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Jasper R Daube

Publications and source records attributed to Jasper R Daube.

12 recordsLinked to original sources
PubMed2006

Motor unit number estimates--from A to Z.

Quantitation has become an increasingly important part of clinical EMG. Most aspects of peripheral nerve and muscle function can be evaluated quantitatively using commonly available neurophysiologic methods. Because of the effects of collateral sprouting and reinnervation, techniques to measure the number of motor units supplying a muscle have been more difficult to develop. Motor unit number estimation (MUNE) consists of a number of different methods that evaluate the last unmeasured variable in nerve disease. The various MUNE techniques and their common technical issues will be reviewed, and potential clinical and research applications emphasized.

Action Potentials↗
PubMed2006

Motor unit number estimates correlate with strength in polio survivors.

Motor unit number estimation (MUNE) has been proposed as an outcome measure in clinical trials for the motor neuron diseases. One major criticism of MUNE is that it may not represent a clinically meaningful endpoint. We prospectively studied a cohort of polio survivors over a period of 15 years with respect to MUNE and strength. We identified a significant association between thenar MUNE and arm strength, extensor digitorum brevis MUNE and leg strength, and the summated MUNE and global strength of the polio survivors. These findings confirm the clinical relevance of MUNE as an outcome measure in the motor neuron diseases and provide further validation for its use in clinical trial research.

Aged↗
PubMed2006

Electrophysiological findings in a cohort of old polio survivors.

A population-based cohort of poliomyelitis survivors was established and followed for 15 years (mean time since polio was 40 years). Over time, the cohort demonstrated a modest decline in summated compound muscle action potential amplitudes (CMAP) and a moderate decline in the summated motor unit number estimates (MUNE). There was no association between symptoms of late deterioration and magnitude of decline. Rather, the presence of these symptoms was associated with the magnitude of the residual deficits. Two patterns of neuron loss were modeled (linear and proportional decline). The summated MUNE was a more sensitive measure of loss of motor units than was the summated CMAP and appears to be a more valid measure of attritional loss of anterior horn cells. Of these two models of neuron loss, the proportional loss of motor neurons was a better fit of the data than a linear loss.

Action Potentials↗
PubMed2005

A 15-year follow-up of neuromuscular function in patients with prior poliomyelitis.

A population-based cohort of poliomyelitis survivors was established and followed for 15 years (mean time since poliomyelitis was 40 years). Over time, the cohort demonstrated only a modest decline in function as measured by strength measurements, electrophysiologic assessments, and timed functional tasks. There was no association between symptoms of late deterioration and magnitude of decline. Rather, the presence of these symptoms was associated with the magnitude of the residual deficits.

Adult↗
PubMed2004

Decrement in surface-recorded motor unit potentials in amyotrophic lateral sclerosis.

BACKGROUND: A decrement to repetitive stimulation sometimes occurs in ALS. The ability to isolate individual surface-recorded motor unit potentials (SMUPs) indirectly allows the analysis of the decrement by comparing the effect of different rates of stimulation on the size of the isolated SMUP. METHODS: The median or ulnar nerve or both were studied in 11 patients with reduced compound muscle action potential (CMAP) amplitude. Isolated SMUPs were identified and studied using standard electrophysiologic techniques. One- and 3-Hz stimulation frequencies were compared in isolated SMUP by collecting > or =100 responses to a nonvarying stimulus. Changes in individual SMUP size and activation with change in stimulus frequency were compared with the size of the SMUP and with the CMAP decrement to a train-of-four stimulus. RESULTS: Fifteen studies were obtained from the 11 subjects. Eight studies showed a decrement of the total CMAP to a train-of-four stimulus. Twenty-nine well-defined, isolated SMUPs were studied. SMUP size reductions of 1 to 16% occurred with an increase in the stimulus frequency. No conduction block of individual SMUP occurred with the SMUP size reduction. No consistent change in variance was found. The SMUP size reduction was related to the size of the CMAP and the CMAP train-of-four decrement and less so to the size of the SMUP. CONCLUSION: The decrement of the total compound muscle action potential to repetitive stimulation appears to arise from individual surface-recorded motor unit potentials and does not result from loss of activation of the main motor axon. The probable mechanism lies at the nerve terminal and neuromuscular junction. No consistent change in variance occurs with different rates of stimulation.

Action Potentials↗
PubMed2003

Individual attributes versus composite scores of nerve conduction abnormality: sensitivity, reproducibility, and concordance with impairment.

Composite scores may be more sensitive and reproducible than single attributes of nerve conduction for detection of peripheral neuropathy, but this requires validation in large patient cohorts. Also, the concordance of individual attributes versus composite scores with clinical measures of severity has not been tested. Here, we study these issues in prospectively studied cohorts: diabetic patients from Rochester, Minnesota (RDNS; n = 396); chronic inflammatory demyelinating polyneuropathy (CIDP) patients (n = 55); and multifocal motor neuropathy (MMN) patients (n = 18). With specificity fixed at the 97.5 percentile, we found that, in generalized polyneuropathies (diabetic and CIDP), composite scores (especially ones including conduction velocity, distal latencies, and F-waves) of individual or multiple nerves tended to be more sensitive than individual attributes. By contrast, for multiple mononeuropathies, some individual attributes or composite scores of individual nerves were more sensitive than composite scores. In diabetic polyneuropathy, composite scores tended to be more reproducible than individual attributes of nerve conduction. Highly significant correlations were found between individual attributes or composite scores and neurologic impairment in diabetic polyneuropathy and in CIDP; in general, correlation coefficients were higher for composite scores. These correlations were higher for amplitudes than for conduction velocities or distal latencies. We conclude that, with the availability of microprocessors and normative databases, electromyographers may increasingly seek to express nerve conduction abnormality also as composite scores of individual or several nerves.

Diabetic Neuropathies↗
PubMed2003

Effect of changing data collection parameters on statistical motor unit number estimates.

The effect of number of samples and selection of data for analysis on the calculation of surface motor unit potential (SMUP) size in the statistical method of motor unit number estimates (MUNE) was determined in 10 normal subjects and 10 with amyotrophic lateral sclerosis (ALS). We recorded 500 sequential compound muscle action potentials (CMAPs) at three different stable stimulus intensities (10-50% of maximal CMAP). Estimated mean SMUP sizes were calculated using Poisson statistical assumptions from the variance of 500 sequential CMAP obtained at each stimulus intensity. The results with the 500 data points were compared with smaller subsets from the same data set. The results using a range of 50-80% of the 500 data points were compared with the full 500. The effect of restricting analysis to data between 5-20% of the CMAP and to standard deviation limits was also assessed. No differences in mean SMUP size were found with stimulus intensity or use of different ranges of data. Consistency was improved with a greater sample number. Data within 5% of CMAP size gave both increased consistency and reduced mean SMUP size in many subjects, but excluded valid responses present at that stimulus intensity. These changes were more prominent in ALS patients in whom the presence of isolated SMUP responses was a striking difference from normal subjects. Noise, spurious data, and large SMUP limited the Poisson assumptions. When these factors are considered, consistent statistical MUNE can be calculated from a continuous sequence of data points. A 2 to 2.5 SD or 10% window are reasonable methods of limiting data for analysis.

Action Potentials↗
PubMed2003

Edward H. Lambert.

Explore the source record for details and available documents.

Electromyography↗
PubMed2002

Obturator neuropathy: causes and outcome.

To study causes of obturator neuropathy and to correlate them with outcome, we retrospectively studied patients seen at the Mayo Clinic electromyography (EMG) laboratory from 1975 through 1999 with a diagnosis of obturator neuropathy. Twenty-two patients with obturator neuropathy were identified. The clinical outcome of patients with acute obturator neuropathy treated conservatively was good regardless of etiology or severity.

Adult↗