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Biomedical subjects

J R Daube

Publications and source records attributed to J R Daube.

At least 55 records · Page 3Linked to original sources
PubMed1991

Treatment of essential tremor with methazolamide.

We treated 28 patients (16 women and 12 men) who had essential tremor with methazolamide. Their median age was 69 years (range, 34 to 89 years), and the median duration of tremor was 16 years (range, less than 1 to 69 years). Fifteen cases were familial and 13 were sporadic. Improvement in 10 patients who continued taking the drug ranged from moderate to complete relief. In addition, four patients had marked improvement and two had moderate improvement but discontinued use of the drug because of side effects. Five patients with a mild response and seven with no response also discontinued methazolamide therapy. The maximal mean daily dose was 203 mg for all patients and 129 mg (maintenance dose) for the patients who continued taking the drug. Side effects consisted primarily of somnolence, nausea, epigastric discomfort, anorexia, paresthesias, and numbness. No aplastic anemia was noted in any of the patients. The median duration of follow-up was 6 months (range, 10 weeks to 29 months). The therapeutic effect seemed unrelated to a family history of tremor, the effect of alcohol, or the responsiveness to propranolol or primidone. Methazolamide may be an effective drug in the treatment of some patients with essential tremor, particularly those with head and voice tremor.

Adult↗
PubMed1991

Effects of alterations in pulmonary function and sleep variables on survival in patients with amyotrophic lateral sclerosis.

Breathing abnormalities and nocturnal hypoventilation occur in patients with amyotrophic lateral sclerosis (ALS). A prospective study was undertaken to determine the relationship of pulmonary function test abnormalities with quality of sleep and survival in 21 patients with ALS. Results of spirometry including determination of maximal respiratory pressures and arterial blood gases were compared with several formal polysomnographic variables and then also with 18-month survival. The patients had mild to moderate pulmonary function deficits, but the quality of sleep was best related to age (mean age, 58.5 years). The results of pulmonary function tests and arterial blood gas measurements did not correlate well with the presence of nocturnal breathing events or survival time, but the maximal inspiratory pressure was 86% sensitive for predicting the presence of a nocturnal oxygen saturation nadir of 80% or less and 100% sensitive for predicting 18-month survival. Although obstructive breathing events occurred, the primary explanation for the decline in nocturnal oxygen saturation was hypoventilation. We conclude that routine pulmonary function tests may be useful for screening for reductions in nocturnal oxygen saturation and also may have prognostic value. Further studies may determine whether treatment of nocturnal hypoventilation will have an effect on survival in patients with ALS who have breathing impairment.

Adult↗
PubMed1991

Failure of motor evoked potentials to predict neurologic outcome in experimental thoracic aortic occlusion.

Motor evoked potential monitoring was tested as an alternative to somatosensory evoked potential monitoring in evaluating spinal cord function during thoracic aortic occlusion in dogs. Twenty-seven animals underwent 60 minutes of cross-clamping of the proximal descending thoracic aorta with (n = 18) or without (n = 9) cerebrospinal fluid drainage. Spinal cord blood flow was measured with microspheres, and neurologic outcome was evaluated at 24 hours with Tarlov's scoring system. Cerebrospinal fluid drainage improved neurologic outcome (p less than 0.05). Motor evoked potentials recorded over the lumbar spinal cord were lost in 9 of 20 dogs with ischemic cord injury and were not lost in any of the 7 dogs that were neurologically normal. Somatosensory evoked potential were lost in 19 of 20 paraplegic/paraparetic dogs and lost in 3 of 7 normal dogs (p less than 0.01). After reperfusion, motor evoked potentials returned in all nine neurologically injured dogs that lost the potentials and were still present at 24 hours. Changes in amplitude, latency, or time until loss or return of motor evoked potentials or somatosensory evoked potentials did not predict neurologic injury. Loss of somatosensory evoked potentials had a high sensitivity (95%) but had low specificity (67%) because of peripheral nerve ischemia. Loss of motor evoked potentials recorded from the spinal cord had high specificity (100%) but a low sensitivity (46%) and was therefore not a reliable predictor of neurologic injury. Return of motor evoked potentials during reperfusion did not correlate with functional recovery. Motor evoked potentials stimulated in the cortex and recorded from the spinal cord had low overall accuracy (59%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

When is an apparent excess of neurologic cases epidemiologically significant?

To conserve clinical and public health resources, it is necessary to screen reports from the community of an excess or cluster of cases of chronic neurologic diseases for potential epidemiologic significance, ie, to identify those clusters that may have occurred owing to the operation of an underlying etiologic cause rather than to chance alone. Traditionally, the probability that such a cluster has occurred by chance within the reporting community is computed, ignoring the fact that many other similar communities have not reported a cluster. We propose a modified approach that takes this larger universe of communities into account, thereby raising the threshold for potential epidemiologic significance. As a result, the lowest value for the ratio of observed-to-expected cases that may be considered of epidemiologic significance should be increased by factors of 2 for small clusters (one to three expected cases), 1.5 for intermediate clusters (seven to 30 expected cases), and 1.3 for large clusters (60 to 90 expected cases). Consequently, case ascertainment and full field investigations can be reserved for only those reports that, if confirmed, would represent a cluster not due to chance alone. We illustrate this with a case from our own experience.

Amyotrophic Lateral Sclerosis↗
PubMed1991

Late effects of paralytic poliomyelitis in Olmsted County, Minnesota.

We identified a cohort of 300 individuals who had paralytic polio between 1935 and 1955. All lived in Olmsted County, Minnesota. From the 247 survivors, we selected 50 subjects for detailed historical, functional, psychological, clinical, and electrophysiologic evaluation. Sixty-four percent of these 50 survivors complained of new symptoms of muscle pain, fatigue, and weakness after a period of prolonged stability. This led to changes in lifestyle or activity in only 18%. The likelihood of expressing new complaints was not related to present age or interval since polio, and electrophysiologic testing did not distinguish between those with or without new problems. The development of new difficulties in a limb was most strongly predicted by significant paralysis of that limb at the time of the acute illness. Patients with leg weakness were twice as likely to complain of new problems compared to those with arm weakness. Elevated creatine kinase levels were present only in those with new complaints.

Cohort Studies↗
PubMed1991

Epidemiologic correlates of sporadic amyotrophic lateral sclerosis.

We evaluated 74 selected patients with amyotrophic lateral sclerosis (ALS) and 201 matched controls for risk factors for ALS by a case-control design and a sequential questionnaire/interview technique to quantitate biographic data. We analyzed occupational and recreational data only for 47 male patients and 47 corresponding patient controls; data for women were insufficient. We used nonparametric analyses to evaluate five primary comparisons of ALS patients with controls: (1) more hard physical labor, p not significant (NS); (2) greater frequency of neurodegenerative disease in family members, p NS; (3) greater exposure to lead, p less than 0.05; (4) more years lived in a rural community, p NS; and (5) more trauma or major surgery, p NS. Men with ALS had worked more frequently at blue-collar jobs (although not a statistically significant difference, p = 0.10) and at welding or soldering (p less than 0.01). These results suggest that there may be an association between ALS in men and exposure to lead vapor. The limited nature of the association favors a multifactorial etiologic mechanism of ALS.

Adult↗
PubMed1990

Does low-intensity helium-neon laser irradiation alter sensory nerve active potentials or distal latencies?

The effect of 1 mW helium neon continuous-wave (0.633 microns) laser irradiation on superficial radical sensory and median sensory nerve function was examined in a double-blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low-energy lasers of this power and wavelength alter nerve function.

Action Potentials↗
PubMed1990

A comparison of magnetic and electrical stimulation of spinal nerves.

The utility of the magnetic coil for stimulation of the cervical spinal nerves was compared to electrical stimulation by a monopolar needle cathode placed onto the spinal lamina in six volunteers. No statistical difference in average amplitudes or areas of evoked CMAPs was found although the size of the magnetic coil evoked potentials was less at C7-8 in several subjects. Electrical stimulation resulted in depolarization at a more proximal site. Electrical stimulation was associated with more discomfort, especially at C5-6. We conclude that electrical stimulation using a monopolar needle as the cathode is the superior technique for the clinical electrophysiologic study of the proximal brachial plexus and cervical spinal nerves.

Action Potentials↗
PubMed1990

The electrophysiologic profile of Dejerine-Sottas disease (HMSN III).

Electrophysiologic studies in 11 patients with Dejerine-Sottas disease (hereditary motor and sensory neuropathy type III, HMSN III) showed median and ulnar motor nerve conduction velocities less than 6 m/sec in all but 1 patient. Marked temporal dispersion without conduction block was present in all patients. Uniform slowing in adjacent motor nerves was consistent with other studies of inherited neuropathies, although marked temporal dispersion may make HMSN III more difficult to distinguish from acquired neuropathies than other hereditary conditions. The electrophysiologic features of HMSN III patients were significantly different from a series of patients with other hereditary neuropathies chosen because of very slow nerve conduction velocity.

Adolescent↗
PubMed1990

How frequently does classic amyotrophic lateral sclerosis develop in survivors of poliomyelitis?

There is a paucity of reports of classic amyotrophic lateral sclerosis (ALS) developing in survivors of paralytic poliomyelitis. We describe a patient with classic ALS and an antecedent paralytic disease thought to have been poliomyelitis from which she recovered completely. If the paucity of ALS preceded by true poliomyelitis is not merely a matter of underreporting, antecedent paralytic poliomyelitis may have a protective role against the development of ALS. This has implications relevant to pathogenesis and to projected secular trends of ALS incidence since the introduction of poliomyelitis vaccines. There is a need to establish the incidence of cases of classic ALS in patients with antecedent poliomyelitis.

Aged↗
PubMed1990

The syndrome of acute sensory neuropathy: clinical features and electrophysiologic and pathologic changes.

We followed 42 patients with clinically defined pure sensory neuropathy of acute or subacute onset for 2 to 35 years. The symptoms began in the upper limbs in 23 patients, in the lower limbs in 13, symmetrically in all 4 limbs in 4, and the face was 1st affected in 2. For 19 patients, the symptoms began asymmetrically. Electrophysiologic testing typically showed absence of sensory potentials. Spinal fluid was usually acellular with a normal protein level. Sural nerve biopsy in 22 patients showed loss of large myelinated fibers and axonal atrophy without inflammation. Six of the patients died: 4 of unrelated causes and 2 of subdural hemorrhages. Only 2 patients had severe functional impairment. Twenty-two had significant sensory deficit but were able to carry out most of their usual activities. In 8, the symptoms had resolved completely. The acute, often focal onset suggests an immune-mediated or vascular process at the level of the posterior root or dorsal root ganglion.

Aged↗
PubMed1989

3,4-Diaminopyridine in the treatment of Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome is characterized by muscle weakness, hyporeflexia, and autonomic dysfunction, which result from impaired release of acetylcholine from cholinergic nerve terminals. It is frequently associated with cancer, it is autoimmune-mediated, and treatment has been unsatisfactory. 3,4-Diaminopyridine enhances the release of acetylcholine. In this prospective, double-blind, placebo-controlled crossover study of 12 patients with Lambert-Eaton myasthenic syndrome (7 of whom had cancer), 3,4-diaminopyridine in doses up to 100 mg per day was effective in treating both the motor and the autonomic deficits of the syndrome. Muscle strength increased from an average of 70 percent of normal to 81 percent of normal in the upper extremities, and from 45 to 65 percent of normal in the lower extremities. The amplitudes of compound-muscle-action potentials nearly doubled, increasing from an average of 2.9 mV to 5.0 mV in the arm and from 1.6 mV to 3.1 mV in the leg. Autonomic symptoms were relieved. One patient had a seizure after 10 months of treatment, but other side effects from the drug were minimal and dose-related. We conclude that 3,4-diaminopyridine, either alone or in conjunction with other therapies, may be useful in the treatment of Lambert-Eaton myasthenic syndrome.

4-Aminopyridine↗
PubMed1989

Electromyographic evaluation of an accessory hand muscle.

Accessory hand muscles consistent with extensor digitorum brevis manus muscles were noted in a young woman. Well-defined compound muscle action potentials were elicited in these muscles with stimulation of the radial nerve. Needle electromyography showed poor recruitment and large motor unit potentials with frequent cramp discharges only in the anomalous muscles. Therefore, the extensor digitorum brevis manus is innervated by the posterior interosseous nerve, and symptoms may be due to chronic denervation and cramping.

Adult↗
PubMed1989

Diazepam improves recording of lumbar and neck somatosensory evoked potentials.

To determine whether the decrease in muscle artifact provided by diazepam is of sufficient clinical value to justify its use, somatosensory evoked potentials recorded in examinations of 73 consecutive patients were compared with those recorded from 33 subsequent patients who were given 10 mg of diazepam orally just before the examination. With diazepam pretreatment there was clear improvement in the quality of lumbar and neck recordings--increased reproducibility and definition and ease of measurement--and also greater tolerance of the procedure and a slight shortening of time required for the test.

Adult↗
PubMed1989

Preferential activation of muscle fibers with peripheral magnetic stimulation of the limb.

Magnetic and electric activation of limb nerve and muscle were compared in normal subjects of different age, gender, and habitus. Direct stimulation of nerve and muscle showed that activation of intramuscular nerve fibers in the arm and leg occurs at a lower threshold for magnetic stimulation than for electric stimulation. Sensory nerve fibers had a lower threshold with electric stimulation. Muscle activation and stimulus artifact with magnetic stimulation precluded reliable recording of distal sensory nerve action potential in all subjects.

Adult↗
PubMed1989

Electrophysiological signs of arteriovenous malformations of the spinal cord.

A characteristic pattern of electrophysiological changes was found in 24 patients with confirmed spinal cord arteriovenous malformations (AVMs). The AVMs were limited to the thoracic cord in seven, involved the conus and the cauda equina in 10, and involved all levels in six. Of the patients, 88% had at least one definite electrophysiological abnormality: nerve conduction studies showed abnormal results in 43% (10 of 23), needle electromyography in 77% (17 of 22), and tibial somatosensory evoked potentials in 88% (7 of 8). The pattern of involvement was of scattered, multiple, bilateral thoracolumbosacral radiculopathies, consistent with axonal or neuronal destruction, associated with paraspinal fibrillations or abnormal activation of motor unit potentials. Electrophysiological abnormalities were seen in most patients with lower motor neuron clinical deficit. These abnormalities depended on the caudal extension of the AVM, on an arterial supply at T-10 or below, and on the duration of symptoms. In addition to the expected abnormalities in the distribution of the AVM location, four patients had electrical changes at a distance, which may have been due to venous stasis.

Action Potentials↗
PubMed1988

Lumbar radiculopathy after spinal fusion for scoliosis.

In 184 patients with no preoperative neurologic deficit who underwent operation for idiopathic scoliosis, somatosensory evoked potential monitoring was used. Four patients had neurologic deficits postoperatively. Two patients developed mild signs of intraspinal lesions involving upper motor neurons at high lumbar levels that resolved over 3-5 months. These patients and two others developed evidence of unilateral, moderate, lower motor neuron damage that was confirmed on electromyography. No changes in somatosensory evoked potentials occurred in these patients. Lumbar root damage may be difficult to recognize after operation and should be considered in patients with neurologic deficit after scoliosis surgery.

Adolescent↗