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Biomedical subjects

G Hofmann

Publications and source records attributed to G Hofmann.

152 records · Page 9Linked to original sources
PubMedDate not supplied

Age-related decline in body cell mass in elderly men and women, determined by a noninvasive nuclear technique: effects of physical activity and dietary potassium intake.

The body cell mass (BCM) represents the actively metabolizing cellular components of the human body. In this study, the hypothesis was tested that physical activity and a sufficient dietary intake of potassium attenuate the age-related decline in BCM in the elderly. Cross-sectional data were collected in 82 male and 79 female non-institutionalized elderly (60-90 years) from Mainz, Germany, and were analyzed by age groups. BCM was calculated from total body potassium, measured by whole-body counting of naturally occurring 40K. Physical activity level (PAL) was assessed by a standardized questionnaire. Dietary intake of potassium (DIP) was estimated from a 7-day food diary. The results showed the following trends: (1) BCM decreased continuously from age 60 to 90 years by 11.2% (men) and 7.0% (women). BCM was inversely correlated with age in both sexes (men, P < 0.001; women, P < 0.05), but significant age group differences only existed for men (P < 0.01, one-way analysis-of-variance). Women had less BCM than men in all age groups (P < 0.001, t tests). (2) Correlation analyses demonstrated that in both sexes PAL declined with advancing age (P < 0.05), whereas DIP did not change significantly with age. (3) In both sexes, BCM showed a strong positive correlation with PAL (P < 0.001), but did not correlate significantly with DIP. Multiple linear regression analysis (independent variables were PAL, DIP, age, height, weight) demonstrated that PAL, age, and height explained 45% of the variability in BCM in men. In women, PAL was the only significant predictor of BCM, explaining 23% of the variance. The study supports the hypothesis that the level of physical activity is associated with the decline of BCM in the elderly.

Age Factors↗
PubMedDate not supplied

Modelling of components of the human middle ear and simulation of their dynamic behaviour.

In order to get a better insight into the function of the human middle ear it is necessary to simulate its dynamic behaviour by means of the finite-element method. Three-dimensional measurements of the surfaces of the tympanic membrane and of the auditory ossicles malleus, incus and stapes are carried out and geometrical models are created. On the basis of these data, finite-element models are constructed and the dynamic behaviour of the combinations tympanic membrane with malleus in its elastic suspensions and stapes with annular ligament is simulated. Natural frequencies and mode shapes are computed by modal analysis. These investigations showed that the ossicles can be treated as rigid bodies only in a restricted frequency range from 0 to 3.5 kHz.

Computer Simulation↗
PubMedDate not supplied

Comparison of the TEMPO+ ear-level speech processor and the cis pro+ body-worn processor in adult MED-EL cochlear implant users.

A study was conducted to compare the new MED-EL TEMPO+ ear-level speech processor with the CIS PRO+ body-worn processor in the COMBI 40/COMBI 40+ implant system. Speech tests were performed in 46 experienced subjects in two test sessions approximately 4 weeks apart. Subjects were switched over from the CIS PRO+ to the TEMPO+ in the first session and used only the TEMPO+ in the time between the two sessions. Speech tests included monosyllabic word tests and sentence tests via the telephone. An adaptive noise method was used to adjust each subject's scores to approximately 50%. Additionally, subjects had to complete a questionnaire based on their 4 weeks of experience with the TEMPO+. The speech test results showed a statistically significant improvement in the monosyllabic word scores with the TEMPO+. In addition, in the second session, subjects showed a significant improvement when using the telephone with the TEMPO+, indicating some learning in this task. In the questionnaire, the vast majority of subjects found that the TEMPO+ allows equal or better speech understanding and rated the sound quality of the TEMPO+ higher. All these objective and subjective results indicate the superiority of the TEMPO+ and are mainly attributed to a new coding strategy called CIS+ and its implementation in the TEMPO+. In other words, based on the results of this study, it appears that after switching over from the CIS PRO+ to the TEMPO+, subjects are able to maintain or even improve their own speech understanding capability.

Adult↗