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Biomedical subjects

E W Johnson

Publications and source records attributed to E W Johnson.

At least 127 records · Page 7Linked to original sources
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

Total joint arthroplasty. The knee.

Total knee replacement has become an established form of treatment for gonarthrosis and usually results in excellent relief of pain and approximately 90 degrees of joint motion with satisfactory joint stability. The anatomic stability that cannot be restored at surgery must be provided for by additional prosthetic stability. Fixation of prosthetic devices, particularly in the tibia, is marginal and results in an increased incidence of loosening when the quality of bone is weak, as in osteoporosis, or when shear stress is increased because of malalignment or prosthetic constraint. Resurfacing techniques provide the greatest options if surgical revision is necessary. Surgical goals should be realistically assessed so as to maintain the best potential for future treatment options.

Arthroplasty↗
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↗
PubMed1977

Auditory test results in 500 cases of acoustic neuroma.

Auditory test results in the first 53 causes of this series of 500 acoustic neuromas were reported in 1964. Subsequent studies involving larger numbers of patients detailed new results based on these additional cases. Five hundred cases of surgically confirmed acoustic neuromas were analyzed. Pure-tone loss configurations, speech discrimination, auditory adaptation as measured by the modified tone decay test, Bekesy audiometry, short increment sensitivity index test, and alternate binaural loudness balance test data were evaluated. The results of this investigation in general confirm previous studies, although percentage figures for positive tests differed in the large series. Acoustic reflex results were reported for those patients evaluated more recently. Slightly more than half of the cases had inconsistent audiometric results in one or more aspects. Inconsistencies to the tests were examined in detail. Consistent responses to the tests appear to be related to the size of the lesion. The full battery of audiologic tests is of importance in the differential diagnosis of acoustic neuromas.

Adolescent↗
PubMed1977

Huntington disease: early indentification by H reflex testing.

This investigation was undertaken to determine the potential use of the H reflex of Hoffmann as a means of early detection of Huntington disease. Three groups of subjects were tested: 9 having Huntington disease, 8 first-generation offspring "at risk" of Huntington disease, and 30 normal persons as controls. The deep peroneal nerve was stimulated by a monopolar needle electrode, and the muscle potentials of the anterior tibialis and the extensor digitorum brevis were recorded with surface elctrodes. The action potentials were examined for the direct M response and the presence or absence of an H reflex response. The H reflex response was found in the anterior tibialis muscle, at least unilaterally if not bilaterally, in eight of nine subjects with Huntington disease and in five of eight persons at risk. The H reflex was present in 1 of 30 controls unilaterally. This significant difference between the patients with Huntington disease and at risk subjects compared to the control group, indicates that H reflex testing may be useful for the early identification of at risk individuals who will ultimately develop Huntington disease. This would be most helpful in family counseling terms, and also may aid in further understanding of this complex diseases.

Adolescent↗
PubMed1977

Does allergy play a role in fibrositis?

Twenty patients with active fibrositis and no underlying disease (and with normal electromyographic findings) were evaluated for the possible role of an active allergic process in their conditions. A definite atopic history was obtained in just fewer than 50% of the patients, and an allergic diathesis in slightly more than 50% of the patients' families. Serum immunoglobulin E levels and eosinophil counts for all 20 patients fell within the normal range. Thus the traditional allergic reaction (type I hypersensitivity) would seem unlikely as a mediator of fibrositis.

Adult↗
PubMed1977

Electromyographic insertional activity mechanically provoked in the biceps brachii.

Clinically, some electromyographers have felt that electrical activity provoked by needle insertion becomes prolonged prior to the development of positive sharp waves and fibrillation potentials in pathologic conditions. The significance of this is unclear as this electrical activity has not been quantitatively studied in normal subjects. To approach this problem, this study was designed to evaluate insertional activity in normal subjects. A mechanical electrode inserter was designed and assembled. Insertional activity was recorded and analyzed in 20 normal subjects. Sharp spike activity, a component of the total insertional activity, was found to continue for 48 +/- 18 msec following the cessation of electrode movement in the biceps brachii.

Electrodes↗
PubMed1977

Walter J. Zeiter Lecture: pathokinesiology of Duchenne muscular dystrophy: implications for management.

Management of Duchenne muscular dystrophy from the beginning of Duchenne's description has always been fragmentary. Even today the operations recommended, bracing suggested and exercise regimens prescribed are not coherent with the pathokinesiologic features of the condition. A review of the course of Duchenne muscular dystrophy in 90 patients over a 16-year period clarified the pathokinesiology of this predictable progressive condition.

Child↗
PubMed1977

Infantile Erb's palsy (Smellie's palsy).

Our experience with 32 infants seen with Erb's palsy, of whom 11 were followed as long as 18 years, suggests two management axioms. First, it is probably harmful to the infant to use airplane splints. Seocnd, passive stretching of the tight scapulohumeral adductors and passive normal range of motion exercises to shoulder and elbow will usually give a successful outcome in this obstetrical complication. Finally, even though the shoulder muscles regain their strenght, the "Erb engram" may remain as a mark of Erb's palsy.

Child↗
PubMed1977

Results after hemiarthroplasty of the hip using a cemented femoral prosthesis. A review of 109 cases with an average follow-up of 36 months.

Hip arthroplasty using the Thompson femoral prosthesis with methyl methacrylate fixation was performed on 109 hips in 106 patients. During an average follow-up period of 36 months, 26 patients died. Fifty-one procedures were performed for fresh fractures of the femoral neck and results were satisfactory in this group provided the patient was minimally active. Results were unsatisfactory in patients who had idiopathic avascular necrosis (18), painful, failed noncemented prostheses (6), and osteoarthritis (3). In these last three groups, one-half required conversion to total hip arthroplasty and an additional one-third had pain. Reoperation was required in 22 cases. Intraoperative death occurred in one elderly patient after insertion of cement. Results suggest that the primary indication for this procedure is in the minimally ambulatory or nonambulatory elderly osteoporotic patient who has a fresh fracture of the femoral neck.

Adult↗
PubMed1976

Physiological and morphological effects of post-ganglionic axotomy on presynaptic nerve terminals.

1. Electrophysiological and electron microscope studies were done on cells in the ciliary ganglion of chickens which had been axotomized on the day of hatching. 2. By the third day after post-ganglionic axotomy both electrical and chemical transmission through the ganglion were severely depressed; by the fifth day ganglionic transmission had disappeared. 3. Action potential initiation and conduction in axotomized cells and in their associated presynaptic nerve terminals were unimpaired 3-4 days after axotomy. 4. Depression of ganglionic transmission in 3-4 day axotomized preparations was due to a reduction in amplitude of both the excitatory post-synaptic potential (e.p.s.p.) and the electrical coupling potential in individual ganglion cells. 5. In addition to being reduced in amplitude, e.p.s.p.s in axotomized cells were more subject to fatigue during low frequency (1/sec) stimulation. 6. The reduction in e.p.s.p. amplitude was due to a reduction in both the mean quantal content of the e.p.s.p.s and the calculated depolarization produced by an individual quantum of transmitter. On the average the e.p.s.p. was reduced by a factor of about 4, the mean quantum content to about two thirds normal and the quantal size to about a third normal, compared with responses in unaxotomized cells of the same age. 7. Ultrastructural studies revealed a progressive maturation of pre-synaptic terminals in normal ganglia between 0 and 9 days after hatching. Over this period the content of synaptic vesicles and mitochondria in the terminals increased and the background matrix became more dense. 8. After axotomy these signs of maturation was abolished or reversed, particularly from the third day onward. In addition there was an increase in the number of cell sections in which no synaptic terminals were observed. 9. It was concluded that loss of synaptic transmission was due to at least three factors: a reduction in release of transmitter from presynaptic terminals, a reduction in quantal size, probably due to a loss of post-synaptic sensitivity, and a partial loss of presynaptic contact.

Action Potentials↗
PubMed1976

Errors in EMG reporting.

In a review of 112 electromyographic reports from 112 different electromyographers, errors were classified as anatomic, terminologic, technical and interpretative. Ninety-seven of the reports had substantive errors. The EMG report should be complete, precise, accurate and logical and include a summary of the anatomic and neurophysiologic data with a translation into a probable clinical diagnosis.

Diagnostic Errors↗
PubMed1976

Electromyographic findings in the extensor digitorum brevis in a normal population.

Some electromyographers suggest the diagnosis of radiculopathy when electromyographic examination reveals abnormalities in only one muscle, the extensor digitorum brevis. We studied 70 volunteers free of neuromuscular disease and found electromyographic abnormalities in 11. We conclude that abnormal electrical activities found solely in the extensor digitorum brevis may not be diagnostically signifcant for lumbosacral radiculopathy.

Action Potentials↗