Differences in the handling of the EMG examination at seven European laboratories

This study was undertaken to analyse epidemiological and methodological differences in referral pattern, examination techniques and distribution of diagnoses among different European EMG laboratories. Seven European EMG laboratories filled in questionnaires and sampled 700 cases retrospectively. The use of needle or surface electrodes for nerve studies and the selection of quantitative techniques for muscle studies exhibited considerable variation. The pattern of referral varied with respect to the type of referral source and the neurological expertise of the referring physician. The proportion of patients without any neurophysiological abnormality ranged from 16 to 33%. The 3 most common diagnostic groups were mononeuropathies, polyneuropathies and radiculopathies although a great inter-laboratory variation was found. The proportion of patients with multiple diagnoses varied from 0 to 23% and most of these diagnoses were from a few known combinations. The presence of an inter-laboratory variation suggests that the quality of the EMG examination may be improved by focussing on the use of techniques, strategies and diagnostic criteria.

Electromyography and biopsy correlation with suggested protocol for evaluation of the floppy infant

Eighty infants with nonarthrogrypotic floppy infant syndrome (FIS) were evaluated between 1979 and 1990. Electromyographic data were correlated with results of muscle and nerve biopsies in 41 of 80 who had concomitant biopsies (38) or other diagnostic analyses (3). A diagnosis was made of Werdnig-Hoffmann disease (WHD) in 15, a congenital infantile polyneuropathy (IPN) in 3, neuromuscular transmission defect (NMTD) in 2, myopathy in 12, and presumed "central" hypotonia in 9. A very positive correlation rate between nerve conduction studies with electromyography and biopsy results was found in 93% (14 of 15) with WHD and 100% in IPN (3 of 3). However, only 4 of 10 infants (40%) with biopsy-proven myopathy had an abnormal EMG. Only once did the results of electromyography and biopsy conflict.

Content of physician referrals to physical therapists at clinical education sites in Indiana

BACKGROUND AND PURPOSE

The content of physician referrals to physical therapists was studied as an indicator of the level of decision making required of physical therapists.

SUBJECTS AND METHODS

Seventeen managers of clinical education sites in Indiana provided diagnosis and treatment information on a total of 2,267 patient referrals.

RESULTS

Differential diagnoses were specified in 39.6% of the referrals, and specific treatment orders were present in 32.6% of the referrals. Outpatient referrals contained significantly fewer diagnoses (29.1%) and specific orders (28.2%) than did inpatient referrals (56.0% and 39.5%, respectively).

CONCLUSION AND DISCUSSION

These results indicate that physical therapists working in clinical education sites in Indiana must frequently exercise independent decision-making skills in determining the nature of the patient complaint and the appropriate treatment for the complaint. Academic programs that choose to expose students to a full range of decision-making situations should ensure a balance between inpatient and outpatient experiences.

Serial MRI in infantile bilateral striatal necrosis

A 3-year-old girl with left hemiparesis suffered from bilateral paresis, motor rigidity, gait disturbance, axial hypotonia, dysarthria, apathy, and incontinence. After steroid therapy, mild improvement occurred, but muscle weakness, gait disturbance, and rigidity remained. Leigh encephalopathy was excluded on the basis of muscle biopsy and laboratory findings. Computed tomography and serial magnetic resonance imaging at an early stage revealed right-sided dominant lesions in the putamen and caudate nucleus and later bilateral striatal lesions, appearing as hyperintense signals on T2-weighted images and mixtures of hypo- and hyperintense signals on T1-weighted images. This is the first demonstration of serial magnetic resonance imaging findings in infantile bilateral striatal necrosis.

[Critical analysis of the results of muscle biopsies and of the methods used in 889 cases of neuromuscular disorders]

The contribution of muscle biopsies to the diagnosis of neuromuscular disorders and the indications of various methods of examination are investigated by analysis of 889 biopsies from patients suffering from myopathic and/or neurogenic disorders. Histo-enzymatic studies performed on frozen material as well as immunohistochemistry and electron microscopy allowed to provide specific diagnoses in all the neurogenic disorders (polyneuropathies and motor neuron diseases), whereas one third of myopathies remained uncertain. Confrontation of neuropathological data with the clinical indications for histological investigations shows that muscle biopsies reveal the diagnosis in 25% of the cases (mainly in congenital and metabolic myopathies) and confirm and/or complete the clinical diagnosis in 50%. In the remaining cases with non specific abnormalities neuropathological investigations may help the clinician by excluding well defined neuromuscular disorders. Analysis of performed studies and results of investigations show the contribution and specificity of each method for the diagnosis. Statistical evaluation of this series indicates that cryostat sectioning for histo- and immunochemical and electron microscopy increases the rate of diagnoses of neuromuscular diseases: full investigation was necessary for the diagnosis in 30% of the cases. The interpretation of the wide range of pathological reactions in muscles requires a close cooperation with the clinician.

Degenerative neuromuscular diseases with a late onset. Clinical, electrophysiological and morphological study

This study carried out clinical, electrophysiological and morphological investigations (sural nerve and gastrocnemius muscle biopsies) in a group of 47 patients with neuromuscular disease of a certain or supposed degenerative origin and a late onset (over the age of 30 yrs.). It aimed the evidence of the eventual particularities of such diseases with a delayed onset. The equal involvement of sexes, the insidious onset, the clinical picture similar to that of the corresponding diseases with an onset at the usual age were observed. Regardless of the age, some interesting associations of the polyneuropathy with other diseases or its presence with in these diseases (Parkinsonism, Addison's disease, multiple symmetrical lipomatosis, etc.) were noticed, too. Electrophysiological examinations showed no particularities. Neither did the muscular morphological picture in most of the cases presenting neurogenic lesions with a moderate intensity. The sural nerve biopsy evidenced in 70% of the cases a moderately intense neuropathy of an axonal type ("dying back"), with or without secondary lesions of segmental demyelination and with the signs of a live regenerative activity.

Neuromotor precursors of schizophrenia

Previous research suggests that in addition to being a characteristic of schizophrenia, neuromotor dysfunction also predates the onset of the syndrome. The research reported here was intended to examine further the neuromotor development of children with preschizophrenia traits. This study is part of a larger "archival-observational" project that uses childhood home movies to explore the developmental precursors of schizophrenia. Group comparisons revealed a higher rate of neuromotor abnormalities in the preschizophrenia children when compared to their healthy siblings, preaffective disorder subjects, the healthy siblings of patients with affective disorder, and subjects from families with no mental illness. The preschizophrenia subjects also showed poorer motor skills when compared to their healthy siblings and preaffective disorder subjects. When diagnostic group comparisons were made within age spans, the group differences were significant only in the first 2 years of life. Post hoc analyses also revealed that the preschizophrenia subjects' neuromotor abnormalities occurred primarily on the left side of the body. The abnormalities included choreoathetoid movements and posturing of the upper limbs, similar to the motor signs described in earlier reports on diagnosed schizophrenia patients. The findings are discussed in light of their implications for the developmental origins of schizophrenia. Limitations of the study, including problems with sample representativeness and the reliance on observational data, are also discussed.

Neuroimaging of epilepsy, movement disorders, and degenerative diseases

Neuroimaging has improved the understanding, diagnosis, and management of several neurologic diseases and syndromes. Recent advances in the neuroimaging of epilepsy, movement disorders, and degenerative diseases of the nervous system are reviewed. Current research confirms that structural and functional neuroimages each provide unique, clinically useful information in these disorders. Quantification of images improves their diagnostic sensitivity and specificity. Presymptomatic or early neurochemical changes have been identified and followed longitudinally in several neurodegenerative diseases, providing a method for monitoring response to therapeutic intervention and pathophysiologic hypothesis testing. Functional activation studies and receptor-specific radioligands continue to advance our understanding of these disorders. Future methods will take increasing advantage of both the ability to measure neuropharmacological and neurochemical changes in vivo, and the ability to combine images and information obtained with distinct structural and functional neuroimaging modalities.

Motor unit populations in healthy and diseased muscles

The numbers of functioning motor units can be estimated in proximal and distal muscles of human limbs by an electrophysiological technique in which the mean sizes of the motor unit potentials are compared with the maximum M-waves of the same muscles. Although manual methods of estimation have been used successfully in the past, the introduction of automated techniques has brought considerable advantages, including greater objectivity and reduced contamination of the results by "alternation." In healthy subjects, the intrinsic muscles of the hand have approximately 100 motor units each, and the biceps brachii muscle has only slightly more. With advancing age, there is a loss of motor units, which appears to be more pronounced in distal muscles. The motor unit estimating methodology has been found to be of value in the diagnosis and assessment of patients suspected of having muscle denervation. In amyotrophic lateral sclerosis, the mean rate of motor unit loss is swift, whereas in late-onset cases of spinal muscular atrophy, the reduction in the motor unit population does not appear to progress. In only the most rapidly deteriorating cases of post-polio syndrome is it possible to demonstrate further loss of motor units. In all of these denervating disorders, and in peripheral neuropathies, the importance of collateral reinnervation as a compensatory mechanism is emphasized.

Sensory and motor neuropathy caused by excessive ingestion of vitamin B6: a case report

We describe a patient who developed a severe sensory and a mild motor neuropathy. This syndrome was due to massive and prolonged ingestion of vitamin B6 (10 g daily for 5 years). To our knowledge this is the first published case of motor neuropathy caused by chronic abuse of vitamin B6.

[Hereditary dentatorubro-pallidoluysian atrophy (DRPLA): clinical studies on 45 cases]

The term of dentatorubral and Pallidoluysian atrophy (DRPLA) was first introduced by Smith, who proposed that there was a combination of cerebellar ataxia with choreoathetosis based on DRPL lesions. In 1972, Naito et al. reported two families with progressive myoclonus epilepsy (PME) syndrome with cerebellar ataxia, and hyperactive deep tendon reflexes. In 1977, Oyanagi et al. reported 4 autopsied cases of PME, and pointed out degenerative lesions in the DRPL systems. In 1982, Naito and Oyanagi reported this type of PME to be hereditary DRPLA, with a clinicopathological disease entity. This type of PME with DRPLA has been made a major category, especially in Japan. In this article, clinicopathological features of the hereditary DRPLA will be reviewed on the basis of 45 patients with this disease. The disease was inherited as an autosomal dominant fashion, and induces a wide rage of clinical features depending upon the age of onset, ranging from 3 years to 69 years of age. The initial symptoms were variable according to the age of onset and mental retardation was the most prominent symptom in the patients in which the disease started in the first decade and with an epileptic seizure in the second decade. In the following next two decades, the incidence of epileptic seizure, as initial symptoms was decreased to 23% and gait disturbance and ataxia in 38% of the patients, which increased to 73% in the 5th and 6th decades. The cardinal symptoms of hereditary DRPLA includes mental retardation, epileptic seizure and myoclonus, cerebellar ataxia with gait disturbances, psychological symptoms including clonus, cerebellar ataxia with gait disturbances, psychological symptoms including character changes, and dementia.(ABSTRACT TRUNCATED AT 250 WORDS)

Immune-mediated neuropathies

Identification of immune-mediated neuropathies is important as these disorders often respond to treatment. Patterns of binding of serum M (monoclonal) proteins and autoantibodies correlate with, and may be diagnostic markers for, specific polyneuropathy syndromes. There is evidence that some of these antibodies may play a pathogenic role in polyneuropathy syndromes. Identification of specific immune polyneuropathy syndromes provides guidance regarding immunosuppressive regimens that may be effective treatments.

Evoked potentials, magnetic stimulation studies, and event-related potentials

With the technique of transcranial magnetic stimulation it is possible to study the function of motor pathways in normal subjects and in patients with neurologic disease. In conjunction with both evoked and event-related potentials, transcranial magnetic stimulation can be used to probe the processes involved in analyzing sensory input and in preparing for motor output.

Diffuse white matter disease in three children: an encephalopathy with unique features on magnetic resonance imaging and proton magnetic resonance spectroscopy

Amongst 21 children with unclassified white matter diseases three patients could be characterised by an identical clinical picture, magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) findings as a probably distinct entity. Following a normal early development they later showed rapidly progressive motor symptoms (ataxia, spasticity) leading to severe handicap within one or two years after onset. Later on bulbar symptoms, optic atrophy and epileptic seizures occurred. The MRI showed a diffuse homogeneous hypodensity of the white matter almost identical to the signal of the ventricles. MRS revealed a near total absence of N-acetylaspartate, choline and creatine and an increase of lactate and glucose. One girl and one boy were siblings, indicating an autosomal recessive trait.

Multiply sectioned Bayesian networks for neuromuscular diagnosis

A prototype neuromuscular diagnostic system (PAINULIM) that diagnoses painful or impaired upper limbs has been developed based on Bayesian networks. This paper presents nonmathematically the major knowledge representation issues that arose in the development of PAINULIM. Motivated by the computational overhead of large application domains, and the desire to provide a user with an interface that gives a focused display of a subdomain of current interest, we built PAINULIM using the idea of multiply sectioned Bayesian networks. A preliminary evaluation of PAINULIM with 76 patients has demonstrated good clinical performance.

Significant improvement of stiff-person syndrome after paraspinal injection of botulinum toxin A

Following several months of low back pain, a 36-year-old man developed progressive stiffness of the abdominal, low back, and thigh muscles. On examination, these muscles demonstrated marked hypertonia consistent with the clinical diagnosis of stiff-person syndrome. The patient demonstrated increased lumbar lordosis and had focal hyperhidrosis at different sites. Electromyography showed continuous activity of the paraspinal and thigh muscles, and serum and cerebrospinal fluid antibodies to glutamic acid decarboxylase (GAD) were markedly elevated. Diazepam and Lioresal offered partial pain relief. Paraspinal muscle administration of botulinum toxin A reduced the tone of paraspinal and thigh muscles significantly and resulted in marked improvement of ambulation and cessation of pain.