Corticospinal tract degeneration in the progressive muscular atrophy variant of ALS

Mutations in CHMP2B in lower motor neuron predominant amyotrophic lateral sclerosis (ALS)

BACKGROUND

Amyotrophic lateral sclerosis (ALS), a common late-onset neurodegenerative disease, is associated with fronto-temporal dementia (FTD) in 3-10% of patients. A mutation in CHMP2B was recently identified in a Danish pedigree with autosomal dominant FTD. Subsequently, two unrelated patients with familial ALS, one of whom also showed features of FTD, were shown to carry missense mutations in CHMP2B. The initial aim of this study was to determine whether mutations in CHMP2B contribute more broadly to ALS pathogenesis.

METHODOLOGY/PRINCIPAL FINDINGS

Sequencing of CHMP2B in 433 ALS cases from the North of England identified 4 cases carrying 3 missense mutations, including one novel mutation, p.Thr104Asn, none of which were present in 500 neurologically normal controls. Analysis of clinical and neuropathological data of these 4 cases showed a phenotype consistent with the lower motor neuron predominant (progressive muscular atrophy (PMA)) variant of ALS. Only one had a recognised family history of ALS and none had clinically apparent dementia. Microarray analysis of motor neurons from CHMP2B cases, compared to controls, showed a distinct gene expression signature with significant differential expression predicting disassembly of cell structure; increased calcium concentration in the ER lumen; decrease in the availability of ATP; down-regulation of the classical and p38 MAPK signalling pathways, reduction in autophagy initiation and a global repression of translation. Transfection of mutant CHMP2B into HEK-293 and COS-7 cells resulted in the formation of large cytoplasmic vacuoles, aberrant lysosomal localisation demonstrated by CD63 staining and impairment of autophagy indicated by increased levels of LC3-II protein. These changes were absent in control cells transfected with wild-type CHMP2B.

CONCLUSIONS/SIGNIFICANCE

We conclude that in a population drawn from North of England pathogenic CHMP2B mutations are found in approximately 1% of cases of ALS and 10% of those with lower motor neuron predominant ALS. We provide a body of evidence indicating the likely pathogenicity of the reported gene alterations. However, absolute confirmation of pathogenicity requires further evidence, including documentation of familial transmission in ALS pedigrees which might be most fruitfully explored in cases with a LMN predominant phenotype.

EFNS guidelines on the use of neuroimaging in the management of motor neuron diseases

BACKGROUND AND PURPOSE

These European Federation of Neurological Societies guidelines on neuroimaging of motor neuron diseases (MNDs) are designed to provide practical help for the neurologists to make appropriate use of neuroimaging techniques in patients with MNDs, which ranges from diagnostic and monitoring aspects to the in vivo study of the pathobiology of such conditions.

METHODS

Literature searches were performed before expert members of the Task Force wrote proposal. Then, consensus was reached by circulating drafts of the manuscript to the Task Force members and by discussion of the classification of evidence and recommendations.

RESULTS AND CONCLUSIONS

The use of conventional MRI in patients suspected of having a MND is yet restricted to exclude other causes of signs and symptoms of MN pathology [class IV, level good clinical practice point (GCPP)]. Although the detection of corticospinal tract hyperintensities on conventional MRI and a T2-hypointense rim in the pre-central gyrus can support a pre-existing suspicion of MND, the specific search of these abnormalities for the purpose of making a firm diagnosis of MND is not recommended (class IV, level GCPP). At present, advanced neuroimaging techniques, including diffusion tensor imaging and proton magnetic resonance spectroscopic imaging, do not have a role in the diagnosis or routine monitoring of MNDs yet (class IV, level GCPP). However, it is strongly advisable to incorporate measures derived from these techniques into new clinical trials as exploratory outcomes to gain additional insights into disease pathophysiology and into the value of these techniques in the (longitudinal) assessment of MNDs (class IV, level GCPP).

Pseudopolyneuritic form of ALS revisited: clinical and pathological heterogeneity

Pseudopolyneuritic form of ALS is a subtype of ALS characterized by distal weakness of the unilateral lower limb and absence of Achilles tendon reflex (ATR) at disease onset. Recognition of this form of ALS is important for clinicians because the combination of distal weakness of the lower limb and absence of ATR usually suggests peripheral neuropathy. We reviewed the clinical records of 42 autopsy-proven sporadic ALS cases and found three cases that showed onset of weakness of the unilateral lower limb with distal dominance and absence of ATR. The disease duration in the three cases was 2, 3 and 19 years, respectively. The clinical features of the patient with a course of 19 years had been restricted to lower motor neuron signs. Histopathologically, consistent findings in the three cases were severe motor neuron loss throughout the whole spinal cord, with relative preservation of the hypoglossal nucleus. Reflecting this finding, TDP-43-positive neuronal cytoplasmic inclusions in the spinal cord were sparse in two cases, and absent in a third. In the patient showing a clinical course of 19 years, mild corticospinal tract degeneration appeared to correspond to the absence of upper motor neuron signs and prolonged disease duration. In this case only, Bunina bodies were not demonstrated. In this study, we clarified the clinical and pathological heterogeneity of this form of ALS.

Study of 962 patients indicates progressive muscular atrophy is a form of ALS

BACKGROUND

Progressive muscular atrophy (PMA) is clinically characterized by signs of lower motor neuron dysfunction and may evolve into amyotrophic lateral sclerosis (ALS). Whether PMA is actually a form of ALS has important consequences clinically and for therapeutic trials. We compared the survival of patients with PMA or ALS to analyze the clinical features that influence survival in PMA.

METHODS

We reviewed the medical records of patients with PMA (n = 91) or ALS (n = 871) from our ALS Center and verified survival by telephoning the families or using the National Death Index.

RESULTS

In PMA, patients were more likely to be male (p < 0.001), older (p = 0.007), and lived longer (p = 0.01) than in ALS. Cox model analysis suggested that the risk of death increased with age at onset in both patient groups (p < 0.005). Upper motor neuron (UMN) signs developed in 22% of patients with PMA within 61 months after diagnosis. Demographic and other clinical variables did not differ at diagnosis between those who did or did not develop UMN signs. In PMA, the factors present at diagnosis that predicted shorter survival were greater number of body regions affected, lower forced vital capacity, and lower ALS Functional Rating Scale-Revised score. Noninvasive ventilation and gastrostomy were used frequently in PMA.

CONCLUSION

Although patients with progressive muscular atrophy (PMA) tended to live longer than those with amyotrophic lateral sclerosis (ALS), shorter survival in PMA is associated with the same risk factors that predict poor survival in ALS. Additionally, PMA is relentlessly progressive, and UMN involvement can occur, as also reported in imaging and postmortem studies. For these reasons, PMA should be considered a form of ALS.

Clinical patterns in progressive muscular atrophy (PMA): A prospective study

Progressive muscular atrophy (PMA) is a form of motor neuron disease, but its outcome is not well defined, and the aim was to study the pattern of clinical progression in PMA. We studied 10 patients prospectively for 12 months. None showed clinical signs of upper motor neuron involvement at presentation or during follow-up, and all had normal transcranial magnetic stimulation studies. Four had upper limb onset, four lower limb onset and two axial onset. We used neurophysiological and strength measurements and a clinical rating scale (ALS-FRS). Seven other patients presenting with a PMA syndrome developed upper motor neuron signs during a one-year period of observation and were excluded from the study. The rate of progression was variable. At six months, only motor unit number estimation (MUNE) and ALS-FRS had decreased significantly. The Neurophysiological Index (NI) and M-wave amplitude measurements decreased at 12 months. Two patients with axial-onset disease progressed rapidly to respiratory failure. Overall the pattern of change resembled that of ALS, although some patients progressed very slowly. Axial onset, however, predicts the early onset of respiratory failure, and a poor prognosis.

Epidemiology of ALS in Padova district, Italy, from 1992 to 2005

BACKGROUND AND PURPOSE

Several studies have reported an increase in ALS incidence in recent years but population-based studies in Europe do not confirm this trend. To analyze ALS incidence over time we conducted a retrospective incidence study in the Padova district of Italy (1992 to 2005). We had previously conducted a survey in the same area in the years 1980-1991.

METHODS

We used the archives of all the neurological wards of the Padova district to identify all subjects with a discharge diagnosis of ALS or motor neuron disease and resident in the Padova district.

RESULTS

We ascertained 182 patients (85 males and 97 females; male:female ratio 0.88:1) over the 14-year study period. The annual incidence rates adjusted by sex and age increased from 1.31/100,000/year in the years 1992-1994 to 1.92/100,000/year in the years 2004-2005.

CONCLUSIONS

This study confirmed an ALS incidence increase over the last 25 years in the Padova district. The increase in incidence may be partially explained by the ageing of the general population rather than by an improved diagnostic assessment.

Transcranial magnetic stimulation in ALS: utility of central motor conduction tests

OBJECTIVE

To investigate transcranial magnetic stimulation (TMS) measures as clinical correlates and longitudinal markers of amyotrophic lateral sclerosis (ALS).

METHODS

We prospectively studied 60 patients with ALS subtypes (sporadic ALS, familial ALS, progressive muscular atrophy, and primary lateral sclerosis) using single pulse TMS, recording from abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. We evaluated three measures: 1) TMS motor response threshold to the ADM, 2) central motor conduction time (CMCT), and 3) motor evoked potential amplitude (correcting for peripheral changes). Patients were evaluated at baseline, compared with controls, and followed every 3 months for up to six visits. Changes were analyzed using generalized estimation equations to test linear trends with time.

RESULTS

TMS threshold, CMCT, and TMS amplitude correlated (p < 0.05) with clinical upper motor neuron (UMN) signs at baseline and were different (p < 0.05) from normal controls in at least one response. Seventy-eight percent of patients with UMN (41/52) and 50% (4/8) of patients without clinical UMN signs had prolonged CMCT. All three measures revealed significant deterioration over time: TMS amplitude showed the greatest change, decreasing 8% per month; threshold increased 1.8% per month; and CMCT increased by 0.9% per month.

CONCLUSIONS

Transcranial magnetic stimulation (TMS) findings, particularly TMS amplitude, can objectively discriminate corticospinal tract involvement in amyotrophic lateral sclerosis (ALS) from controls and assess the progression of ALS. While central motor conduction time and response threshold worsen by less than 2% per month, TMS amplitude decrease averages 8% per month, and may be a useful objective marker of disease progression.

Amyotrophic lateral sclerosis: A 40-year personal perspective

Amyotrophic lateral sclerosis (ALS) or motor neuron disease (MND) shares with other neurodegenetrative disorders of the aging nervous system a polygenic, multifactorial aetiology. Less than 10% are familial and these too probably are associated with several interactive genes. The onset of ALS predates development of clinical symptoms by an unknown interval which may extend several years. The cause of neurodegeneration remains unknown but a common end-point is protein misfolding which in turn causes cell function failure. The complex nature of ALS has hindered therapeutic advances. In recent years longer survival is attributable largely to institution of non-invasive ventilation with BiPAP and timely implementation of percutaneous endoscopic gastrostomy (PEG) feeding. Symptomatic treatment has advanced improving quality of life. Several encouraging avenues of therapy for ALS are beginning to be emerge raising hope for real benefit. They include protective autoimmunity, vaccines against misfolded protein epitopes and other deleterious species, new drug delivery systems employing nanotechnology and the potential of stem cell therapy.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive muscular paralysis reflecting degeneration of motor neurones in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Incidence (average 1.89 per 100,000/year) and prevalence (average 5.2 per 100,000) are relatively uniform in Western countries, although foci of higher frequency occur in the Western Pacific. The mean age of onset for sporadic ALS is about 60 years. Overall, there is a slight male prevalence (M:F ratio approximately 1.5:1). Approximately two thirds of patients with typical ALS have a spinal form of the disease (limb onset) and present with symptoms related to focal muscle weakness and wasting, where the symptoms may start either distally or proximally in the upper and lower limbs. Gradually, spasticity may develop in the weakened atrophic limbs, affecting manual dexterity and gait. Patients with bulbar onset ALS usually present with dysarthria and dysphagia for solid or liquids, and limbs symptoms can develop almost simultaneously with bulbar symptoms, and in the vast majority of cases will occur within 1-2 years. Paralysis is progressive and leads to death due to respiratory failure within 2-3 years for bulbar onset cases and 3-5 years for limb onset ALS cases. Most ALS cases are sporadic but 5-10% of cases are familial, and of these 20% have a mutation of the SOD1 gene and about 2-5% have mutations of the TARDBP (TDP-43) gene. Two percent of apparently sporadic patients have SOD1 mutations, and TARDBP mutations also occur in sporadic cases. The diagnosis is based on clinical history, examination, electromyography, and exclusion of 'ALS-mimics' (e.g. cervical spondylotic myelopathies, multifocal motor neuropathy, Kennedy's disease) by appropriate investigations. The pathological hallmarks comprise loss of motor neurones with intraneuronal ubiquitin-immunoreactive inclusions in upper motor neurones and TDP-43 immunoreactive inclusions in degenerating lower motor neurones. Signs of upper motor neurone and lower motor neurone damage not explained by any other disease process are suggestive of ALS. The management of ALS is supportive, palliative, and multidisciplinary. Non-invasive ventilation prolongs survival and improves quality of life. Riluzole is the only drug that has been shown to extend survival.

Upper motor neuron and extra-motor neuron involvement in amyotrophic lateral sclerosis: a clinical and brain imaging review

There is an ongoing discussion whether ALS is primarily a disease of upper motor neurons or lower motor neurons. We undertook a review to assess how new insights have contributed to solve this controversy. For this purpose we selected relevant publications from 1995 onwards focussing on (1) primary targets and disease progression in ALS and variants of ALS, (2) brain imaging markers for upper motor neuron lesion, and (3) evidence for ALS being a multisystem disorder. Clinically, upper motor and lower motor neuron symptoms can occur in any order over time. Brain imaging markers show upper motor neuron involvement in early disease. Overlap syndromes of ALS and dementia, and involvement of autonomic and sensory nerves occur frequently. PET/SPECT scans, functional MRI and voxel based morphometry studies clearly show abnormalities in extra-motor areas of the brain. Pathologically, the 43 kDa TAR DNA-binding protein (TDP-43) provides a clue to these overlapping disorders. In conclusion, evidence accumulates that ALS is a multisystem disorder rather than a pure lower and/or upper motor neuron disorder.

How people with motor neurone disease talk about living with their illness: a narrative study

AIM

This paper is a report of a study which explores patients' experiences and how they talk about living and coping with motor neurone disease.

BACKGROUND

Living with motor neurone disease is challenging, frightening and disabling. It leads to progressive physical decline, normally with a prognosis of 3-5 years. Patients have to deal with many problems, including loss of mobility and the inability to communicate. There is little evidence about how people manage these problems or live with this illness.

METHOD

Narrative case studies were used, the unit of analysis being a patient living in their own home or a care home. Thirteen adults were recruited through purposeful sampling. Longitudinal narrative interviews were conducted at three-monthly intervals over an 18-month period in 2005-06. Interviews were analysed focusing on the form and content of the patients' narratives.

FINDINGS

Four types of narrative, or storyline were identified. The sustaining storyline is about living life as well as possible through keeping active and engaged in life. In contrast, the enduring storyline concerns living in an insurmountable situation leaving the person feeling disempowered, unable to fight for life or against death. Survival is the essence of the preserving storyline, while the fracturing storyline concerns loss and fear of what is to come.

CONCLUSION

Storylines help make sense of complex narratives by encouraging closer attention and active listening to the stories and serve as organizing threads to help patients, families and healthcare professionals better understand living with motor neurone disease.

[An autopsy case of amyotrophic lateral sclerosis with ampulla cardiomyopathy]

We herein report an autopsy case of a 63-year-old man with amyotrophic lateral sclerosis (ALS) who developed "ampulla cardiomyopathy." At the age of 56, he noticed a progressive weakness in his right upper extremity. One year later, a progressive weakness of the left upper extremity began. Dropped head and progressive weakness of the lower extremities emerged at the ages of 61 and 62, respectively. Intravenous immunoglobulin and plasma-exchange therapies did not improve his weakness. At the age of 63, one month before his death, he was hospitalized due to aspiration pneumonia. A tracheostomy was performed to secure his airway. Four days after the operation, an ST elevation of his electrocardiogram was incidentally found on the ECG monitor. An echocardiogram revealed diffuse hypokinesia of the wall of the left ventricle except in the basal portion, which is the typical finding of "ampulla cardiomyopathy." Wall motion of the left ventricle improved and his circulatory condition was stabilized after treatment, but his condition thereafter worsened again and he died 3 weeks later. An autopsy examination revealed diffuse fibrosis and degeneration of the cardiomyofibers. Neuropathological examination revealed neuronal cell loss, Bunina bodies and skein-like inclusions in the hippoglossal nuclei. In the thoracic spinal cord, degenarated anterior horn cells were seen and macrophage permeation in the corticospinal tract were shown by CD68 immunostaining. Therefore, the final neuropathological diagnosis was ALS. This report is the first autopsy case of ALS complicated with "ampulla cardiomyopathy."

Heterogeneity in motoneuron disease

Recently, mutations in several genes have been identified as primary causes for the degeneration of motoneurons and their axons. Strikingly, mutations in the same genes were associated with clinically different motoneuron syndromes. The identity of these genes also shed light on the mechanisms of motoneuron degeneration and revealed that overlapping motoneuron phenotypes might be caused by heterogeneous molecular mechanisms. Overall, these findings have challenged the diagnostic classification system set by clinical judgement and triggered the notion of heterogeneity in motoneuron disease. It will now be especially relevant to identify the mechanisms and principles that motoneuron diseases have in common, as this will allow us to identify the most relevant therapeutic targets. On the other hand, heterogeneity in motoneuron disease also implies that finding a monotherapy cure for motoneuron disease will be challenging and that pre-clinical testing of therapeutic targets should not be limited to a single animal model.

Cortical activation during motor imagery is reduced in Amyotrophic Lateral Sclerosis

The neural correlates of motor execution in Amyotrophic Lateral Sclerosis (ALS) are challenging to investigate due to muscle weakness. Alternatives to traditional motor execution paradigms are therefore of great interest. This study tested the hypothesis that patients with Amyotrophic Lateral Sclerosis (ALS) would show increased cortical activation during motor imagery compared to healthy controls, as seen in studies of motor execution. Functional MRI was used to measure activation during a block design paradigm contrasting imagery of right hand movements against rest in 16 patients with ALS and 17 age-matched healthy controls. Patients with ALS showed reduced activation during motor imagery in the left inferior parietal lobule, and in the anterior cingulate gyrus and medial pre-frontal cortex. This reduction in cortical activation during motor imagery contrasts with the pattern seen during motor execution. This may represent the disruption of normal motor imagery networks by ALS pathology outside the primary motor cortex.

Low yield in screening patients with sporadic motor neuron disease for Kennedy disease

The diagnostic yield of testing for Kennedy disease in patients diagnosed with sporadic motor neuron disease (MND) is unclear. We measured the CAG repeat lengths in the androgen receptor gene of patients with progressive limb weakness who had either upper and lower motor signs (n = 130), or lower motor neuron signs alone (n = 30). Only one patient with a long history of lower motor weakness had a repeat length in the Kennedy disease range. Testing for Kennedy disease is unlikely to benefit MND patients with upper motor neuron signs or those with a short history of lower motor signs.

Monomelic neurogenic syndromes: a prospective study

Monomelic neurogenic syndromes are rare. Their classification and prognostic features have not been addressed in the European population. A prospective study of 17 patients with monomelic neurogenic amyotrophy, of upper or lower limb onset, with progression limited to one limb for three or more years. Clinical and neurophysiological studies were performed in the subsequent 3 or more years. Fifteen patients were of European origin and two were Asian. Those presenting with proximal monomelic weakness or with involvement of the posterior compartment of the lower leg showed no further progression after the initial period of development of the syndrome. Brisk reflexes in wasted muscles did not predict progression. Electromyographic signs of denervation in the opposite limb at presentation did not predict later progression. Transcranial magnetic stimulation (TMS) features of corticospinal dysfunction were a useful predictor of subsequent progression (p=0.01). One patient with lower limb onset developed conduction block with weakness in an upper limb nine years after presentation, and this upper limb weakness responded to IVIg therapy. This adult-onset European group of patients is different as compared with juvenile-onset Asian cases. The clinical syndromes appear heterogeneous, but neurophysiological investigations, in particular TMS, can be helpful in determining prognosis. Multifocal motor neuropathy should be considered when there is progression, even years after onset.

Spatial Profiling of the Corticospinal Tract in Amyotrophic Lateral Sclerosis Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE

Diffusion tensor imaging (DTI) was used as a noninvasive method to evaluate the anatomy of the corticospinal tract (CST) and the pattern of its degeneration in amyotrophic lateral sclerosis (ALS).

METHODS

Fourteen patients with ALS and 15 healthy controls underwent DTI. Parameters reflecting coherence of diffusion (fractional anisotropy, FA), bulk diffusion (apparent diffusion coefficient, ADC), and directionality of diffusion (eigenvalues) parallel to (lambda( parallel)) or perpendicular to (lambda( perpendicular)) fiber tracts were measured along the intracranial course of the CST.

RESULTS

FA and lambda( parallel) increased, and ADC and lambda( perpendicular) decreased progressively from the corona radiata to the cerebral peduncle in all subjects. The most abnormal finding in patients with ALS was reduced FA in the cerebral peduncle contralateral to the side of the body with the most severe upper motor neuron signs. lambda( parallel) was increased in the corona radiata. Internal capsule FA correlated positively with symptom duration, and cerebral peduncle ADC positively with the Ashworth spasticity score.

CONCLUSION

There is a spatial dependency of diffusion parameters along the CST in healthy individuals. Evidence of intracranial CST degeneration in ALS was found with distinct diffusion changes in the rostral and caudal regions.

Muscle Nogo-a expression is a prognostic marker in lower motor neuron syndromes

OBJECTIVE

A proportion of patients with pure lower motor neuron syndrome (LMNS) progress to amyotrophic lateral sclerosis (ALS). Early detection of this progression is impossible, which delays the patient's access to treatment. Muscle expression of Nogo-A is a new candidate marker of ALS. We tested whether detection of Nogo-A in a muscle biopsy from patients with LMNS predicts progression to ALS.

METHODS

Thirty-three patients who had undergone a muscle biopsy during the diagnostic workup of spinal LMNS were observed for 12 months. Nogo-A expression was measured by Western blot in muscle biopsy samples and compared with the final diagnosis.

RESULTS

Nogo-A expression was detected in 17 patients and was absent in 16 patients. The detection of Nogo-A in muscle biopsy samples from LMNS patients correctly identified patients who further progressed to ALS with 91% accuracy, 94% sensitivity, and 88% specificity. In patients who later developed typical ALS, Nogo-A may be detected as early as 3 months after the onset of symptoms.

INTERPRETATION

Nogo-A test is able to identify ALS early in the course of the disease when diagnosis is difficult, requiring further progression. Use of the test in clinical practice may shorten the delay before introduction of neuroprotective drugs or inclusion in clinical trials.

Differential expression of molecular motors in the motor cortex of sporadic ALS

The molecular mechanisms underlying the selective neurodegeneration of motor neurons in amyotrophic lateral sclerosis (ALS) are inadequately understood. Recent breakthroughs have implicated impaired axonal transport, mediated by molecular motors, as a key element for disease onset and progression. The current work identifies the expression of 15 kinesin-like motors in healthy human motor cortex, including three novel isoforms. Our comprehensive quantitative mRNA analysis in control and sporadic ALS (SALS) motor cortex specimens detects SALS-specific down-regulation of KIF1Bbeta and novel KIF3Abeta, two isoforms we show to be enriched in the brain, and also of SOD1, a key enzyme linked to familial ALS. This is accompanied by a marked reduction of KIF3Abeta protein levels. In the motor cortex KIF3Abeta localizes in cholinergic neurons, including upper motor neurons. No mutations causing splicing defects or altering protein-coding sequences were identified in the genes of the three proteins. The present study implicates two motor proteins as possible candidates in SALS pathology.

Altered cortical activation during a motor task in ALS. Evidence for involvement of central pathways

OBJECTIVE

To test the hypothesis that patients with amyotrophic lateral sclerosis (ALS) show increased cortical activation during a motor task compared to both healthy controls and patients with muscle weakness due to peripheral lesions.

METHODS

Functional magnetic resonance imaging (fMRI) was used to measure activation during a block design paradigm contrasting right hand movements against rest in sixteen patients with ALS, seventeen healthy controls and nine patients with peripheral lesions. The groups were matched for age and gender and the two patient groups were matched for their degree of upper limb weakness. Analysis used a non-parametric approach to perform a 3 way hypothesis-driven comparison between the groups.

RESULTS

During the motor task, patients with ALS showed increased cortical activation bilaterally, extending from the sensorimotor cortex [Brodmann areas (BA) 1, 2, 4] posteriorly into the inferior parietal lobule (BA 40) and inferiorly to the superior temporal gyrus (BA 22) when compared to peripheral lesion patients and controls. In addition, ALS patients showed reduced activation in the dorsolateral prefrontal cortex (DLPFC) extending to anterior and medial frontal cortex (BA 8, 9, 10, 32).

CONCLUSIONS

We conclude that alterations in cortical function in ALS differ in sensorimotor and prefrontal regions. Importantly, we have shown that these changes do not reflect confounding by weakness or task difficulty, but are likely to be related to upper motor neuron pathology in ALS.

Pathways and genes differentially expressed in the motor cortex of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal disorder caused by the progressive degeneration of motoneurons in brain and spinal cord. Despite identification of disease-linked mutations, the diversity of processes involved and the ambiguity of their relative importance in ALS pathogenesis still represent a major impediment to disease models as a basis for effective therapies. Moreover, the human motor cortex, although critical to ALS pathology and physiologically altered in most forms of the disease, has not been screened systematically for therapeutic targets.

RESULTS

By whole-genome expression profiling and stringent significance tests we identify genes and gene groups de-regulated in the motor cortex of patients with sporadic ALS, and interpret the role of individual candidate genes in a framework of differentially expressed pathways. Our findings emphasize the importance of defense responses and cytoskeletal, mitochondrial and proteasomal dysfunction, reflect reduced neuronal maintenance and vesicle trafficking, and implicate impaired ion homeostasis and glycolysis in ALS pathogenesis. Additionally, we compared our dataset with publicly available data for the SALS spinal cord, and show a high correlation of changes linked to the diseased state in the SALS motor cortex. In an analogous comparison with data for the Alzheimer's disease hippocampus we demonstrate a low correlation of global changes and a moderate correlation for changes specifically linked to the SALS diseased state.

CONCLUSION

Gene and sample numbers investigated allow pathway- and gene-based analyses by established error-correction methods, drawing a molecular portrait of the ALS motor cortex that faithfully represents many known disease features and uncovers several novel aspects of ALS pathology. Contrary to expectations for a tissue under oxidative stress, nuclear-encoded mitochondrial genes are uniformly down-regulated. Moreover, the down-regulation of mitochondrial and glycolytic genes implies a combined reduction of mitochondrial and cytoplasmic energy supply, with a possible role in the death of ALS motoneurons. Identifying candidate genes exclusively expressed in non-neuronal cells, we also highlight the importance of these cells in disease development in the motor cortex. Notably, some pathways and candidate genes identified by this study are direct or indirect targets of medication already applied to unrelated illnesses and point the way towards the rapid development of effective symptomatic ALS therapies.

Predictors of delay in the diagnosis and clinical trial entry of amyotrophic lateral sclerosis patients: A population-based study

BACKGROUND

The El Escorial and the revised Airlie House diagnostic criteria for amyotrophic lateral sclerosis (ALS) were introduced to select patients for clinical trials. Heterogeneity of clinical presentation at onset and delay in diagnosis may decrease the likelihood for trial entry.

OBJECTIVE

Identify risk factors for delay in the diagnosis and trial exclusion.

METHODS

ALS incident cases were identified with El Escorial (EEC) and Airlie House criteria (AHC) through a population-based registry established in Puglia, Southern Italy, in the years 1998-99.

RESULTS

130 ALS incident cases were diagnosed with a median interval between onset of symptoms and diagnosis of 9.3 months and not different across both EEC and AHC categories. Twenty percent of cases were not eligible for clinical trials according to the AHC. About 5% of subjects in this series died with only lower motor neuron signs. Predictors for delay in the diagnosis were age between 65 and 75 years and spinal onset while fasciculations and cramps as first symptoms were predictors of exclusion from trials.

CONCLUSIONS

In this population-based series, diagnostic delay was longer in subjects with spinal onset and age between 65 and 75 and fasciculation as first symptoms. About 80% of incident cases were trial eligible with AHC criteria. However, a significant number of subjects with ALS, characterized by a limited spread of signs, were not trial eligible while alive.

Upper motor neuron involvement in X-linked recessive bulbospinal muscular atrophy

OBJECTIVE

Clinicopathological findings of X-linked recessive bulbospinal muscular atrophy (SBMA) are indicative of lower motor neuron and primary sensory neuron involvement. The aim of our study was to investigate the presence of subclinical upper motor neuron (UMN) dysfunction in this disease.

METHODS

Two siblings with clinical presentation, routine electrophysiological tests, histopathological features of muscle and nerve biopsies and genetic testing consistent with diagnosis of SBMA underwent transcranial magnetic stimulation (TMS). The analysed parameters were motor evoked potential (MEP) threshold, silent period (SP) and central motor conduction time. Intracortical inhibition with paired pulses from 1 to 6ms interstimulus intervals (ISIs) was evaluated in the older brother.

RESULTS

MEP parameters were significantly altered in limb and cranial muscles and MEP suppression after paired stimulation significantly reduced in the older brother. MEP abnormalities were present in one lower limb, but SP abolished in all limbs, in the younger brother.

CONCLUSIONS

Subclinical involvement of UMNs may be present in patients affected by SBMA. This finding suggests that the array of neuronal systems whose function may be affected by the pathogenic process of SBMA is larger than it was considered so far.

SIGNIFICANCE

TMS is a sensitive diagnostic tool for the identification of UMN dysfunction and should be included in the diagnostic evaluation of patients with SBMA.

Recent advances in the genetics of amyotrophic lateral sclerosis and frontotemporal dementia: common pathways in neurodegenerative disease

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease classically defined by the impairment of the voluntary motor system and ubiquitin-positive intraneuronal aggregates in anterior horn cells. Frontotemporal dementia (FTD) is a common form of neurodegenerative dementia and presents with personality change associated in a significant subgroup of patients with cortical ubiquitin-only neuropathology (FTD-U). Careful study of ALS as well as FTD patient cohorts suggests clinical as well as pathological overlap of ALS with FTD. The idea that this reflects a shared pathogenesis has received strong support from the identification of new genetic loci on chromosome 9p and of mutations in specific genes (CHMP2B and DCN1) in families with co-segregation of ALS and FTD. The identification of two further genetic causes of FTD-U with (rare) ALS (PGRN) or without ALS (VCP) also provides a starting point for exploring the pathways associated with ubiquitin-mediated protein mishandling in FTD-U and ALS. Pure ALS, through ALS with cognitive impairment and ALS-FTD to pure FTD-U, may represent a continuous spectrum of ubiquitin-associated neurodegenerative disease.

Cerebral degeneration predicts survival in amyotrophic lateral sclerosis

OBJECTIVE

To determine the relationship of cerebral degeneration with survival in amyotrophic lateral sclerosis (ALS).

METHODS

Patients with probable or definite ALS underwent magnetic resonance spectroscopic imaging (MRSI) of the brain between July 1996 and May 2002, and were followed prospectively until March 2004. Creatine (Cr), choline (Cho) and the neuronal marker N-acetylaspartate (NAA) were quantified as ratios in the motor cortex.

RESULTS

In 63 patients compared with 18 healthy people, NAA/Cho was reduced by 13% (p<0.001), NAA/Cr was reduced by 5% (p = 0.01) and Cho/Cr was increased by 8% (p = 0.01). NAA/Cho was used for survival analysis, given its larger effect size and superior test accuracy (a sensitivity of 67% and a specificity of 83%). Median survival after MRSI was 24 months. Multivariate analysis showed reduced survival for lower NAA/Cho (hazard ratio (HR) 0.24, 95% confidence interval (CI) 0.08 to 0.72, p = 0.01), older age (HR 1.03, 95% CI 1.00 to 1.06, p = 0.04) and shorter symptom duration (HR 0.96, 95% CI 0.93 to 0.99, p = 0.01). Patients with NAA/Cho <2.11 had a reduced survival of 19.4 v 31.9 months (HR 2.05, 95% CI 1.12 to 4.03, p = 0.02).

CONCLUSIONS

Cerebral degeneration is predictive of reduced survival in ALS.

Amyotrophic Lateral Sclerosis: Diffusion-Tensor and Chemical Shift MR Imaging at 3.0 T

PURPOSE

To prospectively determine whether diffusion-tensor magnetic resonance (MR) imaging in conjunction with two-dimensional chemical shift imaging can assist in identifying upper motor neuron involvement and whether disease severity and duration can be predicted based on imaging parameters in patients with amyotrophic lateral sclerosis (ALS).

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. Fifteen patients with ALS (12 men, three women; mean age, 57.3 years) with clinical evidence of upper motor neuron involvement and 10 healthy control subjects (five men and five women; mean age, 49.4 years) were studied. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured from the corticospinal tracts at the level of the internal capsule. Average N-acetylaspartate (NAA)/creatine-phosphocreatine (Cr) and NAA/choline-containing compounds (Cho) ratios were calculated from the precentral gyrus. Student t test, multiple linear regression analysis, and Spearman correlation coefficients were employed to quantify relationships between imaging and clinical parameters.

RESULTS

Patients with ALS exhibited significantly reduced FA values and NAA/Cr and NAA/Cho ratios compared with values in control subjects (P<.05) for both affected and nonaffected sides of the brain. ADC was elevated significantly in the affected side (P<.05) and was an independent predictor of disease duration after adjusting for age; however, FA values and NAA/Cr ratios for the affected side were even stronger predictors of disease duration. Moderate but statistically significant correlation was found between the FA values for the affected side and the ALS Functional Rating Scale Revised (ALSFRS-R) score (r=0.51, P<.05). The NAA/Cr ratio also correlated with both the ALSFRS-R and upper motor neuron scores (r=0.50 and 0.54, respectively; P<.05).

CONCLUSION

Diffusion-tensor and two-dimensional chemical shift MR imaging spectroscopy can be used to identify upper motor neuron involvement and predict disease duration in patients with ALS.

Motor neuron disease in a patient with a mitochondrial tRNAIlemutation

OBJECTIVE

Motor neuron disease (MND) is a common neurodegenerative condition for which the underlying cause is uncertain in many patients. We identified a patient with clinical features suggestive of MND but additional cardiac and metabolic symptoms. We wished to determine if the clinical features were due to a mitochondrial DNA mutation.

METHODS

The brain and spinal cord were studied using neuropathological techniques and agenetic defect investigated in individual neurons.

RESULTS

There were atypical neuropathological features and genetic studies identified a pathogenic, heteroplasmic mitochondria tRNA(Ile) (4274T>C) mutation.

INTERPRETATION

This case adds to the phenotypic variation seen in mitochondrial DNA disease but also highlights the potential role of mitochondrial dysfunction in the cause of MND.

Diagnostic investigation and multidisciplinary management in motor neuron disease

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. ALS is a progressive neurodegenerative disorder, involving motor neurons in the cerebral cortex, brainstem and spinal cord, presenting with a combination of upper and lower motor neuron signs. Etiology remains undetermined, although a multifactorial origin is widely accepted including genetic factors, auto-immunity, oxidative stress, glutamate excitotoxicity and abnormal neurofilament aggregation. The absence of specific diagnostic testing, and variable clinical presentations make the diagnosis of ALS challenging, relying upon correlation of clinical, electrophysiological and neuroimaging data. The disease is relentlessly progressive, with dysarthria, dysphagia, tetraparesis, and respiratory insufficiency due to ongoing respiratory muscle paresis. There is no specific treatment for ALS. Riluzole, a glutamate antagonist, is the only FDA approved drug for ALS, but has only a modest effect on survival. The multiplicity and progressiveness of the disabilities in ALS, highlights the need for a coordinated multidisciplinary rehabilitation program managing symptoms, respiratory care, dysphagia and nutrition, dysarthria and communication, physical and occupational therapy. The main goals are to prolong independence, prevent complications and improve quality of life.

Diffusion-tensor MR imaging of corticospinal tract in amyotrophic lateral sclerosis and progressive muscular atrophy

PURPOSE

To prospectively evaluate several diffusion-tensor magnetic resonance (MR) imaging indexes (mean diffusivity [MD], fractional anisotropy [FA], and eigenvalues) of corticospinal tract impairment in patients with progressive muscular atrophy (PMA) and patients with amyotrophic lateral sclerosis (ALS).

MATERIALS AND METHODS

This study had institutional review board approval, and written informed consent was obtained from all subjects. Eight male patients with PMA (mean age, 63 years +/- 13 [standard deviation]), eighteen patients with ALS (14 men and four women; mean age, 64 years +/- 7), and twelve control subjects (four men and eight women; mean age, 65 years +/- 6) underwent diffusion-tensor MR imaging at which 25 spin-echo echo-planar imaging diffusion-weighted images (b = 1000 sec/mm2) were acquired along noncollinear directions. MD and FA were measured along the corticospinal tracts in each patient and subject. Changes in diffusion along and orthogonal to fiber bundles in patients were evaluated by using diffusion-tensor eigenvalues. Differences in diffusion-tensor imaging indexes between patients with PMA and those with ALS, as compared with these indexes in control subjects, were evaluated with Mann-Whitney testing. Correlations between diffusion-tensor imaging indexes and clinical variables were estimated with Pearson and Spearman rank correlation testing.

RESULTS

As compared with MD (697.1 x 10(-6) mm2/sec +/- 28.1) and FA (0.585 +/- 0.032) in control subjects, MD was typically significantly increased (734.7 x 10(-6) mm2/sec +/- 41.2, P = .035) and FA significantly decreased (0.534 +/- 0.053, P = .037) along the corticospinal tracts in patients with ALS, while these parameters showed no significant change in patients with PMA (MD, 707.0 x 10(-6) mm2/sec +/- 44.2; FA, 0.559 +/- 0.028). Estimation of diffusion-tensor eigenvalues revealed normal diffusion along fiber tracts in all patients, while diffusion was increased orthogonal to fiber tracts only in patients with typical ALS. In patients with ALS, MD correlated with disease duration while FA correlated with disease severity.

CONCLUSION

Diffusion-tensor MR imaging reveals corticospinal tract impairment in ALS but not in PMA.

Incidence of amyotrophic lateral sclerosis in southern Italy: a population based study

BACKGROUND

While the incidence of amyotrophic lateral sclerosis (ALS) is similar across the world (range, 1.0 to 2.5/100,000), a latitude gradient from north to south has been observed.

OBJECTIVE

To determine the incidence of ALS in Puglia, a region of south eastern Italy, and to test the latitude gradient hypothesis comparing the present study with findings in studies conducted with the same design in a northern latitude.

METHODS

Puglia (4,086,613 residents in 2001) is the site of a multicentre-multisource prospective population based registry established in 1997. All incident ALS cases during the period 1998-99 were enrolled and followed up. Cases were classified using the first and the revised El Escorial criteria.

RESULTS

During the study period 130 cases were enrolled. The annual crude incidence for ALS in Puglia for the two year period 1998-99 was 1.6/100,000 (95% confidence interval, 1.3 to 1.9). The incidence was higher for men (incidence rate (IR) = 2.1 (1.7 to 2.7) than for women (IR = 1.2 (0.9 to 1.5)) in all age groups, with a male to female ratio of 1.6. For both men and women, the incidence increased through age 75 and declined rapidly afterwards. The mean annual incidence adjusted by age and sex to the 2001 Italian population was 1.7/100,000 (1.4 to 2.0).

CONCLUSIONS

ALS incidence is within a narrow range across countries, with a peak between 65 and 75 years and a higher incidence in men. A north to south latitude gradient of ALS incidence is not supported by the results of cohort studies.

MR-Pathologic Comparison of the Upper Spinal Cord in Different Motor Neuron Diseases

This MRI study was performed to evaluate in vivo alterations of the spinal cord in defined subgroups of motor neuron diseases. Standard MRI examinations of the cervical and thoracic spinal cord in sporadic amyotrophic lateral sclerosis (ALS; n = 39), sporadic lower motor neuron disease (LMND; n = 19), Kennedy's disease (KD; n = 19) and a control group (n = 96) were analyzed with respect to spinal cord signal changes and the thickness of the spinal cord. No significant changes in thickness or signal alterations were observed when comparing ALS, LMND and control groups with one another. However, in KD patients significant upper spinal cord atrophy was detected at the cervical level as compared with all other groups. At the thoracic level, KD patients had significant upper cord atrophy as compared with controls and LMND. Marked atrophy of the upper spinal cord seems to be a feature of the KD-associated central-peripheral distal axonopathy.

Assessment of disease progression in motor neuron disease

Motor neuron disease (MND) is characterised by progressive deterioration of the corticospinal tract, brainstem, and anterior horn cells of the spinal cord. There is no pathognomonic test for the diagnosis of MND, and physicians rely on clinical criteria-upper and lower motor neuron signs-for diagnosis. The presentations, clinical phenotypes, and outcomes of MND are diverse and have not been combined into a marker of disease progression. No single algorithm combines the findings of functional assessments and rating scales, such as those that assess quality of life, with biological markers of disease activity and findings from imaging and neurophysiological assessments. Here, we critically appraise developments in each of these areas and discuss the potential of such measures to be included in the future assessment of disease progression in patients with MND.

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.

Familial amyotrophic lateral sclerosis with His46Arg mutation in Cu/Zn superoxide dismutase presenting characteristic clinical features and Lewy body-like hyaline inclusions

We evaluated the characteristic clinical features of one family of familial amyotrophic sclerosis (FALS) with a His46Arg mutation in the enzyme Cu/Zn superoxide dismutase (SOD1). Codon 46 encodes the binding site for copper and the His46Arg mutation may result in decreased copper binding and copper toxicity. The disease duration of this family was 17.8+/-13.2 years (mean+/-S.D.) with the age at onset being 42.9+/-4.7 years old (mean+/-S.D.). The initial sign was distal weakness of the unilateral lower limb, extending to the other lower limb. An autopsy was performed on a 62-year-old female member of the family who had the mutation. Her disease duration was 23 years, and she died of tonsillar herniation caused by metastasis of colon cancer in the cerebellum. Neuropathological findings showed marked loss of large anterior horn cells and very mild degeneration of corticospinal tracts as well as posterior columns. The number of nuclei of Clark's column was reduced. Lewy body-like hyaline inclusion bodies (LBHIs) were frequently seen in the remaining anterior horn cells. Astrocytic hyaline inclusions (Ast-HIs) were also seen. This is the first autopsy report of FALS with a His46Arg mutation presenting neuronal LBHIs and Ast-HIs. The formation of LBHIs and Ast-HIs may be dependent on the phenotype of the preferential lower motor neuron involvement in FALS with a SOD mutation and long disease duration.

A polymorphism in the poliovirus receptor gene differs in motor neuron disease

Poliovirus has been implicated in the etiology of sporadic motor neuron disease. DNA polymorphisms in the poliovirus receptor gene (PVR) are associated with persistent poliovirus infection in cell culture. PVR DNA polymorphisms were therefore studied in 110 cases of amyotrophic lateral sclerosis, 30 cases of progressive muscular atrophy (a disorder of lower motor neurons) and 280 normal controls. In exon 2 of PVR the heterozygous Ala67Thr change was detected in 20.0% of progressive muscular atrophy, 11.8% of amyotrophic lateral sclerosis and 6.8% of control subjects. The frequency of the polymorphism was significantly higher in patients with progressive muscular atrophy than in controls. Differences in the poliovirus receptor gene may result in slowly progressive viral cytopathic effects that lead to lower motor neuron forms of motor neuron disease.