Ageing and surface EMG activity patterns of masticatory muscles. J Oral Rehabil
ABSTRACT The purpose of this study was to evaluate the influence of age on the electromyographic activity of masticatory muscles. All volunteers were Brazilian, fully dentate (except for Group I - mixed dentition), Caucasian, aged 7-80, and divided into five groups: I (7-12 years), II (13-20 years), III (21-40 years), IV (41-60 years) and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided with respect to gender (20 M/20 F). Surface electromyographic records of masticatory muscles were obtained at rest and during maximal voluntary contraction, right and left laterality, maximal jaw protrusion and maximal clenching in the intercuspal position. Statistically significant differences (P < 0.05) were found in all clinical conditions among the different age groups. Considerably different patterns of muscle activation were found across ages, with greater electromyographic activity in children and youth, and decreasing from adults to aged people.
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- "These effects have not yet been investigated in the spinal musculature of quadrupeds. Surface electromyography (sEMG) is currently successfully used to identify muscle activity changes in human diseases, such as Parkinson's (Cecílio et al., 2010), and ageing, for example in masticatory muscles (Meigal et al., 2009). Many of these findings are thought to be transferrable to the activity of deeper muscles, but clearly, without evidence based data, this remains an assumption prior to the measurement of the deeper muscles themselves. "
ABSTRACT: In vertebrates ageing is characterised by reduced viscoelasticity of the ligamentous and tendineous structures and fibre changes in muscle. Also, some vertebral joint degeneration develops with ageing. The aim of this study was to apply dynamic time warping to compare the temporal characteristics of the surface electromyography (sEMG) data and to illustrate the differences in the pattern of muscle use during tasks of daily life in old and mature horses. In vivo kinematics (24 skin markers) and sEMG measurements of neck extensors and flexors were taken in five mature horses (aged 10±2 years, half of mean life expectancy) and five old horses (aged 25±5 years, older than the mean life expectancy). All horses had the same level of activity in the 12 months prior to the measurement. Tasks measured were neck flexion and neck extension as well as neutral neck position. Muscle activation, minimum and maximum muscle activation were collected. Quartiles of muscle activity based on the maximum observed activity of each muscle were calculated to document the relative increase of activity level during the task. Kinematics as well as overall muscle activity patterns were similar across horses and age groups. However, in the neutral position old horses showed increased extensor activity compared to mature horses, indicating that old equine muscle requires more activity to counteract gravity. Dynamic time warping specified optimal temporal alignments of time series, and different temporal performances were identified. The age groups differed during the flexion task, while neck extension and neutral neck position were more similar. The results of this study show that even in the second half of life and in the absence of muscle disuse the muscular strategy employed by horses continues to be adapted.Comparative Exercise Physiology 07/2014; 10(2):75-88.. DOI:10.3920/CEP140001
Conference Paper: Almost complete address translation (ACATS) disk array declustering[Show abstract] [Hide abstract]
ABSTRACT: We present a novel declustering scheme (ACATS) for reliability stripes in an orthogonal disk array. Our scheme is deterministic, run-time efficient and provides frequently the best possible and always an almost best possible distribution of failure-induced incremental rebuild workloads. Our scheme provides protection against single disk as well as single string failures within the disk array. Our approach presents a framework in which the Level 5 RAID organization logically appears as a Level 4 RAID; it facilitates the provision of distributed sparing in exactly the same manner ACATS does not require the existence of a suitably configured block design or of a run-time efficient pseudo-random number generator; it is applicable to arbitrarily configured orthogonal disk arrays. Our scheme is faster than declustering schemes that use pseudo-random permutations and achieves better uniformity of disk loads during a disk rebuild; it is simpler than schemes based on block designs. ACATS provides a rich spectrum of declustering schemesParallel and Distributed Processing, 1996. Eighth IEEE Symposium on; 11/1996
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ABSTRACT: A hybrid control scheme is proposed that combines the advantages of various artificial intelligence technologies to better model and control transient behavior of a nonlinear system, even as its parameters are modified, via the ability to extract the cause of a change in a system's outputs. Appropriate techniques are developed for all stages of the development process, in an effort to reduce the amount of recalibration necessary by using a similar approach each timeIntelligence and Systems, 1996., IEEE International Joint Symposia on; 12/1996