural history controls, the so-called minimization method for treatment allocation, and the futility approach.

Natural history and clinical features of the flail arm and flail leg ALS variants

OBJECTIVE

We sought to define the significance of brachial amyotrophic diplegia (flail arm syndrome [FA]) and the pseudopolyneuritic variant (flail leg syndrome [FL]) of amyotrophic lateral sclerosis (ALS; motor neuron disease).

METHODS

We analyzed survival in clinic cohorts in London, UK (1,188 cases), and Melbourne, Australia (432 cases). Survival from disease onset was analyzed using the Kaplan- Meier method and Cox proportional hazards model.

RESULTS

In the London cohort, the FA syndrome represented 11% and the FL syndrome 6% of the sample. Median survival was 35 months for limb onset and 27 months for bulbar onset ALS, whereas this was 61 months for FA syndrome (p < 0.001) and 69 months for FL syndrome (p < 0.001). Five-year survival in this cohort was 8.8% for bulbar onset, 20% for limb onset, 52% for FA syndrome, and 64% for FL syndrome. The ratio of men to women was 4:1 in the FA group compared to 2:1 in other limb onset cases. Excluding lower motor neuron FA and FL cases, progressive muscular atrophy comprised 4% of the sample and had a prognosis similar to typical limb onset ALS. In the Melbourne cohort, median survival for limb onset ALS was 31 months, bulbar onset 27 months, FA syndrome 66 months (p < 0.001), and FL syndrome 71 months (p = 0.001).

CONCLUSIONS

The flail arm (FA) and flail leg (FL) syndromes had significantly better survival than typical amyotrophic lateral sclerosis (ALS) or progressive muscular atrophy cases that were not classified as FA or FL. Our findings underline the clinical and prognostic importance of the FA and FL variants of ALS.

[Progressive muscular atrophy: clinical and laboratory study in eleven patients]

Progressive muscular atrophy (PMA), an infrequent type of motor neuron disease (MND), is a predominantly lower motor neuron degeneration, causing muscle wasting and weakness with loss of weight and fasciculations. The diagnosis is based on rigid criteria, considering clinical aspects and eletroneuromyography findings. Blood tests and radiological investigation are necessary to look for other diagnosis mimicking PMA. We herein present 11 patients with PMA (5.9% of all our MND patients), 9 men and 2 women, which onset of symptoms occurred mainly under de age of 50, with a mean of 45.5 years. Cramp was the most frequent symptom preceding muscular weakness. Muscle pain, fatigue and fasciculations were also cited as starting symptoms. Asymmetric weakness of the arms was the most frequent pattern of onset of the disease. Bulbar muscular weakness developed in all patients during the course of the disease. Predisposing factors and distinctive clinical outcome was not observed in any of the patients. Ophthalmoparesis and sphincter dysfunction were seen in two patients who had a prolonged time in artificial respiratory assistance. Immunosuppressive therapy was ineffective in all patients. Progressive course was seen in all cases and the mean survival time was 44 months.

Diagnostic delay in amyotrophic lateral sclerosis: what scope for improvement?

The average time taken from symptom onset to diagnosis in motor neuron disease is many months and has shown no sign of improving despite the introduction of riluzole therapy. We performed a retrospective analysis of the time to diagnosis in 57 patients using a structured interview with the patients and/or their carers. In this cohort, studied in England and Wales, the mean time from onset to diagnosis was 16.2 months. An initial incorrect diagnosis, refusal to consider the diagnosis when it was suggested by the informed patient, failure to consider a neurological cause for the patient's symptoms, and failure to make early referral to a neurologist were the major factors leading to delayed diagnosis. Bulbar symptoms were more likely to lead to correct diagnosis than limb-onset features. Ten of our patients made the diagnosis by consulting reference books or the Internet before they were informed of it by their physician.

Progressive muscular atrophy variant of familial amyotrophic lateral sclerosis (PMA/ALS)

Twelve cases of adult-onset progressive muscular atrophy variant of amyotrophic lateral sclerosis (PMA/ALS) were studied in a small rural population of 1500 in the Republic of Belarus (former Soviet Union). The patients were members of three apparently related kindreds, each showing autosomal dominant pattern of disease inheritance. The average age at clinical onset ranged from 26 to 57 years (mean, 40 years). Each patient suffered from skeletal muscle weakness and wasting, starting in the limbs and spreading to the trunk and neck, with very limited bulbar and no upper motor neuron involvement. Death from respiratory failure occurred from 13 to 48 months (mean, 28 months) after first symptoms. Dramatically decreased number of spinal motor neurons was the most characteristic neuropathologic feature in two autopsied cases. Most of the remaining degenerating neurons contained intracytoplasmic hyaline inclusion bodies. A D101N mutation in exon 4 of the SOD1 gene was identified in a PMA/ALS patient and in one of her three unaffected children. Our data support the view that some subtypes of familial ALS associated with SOD1 mutations may present as PMA. Diagnostic criteria of ALS should be accordingly modified to include the PMA variant of familial ALS.

Consensus guidelines for the design and implementation of clinical trials in ALS. World Federation of Neurology committee on Research

BACKGROUND

In 1994 consensus guidelines were developed for conducting clinical trials in ALS. With growing experience in clinical trials, it has become clear that a number of further guidelines were needed.

METHODS

Under the auspices of the World Federation of Neurology Committee on Research, a multinational group of neurologists, statisticians, patient advocates, representatives from the pharmaceutical industry as well as regulatory agencies developed consensus about a number of revisions to the existing guidelines during a 2 day conference in April 1998.

RESULTS

Expanded areas of focus include greater protection of patient rights, more detailed guidelines for outcome measures statistical analyses, disclosure of study results and improved interaction between investigators and the corporate sector.

COMMENT

Substantial progress has been made in standardizing and improving the quality of clinical trials in ALS through these consensus guidelines.

Amyotrophic lateral sclerosis: mortality risk during the course of the disease and prognostic factors. The Netherlands ALS Consortium

We performed a historical cohort study of 307 untreated patients with probable or definite amyotrophic lateral sclerosis in order to investigate whether the mortality risk changed during the disease course and to identify prognostic factors at diagnosis. Patients were diagnosed in one of the academic hospitals in The Netherlands and followed-up for at least 6 years after diagnosis. The median survival from diagnosis was 1.4 years (95% confidence interval, 1.3-1.6 years) with an estimated 5- and 10-year survival of 20 and 8%, respectively. Mortality was at its maximum in the second year after diagnosis and declined considerably thereafter. Observed mortality approached the expected mortality in patients who survived diagnosis 6 or more years. In univariate and multivariate analyses, young age, limb onset, and a long delay between initial weakness and diagnosis were associated with lower mortality. The better prognosis of limb-onset patients was not observed in females. Patients with initial respiratory muscle weakness, had the worst prognosis with a median survival of only 2 months. The significantly greater mortality of older patients proved not to result from a rise in expected mortality only. In conclusion, the annual mortality risk in ALS does not remain constant throughout the disease and depends on age at diagnosis, site of onset, diagnostic delay, but also on the time since diagnosis. These findings may have consequences for the planning of symptomatic care and the design and analysis of therapeutic trials.

Prognosis of amyotrophic lateral sclerosis and the effect of referral selection

We followed two cohorts of Amyotrophic Lateral Sclerosis (ALS) patients to examine the survival and prognostic factors of ALS and the impact of selective referral on prognosis of ALS. The first cohort consisted of population-based incident ALS cases from Harris County, Texas, first diagnosed between 1985 and 1988. The second was a clinical series from a tertiary care center in Houston, Texas, diagnosed between 1977 and 1989. The overall 3-year survival was 29% in the incidence cohort and 32% in the referral cohort; however, the 5-year survival was much lower for the incidence cohort than the referral cohort (4% vs 21%). The large difference in 5-year survival was not explained by the distributions of prognostic factors in the two cohorts but due to stronger unfavorable effects of prognostic factors in the incidence cohort than the referral cohort. In both cohorts, older age at diagnosis, bulbar onset, and positive family history of ALS were unfavorable prognostic factors while blacks had better survival than whites or hispanics. We confirmed that longer duration from onset to diagnosis was a favorable prognostic factor in both cohorts but the effect was more pronounced in the referral series.

What do we really know about amyotrophic lateral sclerosis?

The cause of amyotrophic lateral sclerosis is unknown. In this review clinical and scientific data that are pertinent to understanding this disease are reviewed. There are currently several major controversies concerning the possible role of immunological factors, genetic factors, environmental toxins, and viral infection in pathogenesis. These concepts must be considered in relation to what is known about the disease in all its aspects, including epidemiological data, information on the classical and molecular pathology of the disease, and on associated involvement of other systems, e.g., the spinocerebellar pathways and frontal dementia. Only when all this information is assimilated can full understanding of the disease and, hopefully, a logical approach to treatment and prevention, be achieved.

Accuracy of death certificate diagnosis of amyotrophic lateral sclerosis

STUDY OBJECTIVE

The aim was to determine the reliability of official mortality statistics in estimating long term trends of amyotrophic lateral sclerosis (ALS) in Italy.

DESIGN

The study was a mortality follow up of cases of ALS.

SETTING

Piedmond Region, northern Italy.

SUBJECTS

Cases of ALS were identified from multiple sources between 1966 and 1985.

MAIN RESULTS

Cause of death was determined for the cases who died between 1970 and 1985. Death certificates were obtained in 488 out of 510 cases (95.7%). ALS was mentioned in 365 (74.8%) of cases. The most frequent erroneous diagnoses were multiple sclerosis and malignant tumours. Demographic variables, such as sex, age at death, province of death, and calendar year of death, did not influence the percentage of true positive cases significantly.

CONCLUSIONS

The death certificate diagnosis of ALS appears to be adequate for use in descriptive and analytical epidemiology.

New insights in motor neuron disease

In motor neuron disease there is a characteristic pattern of nerve cell loss and degeneration of related pathways. In surviving anterior horn cells several morphologically distinct, but generally non-specific, intracytoplasmic inclusion bodies have been recognized. Recently accumulations of previously unrecognized ubiquitinated material have been described in surviving neurons, which cannot be demonstrated with routine histological methods. These changes appear unique to this disease, and provide a new insight into the underlying pathology that may help understand the pathogenesis of this intriguing disorder. In this article we review the new information on the clinical, toxicological and pathological features of the disease.

Amyotrophic lateral sclerosis in Palermo, Italy: an epidemiological study

The incidence, prevalence and natural course of ALS were determined in the population of the province of Palmero, Italy. The average annual incidence calculated for the years 1973 through 1984, was 044./100.000 inhabitants. The prevalence rate on prevalence day December 31, 1984, was 1.67/100.000 population. The male/female ratio was 1.38. The mean age at onset was 54.3 +/- 11.02. The most common clinical form was the conventional one (61.4%); the bulbar form was more frequent among females than males. The mean duration of the disease was 33.7 +/- 35.8 months. The longest duration belongs to the pseudopolyneuritic form. The median survival was 36 months: 16 months for the bulbar, 36 months for the conventional and 51 months for the pseudopolyneuritic form.

Preclinical and subclinical events in motor neuron disease

It is suggested that in motor neuron disease there is a long preclinical period of relative tolerance and compensation before presentation with apparently focal features. During this phase the disease becomes disseminated through the motor system. The mode of acquisition of the disease, its relation to a possible genetic factor, and the processes leading to tolerance, to latency or progression, to the relative involvement of upper and lower motor neurons, to involvement of spinocerebellar pathways, and to asymmetry are fundamental problems in understanding the disease.

Multiple sclerosis and motor neurone disease: survival and how certified after death

This study assesses the outcome of a random sample of patients with multiple sclerosis (MS) and motor neurone disease (MND) selected from a previous study carried out between the years 1960 and 1972. Of the MND patients who are now dead, 20% of the women and 27% of the men lived longer than five years after hospitalised diagnosis, and two of these patients lived up to 19 years after diagnosis in hospital. Also, 10.7% of the random sample of MND patients were still alive in June 1985. Of the MS deaths 26.4% and of the MND deaths 20.4% did not have these respective conditions recorded on the death certificates.

A survival analysis of 155 cases of progressive muscular atrophy

We performed a survival analysis of 155 cases of progressive muscular atrophy (PMA). In about half the cases, hands were involved first, the lower limbs in 30% and the shoulder girdle in 23%. The lifetables of PMA, adjusted to the expected mortality, showed a survival rate of 61.3% and 56.4% at three and five years, respectively. The location of onset symptoms did not modify the life expectancy, whereas the age of the patients at the moment of first diagnosis had a great influence on the course of the disease. The patients were further subdivided in two groups on the basis of the diffusion of the neuromuscular damage at the moment of the diagnosis. The course of the patients with a localized disease was markedly better than that of subjects with widespread disease. Some hypotheses are made about the latter group of cases.