Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used automatic decomposition electromyography (ADEMG) to study 41 muscles in 29 patients with well-defined peripheral and central motor disorders. In motor neuron diseases motor unit action potentials (MUAPs) showed increased amplitudes, firing rates and firing variability. Relatively large MUAPs sometimes were not identified by the computer program if they lacked sufficient high-frequency signal content, or were too variable in shape. In myopathies the MUAPs showed reduced amplitudes, durations and turns, and sometimes dramatic increases in firing rates. Also, the mean number of MUAPs per recording site was often increased, indicating excessive recruitment. In polymyositis (the best studied myopathy) the nature and magnitude of the MUAP shape and firing abnormalities were usually similar at different levels of contractile force, suggesting that motor units are affected without regard to recruitment order. In upper motor neuron paresis (multiple sclerosis), the shape properties of the MUAPs were normal, but mean firing rates were reduced, and firing variability increased. These findings confirm many of the traditional criteria for distinguishing neurogenic from myopathic disease electrophysiologically at the level of the individual MUAP. In addition, they demonstrate the potential diagnostic sensitivity of MUAP firing rate measurements for detecting neuromuscular dysfunction, and for differentiating between some cases of central and peripheral paresis, but not for distinguishing peripheral neurogenic from myopathic weakness, since firing rates tend to increase in both. Increased firing rate variability may be a marker of central or peripheral neurogenic weakness.
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PMID:Motor unit firing rates and firing rate variability in the detection of neuromuscular disorders. 247 26

Two electrophysiological investigations were used to study 18 patients with multiple sclerosis--F wave characteristics including amplitude, persistence and frequency, which can provide a measure of motoneurone excitability, and magnetic stimulation of the cortex, which enables measurement of conduction along central motor pathways. There was an increase in the mean amplitude and persistence of the F response in patients with abnormal central motor conduction (CMC), although no correlation between the degree of abnormality of CMC and increase in F response amplitude was found. Increase in mean amplitude and persistence of the F response were also found in patients with normal CMC but clinical evidence of a UMN disorder (spasticity and/or weakness); there was no correlation, however, between any single F response characteristic and any particular clinical sign. CMC appears to be the preferred test for detecting subclinical motor lesions in MS: of the patient sides with normal clinical examination, 36% showed abnormal CMC, whereas 23% showed abnormal F responses.
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PMID:F responses and central motor conduction in multiple sclerosis. 248 Feb 23

The post-poliomyelitis syndrome (PPS) refers to symptoms of new weakness, fatigue, and pain years after recovery from acute poliomyelitis. Oligoclonal IgG bands have been reported in the cerebrospinal fluid (CSF) from PPS patients, suggesting that the syndrome is immune mediated or caused by persistent viral infection. We studied 15 paired serum and CSF samples and 6 unpaired CSF samples from a total of 21 patients with a prior history of poliomyelitis. Quantitative immune studies failed to show evidence for increased intrathecal IgG production relative to patients with noninflammatory central nervous system (CNS) disease. We found definite oligoclonal IgG bands in the CSF from only 1 patient, who also carried a diagnosis of multiple sclerosis. An isoelectric focusing poliovirus antigen overlay study showed evidence that suggested a CNS-specific antipoliovirus immune response in only 1 patient. Our results fail to support a dysimmune or persistent viral cause for post-poliomyelitis progressive muscular atrophy or PPS.
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PMID:Isoelectric focusing studies of serum and cerebrospinal fluid in patients with antecedent poliomyelitis. 217 20

Neuromyelitis optica also named Devic's disease is an acute combined optic neuritis and transverse myelitis. It is thought to be a variant of multiple sclerosis, but its clinical presentation probably has only one attack without further recurrence and exacerbation. We present a 12-year-old girl who suffered from sudden onset of lower extremeties weakness, sensory loss and blurred vision after a prodromal URI symptom. CSF examination showed mild pleocytosis, elevated immunoglobulins, mild elevation of protein concentration. No oligoclonal band was detected. Serum virology showed high titer of anti-EB virus antibody. Visual evoke potential showed prolong of latency and decreased amplitude of both eyes. After prednisolone treatment, her visual accuity began to improve on the 7th hospital day and motor function improved on the 11th hospital day. Two years later, she has normal visual accuity, normal motor function and shows no evidence of disease recurrence.
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PMID:Neuromyelitis optica (Devic's disease) report of one case. 256 81

The reliability and validity of an Index of Pulmonary Dysfunction in Multiple Sclerosis (Index) comprised of four readily assessed clinical signs was studied. Forty patients with MS performed pulmonary function testing and underwent clinical evaluation to determine whether or not the Index correctly identified those patients with pulmonary dysfunction. The Index correctly predicted the presence or absence of significant respiratory muscle weakness (defined as Pemax less than 50% of predicted) in 32 (80%) of the subjects. All subjects who had normal expiratory muscle strength (Pemax greater than or equal to 80% of predicted) were correctly classified by the Index; however, not all patients with isolated expiratory muscle weakness were correctly identified. Test-retest reliability, interrater reliability (Spearman rho coefficients of 0.87 and 0.94, respectively), and internal consistency (alpha = .83) of the Index were acceptable. Index scores were not associated with changes in any other PFT results except residual volume, which increased with the severity of respiratory muscle weakness. The Index has acceptable validity and reliability for use in clinical practice to identify those neurological patients with expiratory muscle weakness.
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PMID:Testing of an Index of Pulmonary Dysfunction in Multiple Sclerosis. 258 94

A case of 53-year-old female with multiple sclerosis was reported. In August 1987, she suffered from weakness in her legs and urinary retention. These signs had progressed with incomplete remissions and exacerbations. In March 1988, she developed sensory loss of all modalities below C2 level, spastic paralysis of upper extremities and flaccid paraplegia of lower extremities. Electromyography showed evidence of denervation in affected muscles of all extremities and paraspinal muscles. On lumber puncture, spinal fluid pressure fell to 0 mmH2O after removal of the spinal fluid of 12 ml, and the CSF protein was 740 mg/dl, indicating subarachnoid space block. The oligoclonal band was positive. MRI showed swelling in the cervical and upper thoracic cord, and multiple lesions in the periventricular white matter in the cerebrum. We diagnosed this case as multiple sclerosis in combination with acute polyradiculitis. The spinal subarachnoid block was considered to be caused by the swelling of the spinal cord.
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PMID:[A case of multiple sclerosis with polyradiculitis and spinal subarachnoid block]. 259 27

A 35-year-old woman with a long standing history of relapsing-remitting multiple sclerosis became physically incapacitated by heat-induced muscle weakness while sunbathing and suffered fatal sun exposure. These deleterious effects of increased core temperature on the neurological symptoms have been documented for a half century. Elevation of the patient's core temperature may lead to either transient or permanent neurologic symptoms and signs that predispose to considerable morbidity and mortality.
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PMID:A fatal case of sun exposure in a multiple sclerosis patient. 260 7

Fatigue of tibialis anterior (TA) was induced by repetitive electrical stimulation. Using this test, patients with upper motor neuron muscle weakness owing to multiple sclerosis (MS) and injuries to the spinal cord showed greater fatigability of their TA muscles, suggesting that the muscle fiber population changed toward that typical of fatigable motor units. During repetitive stimulation, in addition to the decrement in tension there was an increase in half-relaxation time of tetanic contractions at 40 Hz in both subjects and patients. The increase in half relaxation during repeated activity was greater in patients with MS and spinal cord injury than in healthy subjects, suggesting that the long-term inactivity affected the efficiency of the Ca2+ uptake mechanism of their muscle fibers. Thus long-term inactivity of patients with upper motoneuron dysfunction leads to increased fatigability of their muscles and exaggerates the slowing of muscle relaxation after prolonged exercise.
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PMID:Muscle fatigue in some neurological disorders. 260 89

In three women with multiple sclerosis, paroxysmal itching occurred. We were able to detect the spinal segment lesions corresponding to the dermatome of paroxysmal itching by magnetic resonance imaging (MRI) in them. Case 1. A 38-year-old woman was admitted with chief complaints of tingling sensation in the left side of the body, left hemiparesis and paroxysmal itching in the neck and left upper extremity. Examination on admission revealed left hemiparesis, mildly exaggerated deep tendon reflexes in the left upper and lower extremities, positive Lhermitte's sign. Superficial sensation was decreased and dysesthetic below the left C3 segment. Vibration and joint sense were moderately decreased in the left upper limb. Painful tonic seizure-like attack occurred in the neck bilaterally. Paroxysmal itching occurred in the neck and left upper extremity corresponding to the cervical spinal segments bilateral C3, left C4 to C6. MRI revealed multiple high signal intensities in the white matter of the cerebral hemispheres, the medullo-cervical junction and the cervical segment C3 to C4 in T2-weighted spin-echo images. The C3 to C4 lesion was found in the left dorsal area of spinal cord in axial image. High signal areas of cervical cords on T2-weighted spin-echo images were reduced in response to adrenocorticosteroid therapy, and paroxysmal itching disappeared. Case 2. A 24-year-old woman complained chiefly of mild tetraparesis and left hand clumsiness. On admission, she had right central facial palsy, mild weakness of all limbs, painful tonic seizure of left upper limb, positive Lhermitte's sign and bilateral Babinski sign. Superficial sense was mildly decreased and dysesthetic in left upper extremity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Paroxysmal itching and magnetic resonance imaging of the spinal cord in multiple sclerosis]. 262 19

The new techniques of percutaneous electric and magnetic stimulation of the motor cortex in conscious man provide a unique opportunity of functional testing of the central motor pathways. These techniques seem to be safe and no immediate or delayed adverse reactions have been reported. The physiological studies so far performed suggest that the structures which are preferentially excited by these methods are the fast conducting pyramidal neurones. It has been shown that a single cortical stimulus is able to activate spinal motoneurones repeatedly. This phenomenon can easily be explained if the cortical stimulus generates multiple descending volleys in the central motor pathways. By comparison with experiments of stimulation of the exposed motor cortex in animals, it is likely that electric brain stimulation directly activates the axons of the pyramidal neurons at their origin and to a lesser extent also recruits these neurons transsynaptically, via some cortical interneurones. Magnetic stimulation of the brain at the vertex seems to act mostly by the latter mechanism. These different modes of action of the two methods of cortical stimulation explain the latency differences of the EMG responses obtained with either technique. Increased excitability of the spinal motoneurones and the existence of multiple descending volleys in response to a single cortical stimulus result in shortening of the latencies and greater amplitude of the responses recorded during voluntary contraction of the target muscle. Stimulation of the motor cortex has been used in pilot studies conducted on patients suffering from various disorders of the central motor pathways, such as multiple sclerosis, cervical spondylosis, motor neurone disease or stroke. The sensitivity of the technique looks promising. In M.S., the EMG responses usually show an increased central conduction latency, a reduced amplitude and a prolonged duration. The severity of the electrophysiological abnormalities is not very well correlated with clinical weakness, but the correlations seems to be better with hyperreflexia and the presence of brisk finger flexor jerks. The same abnormalities are observed in cervical spondylosis, although to a lesser extent. In motor neurone disease, the responses have a moderately increased latency and their size and duration are markedly reduced. Patients with acute hemispheric stroke usually show absent responses on the contralateral side. Finally, electric cortical stimulation can be very useful in monitoring the functional integrity of descending motor tracts during surgical operations performed on the spinal cord.
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PMID:[Percutaneous electric and magnetic stimulation of the motor cortex in man. Physiological aspects and clinical applications]. 264 78


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