Biomedical subjects

M Thum

Publications and source records attributed to M Thum.

3 recordsLinked to original sources

PubMed1995

Standardized task strain and system response times in human-computer interaction.

Involuntary delays in human-computer interaction, for example, system response times (SRTs) can increase stress. In the present study, 40 college-age subjects were randomly divided into an 'incentive' and a 'non-incentive' group'. Subjects performed a computer task with SRTs of 0.5, 1.5, and 4.5s. Physiological, subjective, and performance data were collected during the task. The computer task was designed to individually set difficulty level (i.e., mental strain), thus standardizing the task for all subjects. By using this procedure, changes resulting from SRT duration can be separated from the effects related to task difficulty. The results indicate that both short and long SRTs produced differential psychophysiological changes consistent with different types of stress responses. Short SRTs resulted in higher autonomic and somatic activity, increased positive self-reported emotional states but poorer performance. Long SRTs resulted in increased electrodermal activity, negative self-reported emotional states and better performance.

Adult↗

PubMed1994

Impact of obesity on neuropathic late complications in NIDDM.

OBJECTIVE: This cross-sectional study was aimed to investigate the isolated influence of obesity on peripheral sensorimotor and autonomic neuropathy in patients with long-term non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: Ninety-one long-term NIDDM patients with a mean duration of 13.6 +/- 1.0 years and a mean age of 60.4 +/- 1.0 years were divided into two groups according to their body mass index (BMI) (lean with a BMI < 26.5: n = 41, age = 58.6 +/- 1.7 years, BMI = 23.7 +/- 0.3 kg/m2; and obese with a BMI > or = 26.5: n = 50, age = 61.9 +/- 1.2 years, BMI = 30.5 +/- 0.5 kg/m2). The two groups were not different in age, duration, gender, current parameters of glycemic control, number of smokers, cholesterol, triglycerides, and systolic and diastolic blood pressure. Neuropathic late complications were scrutinized by a standardized clinical examination that delivers a neuropathy score, pupillary autonomic neuropathy assessed by pupillometry, and cardiovascular autonomic neuropathy using a standardized test battery. RESULTS: One-way analysis of variance revealed that obese patients had poor results in the clinical neuropathy test (overall score in obese vs. lean: 71.1 +/- 2.9 vs. 80.6 +/- 3.0 points, 2P = 0.0266; 100 points were absolutely normal). This was particularly true for the discrimination perception (obese vs. lean: 67.0 +/- 4.0 vs. 81.7 +/- 3.3 points, 2P = 0.0073) and the reflex status (obese vs. lean: 57.4 +/- 4.0 vs. 71.8 +/- 4.3 points, 2P = 0.0164). Furthermore, obese patients had a poor result in the respiratory sinus arrhythmia (RSA) test, one of six autonomic function tests (RSA: obese vs. lean in average RSA percentile: 36.9 +/- 4.9 vs. 54.0 +/- 5.9%, 2P = 0.0264). CONCLUSIONS: Obesity influences sensorimotor and autonomic neuropathic late complications. The poor result in RSA in obesity may indicate an interrelation between pathogenesis of obesity and disorders of the respiratory and heart rhythm-generating control centers in the brain stem. Moreover, it could be due to intrathoracic fat deposits that alter lung mobility. Body mass control may be an important approach to reduce neuropathic complications. Beyond that, it seems necessary to control for body mass when comparing neuropathy in two groups of patients with NIDDM.

Adult↗

PubMed1991

Training-overtraining. A prospective, experimental study with experienced middle- and long-distance runners.

Overtraining may be one frequent cause of stagnation or decrease in performance capacity of athletes. Israel (19) differentiates between addisonoid (parasympathetic) and basedowoid (sympathetic) overtraining, characterized by inhibition or excitation. We tried to induce an overtraining syndrome in 8 experienced middle- and long-distance runners, based on an increase in training volume from an average 85.9 km (week 1) to 115.1 km (week 2) and 143.1 km (week 3) to 174.6 km per week (week 4). The influence of this training on cardiovascular, metabolic and hormonal parameters was examined with special respect to plasma and urinary catecholamines. Laboratory testing including graded treadmill running was performed on the days 0, 14 and 28. Training was held six days each week, with nearly 30 km per day in the fourth week. A stagnation in endurance performance capacity (running velocity at the aerobic-anaerobic transition range) and a decrease in maximum working capacity were observed in 6 and a stagnation in 2 of the 8 sportsmen, indicated by a decrease in total running distance from 4719 + 912 m to 4361 + 788 m during incremental treadmill ergometry. The sportsmen could neither improve nor could they even approximately reach their personal records during the subsequent competitive season. Subjective complaints, classified on a four-point scale, increased from 1.2 (week 1) to 3.2 in week 4. Glucose, lactate, ammonia, glycerol, free fatty acids, albumin, LDL, VLDL cholesterol, hemoglobin level (transient), leukocytes, and heart rate (before and during exercise) decreased significantly. Urea, creatinine, uric acid, GOT, GPT, gamma-GT, serum electrolytes (except phosphate and calcium) remained constant at the measuring times, CPK was elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗