Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors.

METHOD

Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change.

RESULTS

Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status.

CONCLUSIONS

We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

Prevalence of depression in amyotrophic lateral sclerosis/motor neuron disease: multi-attribute ascertainment and trajectories over 30 months

Objective: Evidence is equivocal about the prevalence of depression in amyotrophic lateral sclerosis (ALS). This study uses a multi-attribute ascertainment of the prevalence of depression and examines this prevalence over time. Methods: Patients with ALS were recruited into the Trajectories of Outcome in Neurological Conditions (TONiC-ALS) study. Caseness was identified by the Modified-Hospital Anxiety and Depression Scale (M-HADS). In addition, participants provided data on co-morbidities and medication use. A combination of the three was used to derive the estimate for the prevalence of depression, treated or untreated. Longitudinal data were analyzed by trajectory analysis of interval level M-HADS-Depression data. Results: Among 1120 participants, the mean age was 65.0 years (SD 10.7), 60.4% male, and the median duration since diagnosis was 9 months (IQR 4-24). Caseness of probable depression at baseline, defined by M-HADS-Depression, was 6.45% (95%CI: 5.1-8.0). Taken together with antidepressant medication and co-morbidity data, the prevalence of depression was 23.1% (95%CI: 20.7-25.6). Of those with depression, 17.8% were untreated. Trajectory analysis identified three groups, one of which contained the most cases; the level of depression for each group remained almost constant over time. Conclusion: Depression affects almost a quarter of those with ALS, largely confined to a single trajectory group. Prevalence estimates based on screening for current depressive symptoms substantially under-estimate the population experiencing depression. Future prevalence studies should differentiate data based on current symptoms from those including treated patients. Both have their place in assessing depression and the response by the health care system, including medication, depending upon the hypothesis under test.

Clinical Feasibility of Speech Phenotyping for Remote Assessment of Neurodegenerative and Psychiatric Disorders (RHAPSODY): a study protocol

Introduction

The diagnosis of neurodegenerative and psychiatric disorders (NPDs) in primary care can suffer from inefficiencies resulting in misdiagnoses and delayed diagnosis, limiting effective treatment options. The development of speech and language-based profiling biomarkers could aid in achieving earlier motor diagnosis for PD for instance, or more accurate diagnosis of clinically similar or late presenting NPDs.

Objectives

RHAPSODY aims to investigate the feasibility of the remote administration of a battery of speech tasks in eliciting continuous narrative speech across a range of NPDs. The project also aims to determine the feasibility of using acoustic and linguistic biomarkers from speech data to support the clinical assessment and disambiguation of common NPDs

Methods

All participants (n=250) will take part in a single virtual telemedicine video conference with a researcher in which they are screened and complete a battery of speech tasks, in addition to cohort-specific screening measures. Over the following month, participants will be asked to complete a series of short, self-administered speech assessments via a smartphone application.

Results

The speech tasks will be audio-recorded and analysed on Novoic’s technology platform. Objectives will be analysed using measures including average length of speech elicitation for speech tasks, intra- and inter-subject variance, differences in linguistic patterns, and response rates to speech assessments.

Conclusions

The analyses could help to identify and validate speech-derived clinical biomarkers to support clinicians in detecting and disambiguating between NPDs with heterogeneous presentations. This should further support earlier intervention, improved treatment options and improved quality of life.

Disclosure

In terms of significant financial interest and relationships, it is emphasised that the private organisation Novoic, who aim to develop speech algorithms for diagnostic use, is the study’s sponsor and employees or former employees of this company comprise

DNAscan: personal computer compatible NGS analysis, annotation and visualisation

BACKGROUND

Next Generation Sequencing (NGS) is a commonly used technology for studying the genetic basis of biological processes and it underpins the aspirations of precision medicine. However, there are significant challenges when dealing with NGS data. Firstly, a huge number of bioinformatics tools for a wide range of uses exist, therefore it is challenging to design an analysis pipeline. Secondly, NGS analysis is computationally intensive, requiring expensive infrastructure, and many medical and research centres do not have adequate high performance computing facilities and cloud computing is not always an option due to privacy and ownership issues. Finally, the interpretation of the results is not trivial and most available pipelines lack the utilities to favour this crucial step.

RESULTS

We have therefore developed a fast and efficient bioinformatics pipeline that allows for the analysis of DNA sequencing data, while requiring little computational effort and memory usage. DNAscan can analyse a whole exome sequencing sample in 1 h and a 40x whole genome sequencing sample in 13 h, on a midrange computer. The pipeline can look for single nucleotide variants, small indels, structural variants, repeat expansions and viral genetic material (or any other organism). Its results are annotated using a customisable variety of databases and are available for an on-the-fly visualisation with a local deployment of the gene.iobio platform. DNAscan is implemented in Python. Its code and documentation are available on GitHub: https://github.com/KHP-Informatics/DNAscan . Instructions for an easy and fast deployment with Docker and Singularity are also provided on GitHub.

CONCLUSIONS

DNAscan is an extremely fast and computationally efficient pipeline for analysis, visualization and interpretation of NGS data. It is designed to provide a powerful and easy-to-use tool for applications in biomedical research and diagnostic medicine, at minimal computational cost. Its comprehensive approach will maximise the potential audience of users, bringing such analyses within the reach of non-specialist laboratories, and those from centres with limited funding available.

Development and validation of Spasticity Index-Amyotrophic Lateral Sclerosis

OBJECTIVES

Spasticity is a common and disabling feature of amyotrophic lateral sclerosis (ALS). There are currently no validated ALS-specific measures of spasticity. The aim of this study was to develop and use a self-report outcome measure for spasticity in ALS.

METHODS

Following semi-structured interviews with 11 ALS patients, a draft scale was administered across ALS clinics in the UK. Internal validity of the scale was examined using the Rasch model. The numerical rating scale (NRS) for spasticity and Leeds Spasticity scale (LSS) were co-administered. The final scale was used in a path model of spasticity and quality of life.

RESULTS

A total of 465 patients (mean age 64.7 years (SD 10), 59% male) with ALS participated. Spasticity was reported by 80% of subjects. A pool of 71 items representing main themes of physical symptoms, negative impact and modifying factors was subject to an iterative process of item reduction by Rasch analysis resulting in a 20-item scale-the Spasticity Index for ALS (SI-ALS)-which was unidimensional and free from differential item functioning. Moderate correlations were found with LSS and NRS-spasticity. Incorporating the latent estimate of spasticity into a path model, greater spasticity reduced quality of life and motor function; higher motor function was associated with better quality of life.

CONCLUSIONS

The SI-ALS is a disease-specific self-report scale, which provides a robust interval-level measure of spasticity in ALS. Spasticity has a substantial impact on quality of life in ALS.

Establishing the UK DNA Bank for motor neuron disease (MND)

In 2003 the Motor Neurone Disease (MND) Association, together with The Wellcome Trust, funded the creation of a national DNA Bank specific for MND. It was anticipated that the DNA Bank would constitute an important resource to researchers worldwide and significantly increase activity in MND genetic research. The DNA Bank houses over 3000 high quality DNA samples, all of which were donated by people living with MND, family members and non-related controls, accompanied by clinical phenotype data about the patients. Today the primary focus of the UK MND DNA Bank still remains to identify causative and disease modifying factors for this devastating disease.

Lithium in patients with amyotrophic lateral sclerosis (LiCALS): a phase 3 multicentre, randomised, double-blind, placebo-controlled trial

Background

Lithium has neuroprotective effects in cell and animal models of amyotrophic lateral sclerosis (ALS), and a small pilot study in patients with ALS showed a significant effect of lithium on survival. We aimed to assess whether lithium improves survival in patients with ALS.

Methods

The lithium carbonate in amyotrophic lateral sclerosis (LiCALS) trial is a randomised, double-blind, placebo-controlled trial of oral lithium taken daily for 18 months in patients with ALS. Patients aged at least 18 years who had ALS according to the revised El Escorial criteria, had disease duration between 6 and 36 months, and were taking riluzole were recruited from ten centres in the UK. Patients were randomly assigned (1:1) to receive either lithium or matched placebo tablets. Randomisation was via an online system done at the level of the individual by block randomisation with randomly varying block sizes, stratified by study centre and site of disease onset (limb or bulbar). All patients and assessing study personnel were masked to treatment assignment. The primary endpoint was the rate of survival at 18 months and was analysed by intention to treat. This study is registered with Eudract, number 2008-006891-31.

Findings

Between May 26, 2009, and Nov 10, 2011, 243 patients were screened, 214 of whom were randomly assigned to receive lithium (107 patients) or placebo (107 patients). Two patients discontinued treatment and one died before the target therapeutic lithium concentration could be achieved. 63 (59%) of 107 patients in the placebo group and 54 (50%) of 107 patients in the lithium group were alive at 18 months. The survival functions did not differ significantly between groups (Mantel-Cox log-rank χ² on 1 df=1·64; p=0·20). After adjusting for study centre and site of onset using logistic regression, the relative odds of survival at 18 months (lithium vs placebo) was 0·71 (95% CI 0·40–1·24). 56 patients in the placebo group and 61 in the lithium group had at least one serious adverse event.

Interpretation

We found no evidence of benefit of lithium on survival in patients with ALS, but nor were there safety concerns, which had been identified in previous studies with less conventional designs. This finding emphasises the importance of pursuing adequately powered trials with clear endpoints when testing new treatments.

Funding

The Motor Neurone Disease Association of Great Britain and Northern Ireland.

Concordance between site of onset and limb dominance in amyotrophic lateral sclerosis

BACKGROUND

Focality of onset of amyotrophic lateral sclerosis (ALS) is not understood. Attempts to implicate physical exercise in the aetiology of ALS have provided inconsistent results. If physical use of a limb were important in defining the site of onset, then handedness might be expected to influence the side of upper limb-onset disease and footedness likewise in lower limb-onset ALS.

METHODS

ALS patients registered with an internet-based support site were invited to complete an online questionnaire concerning site of onset of symptoms and their dominant hand and foot. A binomial test of proportions was used to investigate the null hypothesis that handedness and footedness do not influence side of onset in upper and lower limb-onset ALS, respectively.

RESULTS

343 ALS patients with limb-onset disease were studied. For upper limb-onset patients, there was concordance for side of onset and handedness (64%; p<0.0006). For lower limb-onset patients, concordance for side of onset and footedness was absent. The frequency of left handedness was commensurate with that found in the general population.

INTERPRETATION

These results are potentially consistent with the hypothesis that exercise influences pathogenesis in ALS since routine physical demands on the upper limb are heavily influenced by limb dominance, whereas in the lower limbs the commonest function is standing or locomotion, which uses both legs equally. However, there may also be an inherent cortical vulnerability underlying upper limb-onset laterality, possibly influenced by changes in neuronal connectivity and cortical excitability in relation to handedness and reflected by the "split hand" phenomenon consistently observed in ALS.

An estimate of amyotrophic lateral sclerosis heritability using twin data

BACKGROUND

Causative gene mutations have been identified in about 2% of those with amyotrophic lateral sclerosis (ALS), often, but not always, when there is a strong family history. There is an assumption that there is a genetic component to all ALS, but genome-wide association studies have yet to produce a robustly replicated result. A definitive estimate of ALS heritability is therefore required to determine whether ongoing efforts to find susceptibility genes are worth while.

METHODS

The authors performed two twin studies, one population- and one clinic-based. The authors used structural equation modelling to perform a meta-analysis of data from these studies and an existing twin study to estimate ALS heritability, and identified 171 twin pairs in which at least one twin had ALS.

RESULTS AND DISCUSSION

Five monozygotic twin pairs were concordant-affected, and 44 discordant-affected. No dizygotic twin pairs were concordant-affected, and 122 discordant-affected. The heritability of sporadic ALS was estimated as 0.61 (0.38 to 0.78) with the unshared environmental component 0.39 (0.22 to 0.62). ALS has a high heritability, and efforts to find causative genes should continue.

A model of ischemic isolated acute liver failure in pigs: standardizing monitoring and treatment

BACKGROUND

Acute liver failure (ALF) models in pigs have been widely used for evaluating newly developed liver support systems. But hardly any guidelines are available for the surgical methods and the clinical management.

METHODS

The study validated several standard operating procedures describing in detail the surgical method and intensive care monitoring and treatment (control of potassium, glucose and bicarbonate levels, cardiovascular and intracranial pressure monitoring, etc.). ALF was induced in animals with a mean of 56 kg. Two surgical methods were compared: ligation of hepatic arteries with either end-to-side portacaval shunt (ESPS) and bile duct ligation or side-to-side portacaval shunt (SSPS) without bile duct ligation.

RESULTS

During total portal vein clamping, the animals in the ESPS group developed severe hypotension, splanchnic congestion and metabolic acidosis. One animal died after approximately 1.5 h. This model therefore represents a multiorgan failure model rather than an isolated ALF model. In the SSPS group, none of these side effects were observed, while clinical, laboratory and histopathological signs of ALF were evident.

CONCLUSIONS

A reproducible model in pigs representing ALF can be established with the help of the standardized monitoring and treatment procedures presented.

Tau levels do not influence human ALS or motor neuron degeneration in the SOD1G93A mouse

BACKGROUND

The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mutations in the tau coding gene MAPT are a cause of frontotemporal dementia, and the H1/H1 genotype of MAPT, giving rise to higher tau expression levels, is associated with progressive supranuclear palsy, corticobasal degeneration, and Parkinson disease (PD). Furthermore, tau hyperphosphorylation and aggregation is a hallmark of Alzheimer disease (AD), and reducing endogenous tau has been reported to ameliorate cognitive impairment in a mouse model for AD. Tau hyperphosphorylation and aggregation have also been described in amyotrophic lateral sclerosis (ALS), both in human patients and in the mutant SOD1 mouse model for this disease. However, the precise role of tau in motor neuron degeneration remains uncertain.

METHODS

The possible association between ALS and the MAPT H1/H2 polymorphism was studied in 3,540 patients with ALS and 8,753 controls. Furthermore, the role of tau in the SOD1(G93A) mouse model for ALS was studied by deleting Mapt in this model.

RESULTS

The MAPT genotype of the H1/H2 polymorphism did not influence ALS susceptibility (odds ratio = 1.08 [95% confidence interval 0.99-1.18], p = 0.08) and did not affect the clinical phenotype. Lowering tau levels in the SOD1(G93A) mouse failed to delay disease onset (p = 0.302) or to increase survival (p = 0.557).

CONCLUSION

These findings suggest that the H1/H2 polymorphism in MAPT is not associated with human amyotrophic lateral sclerosis, and that lowering tau levels in the mutant SOD1 mouse does not affect the motor neuron degeneration in these animals.

Nutritional factors associated with survival following enteral tube feeding in patients with motor neurone disease

BACKGROUND

Motor neurone disease (MND) is a progressive neurodegenerative disease leading to limb weakness, wasting and respiratory failure. Prolonged poor nutritional intake causes fatigue, weight loss and malnutrition. Consequently, disease progression requires decisions to be made regarding enteral tube feeding. The present study aimed to investigate the survival, nutritional status and complications in patients with MND treated with enteral tube feeding.

METHODS

A retrospective case note review was performed to identify patients diagnosed with MND who were treated with enteral tube feeding. A total of 159 consecutive cases were identified suitable for analysis. Patients were treated with percutaneous endoscopic gastrostomy (PEG), radiologically inserted gastrostomy (RIG) or nasogastric feeding tube (NGT). Nutritional status was assessed by body mass index (BMI) and % weight loss (% WL). Serious complications arising from tube insertion and prescribed daily energy intake were both recorded.

RESULTS

Median survival from disease onset was 842 days [interquartile range (IQR) 573-1263]. Median time from disease onset to feeding tube was PEG 521 days (IQR 443-1032), RIG 633 days (IQR 496-1039) and NGT 427 days (IQR 77-781) (P = 0.28). Median survival from tube placement was PEG 200 (IQR 106-546) days, RIG 216 (IQR 83-383) days and NGT 28 (IQR 14-107) days. Survival between gastrostomy and NGT treated patients was significant (P < or = 0.001). Analysis of serious complications by nutritional status was BMI (P = 0.347) and % WL (P = 0.489).

CONCLUSIONS

Nutritional factors associated with reduced survival were weight loss, malnutrition and severe dysphagia. Serious complications were not related to nutritional status but to method of tube insertion. There was no difference in survival between PEG and RIG treated patients.

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.

A large-scale international meta-analysis of paraoxonase gene polymorphisms in sporadic ALS

BACKGROUND

Six candidate gene studies report a genetic association of DNA variants within the paraoxonase locus with sporadic amyotrophic lateral sclerosis (ALS). However, several other large studies, including five genome-wide association studies, have not duplicated this finding.

METHODS

We conducted a meta-analysis of 10 published studies and one unpublished study of the paraoxonase locus, encompassing 4,037 ALS cases and 4,609 controls, including genome-wide association data from 2,018 ALS cases and 2,425 controls.

RESULTS

The combined fixed effects odds ratio (OR) for rs662 (PON1 Q192R) was 1.09 (95% confidence interval [CI], 1.02-1.16, p = 0.01); the genotypic OR for RR homozygotes at Q192R was 1.25 (95% CI, 1.07-1.45, p = 0.0004); the combined OR for rs854560 (PON1 L55M) was 0.97 (95% CI, 0.86-1.10, p = 0.62); the OR for rs10487132 (PON2) was 1.08 (95% CI, 0.92-1.27, p = 0.35). Although the rs662 polymorphism reached a nominal level of significance, no polymorphism was significant after multiple testing correction. In the subanalysis of samples with genome-wide data from which population outliers were removed, rs662 had an OR of 1.06 (95% CI, 0.97-1.16, p = 0.22).

CONCLUSIONS

In contrast to previous positive smaller studies, our genetic meta-analysis showed no significant association of amyotrophic lateral sclerosis (ALS) with the PON locus. This is the largest meta-analysis of a candidate gene in ALS to date and the first ALS meta-analysis to include data from whole genome association studies. The findings reinforce the need for much larger and more collaborative investigations of the genetic determinants of ALS.

SOD1A4V-mediated ALS: absence of a closely linked modifier gene and origination in Asia

Familial amyotrophic lateral sclerosis (ALS) accounts for 10% of all ALS. Approximately 20% of cases are due to mutations in the Cu/Zn superoxide dismutase gene (SOD1). In North America, SOD1(A4V) is the most common SOD1 mutation. Carriers of the SOD1(A4V) mutation share a common phenotype with rapid disease progression and death on average occurring at 1.4 years (versus 3-5 years with other dominant SOD1 mutations). Previous studies of SOD1(A4V) carriers identified a common haplotype around the SOD1 locus, suggesting a common founder for most SOD1(A4V) patients. In the current study we sequenced the entire common haplotypic region around SOD1 to test the hypothesis that polymorphisms in either previously undescribed coding regions or non-coding regions around SOD1 are responsible for the more aggressive phenotype in SOD1(A4V)-mediated ALS. We narrowed the conserved region around the SOD1 gene in SOD1(A4V) ALS to 2.8Kb and identified five novel SNPs therein. None of these variants was specifically found in all SOD1(A4V) patients. It therefore appears likely that the aggressive nature of the SOD1(A4V) mutation is not a result of a modifying factor within the region around the SOD1 gene. Founder analysis estimates that the A4V mutation occurred 540 generations (approximately 12,000 years) ago (95% CI 480-700). The conserved minimal haplotype is statistically more similar to Asian than European population DNA sets, suggesting that the A4V mutation arose in native Asian-Americans who reached the Americas through the Bering Strait.

Amyotrophic Lateral Sclerosis in South-East England: A Population-Based Study

BACKGROUND/AIMS

We aimed to estimate the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in the South East of England. The reported incidence of ALS varies between 0.44 and 3.2 per 100,000 person years. This can partly be explained by differences in design and diagnostic criteria used. There is little population data concerning England, particularly the South East.

METHODS

A population study of South-East England (total population: 2,890,482) was carried out and multiple sources including our tertiary centre and district general hospitals were used for complete case ascertainment.

RESULTS

Between 1 January 2002 and 30 June 2006 we identified 138 people (76 males; 62 females) with a new diagnosis of ALS, giving a crude incidence of 1.06 per 100,000 person years. The projected age- and gender-adjusted annual incidence rate for England and Wales was 1.10 (95% CI 0.80-1.40). 142 people were alive on 30 June 2006, giving a point prevalence of 4.91 per 100,000 population.

CONCLUSION

Our incidence and prevalence rates are similar to those reported in comparable studies from other countries. This argues against the role of a specific exogenous factor in the aetiology of ALS in South-East England.

A locus on chromosome 9p confers susceptibility to ALS and frontotemporal dementia

OBJECTIVE

To perform genetic linkage analysis in a family affected with ALS and frontotemporal dementia (FTD).

METHODS

The authors performed a genome-wide linkage analysis of a four-generation, 50-member Scandinavian family in which five individuals were diagnosed with ALS and nine with FTD. Linkage calculations assuming autosomal dominant inheritance of a single neurodegenerative disease manifesting as either ALS or FTD with age-dependent penetrance were performed. Further analyses for ALS alone and FTD alone were performed. A parametric logarithm of odds (lod) score of 2.0 or greater was required for further study of a potential locus and crossover (haplotype) analysis.

RESULTS

A new ALS-FTD locus was identified between markers D9s1870 and D9s1791 on human chromosome 9p21.3-p13.3. A maximum multipoint lod score of 3.00 was obtained between markers D9s1121 and D9s2154. Crossover analysis indicates this region covers approximately 21.8 cM, or 14Mb.

CONCLUSIONS

A locus on chromosome 9p21.3-p13.3 is linked to ALS-FTD.

Abnormal cortical excitability in sporadic but not homozygous D90A SOD1 ALS

BACKGROUND

Excitotoxicity is one pathogenic mechanism proposed in amyotrophic lateral sclerosis (ALS), and loss of cortical inhibitory influence may be contributory. Patients with ALS who are homozygous for the D90A superoxide dismutase-1 (SOD1) gene mutation (homD90A) have a unique phenotype, associated with prolonged survival compared with patients with sporadic ALS (sALS). In this study, transcranial magnetic stimulation (TMS) was used to explore cortical excitation and inhibition. Flumazenil binds to the benzodiazepine subunit of the GABA(A) receptor, and (11)C-flumazenil positron emission tomography (PET) was used as a marker of cortical neuronal loss and/or dysfunction, which might in turn reflect changes in cortical inhibitory GABAergic mechanisms.

METHODS

Cortical responses to single and paired stimulus TMS were compared in 28 patients with sALS and 11 homD90A patients versus 24 controls. TMS measures included resting motor threshold, central motor conduction time, silent period, intracortical inhibition (ICI), and facilitation. (11)C-flumazenil PET of the brain was performed on 20 patients with sALS and nine with homD90A. Statistical parametric mapping was used to directly compare PET images from the two patient groups to identify those areas of relatively reduced cortical (11)C-flumazenil binding that might explain differences in cortical excitability seen using TMS.

RESULTS

Increased cortical excitability, demonstrated by reduction in ICI, was seen in the patients with sALS but not the homD90A patients. A relative reduction in cortical (11)C-flumazenil binding was found in the motor and motor association regions of the superior parietal cortices of the patients with sALS.

CONCLUSIONS

A cortical inhibitory deficit in sALS was not demonstrable in a homogeneous genetic ALS population of similar disability, suggesting a distinct cortical vulnerability. (11)C-flumazenil PET demonstrated that neuronal loss/dysfunction in motor and motor association areas may underlie this difference. The corollary, that there may be relative preservation of neuronal function in these areas in the homD90A group, has implications for understanding the slower progression of disease in these patients.

No association of the SOD1 locus and disease susceptibility or phenotype in sporadic ALS

Mutations in the copper zinc superoxide dismutase gene (SOD1) are found in 20% of familial and 3% of sporadic ALS patients. SOD1 protein aggregation can be detected in motor neurons of mutation-negative sporadic cases but a pathogenic role for wild-type SOD1 in ALS has not been demonstrated. In this study of 233 ALS cases and 248 controls the authors found no significant association between four individual single nucleotide polymorphisms and a deletion spanning the SOD1 locus (or their combined haplotypes), and disease susceptibility, or phenotype.

Mills' and other isolated upper motor neurone syndromes: in vivo study with 11C-(R)-PK11195 PET

(11)C-(R)-PK11195 positron emission tomography (PET) was used to explore and delineate in vivo the cortical lesion in three clinically isolated upper motor neurone syndromes of similar presentation, with reference to the syndrome of progressive spastic hemiparesis first described by Mills. Three patients with isolated UMN syndromes underwent (11)C-(R)-PK11195 PET of the brain. One patient fulfilled criteria for PLS. Two others had clinical features similar to the cases described by Mills; one of these had a high cervical cord inflammatory lesion previously noted on magnetic resonance imaging. The patient with PLS showed focal increase in the binding of (11)C-(R)-PK11195, indicating microglial activation, in the motor cortex contralateral to the predominantly affected limbs. Of the other two patients, one demonstrated marked increases in binding in the superior frontal region (supplementary motor region) contralateral to the affected limbs. In contrast, no focal areas of increased binding were seen in the cerebral cortex of the third patient, who had a high cervical cord lesion and was presumed to have extra-cerebral inflammatory disease. (11)C-(R)-PK11195 PET demonstrates in vivo that active pathology may be detectable many years after the onset of symptoms, and that it can occur in disparate sites with clinically similar presentations. We conclude that Mills' syndrome is a purely clinical description that should be reserved for patients with a progressive spastic hemiparesis for which no other explanation can be found.

Distinct cerebral lesions in sporadic and 'D90A' SOD1 ALS: studies with [11C]flumazenil PET

Five to ten percent of amyotrophic lateral sclerosis (ALS) cases are associated with mutations of the superoxide dismutase-1 (SOD1) gene, and the 'D90A' mutation is associated with a unique phenotype and markedly slower disease progression (mean survival time 14 years). Relative sparing of inhibitory cortical neuronal circuits might be one mechanism contributing to the slower progression in patients homozygous for the D90A mutation (homD90A). The GABA(A) receptor PET ligand [11C]flumazenil has demonstrated motor and extra-motor cortical changes in sporadic ALS. In this study, we used [11C]flumazenil PET to explore differences in the pattern of cortical involvement between sporadic and genetically homogeneous ALS groups. Twenty-four sporadic ALS (sALS) and 10 homD90A patients underwent [11C]flumazenil PET of the brain. In addition, two subjects homozygous for the D90A mutation, but without symptoms or signs ('pre-symptomatic', psD90A), also underwent imaging. Results for each group were compared with those for 24 healthy controls of similar age. Decreases in the binding of [11C]flumazenil in the sALS group were found within premotor regions, motor cortex and posterior motor association areas. In the homD90A group of ALS patients, however, decreases were concentrated in the left fronto-temporal junction and anterior cingulate gyrus. In the two psD90A subjects, a small focus of reduced [11C]flumazenil binding at the left fronto-temporal junction was seen, similar to the pattern seen in the clinically affected patients. Within the sALS group, there was no statistically significant association between decreases in cortical [11C]flumazenil binding and revised ALS functional rating scale (ALSFRS-R score), whereas the upper motor neuron (UMN) score correlated with widespread and marked cortical decreases over the dominant hemisphere. In the homD90A group, there was a stronger statistical association between reduced cortical [11C]flumazenil binding and the ALSFRS-R, rather than the UMN, score, and also with disease duration. This study provides evidence for differences in the distribution of reduced cortical [11C]flumazenil binding in homD90A compared with sALS patients. We hypothesize that this might reflect differences in cortical neuronal vulnerability.

Detection of serum reverse transcriptase activity in patients with ALS and unaffected blood relatives

BACKGROUND

Retroviral involvement in the etiology of sporadic ALS has been suspected for several years since the recognition that both murine and human retroviruses can cause motor neuron disease-like syndromes. In a pilot study, an increased prevalence of a retroviral marker (reverse transcriptase [RT] activity) was demonstrated in the serum of British patients with ALS. The current investigation was designed to confirm and extend these findings in a geographically distinct patient cohort under blinded testing conditions.

METHODS

A highly sensitive product-enhanced RT assay was employed to test coded sera obtained from 30 American patients with sporadic ALS and from 14 of their blood relatives, 16 of their spouses, and 28 nonrelated, nonspousal control subjects.

RESULTS

Serum RT activity was detected in a higher proportion of ALS patients (47%) than in non-blood-related controls (18%; p = 0.008). The prevalence of RT activity in the serum of spousal controls (13%) was similar to that in other non-blood-related controls. Unexpectedly, the prevalence of serum RT activity in blood relatives of ALS patients (43%) approached that in the ALS patients themselves.

CONCLUSIONS

These results confirm that patients with ALS have a significantly higher prevalence of serum reverse transcriptase (RT) activity than that seen in unrelated control subjects. The finding of a similarly increased prevalence in blood relatives of ALS patients raises the possibility that the observed RT activity might be due to an inherited endogenous retrovirus.

[11C]-WAY100635 PET demonstrates marked 5-HT1A receptor changes in sporadic ALS

The pathogenesis of amyotrophic lateral sclerosis (ALS) remains obscure, but it is now clear that neuronal loss is not confined to the motor cortex, even in cases without dementia. A reliable method of assessing cortical involvement in vivo remains elusive. WAY100635 binds selectively to the 5-hydroxytryptamine (5-HT1A) receptor, which is expressed on pyramidal neurones present throughout the cortex. [11C]-WAY100635 PET is, therefore, a potential marker of cerebral neuronal loss or dysfunction in ALS. Twenty-one ALS subjects and 19 healthy volunteers underwent [11C]-WAY100635 PET of the brain. A cortical template consisting of multiple volumes of interest (VOI) was applied to each individual's [11C]-WAY100635 binding potential (BP) image to determine the regional reduction in binding in ALS patients compared to controls. There was a marked reduction (21%) in both the global cortical and raphe BP of [11C]-WAY100635 in ALS patients (P < 0.001), with regional variations in the VOI analysis that ranged from 16% to 29% decrease compared with the control group, and trends to greater reductions in those with bulbar involvement. To clarify the significance of the global cortical reductions, statistical parametric mapping was used as an alternative method to identify the cortical regions with the most significant decreases in [11C]-WAY100635 binding. SPM analysis revealed the greatest differences between ALS cases and controls in frontotemporal regions, cingulate and lateral precentral gyri. The reductions in cortical [11C]-WAY100635 binding were not related to depression, riluzole or other drug use. We postulate that the reduction of 5-HT1A binding represents loss of, or damage to, neurones bearing these receptors although we cannot exclude the possibility that these reductions reflect alterations in receptor expression or function. Further investigation into the role of the 5-HT1A receptor and the potential of [11C]-WAY100635 PET as a marker of cortical dysfunction in ALS is warranted.

Prolonged survival in motor neuron disease: a descriptive study of the King's database 1990-2002

Motor neuron disease is a clinically heterogeneous disease with significant differences in survival. The authors have characterised a subset of long term survivors seen in a tertiary clinic over a 12 year period in terms of clinical variables and demographics, comparing them with short term survivors and the remaining population. Thirty of 769 patients survived more than 10 years, corresponding to 4% of the total population. Significantly younger onset of disease symptoms and a predominance of pure upper motor neuron signs at presentation characterised the long term survivors, but factors traditionally regarded as being associated with poor prognosis were also well represented. For a few people with motor neuron disease there remains the hope, whatever the initial presentation, that their subsequent survival will be longer than expected.

Prognostic modelling of therapeutic interventions in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a disease with a widely varying prognosis. The majority of patients survive about 3 years, but a significant number survive for 10 years or more, leading to problems in clinical trial design.

OBJECTIVE

To demonstrate that simple clinical variables can be used to construct a robust predictive model for survival, and to assess the effect of a known treatment within this model.

METHODS

We carried out a retrospective multivariate modelling of a database of 841 patients with ALS seen over a 10-year period in a specialist motor neuron disorders clinic. The use of riluzole was tested as a prognostic factor within the model.

RESULTS

A prognostic score generated from one cohort of patients predicted survival for a second cohort of patients (r(2) = 0.78). Prognostic variables included site of onset, age of onset, time from symptom onset to diagnosis, and El Escorial category at presentation. Riluzole therapy was an independently significant prognostic factor (relative risk of death 0.48, P < 0.0001, model chi(2) 297, P < 0.0001).

CONCLUSIONS

Clinical databases can be used to generate multivariate prognostic models in ALS. Such models could be used to predict survival, to improve criteria for matching of patients in future clinical trials, and to test the impact of interventions.

Extramotor involvement in ALS: PET studies with the GABA(A) ligand [(11)C]flumazenil

We used the benzodiazepine GABA(A) marker [(11)C] flumazenil to study cerebral dysfunction in amyotrophic lateral sclerosis (ALS) with PET. Seventeen non-demented patients with clinically definite or probable ALS were scanned and statistical parametric maps were derived to localize changes in regional flumazenil volumes of distribution (FMZVD), which correlate closely with receptor density (B(max)), and the results were compared with those of 17 controls. The ALS group showed statistically significant decreases in relative FMZVD in the prefrontal cortex (areas 9 and 10 bilaterally), parietal cortex (area 7 bilaterally), visual association cortex (area 18 bilaterally) and left motor/premotor cortex (including area 4) (P < 0.001). Relative reductions in FMZVD were also seen in the left ventrolateral and dorsolateral prefrontal cortex (areas 45, 46 and 47), Broca's area and the right temporal (area 21) and right visual association cortex (area 19). These observations suggest that cerebral dysfunction in ALS involves motor/premotor and extramotor areas, particularly the prefrontal regions.

Detection of reverse transcriptase activity in the serum of patients with motor neurone disease

The recognition that both human and murine retroviruses can cause motor neurone disease-like syndromes has raised the possibility that a retrovirus may be involved in the aetiology of motor neurone disease. This possibility was explored by looking for evidence of reverse transcriptase in the serum of motor neurone disease patients. Sera from 56 patients with motor neurone disease and 58 controls were tested by the product-enhanced reverse transcriptase assay, a technique that is approximately a million fold more sensitive than conventional reverse transcriptase assays and capable of detecting very low numbers of retroviral particles. Cell-free reverse transcriptase activity was detected in the serum of 33 of the 56 motor neurone disease patients (59%) but in only 3 of the controls (P < 0.00001). The reverse transcriptase activity was detectable in the presence of a large excess of an effective inhibitor of human cellular DNA polymerases and was therefore tentatively considered to be compatible with a retroviral origin. The reverse transcriptase activity, however, was not found to be due to the presence of known human exogenous retroviruses including HIV-1, HIV-2, HTLV-I, HTLV-II, HRV-5 or human foamy virus, as assessed by PCR-based assays. Further investigations will be required to determine the source of the reverse transcriptase activity observed in these motor neurone disease patient sera.

Recent advances in amyotrophic lateral sclerosis

The mechanisms by which mutations of the SOD1 gene cause selective motor neuron death remain uncertain, although interest continues to focus on the role of peroxynitrite, altered peroxidase activity of mutant SOD1, changes in intracellular copper homeostasis, protein aggregation, and changes in the function of glutamate transporters leading to excitotoxicity. Neurofilaments and peripherin appear to play some part in motor neuron degeneration, and amyotrophic lateral sclerosis is occasionally associated with mutations of the neurofilament heavy chain gene. Linkage to several chromosomal loci has been established for other forms of familial amyotrophic lateral sclerosis, but no new genes have been identified. In the clinical field, interest has been shown in the population incidence and prevalence of amyotrophic lateral sclerosis and the clinical variants that cause diagnostic confusion. Transcranial magnetic stimulation has been used to detect upper motor neuron damage and to explore cortical excitability in amyotrophic lateral sclerosis, and magnetic resonance imaging including proton magnetic resonance spectroscopy and diffusion weighted imaging also provide useful information on the upper motor neuron lesion. Aspects of care including assisted ventilation, nutrition, and patient autonomy are addressed, and underlying these themes is the requirement to measure quality of life with a new disease-specific instrument. Progress has been made in developing practice parameters. Riluzole remains the only drug to slow disease progression, although interventions such as non-invasive ventilation and gastrostomy also extend survival.

Deletions of the heavy neurofilament subunit tail in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron degeneration resulting in paralysis and death, usually within 3 years of onset. Pathological and animal studies implicate neurofilament involvement in ALS, but whether this is primary or secondary is not clear. The heavy neurofilament subunit (NFH) tail is composed of a repeating amino acid motif, usually X-lysine-serine-proline-Y-lysine (XKSPYK), where X is a single amino acid and Y is one to three amino acids. There are two common polymorphic variants of 44 or 45 repeats. The tail probably regulates axonal calibre, with interfilament spacing determined by phosphorylation of the KSP motifs. A previous study suggested an association between sporadic cases of ALS and NFH tail deletions, but two subsequent studies have found none. We have analysed samples from two different populations (UK 207, Scandinavia 323) with age-matched controls for each group (UK 219, Scandinavia 228) and have found four novel NFH tail deletions, each involving a whole motif. These were found in three patients with sporadic ALS and a family with autosomal dominant ALS, although another was also found in two young controls. In all cases motif deletions were only associated with disease when paired with the long NFH allele. The deletions all occurred within a small region of the NFH tail. This has allowed us to propose a structural organization of the tail as well as allowing observed deletions both from this study and previous reports to be organized into logical groups. These results strongly suggest that NFH motif deletions can be a primary event in ALS but that they are not common.

Recessive amyotrophic lateral sclerosis families with the D90A SOD1 mutation share a common founder: evidence for a linked protective factor

Amyotrophic lateral sclerosis (ALS) is a progressive motor neurodegeneration resulting in paralysis and death from respiratory failure within 3-5 years. About 20% of familial cases are associated with mutations in the gene for copper/zinc superoxide dismutase ( SOD1 ), which catalyses the dismutation of the superoxide radical to hydrogen peroxide and oxygen. Experimental evidence suggests mutations act by a toxic gain of function but the mechanism is unknown. There are >60 known SOD1 mutations associated with ALS and all are dominant except for one in exon 4, a D90A substitution which is recessive. D90A pedigrees with dominant inheritance have now been reported and this apparent contradiction needs to be explained. We performed a worldwide haplotype study on 28 D90A pedigrees using six highly polymorphic microsatellite markers. We now show that all 20 recessive families share the same founder (alpha = 0.999), regardless of geographical location, whereas several founders exist for the eight dominant families (alpha = 0.385). This finding confirms that D90A can act in a dominant fashion in keeping with all other SOD1 mutations, but that on one occasion, a new instance of this mutation has been recessive. We propose a tightly linked protective factor which modifies the toxic effect of mutant SOD1 in recessive families.

Mutations in all five exons of SOD-1 may cause ALS

Eight of 38 patients (21%) with familial and 5 of 175 patients (3%) with sporadic amyotrophic lateral sclerosis (ALS) had missense mutations in the SOD-1 gene. Two novel mutations were identified. One in exon 4 substituting leucine with phenylalanine (L84F) in a familial patient and the second in exon 3 at substituting glycine with serine (G72S) in an "apparently" sporadic patient. Over 60 point mutations have now been described in all five exons of SOD-1, involving 43 of the 153 residues. Hypotheses about the toxic role of mutant SOD-1 in the pathogenesis of ALS must account for this molecular diversity.

Lack of evidence for HTLV tax-rex DNA in motor neurone disease

It has recently been claimed (Ferrante et al., 1995. HTLV tax-rex DNA and antibodies in idiopathic amyotrophic lateral sclerosis. J. Neurol. Sci. 129 (Suppl.) 140-144) that human T-lymphotropic virus (HTLV) tax-rex sequences are detectable in the peripheral blood mononuclear cells (PBMCs) of 40% of patients with motor neurone disease (MND). In an attempt to confirm this we employed a highly sensitive 'nested' polymerase chain reaction (PCR) assay, capable of detecting single molecules of HTLV proviral DNA, to look for tax-rex sequences in the PBMCs of 43 patients with MND. We were unable to detect the presence of HTLV tax-rex in any of 43 MND patients tested, using three different PCR primer sets under both high and low stringency conditions. Using the same DNA samples we were able to detect the presence of the single-copy pyruvate dehydrogenase gene, thus demonstrating that the extracted DNA was indeed amplifiable by PCR. To further exclude the possibility that the extracted DNA samples contained unrecognised inhibitory factors we conducted spiking experiments with trace amounts (approximately 10 copies) of HTLV proviral DNA. Spiked samples yielded PCR products of the expected size. We are therefore unable to confirm the presence of HTLV tax-rex sequences in this disease.

Copper/zinc superoxide dismutase 1 and sporadic amyotrophic lateral sclerosis: analysis of 155 cases and identification of a novel insertion mutation

Amyotrophic lateral sclerosis (ALS) is a progressive paralytic disorder resulting from the degeneration of motor neurons in the brain and spinal cord and leading to death within 5 years of symptom onset. The great majority of ALS cases are sporadic, with the familial form (FALS) representing fewer than 10% of all cases. Mutations in the copper/zinc superoxide dismutase 1 (SOD-1) gene have previously been identified as the underlying cause of approximately 20% of FALS cases. As the familial and sporadic forms of the disease are clinically similar, we have sought to determine whether such mutations in SOD-1 underlie any sporadic ALS cases. We have screened 155 sporadic cases by single-strand conformation polymorphism and have identified 4 sporadic cases that possess point mutations in exon 4 of the SOD-1 gene. Two of these mutations are identical to those previously reported in FALS cases. One mutation is novel, resulting in a frameshift at Val118 due to the replacement of G (first base in the last codon of exon 4) by AAAAC. This mutation results in a truncated SOD-1 protein due to the introduction of a stop codon three residues into exon 5.