http://hdl.handle.net/10397/1779 Search the Channel search http://repository.lib.polyu.edu.hk/jspui/simple-search http://hdl.handle.net/10397/2373 Title: Performances of one-dimensional sonomyography and surface electromyography in tracking guided patterns of wrist extension<br/><br/>Authors: Guo, Jing-Yi; Zheng, Yong-Ping; Huang, Qing-Hua; Chen, Xin; He, Junfeng; Chan, Helen L. W.<br/><br/>Abstract: Electromyography (EMG) and ultrasonography have been widely used for skeletal muscle assessment. Recently, it has been demonstrated that the muscle thickness change collected by ultrasound during contraction, namely sonomyography (SMG), can also be used for assessment of muscles and has the potential for prosthetic control. In this study, the performances of one-dimensional sonomyography (1D SMG) and surface EMG (SEMG) signal in tracking the guided patterns of wrist extension were evaluated and compared, and the potentialof 1D SMG for skeletal muscle assessment and prosthetic control was investigated. Sixteen adult normal subjects including eight males and eight females participated in the experiment. The subject was instructed to perform the wrist extension under the guidance of displayed sinusoidal, square and triangular waveforms at movement rates of20, 30, 50 cycles per min. SMG and SEMG root mean squares (RMS) were collected from the extensor carpi radialis, respectively, and their RMS errors in relation to the guiding signals were calculated and compared. It wasfound that the mean RMS tracking errors of SMG under different movement rates were 18.9% ± 2.6% (mean ± SD), 18.3% ± 4.5%, and 17.0% ± 3.4% for sinusoidal, square and triangular guiding waveforms, whilethe corresponding values for SEMG were 30.3% ± 0.4%, 29.0% ± 2.7% and 24.7% ± 0.7%, respectively. Paired t test showed that the RMS errors of SMG tracking were significantly smaller than those of SEMG. Significant differences in RMS tracking errors of SMG among the three movement rates (p<0.01) for all the guiding waveformswere also observed using one-way analysis of variance (ANOVA). The results suggest that SMG signal, based on further improvement, has great potential to be an alternative method to SEMG to evaluate muscle function and control prostheses.<br/><br/>Description: DOI: 10.1016/j.ultrasmedbio.2008.11.017 Mon, 01 Jun 2009 00:00:00 GMT http://hdl.handle.net/10397/2366 Title: Classification of the mechanomyogram signal using a wavelet packet transform and singular value decomposition<br/><br/>Authors: Xie, Hong-Bo; Zheng, Yong-Ping; Guo, Jing-Yi<br/><br/>Abstract: Previous works have resulted in some practical achievements for mechanomyogram (MMG) to control powered prostheses. This work presents the investigation of classifying the hand motion using MMG signals for multifunctional prosthetic control. MMG is thought to reflect the intrinsic mechanical activity of muscle from the lateral oscillations of fibers duringcontraction. However, external mechanical noise sources such as a movement artifact are known to cause considerable interference to MMG, compromising the classification accuracy. To solve this noise problem, we proposed a new scheme to extract robust MMG features by the integration of the waveletpacket transform (WPT), singular value decomposition (SVD) and a feature selection technique based on distance evaluation criteria for the classification of hand motions. The WPT was first adopted to provide an effective time–frequency representation of non-stationary MMG signals. Then, the SVD and the distance evaluation technique were utilized to extract and select the optimal feature representing the hand motion patterns from the MMG time–frequency representation matrix. Experimental results of 12 subjects showed that four different motions of the forearm and hand could be reliably differentiated using the proposed method when two channels of MMG signals were used. Compared with three previously reported time–frequency decomposition methods, i.e. short-time Fourier transform, stationary wavelet transform and S-transform, the proposed classification system gave the highest average classification accuracy up to 89.7%. The results indicated that MMG could potentially serve as an alternative source of electromyogram for multifunctional prosthetic control using the proposed classification method.<br/><br/>Description: DOI: 10.1088/0967-3334/30/5/002 Fri, 01 May 2009 00:00:00 GMT http://hdl.handle.net/10397/2365 Title: An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues<br/><br/>Authors: Huang, Yan-Ping; Zheng, Yong-Ping; Wang, Shuzhe; Chen, Zhong-Ping; Huang, Qing-Hua; He, Yong-Hong<br/><br/>Abstract: A novel noncontact indentation system with the combination of an air jet and opticalcoherence tomography (OCT) was presented in this paper for the quantitative measurement of the mechanical properties of soft tissues. The key idea of this method is to use a pressure-controlled air jet as an indenter to compress the soft tissue in a noncontact way and utilize the OCT signals to extract the deformation induced. This indentation system provides measurement and mapping of tissue elasticity for small specimens with high scanning speed.Experiments were performed on 27 silicone tissue-mimicking phantoms with differentYoung’s moduli, which were also measured by uniaxial compression tests. The regressioncoefficient of the indentation force to the indentation depth (N mm‾¹) was used as an indicator of the stiffness of tissue under air jet indentation. Results showed that the stiffness coefficients measured by the current system correlated well with the corresponding Young’s moduli obtained by conventional mechanical testing (r = 0.89, p < 0.001). Preliminary in vivo tests also showed that the change of soft tissue stiffness with and without the contraction of the underlying muscles in the hand could be differentiated by the current measurement. This system may have broad applications in tissue assessment and characterization where alterations of mechanical properties are involved, in particular with the potential of noncontactmicro-indentation for tissues.<br/><br/>Description: DOI: 10.1088/0957-0233/20/1/015805 Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/10397/2364 Title: Evaluation of bone-tendon junction healing using water jet ultrasound indentation method<br/><br/>Authors: Lu, Min-Hua; Zheng, Yong-Ping; Lu, Hong-Bin; Huang, Qing-Hua; Qin, Ling<br/><br/>Abstract: The re-establishment of bone-tendon junction (BTJ) tissues with the junction, characterized as a unique transitional fibrocartilage zone, is involved in many trauma and reconstructive surgeries. Experimental and clinical findings have shown that a direct BTJ repair requires a long period of immobilization, which may be associated with a postoperative weak knee. Therefore, it is necessary to evaluate the morphologic and mechanical properties of BTJ tissues in situ to better understand the healing process for the purpose of reducing the adverse effects of immobilization. We previously reported a noncontact ultrasound water jet indentation system for measuringand mapping tissue mechanical properties. The key idea was to utilize a water jet as an indenter as well as the coupling medium for high-frequency ultrasound. In this article, we used ultrasound water jet indentation to evaluate the BTJ healing process. The system’s capability of measuring the material elastic modulus was first validated using tissue-mimicking phantoms. Then it was employed to assess the healing of the BTJ tissues after partialpatellectomy over time on twelve 18-week-old female New Zealand White rabbits. It was found that in comparison with the normal control samples, the elastic modulus of the fibrocartilage of the postoperative samples was significantly smaller, while its thickness increased significantly. Among the postoperative sample groups, the elasticmodulus of the fibrocartilage of the samples harvested at week 18 was significantly higher than those harvested at week 6 and week 12, which was even comparable with the value of the control samples at the same sacrifice time. The results suggested that the noncontact ultrasound water jet indentation system provided a nondestructiveway to evaluate the material properties of small animal tissues in situ and thus had the ability to evaluate the healing process of BTJ.<br/><br/>Description: DOI: 10.1016/j.ultrasmedbio.2009.06.1093 Sun, 01 Nov 2009 00:00:00 GMT