Biomedical subjects

W Trojaborg

Publications and source records attributed to W Trojaborg.

At least 19 recordsLinked to original sources

PubMed1992

Turns-amplitude analysis of the electromyographic recruitment pattern disregarding force measurement. II. Findings in patients with neuromuscular disorders.

Turns-amplitude analysis of the electromyographic recruitment pattern was performed on-line in the brachial biceps muscle of 46 patients with neuromuscular disorders using the mean amplitude as an indicator of force. The parameters, peak-ratio (PR) and number of time intervals (TI) from 0 to 1.5 ms, were increased in patients with myopathy. In patients with neurogenic involvement, the characteristic pattern was a decreased PR and a decreased incidence of TI between 0 and 1.5 ms. The results indicate that the two parameters supplement each other as some of the patients were identified only by one or the other. In patients with myopathy, the method had a higher diagnostic yield than the individual motor unit action potential analysis. The method is objective, fast, and reliable.

Action Potentials↗

PubMed1992

Determination of the segmental sensory and motor innervation of the lumbosacral spinal nerves. An electrophysiological study.

The knowledge of the segmental innervation of the skin and muscles of the lower limb in man is inadequate. For this reason, sensory and motor segmental innervation of the lower extremities was examined by electrophysiological methods in 27 normal subjects, one patient with possible L5 radiculopathy and one with possible lumbosacral plexus affection. Needle electrodes were placed at root levels from L3 to S2 using bony landmarks. The electrode was then placed close to the spinal nerve as indicated by a low (less than or equal to 1 mA) threshold necessary to stimulate motor fibres. The position was controlled by X-ray in 10 subjects. Sensory innervation was determined by recording the sensory action potential evoked by stimulating the saphenous nerve at the medial epicondyle (mainly L3 and L4) and at the medial malleolus (mainly L4 and in some L3), the medial plantar nerve at the first plantar interstice (mainly S1, some L5 and S2), the deep peroneal nerve at the first dorsal interstice (mainly L5, some S1), the sural nerve at the dorsolateral aspect of the foot (mainly S1, some L5 and S2) and at the lateral malleolus (mainly S1, some L5 and S2), and the superficial peroneal nerve at the superior extensor retinaculum (mainly L5, S1). The motor innervation was determined by stimulating the spinal nerves supramaximally and recording the evoked responses from the medial and lateral vastus (mainly L3, L4), the anterior tibial (mainly L5), the peroneus longus (L5, S1), the extensor digitorum brevis (mainly S1), the gastrocnemius (mainly S1), the abductor hallucis (mainly S2) and the biceps femoris (mainly L5, S1). Sensory and motor conduction velocity measurements along the leg and across the lumbosacral plexus indicated that there was no difference in a disto-proximal direction, except for a 10% reduction along the most distal part of the sural nerve which, however, might be explained by utilization time. There was therefore no evidence of gradual tapering of nerve fibres in a distal direction. The proximal motor conduction velocity to the most distally placed muscle (abductor hallucis) was about 20% lower than to the proximally placed muscles (gastrocnemius and biceps femoris) suggesting a general difference in fibre calibre.

Action Potentials↗

PubMed1992

Relationship of age to power spectrum analysis of EEG during sleep.

We describe a method of power spectrum analysis of all-night sleep EEGs in 20 normal subjects aged 18-43 years. The analysis calculates the energy of the whole sleep period, the various frequency bands, and selected sleep stages automatically. The numerical value of the energies was directly comparable between subjects, presented in numbers (microV2s) and displayed as a color density spectral array with fixed power values for each color. A significant relationship between age and power spectra was found, in that total energy/minute was higher in younger subjects than in older. The energy in delta sleep/minute also showed an inverse relationship with age.

Adolescent↗

PubMed1992

Effect of growth hormone on human sleep energy.

OBJECTIVE: We wished, by means of power spectrum EEG analysis, to examine REM and delta sleep energy in adults with high and normal plasma growth hormone (GH) concentration. DESIGN: After a 3-day regular sleep/wake schedule, all-night polysomnographic recordings were performed on two consecutive nights before as well as one year after treatment for acromegaly by adenomectomy. The sleep energy was calculated by power spectrum analysis. PATIENTS: We studied nine patients aged 24-45 years with untreated active acromegaly. The same patients were reexamined one year after adenomectomy when plasma GH concentrations were normal. MEASUREMENTS: The acromegaly was verified biochemically by measuring basal plasma GH concentration and plasma GH during hyperglycaemia as well as insulin-like growth factor. Cerebral computer tomography (CT) and magnetic resonance (MR) scans revealed an intrasellar adenoma in all patients. The resulting sleep records obtained before and after adenomectomy were subjected to power spectrum analysis and a manually blinded sleep scoring. RESULTS: The power spectrum analysis showed that when circulating GH was elevated the energy in the REM sleep per minute was significantly higher compared to the REM energy/min after surgery when GH concentration had normalized. A similar relation was found for delta sleep (stage 3 + 4, deep sleep) where the energy per minute was higher before treatment than after. CONCLUSIONS: The study demonstrates that plasma GH concentration was correlated to sleep energy. During high GH concentration the REM and delta sleep energy were high and normalization of plasma GH was followed by normalization of REM and delta sleep energy per time unit.

Acromegaly↗

PubMed1992

Autoimmune reactions in patients with M-component and peripheral neuropathy.

A study of 17 patients with autoimmune axonal or demyelinating peripheral neuropathy in combination with M-component is described. The M-component was associated with MGUS (monoclonal gammopathy of undetermined significance) in 12 patients, CLL in one patient, Waldenström's disease in one patient, and myeloma in three patients. Immunohistological examination with direct and indirect fluorescence showed binding of antibodies to nerve structures of the same class and light chain as seen in the M-component. In five cases of IgM M-component, the demyelinating neuropathy was caused by binding of the IgM M-protein and complement C3b to myelin-associated glycoproteins (MAG). In 12 cases with axonal neuropathy, binding of IgG to the connective tissue of the peri- and endoneurium was found in 50% of cases, IgM in five cases, and IgD in one case. None of the patients had central nervous system (CNS) symptoms. The clinical and therapeutic difficulties are discussed; only two patients with an acute course responded to immunosuppression. A marked co-expression of other autoimmune phenomena is interpreted in the light of cross-reactions between the autoantibody and similar tissue autoantigens.

Adult↗

PubMed1992

EEG abnormalities in 5,893 jet pilot applicants registered in a 20-year period.

On account of EEG findings in jet pilot applicants examined during 1951-1952, the Royal Danish Air Force (RDAF) accepted EEGs as part of the routine procedures for evaluation of the applicants' fitness. The outlook for a successful completion of the training program was poor for those with a paroxysmal abnormal EEG. As a consequence, candidates were excluded from training on the basis of paroxysmal EEG changes regardless of their clinical findings. During 1956-1975 an EEG was obtained from 5,893 applicants for jet pilot training in the RDAF. Of these, 142 (2.4%) were excluded because of an abnormal EEG. Paroxysmal discharges were induced by intermittent photic stimulation in 90%. Generalized or focal paroxysmal changes were present at rest in 6 applicants, during hyperventilation and sleep in 4 each. Four applicants, although asymptomatic, developed epileptic seizures during intermittent photic stimulation.

Adolescent↗

PubMed1992

Multifocal motor neuropathy with conduction block: is it a distinct clinical entity?

We studied 169 patients with motor neuron disease. Seventeen showed abnormal amplitude reduction of the compound muscle action potential. Ten had focal loss of both amplitude and area across a specific segment (conduction block). Eight of the 10 had slowing of conduction across that segment. Nine were men and had prominent hand involvement. Six had probable or definite upper motor neuron signs. Five of the 10 showed immunologic abnormalities (elevated GM1 antibody titers or paraproteinemia), and eight had had symptoms for more than 4 years. Seven of the 17 patients showed loss of amplitude without corresponding loss of area and focal slowing of conduction (temporal dispersion). Five of the seven were men, five had prominent hand involvement, and five had definite or probable upper motor neuron signs. Two had immunologic abnormalities, and ony one had had symptoms for longer than 4 years. Among 152 patients with no abnormality of conduction, 64% wee men, hands were dominantly involved in 34%, upper motor neuron signs were definite or probable in 72%, and 3% had immunologic abnormalities. None had symptoms for more than 4 years. Because there were so many exceptions, we could not define a unique syndrome by criteria involving conduction block, GM1 antibodies, or lack of upper motor neuron signs. The clinical syndrome associated with multifocal conduction block seemed uniform, however, and patients with conduction block had slower progression if there were no upper motor neuron signs.

Action Potentials↗

PubMed1992

Neuropathies.

Explore the source record for details and available documents.

Diabetic Neuropathies↗

PubMed1991

Experimental autoimmune neuropathy with anti-GM1 antibodies and immunoglobulin deposits at the nodes of Ranvier.

Antibodies to GM1 or Gal(beta 1-3)GalNAc are associated with motor or sensorimotor neuropathy and with motor neuron disease. To investigate the role of these antibodies in the neurological disorder, rabbits were immunized with GM1 or with Gal(beta 1-3)GalNAc-BSA, and studied serologically, electrophysiologically and pathologically. Development of antibodies to the immunizing antigens was associated with a fall in the ratio of the amplitudes of the compound muscle action potential evoked by proximal versus distal stimulation of the sciatic nerve. Pathological studies revealed mild axonal degeneration and immunoglobulin deposits at the nodes of Ranvier in peripheral nerve, resembling those reported in a patient with motor neuropathy, motor conduction block and anti-GM1 antibodies. These studies provide evidence that anti-GM1 or anti-Gal(beta 1-3)GalNAc antibodies cause conduction abnormalities and indicate that the antibodies may exert their effect, in part, by binding at the nodes of Ranvier in peripheral nerve.

Animals↗

PubMed1991

Orthodromic sensory conduction along the ring finger in normal subjects and in patients with a carpal tunnel syndrome.

The purpose of the present study was to examine the value of measuring sensory conduction along the median and ulnar nerves of the fourth finger in the diagnosis of a carpal tunnel syndrome (CTS). In 23 controls, sensory conductions along median and ulnar nerves were identical. In 28 of 38 patients with CTS, stimulation of the ring finger revealed a reduced conduction velocity along sensory median nerve fibres in contrast to normal conduction along ulnar sensory nerve fibres. In 5 patients, a sensory action potential was absent over the median nerve and in another 5 sensory conduction was normal along both nerves. We conclude that testing of sensory conduction along the ring finger is useful in about 74% of patients with CTS, while in the remaining 26% other fingers must be examined to establish the diagnosis.

Adult↗

PubMed1991

Acupuncture in angina pectoris: does acupuncture have a specific effect?

To overcome the methodological problems of blinding the patients and the acupuncturist in acupuncture trials, 33 patients with stable angina pectoris, who were randomized to either genuine or sham acupuncture, received electroacupuncture by another acupuncturist, and the change in skin temperature was recorded. It was found that the change in skin temperature correlated significantly with the degree of improvement following both genuine and sham acupuncture. Fourteen patients with no decrease in skin temperature exhibited a significantly better response to acupuncture than 19 patients who showed a decrease in skin temperature (G II). In the former group, there was a 15% median improvement in exercise tolerance (G II 0%), a 67% improvement in anginal attack rate (G II 38%), and an 84% improvement in nitroglycerine consumption (G II 50%). A significant correlation was found between the duration of disease and the effect of acupuncture. It is concluded that both genuine and sham acupuncture have a specific effect on some angina pectoris patients in addition to the effect of pharmacological therapy.

Acupuncture Therapy↗

PubMed1991

Somatosensory evoked potentials from cervical and lumbosacral dermatomes.

A method for recording the somatosensory evoked potentials after stimulation of the cervical and lumbosacral dermatomes is described. Normative values and their ranges are given for each dermatome including left-right differences. A significant correlation was found between latencies and conduction distance. Dermatomal SEPs may play a role in diagnosing cervical and lumbosacral radiculopathies.

Adolescent↗

PubMed1991

Abdominal muscle paralysis associated with herpes zoster.

We describe a 77-year-old women with cutaneous herpes zoster in the area of the right T9-T11 dermatomes complicated by abdominal muscle paralysis. Four months after onset of paralysis, stimulation of appropriate intercostal nerves failed to evoke responses from the corresponding segments of the rectus abdominis muscle. Three months later EMG of these muscle segments revealed profuse denervation activity and spontaneous long-lasting burst of high frequency discharges. Magnetic stimulation applied transcranially and peripherally at T10 evoked responses from the left, but not from the right paralytic rectus abdominis muscle. Electric stimulation of right T10 elicited a markedly delayed, prolonged and polyphasic response in the transverse abdominis muscle and EMG revealed polyphasia and increased motor unit potential duration in muscle segments underlying herpes zoster eruption. One and a half years after onset, the paralysis of the rectus abdominis muscle was still present. A survey of the literature concerning this rare type of zoster paralysis is presented.

Abdominal Muscles↗

PubMed1991

Sleep in acromegaly before and after treatment with adenomectomy.

Daytime somnolence and fatigue are frequently ignored symptoms in acromegaly. To examine whether sleep apnea or other abnormalities in the sleep structure is the underlying cause, 9 young patients with active untreated acromegaly for 2-7 years were studied with all night polysomnography. It revealed a decrease in REM sleep time in all the acromegalics compared to age- and sex-matched normal subjects (p less than 0.001) and also a reduction in delta sleep (p less than 0.05). None had obstructive sleep apnea. At reexamination 12-15 months posttreatment the daytime sleepiness had disappeared in all patients. REM sleep time increased in all patients (p less than 0.001) to normal level; delta sleep time increased moderately (p less than 0.05). Thus sleepiness in patients with high fasting level of growth hormone (GH) is not related to sleep apnea but more likely to a reduced amount of REM sleep time. By normalizing the GH concentration, REM sleep time became normal and the daytime sleepiness disappeared in all patients.

Acromegaly↗

PubMed1990

[Diaphragm pacing by electric stimulation of the phrenic nerves].

Artificial ventilation by electric stimulation of the phrenic nerves has become clinically significant within the past 20 years and, in the world as a whole, approximately 700 patients have been treated with implanted diaphragmatic pacemakers. The two first patients in whom diaphragmatic pacemakers were implanted in Denmark, had sustained accidental fractures of the second cervical vertebra with subsequent high cervical spinal cord lesions with not only tetraplegia but also respiratory arrest. In both patients, diaphragmatic pacemakers were implanted bilaterally and these were employed for 12-14 hours daily while ventilation with a respirator was employed at night. The main indications for diaphragmatic pacing are paralysis of respiration following high cervical spinal traumata and the chronic central hypoventilation syndrome (sleep apnoea of Undine's curse). Diaphragmatic pacing may improve the mode of ventilation and the quality of life for patients with tetraplegia and respiratory insufficiency. On account of the potential technical problems, the risk of complications and the limited number of patients in whom this operation is suitable, implantation of diaphragmatic pacemakers should be concentrated in a few centres and probably only one in Denmark.

Adolescent↗

PubMed1990

Are there motor fibers in the sural nerve?

A case of anomalous innervation of the abductor digiti quinti of the foot (ADQ) via the sural nerve is described. A muscle action potential from the ADQ could be elicited by stimulation of both the sural and the posterior tibial nerves.

Aged↗

PubMed1990

Quantitative electromyography in polymyositis: a reappraisal.

Manual analysis of motor unit action potentials (MUAPs) was performed in 33 patients with polymyositis of whom 16 were studied in the acute stage and 17 in the chronic stage. Contrary to common description of "myopathic potentials" as being of low amplitude, short duration, and polyphasic shape, the quantitated study revealed no difference as to amplitude of short duration MUAPs in patients and normal subjects though short-duration MUAP and short duration polyphasic potentials were 4 and 3 times, respectively, more common in patients than in controls. Although the mean duration of MUAPs usually was significantly shorter in polymyositis than in controls, the average scatter of MUAPs duration was the same in the 2 groups. The average incidence of polyphasic MUAPs was 4 times higher in patients than in controls, as was the incidence of those of long duration. To avoid misinterpretation of EMG findings due to an excess of polyphasic MUAPs, a greater number of individual potentials than usually recommended should be collected allowing a valid estimate of the mean duration of MUAPs of simple configuration.

Action Potentials↗

PubMed1990

Visual evoked potentials in term light-for-gestational-age infants and infants of diabetic mothers.

The latency and amplitude of the first negative peak of visual evoked potentials (VEP) were evaluated in 52 term infants, investigated within 48 h after birth. Sixteen were light-for-gestational-age (LGA), 16 were appropriate-for-gestational-age (AGA) and 20 were infants of diabetic mothers (IDM). The VEP latency was shorter in LGA infants compared to AGA infants, and it was closely related to the birth weight deviation. The VEP latency was inversely related to gestational age and positively related to head circumference. When corrected for gestational age and head circumference, the VEP latency was not significantly different between the subgroups, nor related to the birth weight deviation, ponderal index or skinfold thickness. Thus, it could be argued that the high conduction velocity in LGA infants is due to stress maturation or alternatively due to the smaller head circumference. The VEP amplitude was higher in LGA infants when compared with AGA infants, and inversely related to the birth weight deviation. No differences were found in VEP latency or VEP amplitude between IDM and AGA infants.

Birth Weight↗