Manvinder Kaur

Novel Notch Detection Algorithm for Detection of Dicrotic Notch in PPG Signals

Photoplethysmography (PPG) is a non-invasive optical technique that measures relative blood volume changes in the blood vessels and is widely used for research and physiological studies. Dicrotic notch represent the closure of the aortic semi-lunar valve and subsequent receding blood flow when ventricles relax. Their location is used to calculate systolic time intervals and monitor cardiac function. They play a significant role in early evaluation of various diseases such as sclerosis, occlusion, arterial spasm etc. This paper proposes a novel Notch Detection Algorithm (NDA) for detection of dicrotic notches from PPG signal that are measured by non-invasive photoplethysmography sensors. The proposed algorithm is implemented with the help of self developed Graphical User Interface (GUI) in MATLAB.

siGnum: Graphical user interface for EMG signal analysis

Abstract Electromyography (EMG) signals that represent the electrical activity of muscles can be used for various clinical and biomedical applications. These are complicated and highly varying signals that are dependent on anatomical location and physiological properties of the muscles. EMG signals acquired from the muscles require advanced methods for detection, decomposition and processing. This paper proposes a novel Graphical User Interface (GUI) siGnum developed in MATLAB that will apply efficient and effective techniques on processing of the raw EMG signals and decompose it in a simpler manner. It could be used independent of MATLAB software by employing a deploy tool. This would enable researcher’s to gain good understanding of EMG signal and its analysis procedures that can be utilized for more powerful, flexible and efficient applications in near future.

EMG analysis for identifying walking patterns in healthy males

Electromyography (EMG) signals are the measure of biological potentials associated with the muscle activity. EMG signals acquired from the muscles are highly varying and random in nature that depends on the anatomical location and physiological properties of muscles. This paper investigated the muscle activation patterns during different phases of human walking by acquiring the surface EMG signals from the predominant lower limb muscles namely Gluteus Maximus, Hamstrings (biceps femoris), Quadriceps (rectus femoris) and Soleus with the healthy subjects walking at two pace-normal and fast. Results showed that the time domain {Root Mean Square (RMS)} and the frequency domain {Median frequencies (MDF)} values of healthy subjects are inversely related to each other. Statistical analysis of the results showed a marked variation in the time domain characteristics of the EMG signals for Hamstring and Soleus muscles when walking pace varied. These findings would help to better understand the role of lower limb muscles when walking pace varies. This knowledge would aid in developing and designing EMG based control devices for physically challenged persons in field of rehabilitation.

EMG Asymetricity of Selected Knee Extensor Muscles in Sustained SquatPosture (A Yogic Posture) of Athletes in Relation to their Gender andPerformance

Squat is a popular yogic exercise or posture, most frequently used for quadriceps strengthening and rehabilitation. It is used for evaluation process or test by physiotherapists/clinicians/others associated with rehabilitation of athletes to strengthen their lower-body muscles and connective tissues after joint-related injury. It has been used extensively for therapeutic treatment of ligament lesions, patellofemoral dysfunctions, patellar subluxation and patellar dislocation etc. The purpose of this study was to compare the effect of sustained squat posture (a yogic posture) of athletes among male (n1=32) and female (n2=18) with high and low performance (based upon median split method) on EMG activity of Vastus Medialis (VM) and Vastus Lateralis (VL) muscles for 120 seconds. Squatting was performed at an angle of 135o-150o because strength of knee extensor (muscles) varies between these angles and is an important consideration for the performance of numerous physical daily routine activities such as walking, running, cycling, stepping and driving including development of fundamental skills for different sports across all ages and sex. VM and VL from the Quadriceps muscle group were chosen for recording the physiological signal simultaneously from right and left leg of the subjects, as these muscles determines stress on the patellofemoral joint and stabilizes the patellar bone during squatting. Frequency and time domain variables were selected to extract meaningful information from the EMG signal using the algorithm developed in MATLAB. The selected variables were Median Frequency (MDF), Mean Frequency (MNF), Root Mean Square (RMS) and Integrated EMG (IEMG). Statistical analysis showed significant differences among gender and performance level along with significant bilateral asymmetry in these athletes. Understanding from the findings is pivotal for achieving optimal muscular strength, for the development of strength endurance and reducing the prospect of training-related injuries

Co-Contraction of Knee Stabilizer Muscles during Sustained Squat Posture (A Yogic Posture) in Athletes

Simultaneous activation of muscles across a joint can be defined as muscle co-contraction. Its purpose is to augment the ligament function in maintenance of joint stability, provide resistance to rotation at a joint, and equalize the pressure distribution at the articular surface. The purpose of this study was to investigate the Co-contraction of selected knee stabilizer muscles as a measure of neuromuscular fatigue in relation to gender, performance and side (left and right) of male (n1=32) and female (n2=18) during sustained squat posture (yogic posture). Squat Posture was performed at an angle of 135o-150o because strength of knee stabilizers (muscles) varies from angle to angle and 135o to 150o is prominent angle range having high consideration for the performance of numerous physical daily routine activities such as walking, running, cycling, stepping and driving including development of fundamental skills for different sports across all ages and sex. Vastus Medialis (VM) and Vastus Lateralis (VL) muscles from the Quadriceps group were the knee stabilizers chosen for recording the EMG simultaneously from both right and left legs as these muscles are considered important for stabilization and protection of patellofemoral joint. The statistical analysis applied were ANOVA with post hoc analysis to determine the influence of fatigue in terms of gender, performance and side (left and right). The results showed significant female dominance behavior over males in coactivation of VM and VL muscles along with bilateral Asymetricity during sustained squat posture. The results of this study would help in better understanding the changes in knee stabilizers activation strategies that can help the clinicians and trainers in planning, execution of rehabilitation related to patellofemoral joint injuries.

Comparison of muscle activation patterns among healthy males and females during different lower limb movements

Motion abilities and lifestyle of an individual is highly affected by neuromuscular, musculoskeletal disorders and injuries to the lower limbs. Gender differences in kinematics during running have been speculated to be a contributing factor to the lower extremity injury rate showing disparity between men and women (Farahani and Gunjan, 2015; Chumanov et al., 2008). The purpose of this study was to examine the difference in non-sagittal motion of males and females in four prominent lower limb muscles namely, tibialis anterior (TA), soleus (SOL), hamstrings (biceps femoris) (HM) and quadriceps (rectus femoris) (QUAD) during different locomotion tasks involving knee flexion and extension, ankle plantar flexion and dorsiflexion. Time domain parameters of EMG were used for the quantification of EMG activity of muscles due to its implementation and computation simplicity. Statistical analysis of results demonstrated greater TA, SOL and HM activity in males but greater QUAD activity in females than males.

Influence of gender on coactivation ratio of agonist-antagonist muscle pair during maximum knee contraction

Coactivation is the activation of two or more things together. Simultaneous activity of the muscles acting around a joint is known as muscle coactivation. Coactivation of knee muscles is considered to be an important phenomenon for the stabilization of knee joint. The purpose of this paper was to investigate the influence of gender on Coactivation ratio of agonist-antagonist muscle pair during maximum knee contraction in male (n1=10) and female (n2=10) adult population. The agonist-antagonist muscle pairs considered were Rectus femoris (RF)-Biceps femoris (BF) for determining the Coactivation of quadriceps-hamstring muscle group. This muscle pair is a major contributor in the dynamic stability of the knee joint during movement patterns which are recommended during rehabilitation and are important for daily function. The statistical analysis applied was post hoc analysis to determine least significant differences among the different gender groups. The results showed significant gender differences in the activation patterns of the muscle pair during maximum knee extension. The results of this paper would help to better understand the significance of gender related differences in coactivation ratio that would help to manage the rehabilitation of anterior cruciate ligament (ACL) injuries. This study is a part of a larger intervention study that is being carried out for designing feedback based FES devices.

smRithm: Graphical user interface for heart rate variability analysis

Abstract Over the past 25 years, Heart rate variability (HRV) has become a non-invasive research and clinical tool for indirectly carrying out investigation of both cardiac and autonomic system function in both healthy and diseased. It provides valuable information about a wide range of cardiovascular disorders, pulmonary diseases, neurological diseases, etc. Its primary purpose is to access the functioning of the nervous system. The source of information for HRV analysis is the continuous beat to beat measurement of inter-beat intervals. The electrocardiography (ECG or EKG) is considered as the best way to measure inter-beat intervals. This paper proposes an open source Graphical User Interface (GUI): smRithm developed in MATLAB for HRV analysis that will apply effective techniques on the raw ECG signals to process and decompose it in a simpler manner to obtain more useful information out of signals that can be utilized for more powerful and efficient applications in the near future related to HRV.

Advancements in functional electrical stimulator technology

One of the most exciting recent advances in the neuroprosthetics field has been the application of biosignals in the design of functional electrical stimulation (FES) devices. This review discusses the different approaches in the field of functional electrical stimulation (FES) enabling control of human gait and address fundamental perquisites to enable FES walking systems to become safer, more practical, comfortable and therefore, clinically efficacious. In many forms of disability in humans due to paralysis, it appears possible to regain some measure of functional control of movement through direct electrical stimulation of paralysed muscles. This review provides a comprehensive overview of the advancements in clinical uses of functional electrical stimulation functional and therapeutic applications in subjects with spinal cord injury or stroke. Perspectives on future developments and clinical applications of FES are also presented herewith in this paper.

Design of smart functional electric stimulator for physically challenged person

Paralysed muscles can regain their contraction by providing intact peripheral motor nerves, electrical stimulation. To elicit the muscle contraction of the peripheral nerves fibres may be achieved by activation of motor efferent or through reflex pathways by activation of sensory-afferent nerve fibres. The technique may also include activation of sensory nerve fibres for the purpose of eliciting a perceived response in the skin, which may be used to provide sensory clues to the non-sensory extremity. In more than 40 years of FES research, principles for safe stimulation of neuromuscular tissue have been established, and methods for modulating the strength of electrically induced muscle contractions have been discovered. The FES is a rehabilitation strategy which applies electrical current to the nerves that controls paralysed muscles in order to stimulate functional movement. Functional electrical stimulation includes both therapeutic applications and applications to obtain functional restoration of movement. Functional restoration of movement includes applications to enhance manipulation in the upper extremity or locomotion in the lower extremity.