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Biomedical subjects

D O Wiechers

Publications and source records attributed to D O Wiechers.

18 recordsLinked to original sources
PubMed1992

Eosinophilia-myalgia syndrome: myopathic electrodiagnostic characteristics.

Eosinophilia-myalgia syndrome (EMS) is a disorder characterized by generalized muscle pain and eosinophilia. The etiology of this syndrome appears to be related to the ingestion of L-tryptophan. Most studies to date describe an associated peripheral neuropathy or combined myopathy and peripheral neuropathy. This report presents 2 EMS patients with myopathy, confirmed by muscle biopsy in 1 case and electrophysiology in both cases. No clinical evidence of neuropathy was found. Both routine and single fiber electromyography failed to demonstrate abnormalities, suggesting neuropathy. Electrodiagnostic abnormalities paralleled the clinical course. After 10 months, both patients continued to have symptoms of muscle cramping and reduced endurance, with mild electromyographic abnormalities, perhaps reflecting changes in their motor unit.

Aged↗
PubMed1988

New concepts of the reinnervated motor unit revealed by vaccine-associated poliomyelitis.

A late onset of slowly progressive muscle weakness 30-40 years after acute polio is well known. Previous studies by the author and others have demonstrated transmission abnormalities within the reinnervated motor unit. These transmission abnormalities shown by motor unit action potential (MUAP) instability in size and shape with repetitive discharges occurs in postpolio patients who are and who are not complaining of progressive muscle weakness. Although some reinnervated MUAPs do seem to stabilize their neuromuscular transmission with time in mildly affected muscles, the question arises as to whether or not some MUAPs ever stabilize after polio. Two cases of acute polio personally followed by the author, one over a 9 1/2 year period, are presented. In both cases, in muscles where there are more deinnervated muscle fibers than could possibly be reinnervated, the MUAPs have remained unstable. New concepts of function in the reinnervated motor unit following polio are presented.

Action Potentials↗
PubMed1985

Late effects of poliomyelitis. Part I: Report of five cases.

We present five case reports to illustrate the late effects of acute paralytic poliomyelitis occurring many years after recovery. We emphasize the importance of ruling out common medical causes for the symptoms and address the question of a "postpolio syndrome." The cause of progressive muscle weakness 30 to 40 years after recovery from poliomyelitis remains unknown.

Acute Disease↗
PubMed1985

Acute and latent effect of poliomyelitis on the motor unit as revealed by electromyography.

When polio virus attacks the motor neuron it may be completely destroyed, damaged, or unaffected. Muscle fibers of a destroyed motor neuron are orphaned or reinnervated. Nearby functioning motor units will then send terminal axon sprouts to reinnervate the orphaned muscle fibers. If there are too many orphaned muscle fibers and not enough surviving motor units to reinnervate them, the orphaned muscle fibers will continue to fibrillate until they atrophy and die. The resultant effect of poliomyelitis upon the affected muscle is an overall loss of motor units with the remaining units innervating many more muscle fibers than they originally did. There appears to be a late effect of polio upon these larger reinnervated motor units. After approximately 20 to 30 years, impulse transmission to the muscle fibers of the large reinnervated motor unit begins to fail. These transmission difficulties increase with age and time from recovery. These late onset transmission abnormalities may be factors in patient complaints of fatigue and progressive weakness.

Aged↗
PubMed1985

Single fiber electromyography with a standard monopolar electrode.

A technique of obtaining qualitative single fiber electromyography information with standard monopolar electrodes is described. The technique requires an electromyograph equipped with a trigger and delay line. Single fiber electromyography is an effective tool in dealing with disorders that affect neuromuscular transmission and for observing the recovery of nerve injuries. Since most problems encountered in clinical practice deal with the diagnosis and follow-up of radiculopathies and peripheral nerve compromise, the use of single fiber electromyography in these conditions is of great clinical importance.

Electrodes↗
PubMed1985

Results of a survey of 201 polio survivors.

We present the results of a survey on the late effects of poliomyelitis in 201 persons. The most common new problems were fatigue, weakness in previously affected and unaffected muscles, muscle pain, and joint pain. The median time from poliomyelitis to onset of new problems ranged from 30 to 40 years. Factors at onset of polio most strongly associated with development of these late effects of polio were (1) hospitalization (P less than 0.00001), (2) age greater than 10 years (P less than 0.00001), (3) ventilator use (P less than 0.0029), and (4) paralytic involvement of all four limbs (P less than 0.0240). The differential diagnosis of these new problems, implications for treatment, and areas for future research are discussed.

Activities of Daily Living↗
PubMed1980

Oral telescoping orthosis: an aid to functional rehabilitation of quadriplegic patients.

The possibility of periodontal disease, chipping of various teeth, or extrusion from use of a mouthstick is minimized with a mouthpiece that covers the complete dentition. Even the simplest of these devices permits increased function for the quadriplegic patient. A case is reported of a young man for whom the oral telescoping orthosis was fitted with a mouthpiece that covered the complete dentition. Damage to the hard or soft tissue structures has not been apparent in eight years of use. Furthermore, the functional capability of the patient has been enhanced. The oral telescoping orthosis is recommended for motivated quadriplegic patients who retain sufficient control of the head and oral and pharyngeal muscles.

Adult↗
PubMed1979

Electromyographic changes reviewed in chronic spinal arachnoiditis.

A retrospective study was done to determine if specific electromyographic findings are present in spinal arachnoiditis. The electromyographic (emg) findings in 32 surgically and 35 myelographically diagnosed cases were examined. The cases were categorized into 3 groups. The 1st groups consisted of 37 cases with surgical or myelographic evidence believed to be highly diagnostic of multilevel chronic spinal arachnoiditis. The 2nd group was composed of 23 cases with surgical or myelographic evidence consistent with a localized problem. The 3rd group was a control group with normal or minimal changes on myelography or at surgery. Electromyographic findings were divided into 3 groups of changes: localized, nonlocalized or normal. Localized emg changes were considered to be present over 2 or less root levels in either or both anterior or posterior primary ramus distribution. Nonlocalized changes occurred over more than 2 such levels. A comparative analysis of the myelographic and surgical findings with the emg changes indicated that there was not diagnostic emg picture indicative of chronic spinal arachnoiditis.

Arachnoiditis↗
PubMed1979

Electromyographic insertional activity in normal limb muscles.

A mechanical electrode inserter was used to allow reproducible electromyographic (emg) electrode insertions. The electrical activity provoked by the mechanical insertion was recorded and quantitatively analyzed in the anterior tibialis, the extensor hallucis longus, and the extensor digitorum brevis of unimpaired human subjects. No statistically significant differences were found among these muscles in the total duration of sharp spike activity or in the duration of sharp spike activity following cessation of needle electrode movement. There was a statistically significant reduction in the total duration of mechanically-provoked electrical activity in the extensor digitorum brevis when compared to the anterior tibialis using the technique employed in this study. There was a statistically significant increase in time following the onset of needle electrode movement until the initiation of sharp spike activity in the extensor hallucis longus as compared to the anterior tibialis. Abnormalities are present in the extensor digitorum brevis muscle of clinically unimpaired subjects. Endplate spikes can be recorded as positive-shaped potentials in the endplate zones of muscle. Nonreproducible positive-shaped potentials of unknown etiology are seen to occur singly or in pairs following insertional activity in normal muscle. When examining muscle for the early evidence of provokable positive sharp wave and fibrillation potentials, care must be taken not to mistake normal characteristics of insertional activity for pathological abnormalities.

Electrodes↗
PubMed1979

EMG needle electrodes: electrical impedance.

The electrical impedance of samples of stainless-steel monopolar needle electrodes and concentric electrodes from 3 manufacturers were measured in 154mM saline solution using sine-wave excitation at 4 frequencies from 10Hz to 10kHz. Current densities of less than 2.5x10(-5) amp/cm2 were used. Measurements on both needle and fine-wire electrodes were also made in live rats. Linear dimensions of the exposed tips were measured from which the areas of exposure were calculated. Surface areas of the monopolar needles varied between 0.06 and 0.15mm2. Presoaking of the electrodes for 20 minutes in saline solution containing a small concentration of a wetting agent produced a sixfold to twentyfold reduction in impedance. The average impedance magnitudes of the monopolar electrodes ranged from 1.4 megohms (Momega) at 10Hz to 6.6 kolohms (komega at 10kHz. The phase angle of the impedance due to the capacitive component of the needle-electrolyte impedance ranged between -45 and -71 degrees. The reduction in impedance resulting from presoaking and the concomitant reduction in electronic noise would be an advantage in observing lowamplitude potentials.

Animals↗
PubMed1979

Diffuse abnormal electromyographic insertional activity: a preliminary report.

The authors observed 10 patients referred for electromyographic examination in whom EMG findings were normal except for the presence of provoked positive sharp waves in essentially every muscle tested. The positive sharp waves were present only following needle electrode insertion. No fibrillation or fasciculation potentials were seen. Motor unit action potentials were normal, as were nerve conduction and repetitive stimulation studies. The quantity of provoked positive sharp waves was found to vary from time to time, from muscle to muscle and from 1 region of the muscle to another. Detailed clinical evaluations for neuromuscular disorders, electrolyte and metabolic abnormalities and underlying carcinomas were negative. Muscle biopsy in 2 patients, including histochemical analysis in one of them, was normal. Results of single-fiber electromyography were normal in 1 patient. The abnormality was found in family members and appears to be of an autosomal dominant inheritance.

Action Potentials↗
PubMed1979

Evaluation of equine radial and median nerve conduction velocities.

Eleven ponies and 13 horses were used to develop a technique for determining conduction velocity for the radial and median nerves and establishing normal limits for these values. One pony was euthanatized to determine the course of the radial and the median nerves. From this dissection, both proximal and distal stimulation sites for the radial and the median nerves were selected, as well as areas for recording muscle evoked responses from the abductor digiti I longus (extensor carpi obliquus) and the radial head of the deep digital flexor muscles. The other ten ponies and the horses were used in studies on the stimulation of the nerves and recording of muscle evoked responses from which conduction velocity could be calculated. Conduction velocities for the radial and the median nerves were calculated and recorded.

Animals↗
PubMed1977

Mechanically provoked insertional activity before and after nerve section in rats.

Mechanically provoked insertional activity was recorded at intervals prior to and through the development of positive sharp waves and fibrillation potentials in the gastrocnemius and soleus muscle group of eight male Wistar rats in the normal state, and after the sciatic nerve was cut at the sciatic notch. The wave form and duration of injury potentials were analyzed. Positive sharp waves were found to occur prior to the development of fibrillation potentials. No significant increase in the duration of injury potentials was noted prior to the development of positive sharp waves and fibrillation potentials. The frequent clinical use of the term "prolonged" or "increased" insertional activity as an abnormal finding in a continuum to positive sharp waves is questioned.

Action Potentials↗
PubMed1976

Measurement of motor unit action potentials: procedural considerations.

Many factors influence the observed magnitude and shape of motor unit action potentials (MUAP). Several of these are related to procedures used during the electromyographic examination. An examiner must be aware of the procedural factors which may alter his observations. These include the following: strength of contraction; placement of the ground and reference electrodes; site, depth and pattern of electrode penetration; distance of active electrode penetration; distance of active electrode discharging unit; and separation of observation sites. The number of different MUAP observed and the number of observations of each MUAP become important when formulating a statistical report. The acceptable level of variation between serial samples of the same motor unit may determine the number of different units available for analysis. The selection of the point where the MUAP begins, ends and deflects maximally can influence the recorded observations.

Action Potentials↗
PubMedDate not supplied

Lack of benefit of allopurinol in Duchenne dystrophy.

A double-bline, controlled study was conducted to assess the effects of allopurinol on Duchenne muscular dystrophy. Six patients--three treated with allopurinol and three given a placebo--were followed up for one year and were evaluated by functional and manual muscle testing as well as by determination of serum creatine kinase (CK) levels. Patients in both the allopurinol-treated group and the placebo group deteriorated at varying rates without evidence of therapeutic benefit. To exclude the possibility of error attributable to small sample size, all six patients were treated with allopurinol for an additional eight-week period. Muscle strength continued to deteriorate during this phase of the study.

Allopurinol↗
PubMedDate not supplied

Late changes in the motor unit after acute poliomyelitis.

Patients who have suffered an acute attack of poliomyelitis may develop a clinically evident progression of weakness later in life. A syndrome known as forme fruste amyotrophic lateral sclerosis occurs in severely affected older polio patients. Neither process is well understood. Ten subjects who had had polio at least 22 years prior to examination and had no complaints of rapid progression of weakness were studied. Single-fiber recordings were made from the extensor digitorum communis or the tibialis anterior muscle. Fiber densities were increased in all patients. Eight of 10 patients showed marked abnormalities in jitter in more than 50% of the recordings examined. There was a significant association between the percentage of recordings with abnormal jitter and the time since the attack of polio. Blocking was seen in more than 30% of the recordings examined in 6 of 10 patients. There was a significant association between the percentage of recordings demonstrating blocking and both the chronological age and the number of years since the attack of polio. These abnormalities may represent disintegration with aging in the reinnervated motor units.

Acute Disease↗