Mechanomyographic Parameter Extraction Methods: An Appraisal for Clinical Applications

The research conducted in the last three decades has collectively demonstrated that the skeletal muscle performance can be alternatively assessed by mechanomyographic signal (MMG) parameters. Indices of muscle performance, not limited to force, power, work, endurance and the related physiological processes underlying muscle activities during contraction have been evaluated in the light of the signal features. As a non-stationary signal that reflects several distinctive patterns of muscle actions, the illustrations obtained from the literature support the reliability of MMG in the analysis of muscles under voluntary and stimulus evoked contractions. An appraisal of the standard practice including the measurement theories of the methods used to extract parameters of the signal is vital to the application of the signal during experimental and clinical practices, especially in areas where electromyograms are contraindicated or have limited application. As we highlight the underpinning technical guidelines and domains where each method is well-suited, the limitations of the methods are also presented to position the state of the art in MMG parameters extraction, thus providing the theoretical framework for improvement on the current practices to widen the opportunity for new insights and discoveries. Since the signal modality has not been widely deployed due partly to the limited information extractable from the signals when compared with other classical techniques used to assess muscle performance, this survey is particularly relevant to the projected future of MMG applications in the realm of musculoskeletal assessments and in the real time detection of muscle activity

Integrasi kaedah geospatial dan pemodelan hidrodinamik untuk mengkaji impakkenaikan aras laut terhadap kawasan pantai

Kawasan pesisir pantai merupakan kawasan yang sangat terdedah dan sensitif kepada pelbagai ancaman terutamanya hakisan dan limpahan yang boleh menyebabkan impak negatif kepada kesejahteraan hidup manusia, persekitaran dan ekosistem. Kawasan pesisir pantai di Batu Pahat, Johor sangat terdedah kepada masalah banjir akibat fenomena air pasang dan sebahagian kawasan pantai lain dikategorikan sebagai kawasan hakisan pantai kritikal. Tujuan kajian ini adalah untuk mengenal pasti impak kenaikan aras laut terhadap komuniti pesisir pantai di Batu Pahat. Dengan menggunakan perisian ArcGIS dan MIKE21, kawasan banjir yang berlaku terhadap penempatan komuniti di pesisir pantai Batu Pahat dapat dikenal pasti dan meramalkan impak masa hadapan. Melalui hasil kajian, kawasan pantai di Batu Pahat mengalami kejadian hakisan pantai yang aktif dan jumlah kadar kehilangan tanah di kawasan tersebut sebanyak 415.7 hektar berbanding dengan kadar pemendapan yang hanya mendapat kira-kira 68.52 hektar. Hasil peta-peta risiko inundasi bagi kenaikan aras laut menunjukkan anggaran seramai 50 hingga 1145 populasi daripada jumlah penduduk seramai 28420 orang akan menerima impak kesan dari kenaikan aras laut pada tahun 2013, 2020 dan 2040. Selain itu, daripada 33 batang jalan raya di kawasan kajian, hanya 1 kawasan akan menghadapi kesan kenaikan aras laut pada tahun 2020 dan 2040. Justeru itu, peta risiko inundasi yang disediakan bagi pantai Batu Pahat amatlah berguna untuk mencegah hakisan pantai dan mengurangkan bencana masa depan

Lagrangian coupling two-phase flow model to simulate current-induced scour beneath marine pipelines

This paper presents a Lagrangian coupling two-phase flow model for simulating scour processes beneath a marine pipeline with respect to the sediment and fluid phase interactions. Smoothed Particle Hydrodynamics (SPH) capability is employed to simulate sediment and fluid particles movement, respectively as the Newtonian and non-Newtonian fluids in the framework of two-phase flow modeling. The Sub-Particle Scale (SPS) model also is closured to the fluid phase solver to account for the turbulence effects. The soft contact approach is incorporated in the sediment phase to simulate the interparticle collisions during the local scouring. Following to the Lagrangian coupling model development, the current-induced scour beneath a pipe at tunnel erosion and early stages of lee-wake erosion were explored and then compared with the experiments. The obtained results illustrated the efficiency of the proposed two-phase flow model to reproduce the scour profiles evolution up to the early stages of lee-wake erosion. Within the presented model, the parameters such as pressure field and non-dimensional sediment transport rate beneath the pipe were also estimated

A Study Of Global Warming In Malaysia

The Aim Of This Investigation Is To Study The Global Warming Trend In Malaysia. This Investigation Uses Approximately 50 Years Of Temperature Data Set. Least Square Regression Line, Coupled With Null Hypothesis Tests Were Carried Out To Detect Any Significant Trend. The Most Significant Results Of This Investigation Are: (A) A Significant Increase Of The Mean Annual Temperature, Ranging From 0.99 To 3.44°C Per 100 Years Is Forecasted, And (B) The Mean Annual Temperature Regression Lines (For All The Analyzed Stations) Exhibit That The Global Warming Trend Has Increased In The Past 30 Years. This Last Result Shows A Perfect Agreement With The Latest Report Of The Intergovernmental Panel Of Climatic Change (IPCC)

Estimation of evaporation and evapotranspiration in Malaysia using Penman and Christiansen methods

The objective of this study is two fold. On one hand, to introduce (in Malaysia) the Christiansen's model for evaporation and potential evapotranspiration (PET) that provided exceptionally good results in Central America. On the other hand, the above mentioned model is compared with Penman's model and pan evaporation values. The monthly pan evaporation and PET,and that estimated via Penman and Christiansen models are plotted. The correlation coefficient, the root mean square error (RMSE), mean bias error (MBE) and t-statistic test (t) are performed to evaluate and compare the estimation models. Climatic data (pan evaporation) of Kuala Lumpur and Kota Bahru for the year 1998 and 1999 indicate that both Christiansen and Penman models provide reasonable results of evaporation and PET. However, in this study the Penman model presents better results in estimating the evaporation and PET. In conclusion, within the Malaysian context, the Penman model shows better performance than the Christiansen model

Treatment of chronic back pain using indirect vibroacoustic therapy: A pilot study

BACKGROUND: Low frequency sound wave stimulation therapy has become increasingly popular in the rehabilitation fields,due to its ease, less fatiguing and time efficient application.OBJECTIVE: This 12-week pilot study examines the efficacy of applying low frequency sound wave stimulation (between16-160 Hz) through both hands and feet on relieving pain and improving functional ability in patients with chronic back pain.METHODS: Twenty-three participants with chronic shoulder (eleven participants) or low back pain (twelve participants) underwent a 12-week vibration therapy program of three sessions per week. A low frequency sound wave device comprising fourpiezoelectric vibration-type tactile tranducers enclosed in separate 5-cm diameter circular plates, which generate sinusoidal vibratory stimuli at a frequency of 16-160 Hz, was used in this study. Primary outcome measure was pain sensation measuredusing the Visual Analogue Scale (P-VAS). The secondary outcome measures were pain-related disability measured using thepain disability index (PDI) and quality of life measured using the SF-12.RESULTS: At week 12, significant reductions in pain sensation and pain-related disability were observed, with mean reductionsof 3.5 points in P-VAS and 13.5 points in the PDI scores. Sixty-five percent of the participants had a reduction of at least 3 pointson the P-VAS score, while 52% participants showed a decrease of at least 10 points in the PDI score. Significant improvementwas observed in the SF-12 physical composite score but not the mental composite score.CONCLUSIONS: The preliminary findings showed that passive application of low frequency sound wave stimulation therapythrough both hands and feet was effective in alleviating pain and improving functional ability in patients with chronic back pain

Strategies for Rapid Muscle Fatigue Reduction during FES Exercise in Individuals with Spinal Cord Injury: A Systematic Review.

BACKGROUND:Rapid muscle fatigue during functional electrical stimulation (FES)-evoked muscle contractions in individuals with spinal cord injury (SCI) is a significant limitation to attaining health benefits of FES-exercise. Delaying the onset of muscle fatigue is often cited as an important goal linked to FES clinical efficacy. Although the basic concept of fatigue-resistance has a long history, recent advances in biomedical engineering, physiotherapy and clinical exercise science have achieved improved clinical benefits, especially for reducing muscle fatigue during FES-exercise. This review evaluated the methodological quality of strategies underlying muscle fatigue-resistance that have been used to optimize FES therapeutic approaches. The review also sought to synthesize the effectiveness of these strategies for persons with SCI in order to establish their functional impacts and clinical relevance. METHODS:Published scientific literature pertaining to the reduction of FES-induced muscle fatigue was identified through searches of the following databases: Science Direct, Medline, IEEE Xplore, SpringerLink, PubMed and Nature, from the earliest returned record until June 2015. Titles and abstracts were screened to obtain 35 studies that met the inclusion criteria for this systematic review. RESULTS:Following the evaluation of methodological quality (mean (SD), 50 (6) %) of the reviewed studies using the Downs and Black scale, the largest treatment effects reported to reduce muscle fatigue mainly investigated isometric contractions of limited functional and clinical relevance (n = 28). Some investigations (n = 13) lacked randomisation, while others were characterised by small sample sizes with low statistical power. Nevertheless, the clinical significance of emerging trends to improve fatigue-resistance during FES included (i) optimizing electrode positioning, (ii) fine-tuning of stimulation patterns and other FES parameters, (iii) adjustments to the mode and frequency of exercise training, and (iv) biofeedback-assisted FES-exercise to promote selective recruitment of fatigue-resistant motor units. CONCLUSION:Although the need for further in-depth clinical trials (especially RCTs) was clearly warranted to establish external validity of outcomes, current evidence was sufficient to support the validity of certain techniques for rapid fatigue-reduction in order to promote FES therapy as an integral part of SCI rehabilitation. It is anticipated that this information will be valuable to clinicians and other allied health professionals administering FES as a treatment option in rehabilitation and aid the development of effective rehabilitation interventions

Mechanomyography and Torque during FES-Evoked Muscle Contractions to Fatigue in Individuals with Spinal Cord Injury

A mechanomyography muscle contraction (MC) sensor, affixed to the skin surface, was used to quantify muscle tension during repetitive functional electrical stimulation (FES)-evoked isometric rectus femoris contractions to fatigue in individuals with spinal cord injury (SCI). Nine persons with motor complete SCI were seated on a commercial muscle dynamometer that quantified peak torque and average torque outputs, while measurements from the MC sensor were simultaneously recorded. MC-sensor-predicted measures of dynamometer torques, including the signal peak (SP) and signal average (SA), were highly associated with isometric knee extension peak torque (SP: r = 0.91, p < 0.0001), and average torque (SA: r = 0.89, p < 0.0001), respectively. Bland-Altman (BA) analyses with Lin’s concordance (ρC) revealed good association between MC-sensor-predicted peak muscle torques (SP; ρC = 0.91) and average muscle torques (SA; ρC = 0.89) with the equivalent dynamometer measures, over a range of FES current amplitudes. The relationship of dynamometer torques and predicted MC torques during repetitive FES-evoked muscle contraction to fatigue were moderately associated (SP: r = 0.80, p < 0.0001; SA: r = 0.77; p < 0.0001), with BA associations between the two devices fair-moderate (SP; ρC = 0.70: SA; ρC = 0.30). These findings demonstrated that a skin-surface muscle mechanomyography sensor was an accurate proxy for electrically-evoked muscle contraction torques when directly measured during isometric dynamometry in individuals with SCI. The novel application of the MC sensor during FES-evoked muscle contractions suggested its possible application for real-world tasks (e.g., prolonged sit-to-stand, stepping,) where muscle forces during fatiguing activities cannot be directly measured

Estimation of Electrically-Evoked Knee Torque from Mechanomyography Using Support Vector Regression

The difficulty of real-time muscle force or joint torque estimation during neuromuscular electrical stimulation (NMES) in physical therapy and exercise science has motivated recent research interest in torque estimation from other muscle characteristics. This study investigated the accuracy of a computational intelligence technique for estimating NMES-evoked knee extension torque based on the Mechanomyographic signals (MMG) of contracting muscles that were recorded from eight healthy males. Simulation of the knee torque was modelled via Support Vector Regression (SVR) due to its good generalization ability in related fields. Inputs to the proposed model were MMG amplitude characteristics, the level of electrical stimulation or contraction intensity, and knee angle. Gaussian kernel function, as well as its optimal parameters were identified with the best performance measure and were applied as the SVR kernel function to build an effective knee torque estimation model. To train and test the model, the data were partitioned into training (70%) and testing (30%) subsets, respectively. The SVR estimation accuracy, based on the coefficient of determination (R2) between the actual and the estimated torque values was up to 94% and 89% during the training and testing cases, with root mean square errors (RMSE) of 9.48 and 12.95, respectively. The knee torque estimations obtained using SVR modelling agreed well with the experimental data from an isokinetic dynamometer. These findings support the realization of a closed-loop NMES system for functional tasks using MMG as the feedback signal source and an SVR algorithm for joint torque estimation