The central nervous system in motor neurone disease

Transgenic mouse models of Alzheimer's disease and amyotrophic lateral sclerosis

Over the past several years, there has been enormous progress in generating transgenic mice that model aspects of human neurodegenerative diseases. These studies build upon the efforts of molecular geneticists who have identified a number of genes that, when mutated, cause familial forms of these diseases. In this review, we focus on the mutations that cause familial forms of Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), and transgenic mouse models that develop clinical and pathological abnormalities resembling those occurring in the human diseases.

Sympathetic skin response in amyotrophic lateral sclerosis

OBJECTIVES

The aim of our study was to verify the usefulness of the sympathetic skin response (SSR) as an instrument for assessing autonomic involvement in amyotrophic lateral sclerosis (ALS).

MATERIAL AND METHODS

- We studied palmar and plantar SSR in 31 patients with ALS (mean age: 58.4+/-9.3 years); 48 age-matched healthy subjects constituted the control group.

RESULTS

Palmar SSR was elicitable in all patients, and its latency and amplitude did not significantly differ from that of the controls. Plantar response was evoked in all but 7 patients. The lack of response was significantly related to the functional disability and duration of the disease.

CONCLUSIONS

We conclude that SSR, even the plantar response, cannot be considered a useful tool for detecting early autonomic involvement in ALS.

Diagnosis of amyotrophic lateral sclerosis

This review of the differential diagnosis of amyotrophic lateral sclerosis focuses on two themes. The first is practical, how to establish the diagnosis based primarily on clinical findings buttressed by electrodiagnosis. The main considerations are multifocal motor neuropathy and cervical spondylotic myelopathy. The second theme is the relationship of motor neuron disease to other conditions, including benign fasciculation (Denny-Brown, Foley syndrome), paraneoplastic syndromes, lymphoproliferative disease, radiation damage, monomelic amyotrophy (Hirayama syndrome), as well as an association with parkinsonism, dementia and multisystem disorders of the central nervous system.

Neuronal pathology in the wobbler mouse brain revealed by in vivo proton magnetic resonance spectroscopy and immunocytochemistry

Proton magnetic resonance spectroscopy (1H-MRS) was used to measure the in vivo signal of N-acetylaspartate (NAA), a putative neuronal marker, in the brain of the mutant wobbler mouse, a model of motor neuron disease. The ratio of NAA to creatine-phosphocreatine, an internal standard, was significantly lower in five affected wobbler mice (0.79+/-0.05; mean+/-s.d.) than in five unaffected littermates (0.98+/-0.10, p = 0.006). Ubiquitin and phosphorylated heavy neurofilament immunoreactivities were increased in cortical neurons of affected animals. This is the first demonstration of cerebral neuronal pathology in the wobbler mouse, supporting its use as a model of amyotrophic lateral sclerosis. In vivo IH-MRS and correlative postmortem study of wobbler mouse brain will allow temporal monitoring of neuronal degeneration and responsiveness to neuroprotective pharmacotherapies.

Limited corticospinal tract involvement in amyotrophic lateral sclerosis subjects with the A4V mutation in the copper/zinc superoxide dismutase gene

We examined 11 subjects with inherited amyotrophic lateral sclerosis (familial amyotrophic lateral sclerosis, FALS) associated with the most common copper/zinc superoxide dismutase 1 (SOD1) mutation, an alanine for valine substitution in codon 4 (A4V). Autopsies were performed on 5 subjects. The clinical and pathological findings are described and compared with those of 9 sporadic ALS (SALS) subjects. There was no clinical evidence of upper motor neuron (UMN) involvement in 10 FALS A4V subjects. All subjects had lower motor neuron (LMN) signs and electrophysiological evidence of denervation in at least three limbs. All SALS subjects had signs of both UMN and LMN involvement. Pathological studies found severe abnormalities of LMNs in all FALS and SALS subjects. UMN involvement was either absent or mild in the A4V SOD1 FALS subjects and severe in the SALS subjects. Pathological abnormalities in systems other than the motor neurons were more frequent in the FALS A4V subjects. This information suggests that current diagnostic criteria for ALS, requiring dinical evidence for both upper and lower motor neuron involvement, should be modified; ie, the diagnosis should be deemed established when there is evidence of denervation in three or more limbs and a mutation in the gene for SOD1, even without dinical signs of UMN involvement.

Amyotrophic lateral sclerosis: current issues in classification, pathogenesis and molecular pathology

The classification of amyotrophic lateral sclerosis (ALS) is reconsidered in the light of developments in the molecular pathogenesis and histopathology of the condition. A current view is encapsulated in the El Escorial World Federation of Neurology criteria for the diagnosis of ALS. While intended for research purposes, use of these criteria for entry into clinical trials may result in the exclusion of some patient groups with related disorders that are likely to share aetiological mechanisms but which are not classified as 'definite ALS' or 'probable ALS'. The relationship between ALS and the more restricted motor disorders of progressive lateral sclerosis and progressive muscular atrophy, together with cerebral degenerations including ALS-dementia and ALS-related frontal lobe dementia, are reviewed. The possibility is raised that they all represent syndromic manifestations of a similar pathogenetic cascade whose clinical phenotype depends upon the anatomical selectivity of involvement in each individual. The new evidence regarding the central role of oxidative stress and abnormal glutamatergic neurotransmission in familial and sporadic ALS seem applicable across these disorders. New evidence regarding the molecular pathology of inclusion bodies in these various syndromes, including ubiquitinated inclusions and hyaline conglomerate inclusions, shows striking similarities between them. Marked differences in the anatomical distribution of lesions determine the predominance and type of motor and cognitive features in each syndrome. This concept of a clinicopathological spectrum is potentially of equal relevance to other late onset neurodegenerative disorders including multisystem atrophies, the Lewy body disorders and various manifestations of Alzheimer's disease. It will gain increasing importance as therapies evolve from the symptomatic to those directed at underlying pathogenetic events.

Linkage of the gene for an autosomal dominant form of juvenile amyotrophic lateral sclerosis to chromosome 9q34

We performed genetic mapping studies of an 11-generation pedigree with an autosomal dominant, juvenile-onset motor-systems disease. The disorder is characterized by slow progression, distal limb amyotrophy, and pyramidal tract signs associated with severe loss of motor neurons in the brain stem and spinal cord. The gene for this disorder, classified as a form of juvenile amyotrophic lateral sclerosis (ALS), is designated "ALS4." We performed a genomewide search and detected strong evidence for linkage of the ALS4 locus to markers from chromosome 9q34. The highest LOD score (Z) was obtained with D9S1847 (Z=18.8, recombination fraction of .00). An analysis of recombinant events identified D9S1831 and D9S164 as flanking markers, on chromosome 9q34, that define an approximately 5-cM interval that harbors the ALS4 gene. These results extend the degree of heterogeneity within familial ALS syndromes, and they implicate a gene on chromosome 9q34 as critical for motor-neuron function.

Degeneration of the pyramidal tracts in patients with amyotrophic lateral sclerosis. A premortem and postmortem magnetic resonance imaging study

To investigate focal hyperintensity in the internal capsule (IC) on magnetic resonance images (MRIs) and its clinical significance, 80 patients with amyotrophic lateral sclerosis (ALS) and 80 sex- and age-matched normal control subjects were studied. On T2-weighted images, hyperintense foci were found in the posterior part of the posterior limb (PL) of the IC in 41 (51%) of 80 control subjects. However, no subject showed increased signal intensities on proton density-weighted images. Hyperintense foci were also observed in the posterior part of the PL of the IC on T2-weighted images in 52 (65%) of 80 ALS patients and on proton density-weighted images in 26 (65%) of 40 ALS patients; the abnormally intense foci were seen at the same anatomical location in the IC as those in the normal control subjects. On postmortem MRI, the abnormally intense foci were found in the posterior part of the PL of the IC in the formalin-fixed brains from 9 ALS patients. Three normal control subjects did not show signal intensity changes on postmortem MRI. On histological examination of 9 ALS brains, distinct myelin pallor and gliosis were found in the posterior third of the PL of the IC. Proton density-weighted images appear to be useful to distinguish neuropathological changes in the corticospinal tract of ALS patients.

Cognitive function in amyotrophic lateral sclerosis

Cognitive function in patients with amyotrophic lateral sclerosis (ALS) has drawn recent attention. However, the pathogenesis of cognitive dysfunction in patients with ALS remains uncertain. To explore the underlying mechanism for cognitive dysfunction further, we studied 26 patients with ALS (15 male and 11 female; age from 36 to 67 years) by using neuropsychological batteries, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). We also evaluated these patients and an additional 26 age- and sex-matched normal controls using neuropsychological batteries with special attention to the frontal lobe function. On the basis of neuropsychological examination, we classified patients into three groups using cluster analysis. Age, education level and severity were comparable across these subgroups. Neuropathologic examination was subsequently carried out in six patients. Patients in Group 1 and 2 had low scores on all measures compared to patients in Group 3 and normal controls. Patients in Group 1 and 2 had frontal atrophy on MRI and reduced isotope uptake in the frontal region on SPECT, which was more evident in patients in Group 1. On neuropathologic examination, patients in Group 1 showed spongy degeneration and neuronal loss in the frontal lobe. Patients in Group 3 showed no notable pathology in the frontal region. The gradient distribution of the scores for attention and executive function, as well as SPECT findings suggested the presence of a continuum of cognitive disability in patients with ALS corresponding to the pathologic process in the frontal lobe ranging from significant impairment to normality. We, therefore, believe that inattention and executive dysfunction alternatives may evolve in patients with ALS corresponding to the pathologic process in the frontal lobe.

Brain and spinal cord MRI in motor neuron disease

Images

Neuropathology of sporadic amyotrophic lateral sclerosis of long duration

We performed post-mortem examinations of three patients with progressive neurogenic amyotrophy of long duration. One patient had been clinically diagnosed as having sporadic amyotrophic lateral sclerosis (ALS) and two had been diagnosed with progressive spinal muscular atrophy (PSMA). The disease durations were 10, 17 and 20 years, respectively, and all of the patients died of respiratory failure with no artificial respiratory support. In all of the patients, both the upper and lower motor neuron systems were affected; degeneration of the former was definite, but was milder than that usually encountered in sporadic ALS patients, and the histopathology of the latter was identical to that of sporadic ALS. Light microscopy revealed Bunina bodies, which are characteristic of sporadic ALS, in the remaining anterior horn cells of each patient. In addition, ubiquitin-positive skein-like inclusions were also identified, immunohistochemically, in the remaining anterior horn cells of each patient. Neuron counts indicated that the number of neurons was preserved in Clarke's column in these patients, but was significantly reduced in the intermediolateral nucleus, compared with control subjects. Based on these findings, we think that these three patients, with long disease durations, were affected by essentially the same underlying disease process as that of sporadic, classical ALS. Moreover, we question the neuropathological occurrence of sporadic ALS without involvement of the upper motor neuron system, namely, pure PSMA or lower motor neuron disease.

High signal intensity on T1 weighted MRI of the anterolateral column of the spinal cord in amyotrophic lateral sclerosis

OBJECTIVE

To investigate MRI abnormalities in patients with amyotrophic lateral sclerosis.

METHODS

Fourteen patients with amyotrophic lateral sclerosis underwent MRI of the head and spinal cord using T1 and T2 weighted images. Forty age matched controls (29 with other neurological diseases, 11 with non-neurological diseases) underwent MRI of the cervical spinal cord using T1 and T2 weighted images.

RESULTS

In all the control patients, the signal intensity of the posterior column was equal or slightly hypointense compared with the anterolateral column of the cervical spinal cord on T1 weighted images. However, eight of 14 patients with amyotrophic lateral sclerosis showed pronounced high signal intensity in the anterolateral column of the spinal cord on T1 weighted MRI, which also disclosed high signal intensity of the intracranial corticospinal tract in two of the 14 patients. T2 weighted MRI demonstrated high signal intensity of the lateral corticospinal tract of the spinal cord in two, high signal intensity of the intracranial corticospinal tract in five, and low signal intensity of the motor cortex in six of the 14 patients. Two of the 14 patients showed no abnormal findings on MRI.

CONCLUSIONS

High signal intensity of the anterolateral column of the spinal cord of patients with amyotrophic lateral sclerosis is a new imaging abnormality and may be useful for the diagnosis of this disease.

Local cerebral blood flow in motor neuron disease: correlation with clinical findings

Local cerebral blood flow (CBF) measured by xenon-enhanced CT was correlated with the clinical findings in 21 patients with motor neuron disease (mean +/- SD age, 60 +/- 10 years). In 11 patients, CBF was also measured after intravenous injection of 2 mg thyrotropin releasing hormone (TRH). There were no significant differences in CBF of the cerebral cortex, basal ganglia, thalamus, and subcortical white matter with respect to age, duration of illness, or presence (n = 9) or absence (n = 12) of bulbar palsy. In patients with upper motor neuron disturbance (n = 10), however, local CBF in the frontal cortex was significantly lower (p < 0.05) than in those without it (n = 11). Within the frontal cortex, CBF reduction was marked in the upper posterolateral part (p < 0.05) that included the motor and premotor areas. Intravenous administration of TRH did not significantly alter the local CBF in any of the brain regions examined. An additional patient with motor neuron disease and severe dementia showed marked CBF reduction in the frontal lobe, which was in common with but much greater than the reduction in those exhibiting subcortical dementia (e.g., progressive supranuclear palsy). We conclude that in motor neuron disease patients with upper motor neuron involvement, the selective reduction of CBF in brain regions that include primary motor and premotor areas may reflect functional disturbance or neuronal degeneration in these regions. The ameliorating effect of TRH in patients with motor neuron disease, if any, appears not to be related to increases in local CBF or activation of brain function.

Prevalence and correlates of neuropsychological deficits in amyotrophic lateral sclerosis

OBJECTIVE

To determine the prevalence and correlates of neuropsychological impairment in a large cohort (n = 146) of patients with typical, sporadic (non-familial) amyotrophic lateral sclerosis.

METHODS

A battery of neuropsychological tests was administered to patients with amyotrophic lateral sclerosis who were attending a monthly outpatient clinic or who were in hospital undergoing diagnostic tests.

RESULTS

Comparing individual patient's scores with relevant normative data, 35.6% of the patients displayed evidence of clinically significant impairment, performing at or below the 5th percentile on at least two of the eight neuropsychological measures. Deficits were most common in the areas of problem solving, attention/mental control, continuous visual recognition memory, word generation, and verbal free recall. Impairment was most prevalent in patients with dysarthria (48.5%), but 27.4% of non-dysarthric patients were also impaired. Impaired patients had more severe or widespread symptoms of amyotrophic lateral sclerosis than non-impaired patients, and had fewer years of education.

CONCLUSION

Neither the conventional wisdom that cognition is intact in nearly all patients with amyotrophic lateral sclerosis, nor more recent suggestions that cognition is often at least mildly impaired seems to be correct. A minority of patients with amyotrophic lateral sclerosis displayed evidence of significant impairment. Dysarthria, low education, and greater severity of motor symptoms were risk factors for impairment.

Brain and spinal cord MRI in motor neuron disease

Motor neuron disease causes widespread degeneration of motor neurons within both the brain and spinal cord. Brain and spinal cord MRI were performed in 11 patients with motor neuron disease, and in 17 controls. Symmetric areas of high signal within the corticospinal tracts were found in nine patients on T2 weighted spin echo (SE) or fast spin echo (FSE) images of the brain and in eight on T2 or T2* weighed images of the spinal cord. High signal within the posterior limbs of the internal capsules was also found in four controls; this finding in isolation is therefore not pathological. No controls had abnormalities within the spinal cord. Low signal within the motor cortex was found in 10 patients, but was also seen in six controls. Thus MRI often displays characteristic abnormalities within the corticospinal tracts in patients with motor neuron disease, and should be considered in the investigation of suspected cases.

Nonverbal visual attention, but not recognition memory of learning, processes are impaired in motor neurone disease

Pathology outside the motor system is being increasingly recognised in motor neurone disease (MND) and up to 3% of patients may have overt dementia of frontal lobe type; it is not clear whether milder cognitive disturbance is a more frequent feature of the disease. Standard neuropsychological testing can be difficult in MND and we therefore used the microcomputer-controlled Cambridge Neuropsychological Test Automated Battery (CANTAB), which allows accurate assessment in the presence of motor and bulbar dysfunction. The results of subtests evaluating nonverbal visual attention, recognition memory and learning from a large (n = 50) group of patients with MND compared to normal (n = 27) and neurological disease (n = 23) control groups are presented in this report. The MND group showed significant impairment in a focal attention (visual search) task, but no deficits in memory or learning. Inspection of the visual search data showed that up to a quarter of the MND patients scored two or more standard deviations below the mean control score. It is suggested that this reflects pathology in fronto-striatal circuitry.

Cognition, language, and speech in amyotrophic lateral sclerosis: a review

Amyotrophic lateral sclerosis (ALS) is a progressive, adult-onset neurodegenerative disorder manifesting as a relentless loss of motor capabilities and, ultimately, death. Traditionally thought to affect solely the lower motor neurons and corticospinal tracts, recent studies suggest that the pathogenic process of ALS is more extensive, involving dysfunction of cortical grey and white matter with clinical correlates of impairment in cognition and language. The impact of speech and motor deficits are discussed in relation to the issues of assessment of cognition and language. Three case studies are presented for illustrative purposes. Finally, direction for future research to investigate cognitive dysfunction in ALS are presented.

Mouse inoculation studies reveal no transmissible agent in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) resembles the spongiform encephalopathies in its dual pattern of inherited and sporadic cases, its uniform prevalence in different populations, its late onset (suggestive of a long incubation period) and its pathological picture of neuronal degeneration without inflammation. There is a well-established protocol for primary transmission of scrapie and related diseases to mice. Using this, we inoculated four longlived, inbred, mouse strains with cord material fresh-frozen within three hours of death, from a case of ALS or a control case. No motor neuron loss, gliosis or tract demyelination was found in the experimental group. Fifty per cent of each group were observed for more than 600 days. Two types of lesions were found in these animals at death: widespread foci of white matter vacuolation and bilateral thalamic mineral deposits. They were present in the control group at the same incidence and severity as in the experimental group and were thus considered to represent an age-related change. Attention is drawn to them because they have been claimed as significant when found in a transgenic model of spongiform encephalopathy. The results of our carefully-controlled experiment suggest that it is unlikely that ALS is caused by a scrapie-like agent capable of transmission to mice.

Diagnosis in neuromuscular diseases

The diagnosis of neuromuscular diseases can be challenging and successful in the majority of patients, due to advancements in electrophysiology, muscle and nerve biopsy immunohistochemistry, and cytogenetics. This article reviews diverse topics, highlighting these recent achievements, with an emphasis on how they affect the clinical and laboratory diagnosis of specific neuromuscular disorders.

Corpus callosum atrophy in amyotrophic lateral sclerosis

Recent studies have suggested widespread involvement of the cerebral regions other than the primary motor cortex in amyotrophic lateral sclerosis. To investigate atrophy of the corpus callosum as a measure of cerebral pathology, we studied 25 right-handed patients with sporadic amyotrophic lateral sclerosis using magnetic resonance imaging. Five patients had cognitive decline or emotional and personality changes. The ratios of mid-sagittal corpus callosum areas to the midline internal skull surface area on T1-weighted images were analysed. Compared with 25 age- and sex-matched right-handed control subjects, the patients had significantly decreased callosal/skull area ratio, with anterior predominance of the degree of atrophy. The patients with cognitive decline or psychiatric symptoms had substantial atrophy of the anterior fourth of the corpus callosum. These findings suggest that atrophy of the corpus callosum, especially in the anterior half, is present in amyotrophic lateral sclerosis, and that severe atrophy in the anterior fourth is associated with cognitive decline and psychiatric symptoms. Callosal atrophy may reflect the widespread distribution of pathological changes in the cerebral cortex, which are accentuated in the frontal cortex.

Increased sympathetic outflow to muscles in patients with amyotrophic lateral sclerosis: a comparison with other neuromuscular patients

We investigated the effects of muscle loss and limitation of daily activities on sympathetic outflow to muscles by measuring muscle sympathetic nerve activity (MSNA) in 12 patients with amyotrophic lateral sclerosis (ALS) as compared with other 15 neuromuscular patients (controls). The burst incidence of MSNA at rest was significantly higher in patients with ALS, even in elderly patients, compared with controls (p < 0.01). There were no differences in the level of disability, heart rate or blood pressure at rest between two groups. Blood pressure and MSNA were less changed by head-up tilting in patients with ALS compared with controls. MSNA of ALS was not correlated with the disability score, PaO2, PaCO2, forced vital capacity, the disease duration or prognosis. MSNA at rest was increased in ALS patients, regardless of the severity of muscle loss or disability. It might be suggested that autonomic motor neurons seem to become affected by the same pathologic process that kills motor neurons.

Magnetic resonance signal abnormalities along the pyramidal tracts in amyotrophic lateral sclerosis

Magnetic resonance imaging (MRI) studies of the brain were reviewed in 16 patients with amyotrophic lateral sclerosis (ALS), representative of a large and homogeneously studied series, 11 of whom showed signal abnormalities along the pyramidal tracts. These were more frequent in patients with more severe upper motor neuron signs but did not correlate with disease severity. Our study suggests that MRI signal abnormalities along the pyramidal tracts are common in ALS and may reflect the severity of pyramidal tract degeneration.

Magnetic resonance imaging of the corticospinal tracts in amyotrophic lateral sclerosis

In 13 patients with amyotrophic lateral sclerosis (ALS), corticospinal tract lesions on spinal cord, brain and brain stem were examined by MR imaging. In 9 patients, areas of high signal intensity located in the dorsolateral columns coinciding with the lateral corticospinal tracts, were detected on axial T2*-weighted MR imaging of the cervical spinal cord using a gradient echo technique. In two patients, these spinal cord MR abnormalities corresponded well to the postmortem pathological findings of lateral corticospinal tract degeneration. T2-weighted abnormal MR signals along the corticospinal tract at the brain and brain stem were detected in 4 patients, all of whom also showed abnormal signals on cervical cord MR imaging. Four of 13 patients did not show any abnormal signals on brain and brain stem or spinal cord MR imaging. Spinal cord MR imaging provides a useful information regarding upper motor neuron lesions in ALS.

Effects of stimulus velocity and acceleration on smooth pursuit in motor neuron disease

Sinusoidal smooth pursuit eye movements were evaluated in 11 normals, five moderately and four severely affected motor neuron disease (MND) patients, using two target amplitudes and a range of frequencies. This enabled us to examine separately the effects of peak target velocity and acceleration on pursuit gain. Moderately affected patients showed an acceleration, but not a velocity saturation; severely impaired patients' performance declined with increased velocity. Smooth pursuit eye movements are thus impaired in MND, but the nature of this pursuit deficit is complex and changes with the progression of the disease.

Amyotrophic lateral sclerosis with marked neurological asymmetry: clinicopathological study

We attempted to correlate the marked neurological asymmetry observed in two amyotrophic lateral sclerosis patients with their histopathological lesions. Patient 1, a 52-year-old man, developed dysarthria and dysphagia, followed by muscle weakness in the left arm and then of the left leg. Patient 2, a 44-year-old man, developed muscle weakness in the left hand, left leg, tongue with left-sided predominance, right hand and right leg in that order of progression. Both patients exhibited moderate to marked left-sided predominant involvement of the lower motor neuron system, accompanied by retained or hyperactive deep tendon reflexes on the left side in the early stage of their illness. Most of the asymmetry in the lower motor neuron system involvement persisted until the death of the patients. Histopathological examinations, including semiquantitative analysis, revealed that both patients exhibited left-sided predominant degeneration of the lower motor neuron system at those spinal cord levels where the neurological asymmetry was of a moderate to marked degree. In addition left-sided predominant degeneration of the lateral corticospinal tracts was seen in both patients and right-sided predominant involvement of Betz cells in the leg area of the motor cortex of patient 1. This pattern of both the neurological and histopathological asymmetry suggested the probable existence of an intimate somatotopically related linkage between the upper motor neuron system degeneration and lower motor neuron system degeneration in both patients.

Oculomotor function in amyotrophic lateral sclerosis: evidence for frontal impairment

Saccadic eye movements, fixation, and smooth pursuit were recorded in 17 subjects with amyotrophic lateral sclerosis (ALS) and 11 age-matched controls using a magnetic scleral search coil. Reflexive, remembered and antisaccades, and smooth pursuit at four target velocities were studied. Subjects with ALS showed significantly elevated error rates (distractibility) and latency in the antisaccade and remembered saccade paradigms but no abnormality of reflexive saccades. The frequency of small saccades that intruded on steady fixation (square-wave jerks) was also increased in ALS subjects. Peak velocity gain of smooth pursuit and performance on the Wisconsin Card Sort Test did not differ significantly between the two groups. These findings are consistent with prefrontal dysfunction in ALS and provide an independent source of support for the thesis that the pathology of this condition invades frontal cortex.

Motor neuron disease (amyotrophic lateral sclerosis) arising from longstanding primary lateral sclerosis

Three men were initially diagnosed as having primary lateral sclerosis (PLS), but eventually developed amyotrophic lateral sclerosis (ALS) after 7.5, 9, and at least 27 years. Non-familial ALS and PLS might be different manifestations of a single disease or constitute completely distinct entities. The clinical diagnosis of PLS predicts a median survival that is four to five times longer than in ALS.

Involvement of corpus callosum in amyotrophic lateral sclerosis shown by MRI

Abnormal high signal in the corticospinal tracts on MRI has been described in amyotrophic lateral sclerosis. We report a case with further high signal in fibres of the corpus callosum on proton density and T2-weighted spin-echo images, closely matching findings of earlier pathological reports.

Parkinsonism in motor neuron disease: case report and literature review

This report describes a patient who had clinical features of both motor neuron disease and Parkinson's disease. Neuropathological examination and immunocytochemical studies showed that he had motor neuron disease of the progressive muscular atrophy type, and Lewy body Parkinson's disease, with intracytoplasmic inclusion bodies characteristic of both conditions. This is the first detailed description of these two diseases occurring concurrently in the same patient. A review of all previously reported cases of combined motor neuron disease and parkinsonism has led to the following conclusions: (1) that these two neuropathologically defined diseases occur together very infrequently, but (2) that parkinsonism and substantia nigra degeneration are not uncommon as part of the multi-system disease process underlying motor neuron disease.

Topographic involvement of the striatal efferents in basal ganglia of patients with adult-onset motor neuron disease with basophilic inclusions

This report concerns the topographic immunohistochemical analysis of the putamen, globus pallidus (GP) and substantia nigra (SN) of two patients with adult-onset motor neuron disease with basophilic inclusions (MND/BIs), seven patients with sporadic classic amyotrophic lateral sclerosis (sporadic ALS) and five neurologically normal individuals. The striatal efferent terminals of the GP and SN were visualized immunohistochemically using antibodies to met-enkephalin (MEnk) and substance P (SP). In specimens from patients with sporadic ALS and normal subjects there was intense immunostaining for MEnk and SP throughout the external and internal segments of the GP, respectively. By contrast, a marked reduction of MEnk- and SP-positive striatal efferents was seen in the ventrocaudal portions of both GP segments from the MND/BIs patients. Moreover, while MEnk-positive striosomes was readily detected in the putamen of normals and sporadic ALS patients, there was significant reduction in MEnk immunoreactivity, and no evidence of striosomal organization in the putamen of MND/BIs patients. In addition, whereas the SN of patients with sporadic ALS expressed SP, the ventrolateral SN portion of the MND/BIs patient tested had reduced immunoreactivity. The present findings on patients with MND/BIs may represent a reflection of the topographic striatum degeneration in this disease and appear to provide additional evidence for the heterogeneity of MND.

Motor neuron disease with multi-system involvement presenting as tetraparesis, ophthalmoplegia and sensori-autonomic dysfunction

We carried out a postmortem examination on two Japanese patients, 64- and 80-year-old men whose survival was prolonged with an artificial respirator. They had no family history of neuropsychiatric disorders and were suspected, clinically, as having a motor neuron disease that differed from amyotrophic lateral sclerosis (ALS). As well as upper and lower motor neuron impairment, they showed a variety of symptoms, such as sensory disturbances, hypohidrosis, impotence, ophthalmoparesis and/or atonic neurogenic bladder, and their protein content in cerebrospinal fluid was elevated markedly. Pathological examination revealed the following extensive nervous system involvement: (1) the upper and lower voluntary motor systems, including the IIIrd, IVth and VIth cranial nerve nuclei: (2) the reticular formation and its major afferent pathways; (3) the vestibulospinal and tectospinal systems; (4) the spinocerebellar system and the exteroceptive somatic afferent pathways; (5) the dentatorubral and pallidoluysian systems; and (6) the substantia nigra, locus ceruleus and intermediolateral and Onufrowicz's nuclei. Neither Bunina bodies, Lewy body-like hyaline inclusions nor ubiquitin immunoreactive skein-like structures were observed. The distribution of the lesions was quite different from that in patients with ALS and the other known related diseases. Recently, seven autopsied cases with clinical and histopathological similarities to our patients have been reported in Japan. Our conclusion is that our two and these seven patients should be classified as having a new motor neuron disease entity, which can be is differentiated from ALS.

Aluminum neurotoxicity: an experimental approach to the induction of neurofilamentous inclusions

Acute or chronic aluminum neurotoxicity experiments in the rabbit suggest that aluminum can induce phosphorylation of neurofilamentous proteins. This may result in abnormal resistance to degradation or transport of neurofilament protein and so to the accumulation of neurofilaments in abnormal cells. The possible importance of this process in ALS is considered in relation to the neurofilamentous abnormalities characteristic of intraneuronal inclusions in ALS and in other neurodegenerative disorders.

Persistent and transient "conduction block" in motor neuron diseases

Although conduction block indicates dysfunction of peripheral nerve, it may occur in patients with clinically typical motor neuron disease. There are no universally accepted criteria to identify conduction block, so diagnosis may be difficult. In some peripheral neuropathies, conduction block persists over long periods of time. If conduction block persists in motor neuron disease, then a more reproducible means for identification would be available. We repeatedly studied 9 patients with different forms of motor neuron diseases; conduction block was suspected because of excessive loss of the amplitude of motor evoked responses between distal and proximal stimulation sites. Five showed persistent amplitude loss at intervals between 12 and 36 months. All had focal loss of amplitude and area across a specific segment; all were men; none had definite upper motor neuron signs, 2 had probable and 3 had no upper motor neuron signs; 1 had IgM paraproteinemia, one elevated anti-GM1 titers; the duration of symptoms spanned 4-13 years. Four patients had transient loss of amplitude that was not reproduced in intervals between 3 and 13 months. None had focal loss of both amplitude and area; 2 were men; all had definite upper motor neuron signs and none had symptoms for more than 3-13 months; and none had immunological abnormalities. Thus, patients with persistent amplitude loss fulfill other criteria for conduction block, have prolonged survival but otherwise have clinical syndromes indistinguishable from ALS, except that definite upper motor neuron signs seem to be exceptional.

Oculomotor abnormalities in motor neuron disease

To determine whether there are oculomotor abnormalities in motor neuron disease (MND), electro-oculographic recordings were performed prospectively in 16 MND patients and the results compared with age-matched healthy controls. Parameters analysed included random and fixed saccades (latency, velocity and accuracy), smooth pursuit (gain, total harmonic distortion and number of saccadic intrusions) and optokinetic nystagmus (maximal and mean slow component velocity). Increased saccadic latencies and decreased smooth pursuit gain were the main alterations in the MND group. Correlation with clinical variables showed a positive relationship between smooth pursuit saccadic intrusions and the bulbar clinical score and the rate of progression and a lower optokinetic nystagmus maximal velocity in patients with pseudobulbar syndrome. Our results demonstrate the presence of subclinical supranuclear abnormalities in MND, and support the notion that MND is not merely a degeneration of the motor system.

Motor neuron disease/amyotrophic lateral sclerosis--lessons from ubiquitin

Ubiquitin is a stress protein implicated in the degradation of short-lived and abnormal proteins. In a neuropathological study of 43 cases with motor neuron disease/amyotrophic lateral sclerosis (MND/ALS) and 44 control cases the distribution and specificity of Bunina bodies and ubiquitin-reactive inclusions (UBRI) were investigated. The primary motor area showed nerve cell loss in 67%, Bunina bodies in Betz cells (10%) and UBRI in small pyramidal cells (17%). Degeneration of anterior horn cells in all cases coincided with Bunina bodies (84%) and UBRI (98%) in the same location; the motor nuclei of the caudal brain stem were also involved almost to the same degree. More resistant nuclei like the oculomotor nuclei or the Onuf's nucleus showed no degeneration but UBRI in 11% and 18% of cases, respectively. Like the degenerative process, the formation of UBRI was not confined to motor nuclei but also involved the brain stem reticular formation, substantia nigra, and Clarke's nucleus showing that MND/ALS is a multiple system degeneration. UBRI were found in only one control case in the anterior horn cells and in one case in the hypoglossal nucleus showing that UBRI, although not being absolutely specific for MND/ALS, have practical value for the neuropathological diagnosis of that disease. The pathogenetical implications of UBRI in MND/ALS are discussed.

Amyotrophic lateral sclerosis: lower motor neuron disease spreading to upper motor neurons

Contrary to the recently reemphasized notion that the primary neuron involved in amyotrophic lateral sclerosis (ALS) is the cortical (upper) motor neuron (UMN), we believe that the lower motor neuron (LMN) is primarily involved by the retrograde transport of pathogens from neuromuscular junctions, and the disease process spreads monosynaptically to the UMN. Pathologically and epidemiologically, the LMN hypothesis is more logical than the UMN in light of the recent understanding of neuroaxonal transport systems, particularly in regard to anterograde cytoskeleton transport and the kinetics of the force promoting slow axonal transport. By correlating the early pathologic findings, i.e., the swelling of the initial axons and formation of intracytoplasmic inclusions in the LMN, ALS may be regarded as a disease of axonal transport, especially its slow component (SCa). Therapeutic intervention to facilitate SCa should be attempted in ALS.

The prognosis of adult-onset motor neuron disease: a prospective study based on the Scottish Motor Neuron Disease Register

The Scottish Motor Neuron Disease Register (SMNDR) is a prospective, collaborative, population-based project which has been collecting data on incident patients since 1989. In this report we present the clinical features of 229 patients with motor neuron disease (218 sporadic and 11 familial) diagnosed in 1989 and 1990 and compare their prognosis with previous studies of survival. The overall 50% survival from symptom onset was 2.5 years (95% CI, 2.2-3.0) and 5-year survival 28% (95% CI, 20-36%). The presence of progressive bulbar palsy (PBP), either at presentation or developing during the course of the illness, significantly reduced survival and was the most important prognostic indicator. Patients who survived longer than 5 years from symptom onset did not have PBP as part of their presenting illness. The prognosis was worse for women, and this was in part related to the higher frequency of PBP in older women, but age was also an independent adverse risk factor. Differences in survival between this and previous series can probably be explained on the basis of variation in case definition and ascertainment methods.

Motor neuron disease with pallido-luysio-nigral atrophy

A case of motor neuron disease (MND) with pallido-luysio-nigral atrophy (PLNA) is reported. The 45-year-old male patient presented with lower motor neuron symptoms and signs of basal ganglia disturbance. He died after a progressive course of 7 months. Neuropathological examination revealed motor neuron loss at all spinal cord levels with sparing of Onuf's nucleus. Nerve cell loss and gliosis were also present in substantia nigra, globus pallidus, and subthalamic nucleus. The presence of ubiquitin-positive inclusions, a hallmark of most variants of MND, confirms this case as an example of MND. At immunoelectron microscopy the granules were distributed on filamentous material. The combination of clinically apparent PLNA with MND has only been described twice previously. The relationship of this syndrome to other forms of MND and its nosological placement are discussed.

Patterns of neuronal degeneration in the motor cortex of amyotrophic lateral sclerosis patients

We examined patterns of neuronal degeneration in the motor cortex of amyotrophic lateral sclerosis (ALS) patients using traditional cell stains and several histochemical markers including neurofilament, parvalbumin, NADPH-diaphorase, ubiquitin, Alz-50 and tau. Three grades of ALS (mild, moderate, severe) were defined based on the extent of Betz cell depletion. Non-phosphorylated neurofilament immunoreactive cortical pyramidal neurons and non-pyramidal parvalbumin local circuit neurons were significantly depleted in all grades of ALS. In contrast, NADPH-diaphorase neurons and Alz-50-positive neurons were quantitatively preserved despite reduced NADPH-diaphorase cellular staining and dendritic pruning. The density of ubiquitin-positive structures in the middle and deep layers of the motor cortex was increased in all cases. Axonal tau immunoreactivity was not altered. These histochemical results suggest that cortical degeneration in ALS is distinctive from other neurodegenerative diseases affecting cerebral cortex. Unlike Huntington's disease, both pyramidal and local cortical neurons are affected in ALS; unlike Alzheimer's disease, alteration of the neuronal cytoskeleton is not prominent. The unique pattern of neuronal degeneration found in ALS motor cortex is consistent with non-N-methyl-D-aspartate glutamate receptor-mediated cytotoxicity.

Cognitive and memory deficits in untreated Parkinson's disease and amyotrophic lateral sclerosis patients: a comparative study

We investigated the profile of cognitive and memory deficits of 22 Parkinson's disease (PD), 24 amyotrophic lateral sclerosis (ALS) patients and 26 age-matched controls. The patients were at the early phase of the disease and untreated. The ALS patients exhibited deficits in simple visuoperceptual functions and in complex visuoperceptual reasoning (Digit Symbol and Block Design tests), whereas the PD patients showed deficits only in simple visuoperceptual functions. Moreover, both ALS and PD patients had impairment in tasks requiring set shifting from one reaction to another that may suggest frontal lobe dysfunction. The ALS and PD patients also showed impairment in the task of learning a word list with effort-demanding organization of the material to be remembered. However, preserved delayed recall of logical passages suggests that memory, per se, is not impaired in ALS or in PD. The patterns of errors in a test of recognition of learned words imply, at least partially, different underlying deficits in the two diseases. An inability to inhibit irrelevant information may contribute to memory impairment in ALS patients, whereas the memory deficit in PD may derive from lowered motivation or initiating behaviour.