[A case of slowly progressive unilateral spastic hemiparasis, hand clumsiness, limb ataxia and constructional apraxia]

A 65-year-old woman was seen in our clinic because of a 4-year history of slowly progressive left hand clumsiness and left limping. Neurologically, she had left-side spastic hemiparasis including her tongue, hand clumsiness, limb ataxia, constructional apraxia, and memory impairment. Dementia, parkinsonism and lower motor neuron sign were not confirmed. MRI study showed diffuse cerebral atrophy and shrinkage of the right cerebral peduncle and pontine base. SPECT (99mTc-ECD) study revealed hypoperfusion of the right fronto-parietal cortex. This is a rare case presented with slowly progressive left-side spastic hemiparasis, mimicking Mills' syndrome. In addition this case had other cortical signs, such as ipsilateral hand clumsiness, limb ataxia, constructional apraxia. Neuroimaging study suspects that the right front-parietal cortex is the primary lesion. Etiologically atypical motor neuron disease with adjacent cortical involvement is suspected rather than corticobasal degeneration with severe unilateral pyramidal tract degeneration.

ALS, motor neuron disease, and related disorders: a personal approach to diagnosis and management

Motor neuron disease, from diagnostic criteria, laboratory evaluation, communication with patients and their families, and the approach to long-term management represents a daunting challenge for many neurologists. Contained herein is a selective and biased discussion of several common dilemmas and questions that reflect recurring themes in the evaluation and management of patients with suspected motor neuron disease. The answers to these questions represent the author's opinions and are colored by personal experience, pearls graciously given to me by other experts in the field, and selected studies from the neuromuscular literature.

Association of chorea and motor neuron disease

Amyotrophic lateral sclerosis (ALS) is classically characterized by the presence of symptoms or signs of upper and lower motor neuron impairment and sparing of other neuronal systems.1 We report on a patient who was primarily diagnosed as typical ALS and developed chorea 10 years after the onset of motor neuron signs.

An expanded cortical representation for hand movement after peripheral motor denervation

OBJECTIVES

Functional reorganisation of the motor or sensory cortex has been demonstrated in animals after section of mixed peripheral nerves. Here functional changes in the motor cortex specifically after peripheral motor denervation in humans are investigated.

METHODS

Functional MRI (fMRI) was used to study brain activation during a finger flexion-extension task in patients with a late onset, acquired pure motor neuropathy (n=6), contrasting results with those from patients with pure sensory neuropathies (n=4) or healthy controls (n=7).

RESULTS

Increases in the extent of activation in the motor cortex both ipsilateral and contralateral to the hand moved were found in the patients with motor neuropathy. The neuroanatomical localisation of the mixed contralateral sensorimotor cortex activation volume was more posterior for the patients with motor neuropathy than for the healthy controls (mean difference, 12 mm, p<0.05). The pure sensory neuropathy group by contrast showed no change in the extent of activation relative to healthy controls and a trend for more anterior primary sensorimotor cortex activation (p<0.06). To test whether the increased activation volumes found in patients with motor neuropathy were a result simply of factors such as increased effort with movement rather than the motor denervation, patients with hand weakness from inclusion body myositis (n=4) were studied while making similar hand movements. No differences in either the numbers of significantly activated voxels or in their localisation were found relative to healthy controls (n=10).

CONCLUSIONS

These results provide a novel demonstration that peripheral denervation (as distinguished from factors related to weakness) leads to functional reorganisation of the sensorimotor cortex in the adult brain. This suggests that adaptive responses to motor denervation involve the central as well as the peripheral nervous system.

The Spurling test and cervical radiculopathy

STUDY DESIGN

A cross-sectional study design was used.

OBJECTIVE

To determine the sensitivity and specificity of the Spurling test for cervical radiculopathy.

SUMMARY OF BACKGROUND DATA

The Spurling test is an accepted physical examination test, but there is little data on its sensitivity or specificity.

METHODS

From 1988 to 1993, 255 consecutive patients were referred for electrodiagnosis of upper extremity nerve disorders. A Spurling test administered before other testing was performed. The Spurling test was scored as positive if it caused pain or tingling that started in the shoulder and radiated distally to the elbow. After the electrodiagnostic examination, a score was given to each diagnosis in the differential diagnosis according to the likelihood of its presence. To determine the odds ratio, sensitivity, and specificity, chi2 analysis was used. Also, the percentage of subjects with positive results from the Spurling test was calculated for several nerve disease diagnoses.

RESULTS

The Spurling test had a sensitivity of 6/20 (30%) and a specificity of 160/172 (93%). The results were positive in 16.6% of the normal group, in 3.4% of the group with nerve disorders other than a radiculopathy, in 25% of the group with an abnormality not consistent with any specific diagnosis group, in 37.5% of the group with possible radiculopathy, and in 40% of the group with certain radiculopathy.

CONCLUSIONS

The Spurling test is not very sensitive, but it is specific for cervical radiculopathy diagnosed by electromyography. Therefore, it is not useful as a screening test, but it is clinically useful in helping to confirm a cervical radiculopathy.

Protocol for clinical neurophysiologic examination of the pelvic floor

Clinical neurophysiologic examination of the pelvic floor is performed worldwide, but there is no consensus on the choice of tests, nor on technical details of individual methods. Standardized methods are, however, necessary to obtain their valid application in different laboratories for the purpose of collection of normative data, comparison of patient data and organization of multi-center studies. It is proposed that in patients with suspected "lower motor neuron" type lesions concentric needle electromyography (CNEMG) is the most informative test to detect pelvic floor denervation/reinnervation, and the external anal sphincter (EAS) muscle is the most appropriate muscle to be examined (either in isolation-when a selective lesion is suspected-or in addition to examination of other muscles). An algorithm consisting of standardized tests including a standardized approach to CNEMG examination of the EAS is presented. The proposed electrophysiologic assessment consists of a computer-assisted analysis of denervation and reinnervation features of the CNEMG signal, a qualitative assessment of reflex and voluntary activation of EAS motor units, and of electrical (or mechanical) elicitation of the bulbocavernosus reflex in those patients in whom manual anogenital stimulation failed to elicit a robust response in the EAS. The proposed protocol could serve as a basis for further studies on validity, sensitivity and specificity of electrophysiologic assessment in patients with different types of "lower motor neuron" involvement of pelvic floor muscles and sacral dysfunction.

Respiratory function vs sleep-disordered breathing as predictors of QOL in ALS

BACKGROUND

Most patients with ALS have evidence of respiratory muscle weakness at diagnosis, and death is usually due to respiratory failure. Sleep disruption, possibly due to apneas, hypopneas, orthopnea, or REM-related desaturation, is common. The relative impact of these factors on quality of life has not been established.

METHODS

The authors recruited 23 subjects with probable or definite ALS. Quality of life was assessed using generic and specific instruments, and respiratory muscle strength by measurement of vital capacity, maximum static pressures, and sniff nasal inspiratory pressure. Twenty-two subjects underwent polysomnography. Overall limb and axial muscle strength was estimated using a summated muscle score based on the Medical Research Council clinical scale.

RESULTS

On univariate analysis, there were moderate to strong correlations between quality of life and all measurements of respiratory muscle function (R = 0.42-0.82). The correlations with selected polysomnographic indices were weaker and less consistent (R = 0.44-0.59). Multivariate analysis showed that maximum static inspiratory pressure was the strongest independent predictor of quality of life.

CONCLUSION

Quality of life was strongly and independently related to respiratory muscle function. Relations with polysomnographic indices were weaker and were attributable to respiratory muscle weakness. Respiratory muscle weakness is much more important than the frequency of apneas and hypopneas in determining quality of life in ALS.

Botulinum treatment of spasticity: why is it so difficult to show a functional benefit?

Clinical experience seems to indicate that botulinum toxin injections can, in selected patients with upper motor neurone syndrome, reduce spasticity and improve voluntary movement and active function. However, double-blind placebo-controlled trials have had difficulty showing active functional improvement, despite the clear ability of botulinum toxin to reduce spasticity. This prompts a re-analysis of the basic assumption that spasticity impairs voluntary movement and a review of the methodology of the clinical trials. Motor dysfunction is usually caused by weakness and the other "negative" features of upper motor neurone syndrome, rather than muscle overactivity. Recent research has explored the pathophysiological basis of the voluntary movement disorder, in particular the role of the various forms of motor overactivity, which might be amenable to botulinum toxin treatment. The failure of double-blind placebo-controlled clinical trials to show improvement in active function is, to a large extent, a result of their methodology, especially patient selection, injection protocols, and the choice of outcome measures. Clinical trials need to be re-designed and based upon expert experience and a better understanding of the pathophysiology of the motor disorder.

Progressive neuronal and motor dysfunction in mice overexpressing the serine protease inhibitor protease nexin-1 in postmitotic neurons

Perturbation of the homeostasis between proteases and their inhibitors has been associated with lesion-induced or degenerative neuronal changes. Protease nexin-1 (PN-1), a secreted serine protease inhibitor, is constitutively expressed in distinct neuronal cell populations of the adult CNS. In an earlier study we showed that transgenic mice with ectopic or increased expression of PN-1 in postnatal neurons have altered synaptic transmission. Here these mice are used to examine the impact of an extracellular proteolytic imbalance on long-term neuronal function. These mice develop disturbances in motor behavior from 12 weeks on, with some of the histopathological changes described in early stages of human motor neuron disease, and neurogenic muscle atrophy in old age. In addition, sensorimotor integration, measured by epicranial multichannel recording of sensory evoked potentials, is impaired. Our results suggest that axonal dysfunction rather than cell death underlies these phenotypes. In particular, long projecting neurons, namely cortical layer V pyramidal and spinal motor neurons, show an age-dependent vulnerability to PN-1 overexpression. These mice can serve to study early stages of in vivo neuronal dysfunction not yet associated with cell loss.

Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings

OBJECTIVE

To describe the clinical, neurophysiological, and MRI findings in 10 patients with primary lateral sclerosis (PLS).

RESULTS

The course of the disease was very slowly progressive. Spasticity due to upper motor neuron dysfunction was the most prominent sign, but EMG showed slight lower motor neuron signs, such as a mixed pattern on maximal voluntary contraction and enlarged motor unit potentials. One patient had clinically mild lower motor neuron involvement. Central motor conduction times (CMCT) were more prolonged in PLS than is the case in ALS. Minor sensory signs were found on neurophysiological examination, comparable with those in ALS. In four patients serum creatine kinase activity was raised. On MRI cortical atrophy was seen, most pronounced in the precentral gyrus and expanding into the parietal-occipital region.

CONCLUSIONS

PLS is a distinct clinical syndrome, part of the range of motor neuron diseases. Besides pronounced upper motor neuron symptoms, mild lower motor neuron symptoms can also be found, as well as (subclinical) sensory symptoms. PLS can be distinguished from ALS by its slow clinical course, a severely prolonged MEP, and a more extensive focal cortical atrophy.

[Respiratory disorders during sleep in amyotrophic lateral sclerosis]

Amyotropic lateral sclerosis is a severe degenerative disease of the nervous system. Progressive death of central and peripheral motor neurons leads to rapidly extensive paralysis of the four limbs, the bulbar region and the respiratory system. Sleep respiratory disorders is a useful sign to follow in these patients. Apnea is generally central rather than obstructive. Hypoventilation, particularly during REM sleep has been reported and causes nocturnal desaturation. These patients also appear to have a disrupted sleep pattern with a longer phase I and a shorter total duration of sleep. These nocturnal respiratory disorders observed in amyotropic lateral sclerosis are similar to those observed in muscle diseases. Management must however be undertaken very early in these patients because outcome can be rapidly fatal after the development of significant desaturation. Nasal ventilation can improve not only quality of life but also life expectancy for these patients.

[Multifocal motor neuropathy. Immediate response to intravenous immunoglobulin]

Multifocal motor neuropathy, a rare insidious immune-mediated disorder, features muscular weakness and atrophy, as well as areflexia, due to nerve conduction block and is often associated with the presence of anti-GM1 antibody. We report a patient with a nine-year history of progressive upper limb weakness, misdiagnosed as amyotrophic lateral sclerosis, who responded within hours to intravenous immunoglobulin treatment with full recovery of muscle strength. This case highlights the need to search for conduction block in patients with lower motor neuron involvement.

Does primary lateral sclerosis exist? A study of 20 patients and a review of the literature

The question of whether primary lateral sclerosis (PLS) is a nosological entity distinct from amyotrophic lateral sclerosis (ALS) has been the subject of controversy since it was first described in the nineteenth century. PLS has been defined as a rare, non-hereditary disease characterized by progressive spinobulbar spasticity, related to the selective loss of precentral pyramidal neurones, with secondary pyramidal tract degeneration and preservation of anterior horn motor neurones. In the recent clinical literature, the frontier between ALS and neurodegenerative disease remains poorly defined. We studied 20 patients with a diagnosis of PLS. We carried out a variety of tests in order to determine the presence of a more diffuse neurodegenerative process. We also performed a longitudinal electrophysiological evaluation. Our clinical, electrophysiological and pathological investigations provide evidence that the disease has a heterogeneous clinical presentation and that degeneration is not restricted to the central motor system.

The effect of non-invasive positive pressure ventilation (NIPPV) on cognitive function in amyotrophic lateral sclerosis (ALS): a prospective study

OBJECTIVES

Neuropsychological investigations have shown a degree of cognitive dysfunction in a proportion of non-demented patients with ALS. Respiratory muscle weakness in ALS can lead to nocturnal hypoventilation, resulting in sleep disturbance and daytime somnolence. Sleep deprivation of this type may cause impairments in cognitive function, but this has not been formally evaluated in ALS.

METHODS

Cognitive functioning was evaluated in nine patients with ALS with sleep disturbance caused by nocturnal hypoventilation (NIPPV group), and in a comparison group of 10 similar patients without ventilation problems (control group). The NIPPV group then started non-invasive positive pressure ventilation (NIPPV) at night. After about 6 weeks, change in cognitive function was evaluated.

RESULTS

Statistically significant improvement in scores on two of the seven cognitive tests was demonstrated in the NIPPV group postventilation, and a trend towards significant improvement was found for two further tests. Scores in the control group did not improve significantly for these four tests, although an improvement was found on one other test.

CONCLUSIONS

Nocturnal hypoventilation and sleep disturbance may cause cognitive dysfunction in ALS. These deficits may be partially improved by NIPPV over a 6 week period. This has important implications for investigations of both cognitive dysfunction in non-demented patients with ALS, and the effect of ventilation on quality of life.

Medical technology assessment. Electrodiagnosis in motor neuron diseases and amyotrophic lateral sclerosis

In motor neuron diseases/amyotrophic lateral sclerosis (MND-ALS), electrodiagnostic techniques are essential in supporting the diagnosis and excluding other conditions that clinically resemble MND-ALS. Electrodiagnostic techniques can also monitor disease progression and provide prognostic information. Electromyography has an important role in the diagnosis of MND-ALS, but some drawbacks should be borne in mind. Although internationally accepted electrophysiological criteria have been defined to support MND-ALS diagnosis, differences in different laboratories can raise unexpected difficulties in application of diagnosis criteria. Much work needs to be done to increase standardisation of the electrodiagnosis of MND-ALS in order to improve quality. Differential diagnosis with motor axonal neuropathies may be particularly difficult. EMG is an essential tool for the early diagnosis of MND-ALS, which increases potential benefit of therapeutic interventions. A wide discussion among neurophysiologists from different schools could create a sound consensus on early diagnosis of MND-ALS.

An ALS-like syndrome with new HIV infection and complete response to antiretroviral therapy

A 32-year-old woman presenting with a rapidly progressive ALS-like syndrome was found to be HIV positive with a CD4 count of 44/mm(3). The patient recovered completely during 1 year after treatment with nelfinavir, zidovudine, and lamivudine, and recovery is sustained nearly 4 years later. Recovery was accompanied by HIV RNA becoming undetectable in plasma and CSF.

Reversible ALS-like disorder in HIV infection

OBJECTIVE

To describe the clinical features, treatment, and outcome of six cases of HIV-1-associated ALS-like disorder.

METHODS

The authors reviewed patients with HIV infection with neurologic symptoms seen over a 13-year period. Patients were identified by using the El Escorial research diagnostic criteria defining three categories of certainty for definite, probable, or possible ALS. Clinical features, EMG, CSF, serum analyses, and imaging and virological studies were assessed.

RESULTS

Six patients with immunodepression (mean CD4(+) cells = 86.2/mm(3); mean age = 34 years) developed distal motor weakness mimicking a monomelic amyotrophy that subacutely progressed regionally or assumed a symmetric distribution on more than one region. EMG was characteristic of motor neuron disease with no multifocal conduction block. Causes other than HIV-1 were ruled out. The unusual rapid extension of the disease and the positive response to antiretroviral therapy suggest that ALS syndrome and HIV infection are etiologically related. HIV-1 might cause an ALS-like disorder by several mechanisms-via neuronal infection, by secretion of toxic viral substance, by inducing the immune system to secrete cytokines, or by inducing an autoimmune disease.

CONCLUSION

These cases suggest that the association between some motor neuron diseases and HIV infection is not coincidental but pathogenetically related and that ALS-like disorder should be considered an HIV-related neurologic complication.

[Neuropathy of the lower legs and feet in acute intermittent porphyria. A comparison of patients with type 1 diabetes and patients with AIP]

Distal neuropathy was assessed in 339 patients with acute intermittent porphyria (AIP). The chronic neurological signs were symmetrical and similar to those in Type 1 diabetic patients. Significant impairment was found concerning perception, extensor digitorum brevis test, lower leg pain, ankle and knee tendon reflexes but not concerning dry feet, loss of forefoot arch and hammer toes, when comparing patients with manifest vs. latent AIP. The neurological signs were more severe in the diabetic patients (n = 298). Five AIP patients had permanent quadriplegia and renal failure after severe attacks. Patients with manifest AIP had significantly more signs of distal chronic, symmetrical neuropathy of axonal type than had patients with latent AIP. More serious neurological lesions appear to develop after severe attacks.

Diphtheritic polyneuropathy: clinical analysis of severe forms

BACKGROUND

Diphtheritic polyneuropathy (DP) is a dangerous complication of diphtheria, especially its severe forms with bulbar, respiratory tract, and circulatory disturbances. However, the clinical picture of severe forms of DP is practically unknown.

OBJECTIVE

To investigate the clinical features and peculiarities of the course of severe forms of DP.

PATIENTS

Thirty-two patients with severe forms of DP.

RESULTS

The first symptoms of DP developed in most patients 3 to 5 weeks after the onset of diphtheria. The cranial nerves were involved in all patients, most frequently nerves IX and X (32 patients); VII (28 patients); III, IV, and VI (27 patients); and XI (27 patients). One third of the patients had quadriplegia. The remaining patients had quadripareses. Of the 32 patients, 24 underwent artificial ventilation. All patients had sensory signs, proprioceptive more often than superficial. Autonomic disturbances were observed also in all patients. Only 2 of the 32 patients died.

CONCLUSIONS

A direct indication for tracheotomy and artificial ventilation in patients with DP is a decrease of the vital capacity of the lungs below the traditional 16 mL/kg body weight or the development of the paralytic closure of the larynx against the background of the increasing weakness of the respiratory muscles. Characteristic of severe forms of DP is the phenomenon of the oppositely directed change in the neurological symptoms in the second month of the disease: the restoration of the function of the cranial nerves against the background of the further increase of the motor disturbances in the extremities and trunk. Special attention and care should be taken of patients during the period of the appearance of the episodes of vascular collapses-between the fourth and seventh weeks of DP.

Vecuronium-associated axonal motor neuropathy: a variant of critical illness polyneuropathy?

Neuromuscular blocking agents are routinely used as an adjunct therapy for critically ill patients. Unlike many neuromuscular blocking agents, vecuronium does not cause significant histamine release, which may lead to bronchoconstriction. Due to a short duration of action and limited accumulation, vecuronium has been widely used. Prolonged ventilatory dependence due to persistent neuromuscular blockade has been reported in patients treated with vecuronium. We report a case of an 8-year-old girl who had a primarily motor axonopathy presenting with weakness after extended vecuronium administration with prolonged course of recovery. This primarily motor neuropathy with axonal features may be a variant of critical illness polyneuropathy, a rarely reported condition in pediatric patients.