Biomedical subjects

N Mayr

Publications and source records attributed to N Mayr.

At least 37 records · Page 2Linked to original sources

PubMed1991

The sensitivity of transcranial cortical magnetic stimulation in detecting pyramidal tract lesions in clinically definite multiple sclerosis.

We determined central motor conduction time (CMCT) (motor cortex to root C-8 and motor cortex to root S-1) as well as the amplitude of the compound muscle action potentials in the hypothenar and the abductor hallucis muscles on both sides in 44 patients with definite MS. We compared the values with standards obtained from 86 healthy controls and correlated them with the degree of clinical deficit of the limbs examined. Thirty-nine patients (88.6%) showed a prolonged CMCT. By comparison, only 74.4% of patients had abnormal visual evoked potentials.

Action Potentials↗

PubMed1991

[The prognostic value of evoked potentials in early neurologic rehabilitation of patients with the apallic syndrome].

In 22 patients with apallic syndrome brainstem auditory and somatosensory evoked potentials were recorded, in 8 patients the course during rehabilitation was observed. Clinically the patients were scored with Glasgow-coma scale, Karnofsky-index and Goldenberg-scale. The outcome of rehabilitation was estimated by the "Glasgow-outcome scale". No correlation was found between results of evoked potentials and clinical state. First evoked potentials measurements of apallic patients allowed no prognosis. Evoked potentials are an important prognostic factor after severe head trauma, but have no value for the prognosis of apallic patients.

Adolescent↗

PubMed1991

[Sleep and epilepsy].

The frequency of epileptiform discharges shows a wide intraindividual variability; it is influenced by the sleep-waking cycle and by the different stages of sleep: generalized seizures (tonic-clonic, tonic and myoclonic) are activated in nonrapid eye movement sleep, partial seizures tend to have more complex relationships with sleep states. Generally, sleep stages I and II and transit stages have an activating effect on discharges. Rapid eye movement sleep has an "anticonvulsive" effect and focalizes paroxysmal activity. Sleep recordings are useful for localizing a focus in temporal lobe seizures and for differentiation of epileptic seizures from non-epileptic seizure-like sleep disturbances. EEG after sleep deprivation should be used in patients suspected of suffering from epilepsy whose prior EEGs (including hyperventilation, photic stimulation and short sleep) were normal or yielded borderline abnormalities. Epileptiform discharges can--without clinical seizures--produce arousal reactions and sleep disturbances.

Cerebral Cortex↗

PubMed1990

[The value of evoked potentials in brain death diagnosis].

At the moment evoked potentials in Austria are not admitted for diagnosing brain death. Brainstem auditory evoked potentials are proving the loss of the brainstem function, if a primary supratentorial lesion is excluded and if they disappear bilaterally and stepwise. The early components of somatosensory evoked potentials after median nerve stimulation allow the examination of the brainstem and the cortical function, if medullary lesions are excluded. In our study evoked potentials were recorded in 23 patients with bulbar brain syndrome and isoelectric EEG: In 21 (47%) of the 45 examined hearing pathways a component I and in 3 pathways (7%) a component II was found. In 41 examined pathways of median nerve a complete loss of the spinal response was observed in 12 pathways, whereas in 29 pathways (71%) the spinal response was preserved.

Adolescent↗

PubMed1990

[Possibilities and limitations of the automatic analysis of sleep stages using the Oxford system].

34 ambulatory polygraphic sleep-records of young adults were carried out using the Oxford Medilog 9000 recorder. All of the records underwent automatic evaluation by the Oxford Sleep Stager. 10 cases were, in addition, evaluated visually. 4 records could not be analyzed because of artifacts. Thus, 30 subjects were used in the end for establishing standard values of sleep parameters. Automatic versus automatic comparisons and automatic versus visual comparisons of ten polysomnograms were performed epoch-by-epoch. The automatic versus automatic comparison showed agreement in 85.5% of epochs, and the automatic versus visual comparison in 70.4% of epochs. The Sleep Stager showed the best agreement with the visual evaluation in epoch-by-epoch comparison in the REM-stage (93.9%), the worst in stage 1 (32.4%). In calculating the percentages of total night sleep for the respective sleep stages, the automatic analysis showed strongest disagreement with visual evaluation in the REM-stage (plus 7.5%) and in stage 2 (minus 5.2%).

Adult↗

PubMed1990

[The significance of EMG artefacts in isoelectric EEG].

Five potential organ donors showed muscle artefacts during isoelectrical EEG recording. The electromyographic examination revealed MUAP activity occurring as doublets, triplets and quadruplets. All patients had normal blood chemistry except reduced CO2 and increased O2 partial pressures. We assume that the recorded "tetaniform" muscle activity is due to hyperexcitability of the nerve membrane caused by artificial hyperventilation.

Adult↗

PubMed1990

[Transarterial EEG in superselective cerebral angiography].

Transarterial EEG-recording is a complementary method to surface and depth-techniques. In 8 patients having superselective angiography because of diagnosis or therapeutic manoeuvres transarterial EEG-recording was performed. There were only few artefacts and no clinical side effects. The value of this additional information is discussed.

Adult↗

PubMed1989

[The variability of the number and daily distribution of spike wave seizures in two 24-hour long-term EEG recordings made one shortly after the other].

30 patients suffering from primary generalized epileptic seizures were investigated twice in intervals of 1-7 days by means of mobile long-term-EEG monitoring. The total number of paroxysms showed a variability from 53% to 187%, the time of maximum paroxysmal activity varied in between 2.76 hours to 5.40 hours for the whole group; the results for adults, children and patients with/without antiepileptic medication did not differ much. Our findings suggest, that the results of one single 24 hours long-term-EEG investigation must be interpreted with great caution.

Adolescent↗

PubMed1988

[Somatosensory evoked potentials following tibial nerve stimulation. Method and normal values in relation to physical variables].

Somatosensory evoked potentials were recorded in 40 healthy subjects (age: 22-63 years) with gluteal, lumbar, cervical and cortical surface electrodes after stimulation of the tibial nerve. Normal latency values were established in relationship to height and also for the amplitudes of the different components; the latencies of the cortical P40, N50 and P60 were significantly dependent on height, the latency of the cervical N33, the lumbar N22 and the gluteal Ng were dependent on the distance (stimulation--to recording point). The central conduction time showed no dependence on back length. Age dependence (in relation to normal height) was found only in the case of cortical P60.

Adult↗

PubMed1988

[The distal portion of the ulnar nerve--recording technic and normal values].

Normal values for the distal portion of the ulnar nerve are proposed. In 52 normals without clinical symptoms of peripheral nerve lesion the following neurographic parameters were recorded on the right side and in 45 cases on the left side, too: distal latency wrist-hypothenar, compound action potential from hypothenar, distal latency wrist-M, adductor pollicis, compound action potential from the M. adductor pollicis, antidrome nerve conduction velocity wrist-digit V, difference of latencies M. adductor pollicis-hypothenar, difference of compound action potential hypothenar-M. adductor pollicis and side differences of these parameters. A linear regression analysis was performed to investigate the dependence of these parameters from age. Our normal values allow an exact localisation of peripheral lesions of the ulnar nerve (Loge de Guyon, Ramus volaris superficialis, Ramus profundus).

Action Potentials↗

PubMed1988

[Visual evoked potentials as affected by different modes of stimulation].

VEP with 3 different modes of stimulation (pattern-reversal, flash and light-emitting diodes = LED) were performed in 30 subjects with normal vision. Normal values were established and the main components were compared under these 3 conditions of stimulation. The latencies of the main components showed a normal distribution in pattern-reversal and flash stimulation mode, but not in LED stimulation modes. The latency of the main component P2 of pattern reversal stimulation mode as well as the amplitude showed the smallest variance; flash and LED stimulation mode had a longer latency of the main component than pattern reversal stimulation mode. No sex or side differences were observed. In one subject (3%) the main component (P2) of pattern-reversal stimulation mode had a W-form, in LED stimulation mode 63% and in flash stimulation mode 40% of the subjects showed a W-form of the main component. The main component (P2) of pattern-reversal stimulation mode was best correlated with the first component of a W-from in flash and LED stimulation mode. Therefore, from one latency value (LED or flash stimulation mode) a latency value of pattern reversal stimulation mode may be estimated.

Adult↗

PubMed1988

[Neurologic symptoms in inhalation poisoning with metallic mercury].

Nineteen caisson workers had been exposed to metallic mercury vapours while digging tubes underneath the first district of Vienna (exposure between 470 and 2440 min; mean 1621 min). The blood mercury values on admission were between 29 and 166 micrograms/l (mean 75 +/- 34 micrograms/l). The main findings reported are clinical neurologic symptoms, psychic complaints, neurographic results and autonomic parameters (cardiovascular reflexes): 47% complained of headache and tiredness, 37% showed tremor and suffered from sleep disturbances, 26% showed hypersalivation, 16% changes in handwriting, and 11% slight dysarthria. The cardiovascular reflexes (autonomic parameters) were abnormal in 7 of 12 patients. On neurography the distal latency (median nerve) was pathologic in 47%, the distal latency (peroneal nerve) was pathologic in 26%, the antidromic sensory nerve conduction velocity (median nerve) was abnormal in 10%, the motor nerve conduction velocity, compound amplitude and vibratory threshold were normal.

Adult↗

PubMed1987

Influence of television on photosensitive epileptics.

We examined 32 epileptics (20 female; 12 male; aged 6-73 years) who had displayed photoconvulsive reactions to flickering light in the EEG; they were examined with regard to their risks of getting epileptic seizures upon watching television (TV) under certain conditions. On a colour TV set each patient was shown a 3-min videofilm with slow- and fast-moving parts under 16 different conditions. The conditions had the following variables: (1) colour - monochrome; (2) dark room - light room, and (3) four different distances from the screen. In addition, each patient was subjected for 3 min to manipulated image interferences, including the vertical rolling of the picture. The results of this TV stimulation were always negative, i.e. in no patient did TV provoke a reproducible paroxysmal discharge in the EEG, nor was there any epileptic seizure. Our findings are discussed in connection with the corresponding literature.

Adolescent↗

PubMed1987

[Acute effect of prostigmin on lung function and breathing of patients with myasthenia gravis at rest and following ergometric exercise].

The acute effects of a single intravenous Prostigmin injection (0.5 mg) on lung function and gas exchange during rest and bicycle ergometry were measured in 26 patients with myasthenia gravis. The mean age of the patients was 44.6 +/- 17.6 years and the mean duration of myasthenia gravis 5.4 +/- 6.3 years. Lung function parameters obtained from 15 patients showed a normal total lung capacity with an increase in functional residual capacity and residual volume, while vital capacity was diminished. While the application of Prostigmin showed no acute effects on these lung volumes, there was a significant increase in airway resistance, even into the pathologic range. Data obtained during spiro-ergometry concerning gas exchange, circulation and muscle metabolism correspond to those expected from healthy individuals; application of Prostigmin did only influence the heart rate, which can be explained by parasympathomimetic activity. We conclude that dyspnoea in patients with myasthenia gravis need not necessarily be a symptom of the illness itself but can also be caused by therapy; in the latter case bronchodilatators are required.

Adult↗

PubMed1986

[Value of acetylcholine receptor antibodies in myasthenia gravis].

In a retrospective study in 47 patients with myasthenia gravis acetylcholine-receptor-antibody-titers (AChR-AB) were correlated with the severity of the disease. In 18 patients the course of titers was studied and two groups of patients could be differentiated: patients with relative constant and patients with fluctuating titers. Age, age of begin of myasthenia and sex did not influence the titers. Also the duration of the disease and the severity of symptoms did not influence the level of AChR-AB-titers. In this retrospective study the influence of immun-suppressive therapy on the intra-individual course of AB-titers and their correlation with the clinical symptoms could not be judged. Measurement of AChR-AB is of value for the diagnosis of myasthenia gravis and important for judging the clinical course and the effect of therapy.

Adult↗

PubMed1986

[Sensorimotor and autonomous polyneuropathies in diabetic children and adolescents].

In 28 juvenile and adolescent diabetics (14 males, 14 females) ranging in age between 9 and 20 years (mean: 14.9) we investigated several electrophysiological parameters, the vibration threshold and the cardiovascular reflexes in order to determine the incidence of sensomotor and autonomic polyneuropathy. 6 patients showed evidence of sensomotor polyneuropathy, 2 more had signs of autonomic polyneuropathy. Both groups with polyneuropathy did not differ significantly from the whole group of diabetics concerning the mean onset of illness and several metabolic parameters. The mean duration of illness and the average age was clearly higher in the patients with sensomotor polyneuropathy than in the whole group. Out of 5 patients with diabetic retinopathy 3 had signs of sensomotor polyneuropathy. No patient was clinically affected by polyneuropathy. In 1 patient the distal latency and the amplitude of the compound muscle action potential of the peroneal nerve showed pathologic values, in a second patient the maximal conduction velocity of the median nerve was slowed. 4 patients had abnormally high vibration threshold. The heart rate variation during rest was reduced in 2 patients. Significant differences between the diabetics and the controls could only be found concerning the maximum conduction velocities of the peroneal and the median nerve. Our results will be compared and discussed.

Adolescent↗

PubMed1986

[Changes in brain stem potentials in dystrophia myotonica].

In 15 patients with dystrophia myotonica brainstem auditory potentials (BAEP) were examined: in 8 patients (53%) pathological components in the BAEP's (such as increased latency of one peak) and in 80% a pathologic component in the neurography could be found. Comparing the latencies of the peak and the interwave latencies in the patients' and control group there was no significant difference. Hearing disturbances influenced the latencies of the first BAEP-component, increased triglycerides correlated with pathologic nerve conduction velocity and singular pathologic BAEP values correlated with abnormal neurographic parameters. All these correlations emphasize the complexity of alterations in dystrophia myotonica.

Adult↗

PubMed1985

[Diagnosis of myasthenia. Value of tensilon test, repetitive stimulation, staircase phenomenon and acetylcholine receptor antibody titer].

In a retrospective study on 78 patients with myasthenia gravis the diagnostic value of various investigational methods is assessed. On the basis of the results of the Tensilon test, repetitive stimulation, the staircase phenomenon and acetylcholine receptor antibody titre in the different clinical subgroups practical guidelines are proposed for the diagnosis of myasthenia gravis.

Antibodies↗