Biomedical subjects
Publications and source records attributed to J Zeitlhofer.
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OBJECTIVE: To evaluate the safety of edrophonium chloride in the course of the Tensilon test by measurement of hemodynamic and ECG parameters and the observation of adverse events. METHODS: 25 patients with known or suspected myasthenia gravis were included in an open, prospective study concerning the performance of the Tensilon test. Blood pressure, heart rate, continuous ECG and adverse events were recorded 10 minutes following intravenous application of Tensilon. RESULTS: Blood pressure and heart rate did not change significantly during the observation period. One patient on beta-blockers developed a grade I AV block. Self-limiting adverse events of short duration were observed in 11 patients. Serious adverse events such as syncope or hemodynamic deterioration did not occur. CONCLUSION: The Tensilon test appears to be a safe procedure. A detailed clinical cardiac history, the history of medication and twelve lead ECG recordings should be documented in all patients undergoing the Tensilon test. Patients with a history of dysrhythmia receiving digitalis, beta-blocking agents or Ca antagonist therapy should be managed with special care, as Tensilon enhances vagal effects.
In this study we describe an autosomal dominant distal muscular dystrophy in a small Austrian family. The myopathy started in early adulthood with a slowly progressive weakness of the muscles of the anterior tibial compartment, followed by the long finger extensors and sternocleidomastoids in some family members. Other muscles were spared. Histopathology showed fiber size variation and autophagic vacuoles. This disease pattern is similar to Laing distal myopathy, which has been described previously in only one other family.
PURPOSE: To compare the self-reported estimation of sleep quality evaluated by the Pittsburgh Sleep Quality Index (PSQI) and life quality assessed by the Quality of Life Index (QLI). BACKGROUND: The PSQI comprised 19 questions and assessed a wide variety of factors relating to sleep quality. The QLI consisted of 10 items for self assessment of different dimensions of life quality. SUBJECTS: A representative Austrian sample (n = 1049) aged above 15 years. PROCEDURE: Interviews in the homes of the participants. RESULTS: 32.1% could be classified as poor sleepers (37% females, 26.5% males). Sleep quality decreased with increasing age, especially in women. Overall quality of life was highest in younger (15-29 years) and lowest in elderly subjects (over 50 years). Life quality decreased with increasing age. Between subjective sleep quality and quality of life a moderate, significant correlation was found (r2= 0.6721). CONCLUSIONS: Complaints about a bad quality of sleep could be used as a screening method in the exploration of patients' quality of life (QoL).
Excessive daytime sleepiness (EDS) is a frequent symptom of patients with obstructive sleep apnoea (OSA). EDS is a high-risk factor for accidents at work and on the road. Thirty untreated patients with different levels of severity of OSA were studied concerning night sleep and EDS. The criterion for severity was the respiratory disturbance index (RDI): 15 patients were classified as 'moderately' apnoeic (RDI < 40), 15 as 'severely' apnoeic (RDI > 40). Following night-time polysomnography, objective and subjective aspects of EDS were studied. To assess objective EDS the Maintenance of Wakefulness Test (MWT) and a computer-based vigilance performance test were used. Subjective EDS was determined using the Stanford Sleepiness Scale (SSS), the Epworth Sleepiness Scale (ESS) and the Visual Analogue Scales for Performance (VAS-P) and Tiredness (VAS-T). Well-being was assessed using the Scale of Well-Being by von Zerssen (Bf-S/Bf-S'). Severe apnoea patients spent more time in stage 1 and less in slow-wave sleep. MWT latencies tended to be shorter in the severe apnoea group. Vigilance testing revealed no group differences. Patients with moderate apnoea described themselves as more impaired in all subjective scales, but only SSS scores reached statistical significance. Our results suggest that there is no simple correlation between polysomnographic and respiratory sleep variables at night on the one hand, and the extent of EDS on the other hand. Furthermore, subjective and objective evaluation of EDS does not yield the same results. New approaches which allow a more detailed analysis of night sleep and daytime function are required to identify high-risked patients.
We investigated thyroid function and autoimmunity in 74 (61% females) consecutive patients with MG. 30 of these patients were tested twice: the time between the investigations ranging from 1 to 4 years. MG was diagnosed on the basis of typical clinical symptoms, a positive tensilone-test, and/or detectable acetylcholine antibodies and/or repetetive stimulation tests. Eye involvement was present in 86%, concurrent thymomas in 56%. The following parameters were measured in the serum of these patients by commercially available kits: free and total T4, TSH, TSH-Receptor-Antibodies ("TRAB"), antibodies against thyroglobulin (Tg-Ab), against thyroid microsomes (M-Ab) and against acetyl-choline-receptors . An age matched group of 50 patients (54% females) with no known thyroid disease from a cardiological ward and from the neurological outpatient department served as control. There was only 1 MG patient with overt thyroid dysfunction (iodine induced thyrotoxicosis in a patient with autonomous adenoma and no circulating thyroid autoantibodies detected at the second investigation). There were, moreover, 1 euthyroid MG-patient on L-thyroxine therapy with a history of Hashimoto's disease and positive thyroid autoantibodies and 1 other MG-patient with mildly elevated TSH without elevated thyroid antibodies, who has had subtotal thyroidectomy without substitution therapy years before for unknown reasons. Tg-Ab were positive (>360 IU/ml) in 5%, M-Ab were positive (>154 IU/ml) in 15% of the MG patients. The control group had 4% Tg-Ab and 6% M-Ab. TRAB levels were normal in all patients and controls. The relative increase in M-Ab frequency was not statistically significant (x-square test). We conclude from our results, that autoimmune thyroid disease may be associated with MG but that the occurrence of thyroid dysfunction induced by autoimmunity is a very rare phenomenon in MG.
This literature review shows the current knowledge of health effects on humans concerning static, low frequency electric and magnetic fields and high frequency electromagnetic fields up to 300 GHz. Basic physical knowledge and the current thresholds are demonstrated. Different frequency ranges of electromagnetic fields, their natural and technical origins and the different biological effects, especially possible hazards such as cancerogenity or risks for the brain, are discussed. Open questions and future research aspects are demonstrated. Finally electrosensibility and psychological aspects are shown.
In 14 patients with myeloproliferative disorders associated with thrombocytosis, neurological and neuropsychological function were monitored prior to therapy with recombinant human interferon alpha (rIFN; dose 25 mU/week; range 10-35 mU/week) and after 3, 6, 9, and 12 months of treatment. No overt neurological side effects were observed except 1 case of cerebral insult, probably not treatment-related. Attention, memory function, and tapping improved significantly. The P2-N3 amplitudes of visually evoked potentials increased during normalization of platelet counts. Muscular strength and the amplitude of the compound muscle action potential of the median and peroneal nerves increased significantly in an inversely dose-related fashion. In patients with myeloproliferative disorders, long-term therapy with low to intermediate doses of rIFN does not seem to impair neurological function, but rather is associated with enhanced muscle power and the level of mental arousal.
The purpose of this study was to compare median somatosensory evoked potentials (SEP) in patients undergoing carotid endarterectomy (CEA) with routine shunting and nonshunting (excluding the option of selective shunting) and to evaluate the significance of a decrease in the amplitude of the cortically generated waveforms of the SEP and/or an increase in the central conduction time (CCT) on the one hand, and that of a loss of the cortical SEP, on the other. Somatosensory evoked potentials were recorded in 32 patients before, during, and after CEA with routine shunting or nonshunting. The N13 and N20 latency, the CCT, and the N20/P25 amplitude were evaluated. In addition, a meta-analysis of 15 previous studies was performed comprising a total of 3,136 patients. The intraoperative cortical SEP showed no differences between shunted and nonshunted patients, apart from the preclamping value of the N20/P25 amplitude which was lower in the nonshunted subjects. The number of patients with decreased and/or delayed cortical SEP (findings frequently used as criterion for selective shunting) was similar in the two study groups. A loss of the cortical SEP occurred in one patient operated on without an indwelling shunt. None of these patients had a new neurologic deficit after surgery. In the meta-analysis, the positive predictive value of decreased and/or delayed cortical SEP was extremely poor, that of absent cortical SEP was poor to moderate and the prevalence of new neurologic deficits was similar in patients undergoing CEA with routine shunting-nonshunting and those with selective shunting-nonshunting. Our study suggests that decreased and/or delayed cortical SEP are unreliable predictors of the neurological outcome of CEA patients and consequently an unsuitable criterion for selective shunting. The meta-analysis confirms this finding and shows that the neurologic outcome is not improved by using an indwelling shunt selectively based on SEP monitoring.
OBJECTIVES: 1) To examine the diagnostic value of the newly proposed manual carpal compression test (mCCT). 2) To evaluate the test efficacy of a serial use of mCCT and Phalen's test (PT) in the clinical diagnosis of carpal tunnel syndrome (CTS) in comparison with standard nerve conduction studies. MATERIALS AND METHODS: Prospective, controlled study of 47 patients with 63 symptomatic CTS hands according to clinical as well as electrophysiological criteria. In the control group, 39 hands of 20 healthy volunteers were examined. Clinical neurological examination including mCCT and PT and standard nerve conduction studies were always performed: sensory nerve conduction velocity third and fifth digit to wrist, median distal motor latency. Calculation of sensitivity, specificity, positive and negative predictive value for the mCCT, PT and mCCT+PT, i.e. at least one of both tests positive after sequential application. RESULTS: Sensitivity 83% for mCCT, 79% for PT and 92% for mCCT+PT. Specificity 92% for all three conditions. Excellent positive predictive value of 95% and good negative predictive value of 88% for mCCT+PT. CONCLUSION: The serial application of mCCT and PT is very useful in the clinical diagnosis of CTS. This finding facilitates the clinical diagnosis by the primary physician, it helps to improve referral decisions to electrophysiological departments and other ancillary examinations and may reduce costs.
This paper deals with studies of evoked potentials in diseases of the peripheral and central nervous system. Indications and clinical value of visual evoked potentials, brain stem auditory evoked potentials, somatosensory evoked potentials and motor evoked potentials are evaluated for frequent neurological diseases.
Hypersomnia (excessive sleepiness) accompanies many diseases. 14% of the total Austrian population regularly have problems staying awake during the day or are prone to taking spontaneous naps. Hypersomnia is a symptom of the sleep apnea syndrome, which is a risk factor for cerebrovascular disorders. Daytime sleepiness is also a characteristic symptom of narcolepsy, idiopathic hypersomnia, episodic hypersomnia, and many more neurological or psychiatric disorders; it can also be drug induced. Involvement of brain structures which are essential for the regulation of the sleep wake cycle as a result of neurological disorders can likewise lead to hypersomnia. Symptomatic treatment is necessary when treatment of the causal factors is not possible or no improvement has been achieved.
The application of an automatic sleep spindle detection procedure allowed the documentation of the topographic distribution of spindle characteristics, such as number, amplitude, frequency and duration, as a function of sleep depth and of recording time. Multichannel all-night EEG recordings were performed in 10 normal healthy subjects aged 20-35 years. Although the interindividual variability in the number of sleep spindles was very high (2.7 +/- 2.1 spindles per minute stage 2 sleep), all but two subjects showed maximal spindle activity in centro-parietal midline leads. Moreover, this topography was seen in all sleep stages and changed only slightly--to a more central distribution--towards the end of the night. On the other hand, slow (11.5-14 Hz) and fast (14-16 Hz) spindles showed a completely different topography, with slow spindles distributed anteriorly and fast spindles centro-parietally. The number of sleep spindles per min was significant depending on sleep stages, with the expected highest occurrence in stage 2, and on recording time, with a decrease in spindle density from the beginning towards the end of the night. However, spindle amplitude, frequency and individual duration was not influenced by sleep depth or time of the night.
19 middle-aged patients with myasthenia gravis (MG) and 10 age, sex and education-matched controls underwent overnight polysomnography and neuropsychological testing, in order to test the hypothesis of whether cognitive dysfunction and REM-sleep disturbance in MG are related to nocturnal respiratory problems or caused by CNS-involvement. We observed in 60% of the myasthenics central type of sleep apneas and hypopneas with resulting oxygen desaturations occurring during REM-sleep, but no decrease of REM sleep. In neuropsychological testing, we found normal vigilance performance but decreased memory function in the myasthenics. In comparison with patients without sleep apnea, myasthenics with sleep apneas had an impaired memory function.
Recurrent severe hypoglycaemia is often an unsolved problem in diabetic patients under intensified insulin treatment. As no reliable long-term stable blood glucose sensor has yet been developed, registration of other body function changes could help to detect severe hypoglycaemia. A measuring system is described, capable on the one hand of recording EEG, heart rate, peripheral pulse, skin temperature, respiratory movements, skin impedance and arterial blood pressure, and capable of registering plasma glucose, counter-regulatory hormones, symptoms and cognitive performance under experimental conditions during hypoglycaemia, on the other. In a clinical study involving both insulin-induced hypoglycaemia in healthy subjects and insulin-dependent diabetic patients, the practical value and the character of changes of the recorded parameters are investigated. Currently insensitivity to hypoglycaemia, impracticability, complexity or susceptibility to artefacts make use of most parameters unsuitable for hypoglycaemia prevention. It is believed, however, that future efforts could result in indirect registration of hypoglycaemia, including a qualified combination of different parameters, individual adaptation in accordance with particular responses of individual patients, together with new measuring and sensor techniques.
To elucidate neurophysiological characteristics in hypoglycaemia unawareness, we investigated the relationship between electroencephalography (EEG) parameters of vigilance and awareness of various symptom categories early in response to hypoglycaemia in intensively treated diabetic patients with different degrees of hypoglycaemia unawareness. Hypoglycaemia (venous plasma glucose below 2.2 mmol/1) was induced with an intravenous insulin bolus in seven patients with insulin-dependent diabetes mellitus (IDDM) with a history of hypoglycaemia unawareness and repeated severe hypoglycaemia, as well as in a group of seven IDDM patients with good awareness of hypoglycaemia. Both groups were comparable in age, treatment strategy, glycaemic control and level of late complications. Basic cognitive performance and other symptom categories were estimated serially during a period of 2 h following the insulin bolus. A vigilance-controlled EEG was recorded continuously; its automatic analysis included the evaluation of vigilance indices. In the baseline prehypoglycaemic state, hypoglycaemia unaware patients showed higher initial vigilance (p = .05) than the aware group. Unaware patients reported fewer neurogenic (p = .002, mainly cholinergic, p = .009) hypoglycaemia symptoms during hypoglycaemia, and developed an impairment in cognitive performance over time (p = .002). EEG analysis indicated a more rapid decrease in vigilance after the hypoglycaemic stimulus for unaware patients than for aware patients. The lowering of plasma glucose to 3.06-3.89 mmol/l already induced a significant increase in delta and theta, as well as a decrease in alpha relative power only in the unaware group. Differences between groups with regards to the degree of deceleration were most pronounced early, during only slight hypoglycaemia, and topographically spread over central and parietal brain regions. Further lowering of plasma glucose induced an even more pronounced, abrupt increase in slow waves in unaware patients at higher plasma glucose levels than in hypoglycaemia aware subjects (for delta waves at 2.41 +/- 0.16 vs. 1.96 +/- 0.1 mmol/l, p = .04). This preceded the worsening of cognitive performance during hypoglycaemia in unaware patients by 19 +/- 3 min. Hypoglycaemia unawareness associated with previous unconsciousness is associated with- and may be the result of-an early hypoglycaemia-induced reduction in vigilance and an early EEG deceleration, which seems to be a teleologically effective measure for delaying eventual cerebral energy failure in hypoglycaemia.
A group of young patients with insulin-dependent diabetes mellitus (n = 14; 8 men, 6 women; 33.1 +/- 8.9 years) were examined by topographic EEG mapping under normoglycemic and hypoglycemic conditions (glucose levels after intravenous insulin injection down to 32.6 +/- 7.6 mg/dl). From the clinical aspect, 7 of them had a good and 7 had a poor awareness of hypoglycemia. During hypoglycemia, a decrease in alpha activity (p < 0.05), an increase in delta (p < 0.05), and especially in theta activity (p < 0.05) were found. The most sensitive parameter was the alpha/theta ratio. In the range of slight hypoglycemia (50-60 mg/dl) the increase in delta and theta activity showed a topographic maximum in lateral frontal regions. During deep hypoglycemia there was a topographic maximum of slow frequencies in posterior parts of the brain (centrotemporal to parieto-occipital regions). The differences between the group with good and with poor awareness of hypoglycemia were most pronounced during slight hypoglycemia in C3, C4, and Pz (p < 0.05). At lower glucose levels group distinction was no longer possible. These EEG changes correspond to a temporary organic brain syndrome.
Amyotrophic lateral sclerosis is a progressive degenerative disease of upper and lower motor neurons with a prevalence of 4.3/100.000. The clinical symptoms include peripheral weakness and central spastic paresis and bulbar paralysis (weakness of mimic muscles, atrophy of the tongue, dysarthria). The prognosis leads to death within a few years. Pathogenetic factors are free O2-radicals, a disturbance of glutamate-metabolism, abnormal accumulation of neuronal proteins and autoimmunological mechanisms.