Biomedical subjects

A Schabmann

Publications and source records attributed to A Schabmann.

8 recordsLinked to original sources

PubMed1998

Optimal parameters of short-term heart rate spectrogram for routine evaluation of diabetic cardiovascular autonomic neuropathy.

Our aim was to select those parameters of heart rate variability (HRV) within its short-term power spectral analysis (PSA), which have a capability similar to that of the standard Ewing battery of cardiovascular function tests in determining different degrees of cardiovascular autonomic neuropathy (CAN) in diabetes and to compare the usefulness of both methods for diagnostic purposes in the everyday routine. Commonly used standard battery of cardiovascular autonomic function tests evaluated as total Ewing score as well as short-term PSA of HRV were used in 119 diabetic patients (age: 52.7 +/- 9.8, diabetes duration: 22.2 +/- 12.7 years). From this cohort, patients were selected according to the total Ewing score by matching for age, gender, BMI and diabetes type for 3 groups, each of 17 patients, with no CAN (total Ewing score 0-0.5), with early involvement (score 1.0-2.5) and with definite or severe CAN (score 3.0-5.0). Short-term PSA of HRV performed in three positions (supine1-standing-supine2) included frequency-domain and time-domain parameters of HRV. Cumulative spectral power of total frequency band (0.06-0.50 Hz) and spectral power of low-frequency band (0.06-0.15 Hz) during both supine positions proved to be the most selective and discriminating among all patient groups in inter-group comparison and in analysis of discriminance. The correlation between the total Ewing score and the cumulative spectral power of total frequency band was r = -0.87 (P < 0.001). About 83.2% of cases classified by short-term PSA of HRV using the variables selected by analysis of discriminance was congruent with the classification by the total Ewing score alone. Time expenditure for the performance of each examination was 31 +/- 10 min for Ewing test battery vs. 14 +/- 2 min for short-term PSA of HRV (P < 0.001). In summary, the latter method showed similar diagnostic value concerning the CAN as the classical Ewing standard battery of cardiovascular function tests, although its application proved to be shorter, less stressful and more independent from patient cooperation. Cumulative spectral power of total frequency band (LFHF cumpower) can be used for overall description of the degree of cardiac denervation in diabetes while using short-term PSA of HRV.

Adult↗

PubMed1998

Weak relationship between symptom perception and objective hypoglycaemia-induced changes of autonomic function in hypoglycaemia unawareness in diabetes.

To assess the relationship between symptom perception and neurophysiological characteristics in hypoglycaemia unawareness, we investigated the awareness of symptoms, objective changes of autonomic function and counter-regulatory neuroendocrine responses to hypoglycaemia in intensively treated type I (insulin-dependent) diabetic patients with different degrees of hypoglycaemia unawareness. Hypoglycaemia (venous plasma glucose below 2.2 mmol/l) was induced with an intravenous insulin bolus in subjects with a history of repeated severe hypoglycaemia and hypoglycaemia unawareness (n = 10) and in a comparable group with good awareness of hypoglycaemia (n = 8). Autonomic symptoms, selected parameters of autonomic function and counter-regulatory hormones were assessed serially. Although hypoglycaemia was more pronounced in unaware patients (1.6 vs 2.0 mmol/l, P = 0.05), their induced adrenaline response was markedly impaired (delta adrenaline: 1.25+/-1.10 vs 2.55+/-1.46 nmol/l, P = 0.05). Astonishingly, differences between both patient groups in the course of autonomic function changes did not reach the level of significance (P = 0.35-0.92), although the unaware group reported markedly fewer autonomic symptoms, both neurogenic (P = 0.001) and neuroglycopenic (P = 0.04) than the aware group. This study indicates that in hypoglycaemia unawareness even extensive changes in autonomic function are not sufficient for the perception of hypoglycaemia and confirms that the central nervous system plays an important role in the awareness of hypoglycaemia.

Adult↗

PubMed1997

Effects of physical training on heart rate variability in diabetic patients with various degrees of cardiovascular autonomic neuropathy.

OBJECTIVE: To investigate the effects of regularly performed endurance training on heart rate variability in diabetic patients with different degrees of cardiovascular autonomic neuropathy (CAN). METHODS: Bicycle ergometer training (12 weeks, 2 x 30 min/week, with 65% of maximal performance) was performed by 22 insulin-requiring diabetic patients (age 49.5 +/- 8.7 years; diabetes duration 18.6 +/- 10.6 years; BMI 25.1 +/- 3.4 kg/m2): i.e., by 8 subjects with no CAN, 8 with early CAN and by 6 patients with definite/severe CAN. A standard battery of cardiovascular reflex tests was used for grading of CAN, a short-term spectral analysis of heart rate variability for follow-up monitoring of training-induced effects. RESULTS: While the training-free interval induced no changes in spectral indices, the 12-week training period increased the cumulative spectral power of the total frequency band (P = 0.04) but to a different extent (P = 0.039) in different degrees of neuropathy. In patients with no CAN the spectral power in the high-frequency (HF) band (0.15-0.50 Hz) increased from 6.2 +/- 0.3 to 6.6 +/- 0.4 In [ms2]; P = 0.016, and in the low-frequency (LF) band (0.06-0.13 Hz) from 7.1 +/- 0.1 to 7.6 +/- 0.3 in [ms2]; P = 0.08 which resulted in an increase of total spectral power (0.06-0.50 Hz) from 7.5 +/- 0.1 to 8.0 +/- 0.3 in [ms2] (P = 0.05). Patients with the early form of CAN showed an increase of spectral power in HF (5.1 +/- 0.2 to 5.8 +/- 0.1 in [ms2], P = 0.05) and LF bands (5.6 +/- 0.1 to 6.3 +/- 0.1 in [ms2], P = 0.008), resulting in an increase of total power from 6.1 +/- 0.1 to 6.6 +/- 0.1 in [ms2] (P = 0.04), whereas those with definite/severe CAN showed no changes after the training period. Training improved fitness in the whole patient cohort. The increased autonomic tone as assessed by spectral indices disappeared after a training withdrawal period of 6 weeks. CONCLUSIONS: In diabetic patients with no or early CAN, regularly performed endurance training increased heart rate variability due to improved sympathetic and parasympathetic supply, whereas in subjects with definite/severe CAN no effect on heart rate variability could be demonstrated after this kind of training.

Autonomic Nervous System Diseases↗

PubMed1996

Severe hypoglycaemia unawareness is associated with an early decrease in vigilance during hypoglycaemia.

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.

Adult↗

PubMed1995

[To what extent do school and class-specific factors contribute to aggression in schools?].

In a representative study conducted in Vienna and Lower Austria, 14-year-old students from one class each in 79 different schools (N = 1594) answered a questionnaire about their experiences at school, the main focus being on aggressive acts that occurred at school. In a parallel investigation, the students' teachers (N = 554) completed a similar questionnaire. The reports on the frequency of aggressive behavior differed widely among the classes. A comparison of classes with different levels of aggressive behavior showed that solidarity within the classroom and the relationship between teachers and students were closely associated with the frequency of aggressive behavior. In classrooms with frequent aggressive acts there was a negative attitude towards outsiders and the students were less inclined to intervene in an unfair fight. Furthermore, they were more critical of discussions with their teachers. Even after social and familial factors were controlled for, the influence of school-specific factors on the frequency of aggressive behavior at school was quite large, explaining about 25% of the variance. The consequences for counseling of schools and for teacher education are discussed.

Adolescent↗

PubMed1994

[What are the differences between average readings with writing difficulties and children with reading and writing difficulties? Follow-up, kind of writing errors and learning prerequisites].

As part of the Viennese longitudinal study on the development of reading and writing skills, children with spelling problems were differentiated from children with combined reading and spelling problems. It could be shown that children with spelling problems only are a rather inhomogeneous group with regard to their further development. At the end of the eighth grade some children still have circumscribed spelling problems, whereas others have overcome their early problems, and still others have also fallen behind in their reading skills. These groups of children can be differentiated early on by the type of spelling errors they make, by their cognitive abilities and by social factors. Children with combined reading and spelling problems are characterized especially by a lack of phonemic awareness.

Adolescent↗

PubMed1993

[Incidence of emotional problems and behavioral difficulties in school and correlation with reading and writing disorders: results of a longitudinal study].

As a part of a longitudinal study on reading development from the 2th to the 8th grade teachers ratings about behavior problems of school children and their emotional situation were assessed. Problems in motivation and concentration were reported most frequent. Comparing children with poor reading and spelling ability to children without deficits in reading and spelling, differences could be found. Poor readers and spellers showed more dissocial and disturbing classroom behavior. Nevertheless, those problems were as persistent as the problems reported for children, who did not show any reading and spelling difficulties, or increasing in nearly the same ratio over time. This results does not support the hypothesis, that behavior problems may occur as a consequence of learning difficulties.

Adolescent↗

PubMed1993

[Learning to read and write in compulsory education: a longitudinal study of the incidence and stability of reading and writing difficulties in a Vienna school district].

In a longitudinal study, the development of reading and spelling skills was analyzed in about 500 Viennese school children from first through eighth grade. Performance in reading and spelling was tested at least once a year through grade four and then again at the end of eighth grade using standardized reading and spelling tests. The differences among the children in reading and spelling skills were found to be very stabile over time, and if there was difficulty with reading and spelling early on this usually persisted. Only a few of the children who had problems with reading in second grade improved enough so that they attained average scores at the end of eighth grade. The poorest readers read at the same level at the end of fourth grade as average readers did at the end of first grade. At the end of eighth grade these children had attained the level of average readers at the end of second grade. Similarly, poor spellers showed less improvement over time than children with average spelling skills. By the end of eighth grade these children had fallen way behind their peers.

Adolescent↗