Models of care for motor neuron disease: setting standards

Models of care for people with motor neuron disease (MND) must be designed in a patient-centered format, with an in-built flexibility and responsiveness that reflect the evolving nature of the condition. Diagnosis should be made as early as possible. Patients should have early access to centres with specialist knowledge of amyotrophic lateral sclerosis (ALS). Services should be flexible and responsive to the needs of the patient, and operate to best advantage when functioning as a coordinated team that cross-refers internally. Patients with ALS should be empowered to make rational end-of-life decisions based on maximizing quality of life and maintaining dignity. All models of care should be designed to cater for the sudden change from health to chronic illness, and should aim to provide a core of specialties that are patient-oriented, flexible and responsive. Ultimately, models of care should be assessed based on their outcomes.

Management of motor neurone disease

Motor neurone disease is a progressive neurodegenerative disorder leading to severe disability and death. It is clinically characterised by mixed upper and lower motor neurone involvement affecting bulbar, limb, and respiratory musculature. Recent guidelines have established diagnostic criteria and defined management of the condition. In a proportion of familial amyotrophic lateral sclerosis there is a mutation in the gene encoding the enzyme copper/zinc superoxide dismutase 1; this has allowed mutation screening and generated considerable laboratory based research. The diagnosis must be given with care and consideration and close follow up is essential. Management involves a multidisciplinary team based in the hospital and the community. Riluzole is the only drug shown to have a disease modifying effect and has been approved by the National Institute for Clinical Excellence. The essence of care is good symptomatic management, including nutritional support with percutaneous endoscopic gastrostomy and ventilatory care with non-invasive ventilation. Palliative care should be introduced before the terminal stages after careful discussion with the patient and carers. Knowledge of this condition has grown dramatically recently with a parallel improvement in treatment and ability to deal with the most troublesome problems.

Hereditary motor neuropathies and motor neuron diseases: which is which

When Charcot first defined amyotrophic lateral sclerosis (ALS) he used the clinical and neuropathological pattern of vulnerability as a guideline. Similarly other motor neuron diseases such as the spinal muscular atrophies (SMA) and the motor neuropathies (MN) were grouped following clinical criteria. However, ever since the etiology of these diseases has started to be disclosed by genetics, we have learnt that the limits of the syndromes are not as well defined as our forefathers thought. A mutation leading to ALS can also be associated with the clinical picture of spinal muscular atrophy; even more unexpected is the overlap of the so-called motor neuropathies with the clinical syndrome of slowly progressive ALS or that primary lateral sclerosis (PLS) can be caused by the same gene as that responsible for some cases of ALS. In this review we summarise recent work showing that there is a considerable overlap between CMT, MN, SMA, ALS and PLS. Insights into these phenotypes should lead to study of the variants of motor neuron disease and possibly to a reclassification. This comprehensive review should help to improve understanding of the pathogenesis of motor neuron degeneration and finally may aid the research for urgently needed new treatment strategies, perhaps with validity for the entire group of motor neuron diseases.

[Neuropsychological disorders in amyotrophic lateral sclerosis]

Amyotrophic lateral sclerosis (ALS) has traditionally been assumed to be a purely motor disturbance. It is now recognized that 2-5% of patients with ALS develop frontotemporal dementia. Additionally, neuropsychological analysis and functional imaging suggest that a proportion of patients with classical ALS also have neuropsychological impairment. On postmortem examination, ALS patients classified as not demented showed atrophy of the frontotemporal cortex. Conversely, in patients with frontotemporal dementia without known motor impairment, atrophy of spinal and bulbar neurons were found on postmortem examination. It is still not known whether patients with ALS and neuropsychological impairment form a distinct subgroup or if they are part of a continuous spectrum that runs from pure motor impairment to pure neuropsychological impairment.

[Multifocal motor neuropathy: diagnosis and differential diagnosis]

Multifocal motor neuropathy (MMN) is an acquired immune mediated motor neuropathy with characteristic clinical and neurographic features.Clinically, MMN is characterized by progressive, predominantly distal and asymmetrical limb weakness. Neurographic recordings demonstrate features of multifocal demyelination with or without conduction block. Sensory nerves are not affected. Due to strict diagnostic criteria,MMN may be underdiagnosed in patients with motor neuropathies. Since intravenous immunglobulins are an efficient therapy for MMN,clinical and electrophysiological differentiation from other neuromuscular disorders is mandatory to prevent progressive impairment of motor function. We present a patient with MMN and review the clinical, electrophysiological, and histological features. In addition,pathogenesis, differential diagnosis and treatment of MMN are discussed.

Quantitative motor unit potential analysis in routine

This article is a review of the generation of the motor unit potential and modern techniques for its quantification. General comments are made on findings in neurogenic and myopathic conditions. Detailed examples are given from two pathological conditions, ALS and polymyositis. Quantitative parameters are presented and the usefulness of outliers compared to mean values is discussed.

[Cerebellar symptoms in motor neuron diseases. Special form of amyotrophic lateral sclerosis plus syndrome]

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive and selective loss of motor neurons in the cerebral cortex, brainstem, and spinal cord. The upper motor neuron syndrome is characterized by symptoms of spastic paresis. Muscle weakness and atrophy, fasciculations, and cramps are typical signs for the degeneration of the lower motor neurons. In 1994, the El Escorial criteria were proposed for the diagnosis of ALS. These criteria include ALS-plus syndromes, which are defined by an association of ALS with extrapyramidal features or dementia. In this paper, we present two cases of ALS associated with signs of cerebellar degeneration. According to the revised El Escorial criteria, the described unusual combination of upper and lower motor neuron signs in association with cerebellar ataxia can be classified as a specific form of ALS-plus syndromes.

Correlates of Quality of Life in people with motor neuron disease (MND)

OBJECTIVES

Previous work has not found correlations between standardized questionnaire measures of quality of life (QoL) and physical strength/functional ability in people with motor neuron disease (MND). Little is known about the relationship between ratings on an abbreviated self-generated measure of QoL, the Schedule for Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW), and measures of functional status such as the Sickness Impact Profile (SIP), although the former has been rated by people with MND as providing a more valid measure of their own QoL than the latter. The aim of this study was to examine whether self-generated ratings of QoL correlated with measures of physical impairment and self-reported functional status, psychological wellbeing and self-reported cognitive functioning, and with factors such as social support, which elsewhere has been reported to be a determinant of QoL in MND.

DESIGN

The present cross-sectional study investigated between SEIQoL-DW ratings and SIP and the relationship ALS Severity Scale (ALSSS) scores, as well as with self-reported anxiety, depression, social support and everyday cognitive functioning in 31 people with MND.

RESULTS

Overall QoL ratings on the SEIQoL-DW failed to correlate with any of the ALSSS or SIP subscale scores. This was despite the fact that health was nominated as an important QoL-related category by 64.5% of the sample. QoL scores were, however, found to correlate positively with the existence of confiding and emotional support; they also correlated negatively with the presence of self-rated everyday cognitive difficulties but not with affective state.

CONCLUSIONS

Current findings support recent observations that individuals' ratings of their QoL cannot simply be equated with their physical impairment and functional limitations, and that support systems may be important. Cognitive functioning, known to be impaired in some people with MND, should also be considered when evaluating QoL.

Motor neurone disease

Motor neurone disease (MND), or amyotrophic lateral sclerosis (ALS), is a neurodegenerative disorder of unknown aetiology. Progressive motor weakness and bulbar dysfunction lead to premature death, usually from respiratory failure. Confirming the diagnosis may initially be difficult until the full clinical features are manifest. For all forms of the disease there is a significant differential diagnosis to consider, including treatable conditions, and therefore specialist neurological opinion should always be sought. Clear genetic inheritance has been demonstrated in a minority of patients with familial ALS but elucidation of the biological basis of genetic subtypes is also providing important information which may lead to treatments for sporadic forms of the disease. In the absence of curative or disease modifying therapy, management is supportive and requires a multidisciplinary approach. If, as seems likely, complex inherited and environmental factors contribute to the pathogenesis of MND, future treatment may involve a combination of molecular based treatments or restoration of cellular integrity using stem cell grafts.

Sensorimotor functions in transgenic mice expressing the neurofilament/heavy-LacZ fusion protein on two genetic backgrounds

NFH-LacZ transgenic mice are characterized by expression of a non-endogenous fusion protein between a truncated form of mouse NFH (neurofilament of heavy molecular weight) and the complete Escherichia coli beta-galactosidase protein. These transgenic mice were compared to their respective controls on two background strains (C3H and FVB) in several sensorimotor tests. NFH-LacZ mice were deficient in tests requiring balance and equilibrium in a manner generally independent of genetic background. In particular, NFH-LacZ mice fell more quickly than controls from two stationary beams and had fewer rears in an open-field. The transgenic mice were also impaired during the initial trials of sensorimotor learning on the rotorod. We conclude that despite the absence of overt signs of sensorimotor weakness in their home cage, the disruption of the NFH gene, causing neurofilament accumulations in the cell body and diminished axonal calibers of motoneurons, is sufficient to cause motor deficits that resemble the early stages of amyotrophic lateral sclerosis.

Worsening of multifocal motor neuropathy during pregnancy

Three women with multifocal motor neuropathy (MMN) were treated during pregnancy. Compared with their pregestation strength, the women became weaker in previously involved muscles and showed new weakness in previously unaffected muscles. All were treated with IV immunoglobulin during pregnancy and improved in strength. After pregnancy, strength in all patients returned to the prepregnancy state. The authors conclude that pregnancy may worsen MMN.

Mimic syndromes in sporadic cases of progressive spinal muscular atrophy

Described are patients initially diagnosed with progressive spinal muscular atrophy (PSMA), in whom further evaluation established another diagnosis. The authors prospectively investigated incident and prevalent cases of PSMA. Seventeen of 89 patients, after initial registration, were later excluded because reassessment revealed a diagnosis other than PSMA. In 11 of the 17 patients with a revised diagnosis, a potential treatment was available: multifocal motor neuropathy (7), chronic inflammatory demyelinating polyneuropathy (2), inflammatory myopathy (1), and MG (1). Other misdiagnoses included myopathy, syringomyelia, ALS, idiopathic chronic axonal polyneuropathy, and idiopathic brachial plexus neuropathy. One patient with a possible herniated lumbar disk recovered spontaneously.

Outcome of ventilatory support for acute respiratory failure in motor neurone disease

OBJECTIVES

To review the outcome of acute ventilatory support in patients presenting acutely with respiratory failure, either with an established diagnosis of motor neurone disease (MND) or with a clinical event where the diagnosis of MND has not yet been established.

METHODS

Outcome was reviewed in 24 patients with respiratory failure due to MND who received endotracheal intubation and intermittent positive pressure ventilation either at presentation or as a result of the unexpected development of respiratory failure. Patients presenting to local hospitals with acute respiratory insufficiency and requiring tracheal intubation, ventilatory support, and admission to an intensive therapy unit (ITU) before transfer to a regional respiratory care unit were selected. Clinical features of presentation, management, and outcome were studied.

RESULTS

24 patients with MND were identified, all being intubated and ventilated acutely within hours of presentation. 17 patients (71%) were admitted in respiratory failure before the diagnosis of MND had been made; the remaining seven patients (29%) were already known to have MND but deteriorated rapidly such that intubation and ventilation were initiated acutely. Seven patients (29%) died on ITU (between seven and 54 days after admission). 17 patients (71%) were discharged from ITU. 16 patients (67%) received long term respiratory support and one patient required no respiratory support following tracheal extubation. The daily duration of support that was required increased gradually with time.

CONCLUSION

When a patient with MND is ventilated acutely, with or without an established diagnosis, independence from the ventilator is rarely achieved. Almost all of these patients need long term ventilatory support and the degree of respiratory support increases with time as the disease progresses. The aim of management should be weaning the patient to the minimum support compatible with symptomatic relief and comfort. Respiratory failure should be anticipated in patients with MND when the diagnosis has been established.

Multifocal motor neuropathy: clinical and immunological features and response to IVIg in relation to the presence and degree of motor conduction block

OBJECTIVE

To determine whether patients with clinically typical multifocal motor neuropathy (MMN) with or without definite or probable conduction block (CB) differ in terms of clinical presentation, immunological findings, or response to treatment with intravenous immunoglobulin (IVIg).

METHODS

23 consecutive patients were studied with the typical clinical features of MMN, consisting of a progressive multineuropathic motor impairment with minimal or no sensory loss. In 14 patients, electrophysiological studies disclosed the presence of a definite or probable CB according to the criteria proposed by the American Association of Electrodiagnostic Medicine (AAEM) in at least one motor nerve. Six patients had possible CB, defined as a degree of CB 10% less than that required by the AAEM for probable CB, while no CB was detected in three patients.

RESULTS

Patients with possible CB did not differ from those with a definite or probable CB in terms of age at disease onset (mean 38.8 v 38.2 years, respectively), distribution and severity of limb weakness, clinical impairment (mean Rankin score 2.2 in both), and frequency of antiganglioside antibodies (33% v 29%). Patients with possible CB had a longer mean disease duration (9 v 5.9 years, p < 0.05) and a less frequent consistent response to IVIg (67% v 86%) than those with a definite or probable CB. Patients without a detectable CB had a similar frequency of antiganglioside antibodies (33%) but had a longer disease duration (20.3 years), greater impairment (Rankin score 2.7), and more frequent signs of axonal degeneration (41% of examined motor nerves) than patients with CB (13-15%, p < 0.005). Only one patient without detectable CB (33%) consistently improved with IVIg.

CONCLUSIONS

Patients with possible CB were clinically and immunologically indistinguishable from those with definite or probable CB, albeit with a slightly less frequent response to IVIg. This finding suggests that failure to fulfil AAEM criteria for CB in patients with otherwise clinically typical MMN should not preclude this diagnosis and consequently a treatment trial with IVIg. Whether the longer duration and greater severity of the disease and more frequent axonal impairment in patients without detectable CB than in those with CB explain their lower response to IVIg remains to be established.

Videomanofluorometric study in amyotrophic lateral sclerosis

OBJECTIVE

To elucidate the time-course changes of swallowing function in amyotrophic lateral sclerosis (ALS) by videomanofluorometry.

STUDY DESIGN

Videomanofluorometry was conducted on 21 patients with ALS, who were divided into five groups according to type of disease and according to the length of time following the appearance of bulbar symptoms.

METHODS

Videomanofluorometry, which is videofluoroscopic and manometric study conducted simultaneously, was performed on patients in the five groups, and swallowing function in each group was evaluated. Some of the patients were followed up by videomanofluorometry performed several times, and their swallowing function changes over time were investigated.

RESULTS

A decrease of swallowing pressure first appeared in the oropharynx, then the hypopharynx became involved. Oropharyngeal swallowing pressure had already decreased to approximately 50 mm Hg within 6 months after the appearance of bulbar symptoms; however, hypopharyngeal swallowing pressure was relatively maintained until 1 year after the onset of bulbar symptoms. Most of the patients with ALS maintained normal upper esophageal sphincter relaxation, but upper esophageal sphincter spasm was seen in some patients with ALS. Aspiration was seen in eight cases, five of which showed upper esophageal sphincter spasm.

CONCLUSIONS

Patients with ALS gradually face the danger of aspiration as decreases of oropharyngeal and hypopharyngeal swallowing pressure progress. Upper esophageal sphincter spasm occurs in some patients with ALS, and it is an important cause of aspiration. Both videofluoroscopic and manometric evaluation are necessary to assess these conditions, and they are quite useful for follow-up of swallowing function in patients with ALS.

Electrodiagnostic approach to the patient with suspected motor neuron disease

The diagnosis of amyotrophic lateral sclerosis (ALS) per se may be challenging since there is no single diagnostic test for ALS (with the exception of finding a mutation in the SOD1 gene). Additionally, the disease may begin focally and resemble a variety of other neurologic disorders that share clinical features with ALS. This latter point emphasizes an important imperative for the clinician--the need to consider a broad range of peripheral and central nervous system disorders in the process of differential diagnosis of ALS, especially when the disease is in its early stages. The authors review the diagnostic criteria for ALS and discuss which features to consider in determining the degree of certainty or level of confidence in the diagnosis. The authors then enumerate the important differential diagnostic possibilities that emerge from a careful consideration of the clinical features and comment on neuroimaging studies and laboratory tests employed in the diagnostic process. Next, the authors turn their attention to the important role played by electrophysiologic studies in the diagnostic evaluation of the patient with suspected ALS. The authors then return to a focused consideration of selected disorders in the differential diagnosis of ALS and conclude with a summary of their diagnostic approach for this disease.

New insights into the viral theory of amyotrophic lateral sclerosis: study on the possible role of Kaposi's sarcoma-associated virus/human herpesvirus 8

In the last few years, three new herpesviruses, HHV-6, -7 and -8, have been discovered, which share interesting biological characteristics for a possible role in the development of both neurological and lymphoproliferative diseases. In particular HHV-8, besides being strongly associated with Kaposi's sarcoma, is related with several lymphoproliferative diseases. More recently, specific viral sequences belonging to HHV-8 have been detected in autoptic brain specimens from multiple sclerosis patients and controls, suggesting that, similarly to HHV-6, this novel herpesvirus is strongly neurotropic. HHV-8 is an unusual herpesvirus in that it is able to produce homologues of several human gene products, resulting in alterations in cell cycle, in apoptosis and cell-mediated immune responses. To verify a possible relationship between HHV-8 and the development of amyotrophic lateral sclerosis (ALS), we investigated the presence of signs of HHV-8 infection, by both nested polymerase chain reaction (nPCR) and indirect immune fluorescence analysis in ALS patients. Both PCR and serological data did not suggest a clear role of this virus in originating ALS. Nevertheless, new insights into the mechanisms by which viruses may interact with the host cell genome and with the human immune system make the viral hypothesis of ALS still worthy of further studies.

Cognitive impairment and central motor conduction time in chronic alcoholics

The non-invasive technique of transcranial magnetic stimulation (TMS) was used in 62 chronic alcoholics to assess the functional status of descending motor pathways. The main aims of this study were: to investigate asymptomatic upper motor neuron dysfunction in alcoholics as well as to assess its relationship with parameters reflecting the intensity of exposure to alcohol; and to evaluate a possible relationship between central motor conduction time (CMCT) prolongation and neuropsychological measures of alcohol-related brain damage. Compared to control subjects, chronic alcoholics exhibited a significant prolongation of CMCT (23 out of 62 subjects). No significant correlation was found between CMCT prolongation and intensity and duration of abuse, presence of peripheral neuropathy, or brain atrophy on CT scans. Prolongation of CMCT from the upper limb correlated significantly with impairment of frontal skills on neuropsychological testing (p<0.01). These findings suggest that TMS may be a sensitive method for the detection in alcoholics of subtle neurological dysfunction, not confined to motor pathways.

A sensitive flow cytometry method for anti-GM1 antibodies detection

High-affinity anti-GM1 antibodies are frequently described in several nervous system diseases, mainly in multifocal motor neuropathy (MMN) and some acute neuropathies. These antibodies are currently detected using enzyme-linked immunosorbent assay (ELISA) and immuno-thin-layer-chromatography (immuno-TLC) methods. We report in this article a new method based on the incorporation of exogenous GM1 in a selected cell line to detect anti-GM1 antibodies using flow cytometry (FC). This method is evaluated on 80 sera from normal blood donors (NBD) and patients suffering various nervous system diseases. It appears to be as sensitive as our method ELISA for the diagnosis of some motor neuron syndromes.