Cognitive changes predict functional decline in ALS: A population-based longitudinal study

Benefits, pitfalls, and future design of population-based registers in neurodegenerative disease

Population-based disease registers identify and characterize all cases of disease, including those that might otherwise be neglected. Prospective population-based registers in neurodegeneration are necessary to provide comprehensive data on the whole phenotypic spectrum and can guide planning of health services. With the exception of the rare disease amyotrophic lateral sclerosis, few complete population-based registers exist for neurodegenerative conditions. Incomplete ascertainment, limitations and uncertainty in diagnostic categorization, and failure to recognize sources of bias reduce the accuracy and usefulness of many registers. Common biases include population stratification, the use of prevalent rather than incident cases in earlier years, changes in disease understanding and diagnostic criteria, and changing demographics over time. Future registers are at risk of funding shortfalls and changes to privacy legislation. Notwithstanding, as heterogeneities of clinical phenotype and disease pathogenesis are increasingly recognized in the neurodegenerations, well-designed longitudinal population-based disease registers will be an essential requirement to complete clinical understanding of neurodegenerative diseases.

Diagnostic and Prognostic Biomarkers in Amyotrophic Lateral Sclerosis: Neurofilament Light Chain Levels in Definite Subtypes of Disease

Importance

A clearer definition of the role of neurofilament light chain (NFL) as a biomarker in amyotrophic lateral sclerosis (ALS) is needed.

Objectives

To assess the ability of NFL to serve as a diagnostic biomarker in ALS and the prognostic value of cerebrospinal fluid NFL in patients with ALS.

Design, Setting, and Participants

In this single-center, retrospective, longitudinal study, disease progression was assessed by the ALS Functional Rating Score-Revised and the ALS Milano-Torino Staging system at baseline and 6, 12, 24, and 36 months. Cerebrospinal fluid samples were obtained from 176 patients admitted to the Department of Neurosciences of the University of Padua, Padova, Italy, from January 1, 2010, through February 29, 2016. Patients with ALS underwent ambulatory follow-up at the same department.

Main Outcomes and Measures

Levels of NFL.

Results

The study included 94 patients with ALS (64 men [36.4%] and 30 women [17.0%]; median age, 62.5 years), 20 patients with frontotemporal dementia (FTD) (8 men [4.5%] and 12 women [6.8%]; median age, 65 years), 18 patients with motor neuropathies (14 men [8.0%] and 4 women [2.3%]; median age, 63 years), and 44 controls (24 men [13.6%] and 20 women [11.4%]; median age, 54 years). Log-transformed NFL (log[NFL]) concentrations were higher in the ALS and FTD groups compared with the motor neuropathies and control groups (hazard ratio [HR], 2.45; 95% CI, 1.66-3.61; P < .001). Patients with typical ALS (HR, 1.0 [reference]), progressive bulbar palsy (HR, 1.48; 95% CI, 0.58-3.75; P = .41), and upper motor neuron dominant ALS (HR, 0.12; 95% CI, 0.02-0.61; P = .01) had higher levels of NFL than did those with flail arm or leg syndrome (HR, 0.28; 95% CI, 0.08-0.10; P = .049) and progressive muscular atrophy (HR, 0.17; 95% CI, 0.22-1.36; P = .10). There was an inverse correlation between log[NFL] concentration and overall survival (HR, 2.45; 95% CI, 1.66-3.61; P < .001). There was no evidence of different log[NFL] concentrations and survival in genetic ALS.

Conclusions and Relevance

This study confirms the role of NFL as a biomarker in ALS. Elevation in NFL levels in patients with upper motor neuron involvement and FTD might reflect the corticospinal tract degeneration. Low NFL levels in patients with lower motor neuron signs might be a prognostic indicator of milder phenotypes of disease.

Amyotrophic lateral sclerosis - frontotemporal spectrum disorder (ALS-FTSD): Revised diagnostic criteria

This article presents the revised consensus criteria for the diagnosis of frontotemporal dysfunction in amyotrophic lateral sclerosis (ALS) based on an international research workshop on frontotemporal dementia (FTD) and ALS held in London, Canada in June 2015. Since the publication of the Strong criteria, there have been considerable advances in the understanding of the neuropsychological profile of patients with ALS. Not only is the breadth and depth of neuropsychological findings broader than previously recognised - - including deficits in social cognition and language - but mixed deficits may also occur. Evidence now shows that the neuropsychological deficits in ALS are extremely heterogeneous, affecting over 50% of persons with ALS. When present, these deficits significantly and adversely impact patient survival. It is the recognition of this clinical heterogeneity in association with neuroimaging, genetic and neuropathological advances that has led to the current re-conceptualisation that neuropsychological deficits in ALS fall along a spectrum. These revised consensus criteria expand upon those of 2009 and embrace the concept of the frontotemporal spectrum disorder of ALS (ALS-FTSD).

What does the ALSFRS-R really measure? A longitudinal and survival analysis of functional dimension subscores in amyotrophic lateral sclerosis

INTRODUCTION

ALS functional rating scale (revised) (ALSFRS-R) is the most widely used functional rating system in patients with amyotrophic lateral sclerosis (ALS). However, heterogeneity in ALSFRS-R progression renders analysis challenging. We have explored the characteristics of total ALSFRS-R, and ALSFRS-R subscores in longitudinal and survival models, to determine whether subscore analysis enhances the precision of the instrument.

METHODS

All cases with ALSFRS-R scores on the Irish ALS register were included. ALSFRS-R subscores were defined for bulbar, motor and respiratory domains. Longitudinal models were used to visualise fitted total ALSFRS-R and ALSFRS-R subscore progression. In addition, the prognostic value of convenience and computed ALSFRS-R slope and subscore slopes were compared.

RESULTS

407 incident cases were identified with a complete ALSFRS-R measure. 233 (57%) patients were male, and 125 (31%) had bulbar-onset disease. ALSFRS-R bulbar and motor subscore slopes provided a better fit in prognostic models when combined over the total ALSFRS-R slope. Longitudinal analysis revealed that the ALSFRS-R motor subscore deteriorated earlier in spinal-onset disease over bulbar-onset disease, while in bulbar-onset disease the ALSFRS-R bulbar subscore deteriorated earlier and faster than in spinal-onset disease.

DISCUSSION

Our analysis builds on previous knowledge of ALSFRS-R subscores. Decline in ALSFRS-R motor subscores in patients with spinal-onset disease, and decline in ALSFRS-R bulbar subscores in patients with bulbar-onset disease, may predate reported disease onset dates. Respiratory subscores were not prognostically informative after adjustment for bulbar and motor subscores. These results provide robust evidence that the ALSFRS-R should not be reported as a single combined score, but rather as domain specific subscores.

A Cross-sectional population-based investigation into behavioral change in amyotrophic lateral sclerosis: subphenotypes, staging, cognitive predictors, and survival

Objective

Amyotrophic Lateral Sclerosis (ALS) is a clinically heterogeneous neurodegenerative disorder associated with cognitive and behavioral impairment. The primary aim of this study was to identify behavioral subphenotypes in ALS using a custom designed behavioral assessment tool (Beaumont Behavioural Inventory, BBI). Secondary aims were to (1) investigate the predictive nature of cognitive assessment on behavioral change, (2) report the behavioral profile associated with the C9orf72 expansion, (3) categorize behavioral change through disease staging, and (4) to investigate the relationship between cross‐sectional behavioral classification and survival.

Methods

A cross‐sectional population‐based research design was applied to examine behavioral data from ALS patients (n = 317) and healthy controls (n = 66). Patients were screened for the C9orf72 repeat expansion. A subcohort of ALS patients completed an extensive cognitive assessment battery (n = 65), to investigate predictors of behavior change. Principal component analysis (PCA) determined factors associated with altered behavior. Survival data were extracted from the Irish ALS register.

Results

No behavioral changes were reported in 180 patients (57%); 95 patients had mild‐moderate behavioral change (30%); 42 patients met the cut‐off for Clinically Severe Behavioral Change (13%), suggestive of a bvFTD diagnosis. The most frequently endorsed behaviors in ALS were reduced concern for hygiene (36.8%), irritability (36.2%), new unusual habits (33.4%), and increased apathy (31.1%). Five independent factors were identified through factor analysis. Social cognitive performance was predictive of behavior change (P = 0.031), yielding an R² = 0.188. Behavioral categorization (mild/moderate/severe) at the time of assessment was not associated with survival (P = 0.198).

Interpretation

These data imply the presence of distinct subphenotypes of behavioral change in ALS, which most likely reflect subcategories of extramotor network disruption.

From first symptoms to diagnosis of amyotrophic lateral sclerosis: perspectives of an Irish informal caregiver cohort-a thematic analysis

OBJECTIVES

Informal caregivers play an integral part in the management of amyotrophic lateral sclerosis (ALS). The objective of this study was to explore the journey from first problem symptoms to diagnosis from the perspective of informal caregivers providing care to people with ALS.

DESIGN

As part of a semistructured interview, information was collected on a range of caregiver demographic details, and from an open-ended question their experiences of the time of symptom onset to diagnosis. We carried out descriptive statistical analysis and thematic analysis of qualitative data.

SETTING AND PARTICIPANTS

Home interviews with informal caregivers (n=74) of people with ALS attending the National ALS/Motor Neuron Disease Clinic at Beaumont Hospital, Dublin, Ireland.

RESULTS

This was a largely female and spousal cohort of caregivers, living with the patient for whom they provided informal care. The majority of patients were men and were spinal onset. Caregivers described the time from first symptoms to diagnosis. Using a primarily inductive approach, the coding was data driven and the codes and themes derived from the content of these descriptions. Two main themes were identified (1) problem signs and symptoms (A) noticing and (B) reaction; (2) interaction with the health services.

CONCLUSIONS

Exploring the perspectives of caregivers from first problem symptoms to diagnosis provides valuable insights into the development of the condition, impediments to its recognition, help-seeking behaviours and interactions with healthcare services. The journey from early symptoms to diagnosis is important for future decision-making, affects readiness for caregiving and could negatively impact on caregiver health and well-being. The early acknowledgement by healthcare professionals of stressors along the journey to diagnosis, and appreciation of their possible impact on caregivers is important. The separate needs of caregivers should be assessed on a regular basis.

Caregivers of patients with amyotrophic lateral sclerosis: investigating quality of life, caregiver burden, service engagement, and patient survival

Few studies in amyotrophic lateral sclerosis (ALS) have profiled disease-specific features of the condition in conjunction with assessment of caregivers' burden, distress, quality of life, and investigated patient survival. Eighty-four ALS patients and their primary caregivers were enrolled. Patients completed ALS-specific measures of physical and cognitive function, while caregivers completed measures of anxiety, depression, caregiver burden, and quality of life. Patient-caregiver dyads were interviewed about their health-service utilisation. Survival data were obtained through the Irish register for ALS. Participants were dichotomised into low/high groups according to the severity of self-reported caregiver burden, based on statistically derived cut-off scores. High-burdened caregivers (n = 43) did not significantly differ from low-burdened caregivers (n = 41) with respect to disease-specific characteristics, i.e., ALSFRS-R, bulbar- or spinal-onset ALS, disease duration, or survival data. However, significant differences were reported on subjective measures of anxiety (p < 0.000), depression (p < 0.001), distress (p < 0.000), and quality of life (p < 0.000). These data demonstrate the limited impact of ALS patient-related variables, i.e., ALSFRS-R and onset, on caregiver burden in ALS, and identify the importance of the psychological composition of caregivers. This study suggests that the subjective experience of individual caregivers is an important factor influencing the severity of experienced caregiver burden.

Screening for cognitive and behavioural impairment in amyotrophic lateral sclerosis: Frequency of abnormality and effect on survival

OBJECTIVE

To screen for cognitive and behavioural impairment in people with amyotrophic lateral sclerosis (ALS) and controls with neuromuscular disease and to correlate these with clinical features.

METHODS

108 people with ALS and 60 controls with other neuromuscular diseases were recruited and assessed with the Addenbrooke's cognitive examination-III (ACE-III), the frontal assessment battery (FAB), and the executive function component of the Edinburgh cognitive and behavioural ALS screen (ECAS). The Amyotrophic lateral sclerosis-Frontotemporal dementia questionnaire (ALS-FTD-Q) and the Motor Neuron Disease Behavioural instrument (MiND-B) were administered to the caregivers of people with ALS. The prevalence of abnormalities was determined and correlated with clinical features and survival. In 37 people with ALS, serial studies were performed.

RESULTS

The frequencies of cognitive impairment based on the ACE-III and FAB were 30.0% and 14.0%, in ALS and 11.7% and 3.3% in controls, respectively. Age and years of education influence the results of the ACE-III and ECAS executive function. In ALS, the frequencies of behavioural impairment based on ALS-FTD-Q and MiND-B were 32.1% and 39.4%, respectively. There is significant correlation of ALS-FTD-Q and MiND-B with the ALSFRS-R score. ALS participants with cognitive impairment measured with ACE-III had significantly shorter survival time than those without. ALS participants with behavioural impairment measured with ALS-FTD-Q had worse prognosis than those without. No significant difference was found between the first two serial cognitive tests based on ACE-III and FAB by using generalized estimating equation.

CONCLUSION

There is a greater frequency of cognitive impairment in people with ALS than in patients with other neuromuscular diseases. The cognitive and behavioural tests are potential biomarkers of the prognosis of ALS. The results of cognitive tests are stable over 6months and possibly longer.

Epidemiology of amyotrophic lateral sclerosis in Southern Germany

The objective of this study is to determine the current distribution of clinical phenotypes and to estimate future trends of ALS incidence in Western societies. We report on a clinical-epidemiological registry with a capture-recapture rate of >80% and population-based case-control study in ALS patients in South Western Germany. 1163 incidents of ALS were registered. Clinical and neuropsychological data were prospectively collected from 699 cases. The mean age at onset was 66.6 (SD = 11.6) years in prospective cases (N = 699). The site of onset was more frequently bulbar (34.1%) than lumbosacral (30.7%), cervical (27.0%), or thoracic (3.1%). Cognitive deficits (ranging from 27.5 to 42.1%, depending on the screening instrument) and behavioral changes (29%) were frequently detected. The incidence rate dropped markedly after 79 years of age, and bulbar onset as well as cognitive impairment were more frequent in ALS cases >75 years. The mean survival time of ALS cases from first paresis was 31 months. The age-standardized incidence rate (ASR) of ALS in 2012/2013 was found to be 2.4 (95% CI 2.2-2.7) per 100,000 person-years (resulting in an ASR of 3.1/100,000 with 100% coverage). Based on the predicted age distribution of the German population, the incidence of ALS was estimated to be 4.5/100,000 for men and 3.3/100,000 for women in the year 2050. ALS prevalence will rise to about 9.2-9.8/100,000 person-years in Germany in 2050. An increased proportion of patients with bulbar onset and/or cognitive deficits can be used as basic epidemiologic data on ALS for future health care decisions.

Extra-motor abnormalities in amyotrophic lateral sclerosis: another layer of heterogeneity

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease defined by the presence of muscle weakness. The motor features of disease are heterogeneous in site of onset and progression. There are also extra-motor features in some patients. The genetic basis for extra-motor features is uncertain. The heterogeneity of ALS is an issue for clinical trials. Areas covered: This paper reviews the range and prevalence of extra-motor features associated with ALS, and highlights the current information about genetic associations with extra-motor features. Expert commentary: There are extra-motor features of ALS, but these are not found in all patients. The most common is cognitive abnormality. More data is required to ascertain whether extra-motor features arise with progression of disease. Extra-motor features are reported in patients with a range of causative genetic mutations, but are not found in all patients with these mutations. Further studies are required of the heterogeneity of ALS, and genotype/phenotype correlations are required, taking note of extra-motor features.

Neuroimaging Endpoints in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative, clinically heterogeneous syndrome pathologically overlapping with frontotemporal dementia. To date, therapeutic trials in animal models have not been able to predict treatment response in humans, and the revised ALS Functional Rating Scale, which is based on coarse disability measures, remains the gold-standard measure of disease progression. Advances in neuroimaging have enabled mapping of functional, structural, and molecular aspects of ALS pathology, and these objective measures may be uniquely sensitive to the detection of propagation of pathology in vivo. Abnormalities are detectable before clinical symptoms develop, offering the potential for neuroprotective intervention in familial cases. Although promising neuroimaging biomarker candidates for diagnosis, prognosis, and disease progression have emerged, these have been from the study of necessarily select patient cohorts identified in specialized referral centers. Further multicenter research is now needed to establish their validity as therapeutic outcome measures.

Assessing cognitive functioning in ALS: A focus on frontal lobe processes

OBJECTIVE

It is generally acknowledged that at least 50% of individuals with amyotrophic lateral sclerosis (ALS) will exhibit cognitive deficits outside of the characteristic motor neuron involvement. However, a specific cognitive profile has been difficult to ascertain due to disease-related testing barriers and limitations in the sensitivity and specificity of available assessment methods. This study assessed the level of functioning of extramotor frontal cognitive processes in ALS, and the amount of change in the functioning in these processes over time as disease progresses.

METHODS

Empirical tests validated for a model of frontal lobe functioning were modified into an assessment battery appropriate for individuals with ALS in a clinical setting (the ALS-CFB, Computerised Frontal Battery). Twenty ALS participants and 36 age- and education-matched neurologically healthy controls were tested, and a sub-sample of each group (11 ALS and 20 controls) re-tested after approximately nine months.

RESULTS AND CONCLUSIONS

Compared to standard neuropsychological screening tests that did not show a difference between ALS participants and healthy controls, the ALS-CFB illustrated a profile of extramotor frontal dysfunction involving energisation (preparing the neural system to respond) and executive functions, a profile that may be indicative of the nature of neurodegeneration in ALS.

Motor neuron disease: biomarker development for an expanding cerebral syndrome

Descriptions of motor neuron disease (MND) documented more than a century ago remain instantly recognisable to the physician. The muscle weakness, typically with signs of upper and lower motor neuron dysfunction, is uniquely relentless. Over the last 30 years, a wider cerebral pathology has emerged, despite the lack of overt cognitive impairment in the majority of patients. From the initial linkage of a small number of cases to mutations in SOD1, diverse cellular pathways have been implicated in pathogenesis. An increasingly complex clinical heterogeneity has emerged around a significant variability in survival. Defining a cellular signature of aggregated TDP-43 common to nearly all MND and a large proportion of frontotemporal dementia (FTD), has placed MND alongside more traditional cerebral neurodegeneration. With new genetic causes, most notably a hexanucleotide expansion in C9orf72 associated with both MND and FTD, the development of biomarkers against which to test therapeutic candidates is a priority.

Development of an Automated MRI-Based Diagnostic Protocol for Amyotrophic Lateral Sclerosis Using Disease-Specific Pathognomonic Features: A Quantitative Disease-State Classification Study

BACKGROUND

Despite significant advances in quantitative neuroimaging, the diagnosis of ALS remains clinical and MRI-based biomarkers are not currently used to aid the diagnosis. The objective of this study is to develop a robust, disease-specific, multimodal classification protocol and validate its diagnostic accuracy in independent, early-stage and follow-up data sets.

METHODS

147 participants (81 ALS patients and 66 healthy controls) were divided into a training sample and a validation sample. Patients in the validation sample underwent follow-up imaging longitudinally. After removing age-related variability, indices of grey and white matter integrity in ALS-specific pathognomonic brain regions were included in a cross-validated binary logistic regression model to determine the probability of individual scans indicating ALS. The following anatomical regions were assessed for diagnostic classification: average grey matter density of the left and right precentral gyrus, the average fractional anisotropy and radial diffusivity of the left and right superior corona radiata, inferior corona radiata, internal capsule, mesencephalic crus of the cerebral peduncles, pontine segment of the corticospinal tract, and the average diffusivity values of the genu, corpus and splenium of the corpus callosum.

RESULTS

Using a 50% probability cut-off value of suffering from ALS, the model was able to discriminate ALS patients and HC with good sensitivity (80.0%) and moderate accuracy (70.0%) in the training sample and superior sensitivity (85.7%) and accuracy (78.4%) in the independent validation sample.

CONCLUSIONS

This diagnostic classification study endeavours to advance ALS biomarker research towards pragmatic clinical applications by providing an approach of automated individual-data interpretation based on group-level observations.

Eye-Tracking Control to Assess Cognitive Functions in Patients with Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with pathological involvement of upper and lower motoneurons, subsequently leading to progressive loss of motor and speech abilities. In addition, cognitive functions are impaired in a subset of patients. To evaluate these potential deficits in severely physically impaired ALS patients, eye-tracking is a promising means to conduct cognitive tests. The present article focuses on how eye movements, an indirect means of communication for physically disabled patients, can be utilized to allow for detailed neuropsychological assessment. The requirements, in terms of oculomotor parameters that have to be met for sufficient eye-tracking in ALS patients are presented. The properties of stimuli, including type of neuropsychological tests and style of presentation, best suited to successfully assess cognitive functioning, are also described. Furthermore, recommendations regarding procedural requirements are provided. Overall, this methodology provides a reliable, easy to administer and fast approach for assessing cognitive deficits in patients who are unable to speak or write such as patients with severe ALS. The only confounding factor might be deficits in voluntary eye movement control in a subset of ALS patients.

Caregiving in ALS - a mixed methods approach to the study of Burden

Background

Caregiver burden affects the physical, psychological and emotional well-being of the caregiver. The purpose of this analysis was to describe an informal caregiver cohort (n = 81), their subjective assessment of burden and difficulties experienced as a result of providing care to people with Amyotrophic Lateral Sclerosis (ALS).

Methods

Using mixed methods of data collection and analysis, we undertook a comprehensive assessment of burden and difficulties associated with informal caregiving in ALS. As part of a semi-structured interview a series of standardised measures were used to assess quality of life, psychological distress and subjective burden, and in an open-ended question caregivers were asked to identify difficult aspects of their caregiving experience.

Results

The quantitative data show that psychological distress, hours of care provided and lower quality of life, were significant predictors of caregiver burden. From the qualitative data, the caregiving difficulties were thematised around managing the practicalities of the ALS condition, the emotional and psychosocial impact; limitation and restriction, and impact on relationships.

Conclusions

The collection and analysis of quantitative and qualitative data better explores the complexity of caregiver burden in ALS. Understanding the components of burden and the difficulties experienced as a result of caring for someone with ALS allows for better supporting the caregiver, and assessing the impact of burden on the care recipient.

Electronic supplementary material

The online version of this article (doi:10.1186/s12904-016-0153-0) contains supplementary material, which is available to authorized users.

The frontotemporal dementia-motor neuron disease continuum

Early reports of cognitive and behavioural deficits in motor neuron disease might have been overlooked initially, but the concept of a frontotemporal dementia-motor neuron disease continuum has emerged during the past decade. Frontotemporal dementia-motor neuron disease is now recognised as an important dementia syndrome, which presents substantial challenges for diagnosis and management. Frontotemporal dementia, motor neuron disease, and frontotemporal dementia-motor neuron disease are characterised by overlapping patterns of TAR DNA binding protein (TDP-43) pathology, while the chromosome 9 open reading frame 72 (C9orf72) repeat expansion is common across the disease spectrum. Indeed, the C9orf72 repeat expansion provides important clues to disease pathogenesis and suggests potential therapeutic targets. Variable diagnostic criteria identify motor, cognitive, and behavioural deficits, but further refinement is needed to define the clinical syndromes encountered in frontotemporal dementia-motor neuron disease.

Pain in Neurodegenerative Disease: Current Knowledge and Future Perspectives

Neurodegenerative diseases are going to increase as the life expectancy is getting longer. The management of neurodegenerative diseases such as Alzheimer's disease (AD) and other dementias, Parkinson's disease (PD) and PD related disorders, motor neuron diseases (MND), Huntington's disease (HD), spinocerebellar ataxia (SCA), and spinal muscular atrophy (SMA), is mainly addressed to motor and cognitive impairment, with special care to vital functions as breathing and feeding. Many of these patients complain of painful symptoms though their origin is variable, and their presence is frequently not considered in the treatment guidelines, leaving their management to the decision of the clinicians alone. However, studies focusing on pain frequency in such disorders suggest a high prevalence of pain in selected populations from 38 to 75% in AD, 40% to 86% in PD, and 19 to 85% in MND. The methods of pain assessment vary between studies so the type of pain has been rarely reported. However, a prevalent nonneuropathic origin of pain emerged for MND and PD. In AD, no data on pain features are available. No controlled therapeutic trials and guidelines are currently available. Given the relevance of pain in neurodegenerative disorders, the comprehensive understanding of mechanisms and predisposing factors, the application and validation of specific scales, and new specific therapeutic trials are needed.

Multidimensional apathy in ALS: validation of the Dimensional Apathy Scale

AIM

Apathy is a prominent symptom of amyotrophic lateral sclerosis (ALS), but measurement is confounded by physical disability. Furthermore, it has been traditionally measured as a unidimensional symptom despite research demonstrating a multifaceted construct. The new Dimensional Apathy Scale (DAS) has been specifically designed for patients with motor disability to measure 3 neurologically based subtypes of apathy: Executive, Emotional and Initiation. We aimed to explore this behavioural symptom by examining the substructure of apathy in ALS and to determine the reliability and validity of the DAS in patients and their carers.

METHOD

Patients and carers were recruited through the national Scottish Motor Neurone Disease Register and were asked to complete the DAS, the standardised Apathy Evaluation Scale, and the Geriatric Depression Scale-Short Form. 83 patients with ALS, 75 carers and 83 sex-matched, age-matched and education-matched controls participated.

RESULTS

When compared with healthy controls, patients showed a significant increase in apathy on the Initiation subscale, and were significantly less apathetic on the Emotional subscale. Scores on the DAS patient and carer versions did not significantly differ. Internal consistency reliability, convergent and discriminant validity were found to be good for the DAS subscales. There was no association between the DAS and functional disability using the ALS Functional Rating Scale.

CONCLUSIONS

Apathy in ALS is characterised by a specific profile of increased initiation apathy and reduced emotional apathy. The DAS is a reliable and valid measure for the assessment of multidimensional apathy in ALS.

Discordant performance on the 'Reading the Mind in the Eyes' Test, based on disease onset in amyotrophic lateral sclerosis

Executive dysfunction is a core feature of amyotrophic lateral sclerosis (ALS) and is associated with brain atrophy in cortical and subcortical regions. Social cognitive deficits may also be a prominent feature of ALS. This study investigated executive, and social cognitive performance, in a population based cohort of patients with ALS, stratified by disease onset. Participants were recruited as part of a population based study investigating cognitive decline in ALS. Patients carrying pathogenic C9orf72 hexanucleotide repeat were excluded. Participants were stratified based on bulbar (n = 20) or spinal (n = 39) disease onset (n = 59). Matched healthy controls were used to generate culturally specific comparative data for within-patient analyses (n = 59). Results showed that ALS patients performed significantly worse than controls on a number of measures of executive function. When sub-stratified by disease onset, there was a significant difference between bulbar- and spinal-onset patients with respect to the 'Reading the Mind in the Eyes' Test scores (p < 0.001). Conversely, standardized scores of executive function did not differ between the patient groups. In conclusion, patients performed significantly worse than matched controls on measures of executive function. Bulbar-onset ALS patients evidenced more social-affective deficits compared to spinal-onset patients, with matched performance on measures of executive function.

Working Memory Network Changes in ALS: An fMRI Study

We used amyotrophic lateral sclerosis (ALS) as a model of prefrontal dysfunction in order to re-assess the potential neuronal substrates of two sub processes of working memory, namely information storage and filtering. To date it is unclear which exact neuronal networks sustain these two processes and the prefrontal cortex was suggested to play a crucial role both for filtering out of irrelevant information and for the storage of relevant information in memory. Other research has attributed information storage to more posterior brain regions, including the parietal cortex and stressed the role of subcortical areas in information filtering. We studied 14 patients suffering from ALS and the same number of healthy controls in an fMRI-task that allowed calculating separate storage and filtering scores. A brain volume analysis confirmed prefrontal atrophy in the patient group. Regarding their performance in the working memory task, we observed a trend toward slightly impaired storage capabilities whereas filtering appeared completely intact. Despite the rather subtle behavioral deficits we observed marked changes in neuronal activity associated with ALS: Compared to healthy controls patients showed significantly reduced hemodynamic responses in the left occipital cortex and right prefrontal cortex in the storage contrast. The filter contrast on the other hand revealed a relative hyperactivation in the superior frontal gyrus of the ALS patients. This hyperactivation might reflect a possible compensational mechanism for the prefrontal degeneration found in ALS. The reduced hemodynamic responses in the storage contrast might reflect a disruption of prefrontal top-down control of posterior brain regions, a process which was especially relevant in the most difficult high load memory task. Taken together, the present study demonstrates marked neurophysiological changes in ALS patients compared to healthy controls during the filtering and storage of information in spite of largely intact behavior. With respect to the neuronal substrates of the two working memory processes under investigation here, the results suggest that it is rather the degree to which top-down control is required for task completion that determines prefrontal cortex involvement than the specific nature of the process, i.e., storage vs. filtering.

Prospective Validation of 18F-FDG Brain PET Discriminant Analysis Methods in the Diagnosis of Amyotrophic Lateral Sclerosis

An objective biomarker for early identification and accurate differential diagnosis of amyotrophic lateral sclerosis (ALS) is lacking. (18)F-FDG PET brain imaging with advanced statistical analysis may provide a tool to facilitate this. The objective of this work was to validate volume-of-interest (VOI) and voxel-based (using a support vector machine [SVM] approach) (18)F-FDG PET analysis methods to differentiate ALS from controls in an independent prospective large cohort, using a priori-derived classifiers. Furthermore, the prognostic value of (18)F-FDG PET was evaluated.

METHODS

A prospective cohort of patients with a suspected diagnosis of a motor neuron disorder (n = 119; mean age ± SD, 61 ± 12 y; 81 men and 38 women) was recruited. One hundred five patients were diagnosed with ALS (mean age ± SD, 61.0 ± 12 y; 74 men and 31 women) (group 2), 10 patients with primary lateral sclerosis (mean age ± SD, 55.5 ± 12 y; 3 men and 7 women), and 4 patients with progressive muscular atrophy (mean age ± SD, 59.2 ± 5 y; 4 men). The mean disease duration of all patients was 15.0 ± 13.4 mo at diagnosis, with PET conducted 15.2 ± 13.3 mo after the first symptoms. Data were compared with a previously gathered dataset of 20 screened healthy subjects (mean age ± SD, 62.4 ± 6.4 y; 12 men and 8 women) and 70 ALS patients (mean age ± SD, 62.2 ± 12.5 y; 44 men and 26 women) (group 1). Data were spatially normalized and analyzed on a VOI basis (statistical software (using the Hammers atlas) and voxel basis using statistical parametric mapping. Discriminant analysis and SVM were used to classify new cases based on the classifiers derived from group 1.

RESULTS

Compared with controls, ALS patients showed a nearly identical pattern of hypo- and hypermetabolism in groups 1 and 2. VOI-based discriminant analysis resulted in an 88.8% accuracy in predicting the new ALS cases. For the SVM approach, this accuracy was 100%. Brain metabolism between ALS and primary lateral sclerosis patients was nearly identical and not separable on an individual basis. Extensive frontotemporal hypometabolism was predictive for a lower survival using a Kaplan-Meier survival analysis (P < 0.001).

CONCLUSION

On the basis of a previously acquired training set, (18)F-FDG PET with advanced discriminant analysis methods is able to accurately distinguish ALS from controls and aids in assessing individual prognosis. Further validation on multicenter datasets and ALS-mimicking disorders is needed to fully assess the general applicability of this approach.

Cognitive-behavioral screening reveals prevalent impairment in a large multicenter ALS cohort

OBJECTIVES

To characterize the prevalence of cognitive and behavioral symptoms using a cognitive/behavioral screening battery in a large prospective multicenter study of amyotrophic lateral sclerosis (ALS).

METHODS

Two hundred seventy-four patients with ALS completed 2 validated cognitive screening tests and 2 validated behavioral interviews with accompanying caregivers. We examined the associations between cognitive and behavioral performance, demographic and clinical data, and C9orf72 mutation data.

RESULTS

Based on the ALS Cognitive Behavioral Screen cognitive score, 6.5% of the sample scored below the cutoff score for frontotemporal lobar dementia, 54.2% scored in a range consistent with ALS with mild cognitive impairment, and 39.2% scored in the normal range. The ALS Cognitive Behavioral Screen behavioral subscale identified 16.5% of the sample scoring below the dementia cutoff score, with an additional 14.1% scoring in the ALS behavioral impairment range, and 69.4% scoring in the normal range.

CONCLUSIONS

This investigation revealed high levels of cognitive and behavioral impairment in patients with ALS within 18 months of symptom onset, comparable to prior investigations. This investigation illustrates the successful use and scientific value of adding a cognitive-behavioral screening tool in studies of motor neuron diseases, to provide neurologists with an efficient method to measure these common deficits and to understand how they relate to key clinical variables, when extensive neuropsychological examinations are unavailable. These tools, developed specifically for patients with motor impairment, may be particularly useful in patient populations with multiple sclerosis and Parkinson disease, who are known to have comorbid cognitive decline.

Syntactic comprehension deficits across the FTD-ALS continuum

To establish the frequency, severity, relationship to bulbar symptoms, and neural correlates of syntactic comprehension deficits across the frontotemporal dementia-amyotrophic lateral sclerosis (FTD-ALS) disease spectrum. In total, 85 participants were included in the study; 20 amyotrophic lateral sclerosis (ALS), 15 FTD-ALS, 27 progressive nonfluent aphasia (PNFA), and 23 controls. Syntactic comprehension was evaluated in ALS, FTD-ALS, PNFA, and controls using the Test for Reception of Grammar. Voxel-based morphometry examined neuroanatomical correlates of performance. Syntactic comprehension deficits were detected in 25% of ALS (p = 0.011), 92.9% of FTD-ALS (p < 0.001), and 81.5% of PNFA (p < 0.001) patients. FTD-ALS was disproportionately impaired compared to PNFA. Impaired Test for Reception of Grammar performance was frequent in ALS with early bulbar involvement but did not correlate with bulbar impairment overall. Left peri-insular atrophy correlated with syntactic comprehension deficits. Syntactic comprehension deficits are frequent in FTD-ALS, more severe than in PNFA, and related to left peri-insular atrophy. A significant minority of ALS patients are impaired, but the relationship between bulbar symptoms and syntactic impairment is not understood.

Patient journey to a specialist amyotrophic lateral sclerosis multidisciplinary clinic: an exploratory study

Background

The multidisciplinary approach in the management of Amyotrophic Lateral Sclerosis (ALS) has been shown to provide superior care to devolved care, with better survival, improved quality of care, and quality of life. Access to expert multidisciplinary management should be a standard for patients with ALS. This analysis explores the patient journey from symptom onset and first engagement with health services, to the initial visit to a specialist ALS Multidisciplinary Clinic (MDC) in Dublin, Ireland.

Methods

A retrospective exploratory multi-method study details the patient journey to the MDC. Data from medical interviews and systematic chart review identifies interactions with the health services and key timelines for thirty five new patients presenting with a diagnosis of ALS during a 6 month period in 2013.

Results

The time from first symptom to diagnosis was a mean of 16 months (median 13 months), with a mean interval of 19 months (median 14.6) from first symptoms to arrival at the MDC. The majority of patients were seen by a general practitioner, and subsequently by neurology services. There was an average of four contacts with health services and 4.8 investigations/tests, prior to their first Clinic visit. On the first visit to the MDC patients are linked into an integrated ‘system’ that can provide specialist care and link with voluntary, palliative and community services as required.

Conclusions

Engagement with a multidisciplinary team has implications for service utilization and quality of life of patients and their families. We have demonstrated that barriers exist that delay referral to specialist services. Comprehensive data recording and collection, using multiple data sources can reconstruct the timelines of the patient journey, which can in turn be used to identify pathways that can expedite early referral to specialist services.

Inhibitory dysfunction in amyotrophic lateral sclerosis: future therapeutic opportunities

In amyotrophic lateral sclerosis, motor neuron hyperexcitability and inhibitory dysfunction is emerging as a potential causative link in the dysfunction and degeneration of the motoneuronal circuitry that characterizes the disease. Interneurons, as key regulators of excitability, may mediate much of this imbalance, yet we know little about the way in which inhibitory deficits perturb excitability. In this review, we explore inhibitory control of excitability and the potential contribution of altered inhibition to amyotrophic lateral sclerosis disease processes and vulnerabilities, identifying important windows of therapeutic opportunity and potential interventions, specifically targeting inhibitory control at key disease stages.

Frontotemporal Dysfunction and Dementia in Amyotrophic Lateral Sclerosis

Although amyotrophic lateral sclerosis (ALS) is classically considered a disorder exclusively affecting motor neurons, there is substantial clinical, neuroimaging, and neuropathologic evidence that more than half of patients have an associated syndrome of frontotemporal dysfunction. These syndromes range from frontotemporal dementia to behavioral or cognitive syndromes. Neuroimaging and neuropathologic findings are consistent with frontotemporal lobar degeneration that underpins alterations in network connectivity. Future clinical trials need to be stratified based on the presence or absence of frontotemporal dysfunction on the disease course of ALS.

Eye-tracking in amyotrophic lateral sclerosis: A longitudinal study of saccadic and cognitive tasks

A relative preservation of eye movements is notable in ALS, but saccadic functions have not been studied longitudinally. ALS overlaps with FTD, typically involving executive dysfunction, and eye-tracking offers additional potential for the assessment of extramotor pathology where writing and speaking are both impaired. Eye-tracking measures (including anti-saccade, trail-making and visual search tasks) were assessed at six-monthly intervals for up to two years in a group of ALS (n = 61) and primary lateral sclerosis (n = 7) patients, compared to healthy age-matched controls (n = 39) assessed on a single occasion. Task performance was explored speculatively in relation to resting-state functional MRI (R-FMRI) network connectivity. Results showed that ALS patients were impaired on executive and visual search tasks despite normal basic saccadic function, and impairments in the PLS patients were unexpectedly often more severe. No significant progression was detected longitudinally in either group. No changes in R-FMRI network connectivity were identified in relation to patient performance. In conclusion, eye-tracking offers an objective means to assess extramotor cerebral involvement in ALS. The relative resistance of pure oculomotor function is confirmed, and higher-level executive impairments do not follow the same rate of decline as physical disability. PLS patients may have more cortical dysfunction than has been previously appreciated.

Consistent Individual Behavioral Variation: The Difference between Temperament, Personality and Behavioral Syndromes

Simple Summary

The interchangeable usage of the words “personality”, “temperament” and “behavioral syndromes” in animal behavior research has often led to confusion. In this paper, we devise a framework for describing the behavioral phenomenon, betweenindividual/between-population variation, and between/across context variation. This framework can be used to give unique definitions of the three terms, supported by previous literature, giving clarity moving forward in the field of animal behavior.

Abstract

Ethologists use a variety of terminology such as “personality”, “temperament” and “behavioral syndromes” almost interchangeably to discuss the phenomenon of individuals within a population of animals consistently varying from one another in their behavioral responses to stimuli. This interchangeable usage of terminology has contributed to confusion within the field of animal behavior and limits the study of the phenomenon. Here we use a rapid, non-exhaustive and repeatable search strategy literature review to investigate where there were unique distinctions between these three terms and where there was an overlap in their usage. We identified three main areas of confusion in terminology: historical usage which is not updated; a lack of precision between different fields of study; and a lack of precision between different levels of variation. We propose a framework with which to understand and define the terms based on the levels of variation ethologists are interested in. Consistent individual animal behavioral variation relates to the different structures of variation of between-individual/between-population and between and across contexts. By formalizing this framework we provide clarity between the three terms which can be easily defined and understood.

Eye-tracking controlled cognitive function tests in patients with amyotrophic lateral sclerosis: a controlled proof-of-principle study

Amyotrophic lateral sclerosis (ALS) primarily affects motor and speech abilities. In addition, cognitive functions are impaired in a subset of patients. There is a need to establish an eye movement-based method of neuropsychological assessment suitable for severely physically impaired patients with ALS. Forty-eight ALS patients and thirty-two healthy controls matched for age, sex and education performed a hand and speech motor-free version of the Raven's coloured progressive matrices (CPM) and the D2-test which had been especially adapted for eye-tracking control. Data were compared to a classical motor-dependent paper-pencil version. The association of parameters of the eye-tracking and the paper-pencil version of the tests and the differences between and within groups were studied. Subjects presented similar results in the eye-tracking and the corresponding paper-pencil versions of the CPM and D2-test: a correlation between performance accuracy for the CPM was observed for ALS patients (p < 0.001) and controls (p < 0.001) and in the D2-test for controls (p = 0.048), whereas this correlation did not reach statistical significance for ALS patients (p = 0.096). ALS patients performed worse in the CPM than controls in the eye-tracking (p = 0.053) and the paper-pencil version (p = 0.042). Most importantly, eye-tracking versions of the CPM (p < 0.001) and the D2-test (p = 0.024) reliably distinguished between more and less cognitively impaired patients. Eye-tracking-based neuropsychological testing is a promising approach for assessing cognitive deficits in patients who are unable to speak or write such as patients with severe ALS.

Caregiver burden in amyotrophic lateral sclerosis: a cross-sectional investigation of predictors

The objective of the study was to investigate whether cognitive and behavioural impairment in Amyotrophic Lateral Sclerosis (ALS) contributes to caregiver burden, and whether carer burden affects patient outcome. Thirty-three dyads of incident patients with ALS and their primary caregivers (n = 33) completed a series of measures to determine cognitive and behavioural profiles, (patients) and carer burden (carers) to investigate the psychological impact of ALS, and the impact of behavioural change since the onset of ALS. Caregivers were divided into high- and low-burden groups using previously established norms. High burden in carers was associated with significantly higher apathy (p = 0.009), disinhibition (p = 0.005), and executive dysfunction (p = 0.015) in patients. Regression analyses for burden confirmed significant predictors such as change in apathy (r = 0.390, F = 5.19, p = 0.03), disinhibition (r = 0.530, F = 11.32, p = 0.002), and executive dysfunction (r = 0.372, F = 4.66, p = 0.039), with total behaviour change contributing to 31 % of caregiver burden (r = 0.563, F = 4.17, p = 0.015). Total distress as measured by the Hospital Anxiety and Depression Scale was also a significant predictor of caregiver burden, contributing to 38.5 % of variance (r = 0.621, F = 18.79, p < 0.000). Caregiver burden did not affect survival (p = 0.496). Caregiver burden in ALS is modulated by patient's cognitive and behavioural status, but does not significantly impact patient survival.

The expanding syndrome of amyotrophic lateral sclerosis: a clinical and molecular odyssey

Recent advances in understanding amyotrophic lateral sclerosis (ALS) have delivered new questions. Disappointingly, the initial enthusiasm for transgenic mouse models of the disease has not been followed by rapid advances in therapy or prevention. Monogenic models may have inadvertently masked the true complexity of the human disease. ALS has evolved into a multisystem disorder, involving a final common pathway accessible via multiple upstream aetiological tributaries. Nonetheless, there is a common clinical core to ALS, as clear today as it was to Charcot and others. We stress the continuing relevance of clinical observations amid the increasing molecular complexity of ALS.

Female gender doubles executive dysfunction risk in ALS: a case-control study in 165 patients

BACKGROUND

Cognitive impairment, mainly characterised by executive dysfunction, occurs in about half of cases in amyotrophic lateral sclerosis (ALS). There is evidence that gender influences some clinical features of the disease, but its influence on the cognitive spectrum is unknown. Our objective was to investigate the impact of gender on cognitive profiles of patients with ALS.

METHODS

A retrospective study based on an exhaustive neuropsychological battery was performed in a group of 165 (70 females, 95 males) sporadic, non-demented patients with ALS compared with 134 healthy control participants. This assessment primarily focused on executive, memory and language functions.

RESULTS

47 (29%) patients revealed impairment in executive function and 30 (18%) patients revealed cognitive non-executive impairment. Independent from mood tone and clinical variables, a significantly greater executive impairment was determined in female patients than in male patients and control participants. The relative risk for ALS females having impairment in executive function compared with male patients was 2.6 (95% CI 1.6 to 4.4; p=0.0003). ALS females scored lower in Phonemic Fluency, Trial Making, and Wisconsin Card Sorting test.

CONCLUSIONS

Results highlight a significant vulnerability of ALS female patients to develop cognitive dysfunctions peculiar to the disease, independently of bulbar onset. The explicative hypotheses of the data are focused on two interpretative lines not mutually exclusive: the role of gonadal hormones and gender-related brain asymmetry pre-existing to the disease. These findings, never reported before in the literature, can have important implications for models of ALS pathogenesis and for future clinical trial designs.

Predicting prognosis in amyotrophic lateral sclerosis: a simple algorithm

The objective of the study was to develop and validate a practical prognostic index for patients with amyotrophic lateral scleroses (ALS) using information available at the first clinical consultation. We interrogated datasets generated from two population-based projects (based in the Republic of Ireland and Italy). The Irish patient cohort was divided into Training and Test sub-cohorts. Kaplan–Meier methods and Cox proportional hazards regression were used to identify significant predictors of prognoses in the Training set. Using a weighted grading system, a prognostic index was derived that separated three risk groups. The validity of index was tested in the Irish Test sub-cohort and externally confirmed in the Italian replication cohort. In the Training sub-cohort (n = 117), significant predictors of prognoses were site of disease onset (HR = 1.7, p = 0.012); ALSFRS-R slope prior to first evaluation (HR = 2.8, p < 0.0001), and executive dysfunction (HR = 2.11, p = 0.001). The risk group system generated using these results predicted median survival time in the Training set, the Test set (n = 87) and the Italian cohort (n = 122) with no overlap of the 95 % CI (p < 0.0001). In the validation cohorts, a high-risk classification was associated with a positive predictive value for poor prognosis of 73.3–85.7 % and a negative predictive value (NPV) for good prognosis of 93.3–100 %. Classification into the low-risk group was associated with an NPV for bad prognosis of 100 %. A simple algorithm using variables that can be gathered at first patient encounter, validated in an independent patient series, reliably predicts prognoses in ALS patients.

Antisense proline-arginine RAN dipeptides linked to C9ORF72-ALS/FTD form toxic nuclear aggregates that initiate in vitro and in vivo neuronal death

Expanded GGGGCC (G4C2) nucleotide repeats within the C9ORF72 gene are the most common genetic mutation associated with both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Sense and antisense transcripts of these expansions are translated to form five dipeptide repeat proteins (DRPs). We employed primary cortical and motor neuron cultures, live-cell imaging, and transgenic fly models and found that the arginine-rich dipeptides, in particular Proline-Arginine (PR), are potently neurotoxic. Factors that anticipated their neurotoxicity included aggregation in nucleoli, decreased number of processing bodies, and stress granule formation, implying global translational dysregulation as path accountable for toxicity. Nuclear PR aggregates were also found in human induced motor neurons and postmortem spinal cord tissues from C9ORF72 ALS and ALS/FTD patients. Intronic G4C2 transcripts, but not loss of C9ORF72 protein, are also toxic to motor and cortical neurons. Interestingly, G4C2 transcript-mediated neurotoxicity synergizes with that of PR aggregates, suggesting convergence of mechanisms.

Challenges in the Understanding and Treatment of Amyotrophic Lateral Sclerosis/Motor Neuron Disease

With the acceleration in our understanding of ALS and the related motor neuron disease has come even greater challenges in reconciling all of the proposed pathogenic mechanisms and how this will translate into impactful treatments. Fundamental issues such as diagnostic definition(s) of the disease spectrum, relevant biomarkers, the impact of multiple novel genetic mutations and the significant effect of symptomatic treatments on disease progression are all areas of active investigation. In this review, we will focus on these key issues and highlight the challenges that confront both clinicians and basic science researchers.