Dynamics of Revolution Time Variability in Cycling Pattern: Voluntary Intent Can Alter the Long-Range Autocorrelations.
Dynamics of Revolution Time Variability in Cycling Pattern: Voluntary Intent Can Alter the Long-Range Autocorrelations.
Ann Biomed Eng. 2013 May 28;
Warlop TB, Bollens B, Crevecoeur F, Detrembleur C, Lejeune TM
Long-range dependency has been found in most rhythmic motor signals. The origin of this property is unknown and largely debated. There is a controversy on the influence of voluntary control induced by requiring a pre-determined pace such as asking subjects to step to a metronome. We studied the cycle duration variability of 15 men pedaling on an ergometer at free pace and at an imposed pace (60 rpm). Revolution time was determined based on accelerometer signals (sample frequency 512 Hz). Revolution time variability was assessed by coefficient of variation (CV). The presence of long-range autocorrelations was based on scaling properties of the series variability (Hurst exponent) and the shape of the power spectral density (? exponent). Mean revolution time was significantly lower at freely chosen cadence, while values of CV were similar between both sessions. Long-range autocorrelations were highlighted in all series of cycling patterns. However, Hurst and ? exponents were significantly lower at imposed cadence. This study demonstrates the presence of long-range autocorrelations during cycling and that voluntary intent can modulate the interdependency between consecutive cycles. Therefore, cycling may constitute a powerful paradigm to investigate the influence of central control mechanisms on the long-range interdependency characterizing rhythmic motor tasks. HubMed – rehab
Osteoarthritis.
Wien Med Wochenschr. 2013 May 28;
Kerschan-Schindl K
Cricothyroid muscle dysfunction impairs vocal fold vibration in unilateral vocal fold paralysis.
Laryngoscope. 2013 May 27;
Pei YC, Fang TJ, Li HY, Wong AM
Objectives: The relevance of the cricothyroid (CT) muscle in patients with unilateral vocal fold paralysis (UVFP) remains controversial. To clarify the functional significance of the CT muscle in patients with UVFP, the confounding effect of the severity of recurrent laryngeal nerve (RLN) injury should be taken into consideration. In the present study, quantitative laryngeal electromyography (LEMG) was used to measuring the severity of paralysis of the thyroarytenoid- lateral cricoarytenoid (TA-LCA) muscle complex to allow the functional contribution of the CT muscle to be determined. Study Design: Cross-sectional study performed in an otolaryngology outpatient clinic. Methods: Thirty-one patients with a main diagnosis of UVFP were recruited. The main outcome measures included LEMG examination, quantitative LEMG analysis of TA-LCA muscle complex, UVFP-related quality of life questionnaire (Voice Outcome Survey; VOS), voice acoustics analysis, videolaryngostroboscopy and general quality of life questionnaire (SF-36) assessments. Results: The vocal cord position did not differ between patients with and without CT muscle impairment. Patients with both TA-LCA and CT paralysis showed poorer vocal fold vibration (p = 0.048) and higher fundamental frequency (p = 0.02), and the VOS and SF-36 were both poorer compared with patients with only TA-LCA paralysis. Conclusions: Although the vocal cord position was not influenced by CT muscle function, coexisting CT muscle paralysis may damage the voice by impairing vocal fold vibration in UVFP patients. HubMed – rehab