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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3158-3161, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018675

RESUMO

Surface electromyography (sEMG) of the lower limb muscles has been proposed to evaluate motor dysfunctions in Parkinson's disease (PD) patients. Variability in the sEMG could be used as an indicator of poor muscle coordination, but previous studies have reported conflicting results. This study has examined the variability of muscle using the coefficients of variance of Tibialis anterior (TA) and Medial gastrocnemius (MG) lower limb muscles for 24 PD, 24 age matched controls (CO), and 24 young controls (YC), during different phases of the gait cycle. The gait intervals were measured using the inertial measurement unit (IMU). We observed a statistically significant difference between PD and control for the variability of lower limb muscle when comparing the sub-phases of the gait. It was also found that the difference was more pronounced for the TA muscle.


Assuntos
Doença de Parkinson , Caminhada , Eletromiografia , Marcha , Humanos , Músculo Esquelético
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3666-3669, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018796

RESUMO

This study has investigated the efficiency of voice features in estimating the motor Unified Parkinson's Disease Rating Scale (UPDRS) score in Parkinson's disease (PD) patients. A total of 26 PD patients (mean age = 72) and 22 control subjects (mean age = 66.91) were recruited for the study. The sustained phonation /a/, /u/ and /m/ were collected in both off-state and on-state of Levodopa medication. The average motor UPDRS for PD off-state patients was 27.31, on-state was 20.42 and that of controls was 2.63. Voice features were extracted from the phonation tasks and were reduced to the most relevant 6 features for each phonation task using the Least Absolute Shrinkage and Selection Operator (LASSO) feature ranking method. The correlation between the reduced features and motor UPDRS was tested using the Spearman correlation coefficient test. AdaBoost regression learner was trained and used for automatically estimating the motor UPDRS score using the voice features. The results show that the vocal features for /m/ performed best by estimating the motor UPDRS score for PD off-state with the mean absolute error (MAE) of 3.52 and 5.90 for PD on-state. This study shows that assessment of voice can be used for day to day remote monitoring of PD patients.


Assuntos
Doença de Parkinson , Voz , Humanos , Levodopa/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Fonação
3.
IEEE J Transl Eng Health Med ; 8: 2100812, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33014638

RESUMO

Background: The enhancement in the performance of the myoelectric pattern recognition techniques based on deep learning algorithm possess computationally expensive and exhibit extensive memory behavior. Therefore, in this paper we report a deep learning framework named 'Low-Complex Movement recognition-Net' (LoCoMo-Net) built with convolution neural network (CNN) for recognition of wrist and finger flexion movements; grasping and functional movements; and force pattern from single channel surface electromyography (sEMG) recording. The network consists of a two-stage pipeline: 1) input data compression; 2) data-driven weight sharing. Methods: The proposed framework was validated on two different datasets- our own dataset (DS1) and publicly available NinaPro dataset (DS2) for 16 movements and 50 movements respectively. Further, we have prototyped the proposed LoCoMo-Net on Virtex-7 Xilinx field-programmable gate array (FPGA) platform and validated for 15 movements from DS1 to demonstrate its feasibility for real-time execution. Results: The effectiveness of the proposed LoCoMo-Net was verified by a comparative analysis against the benchmarked models using the same datasets wherein our proposed model outperformed Twin- Support Vector Machine (SVM) and existing CNN based model by an average classification accuracy of 8.5 % and 16.0 % respectively. In addition, hardware complexity analysis is done to reveal the advantages of the two-stage pipeline where approximately 27 %, 49 %, 50 %, 23 %, and 43 % savings achieved in lookup tables (LUT's), registers, memory, power consumption and computational time respectively. Conclusion: The clinical significance of such sEMG based accurate and low-complex movement recognition system can be favorable for the potential improvement in quality of life of an amputated persons.

4.
Proc Inst Mech Eng H ; 234(2): 200-209, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31774372

RESUMO

This study reports a surface electromyogram and force of contraction model. The objective was to investigate the effect of changes in the size, type and number of motor units in the Tibialis Anterior muscle to surface electromyogram and force of dorsiflexion. A computational model to simulate surface electromyogram and associated force of contraction by the Tibialis Anterior muscle was developed. This model was simulated for isometric dorsiflexion, and comparative experiments were conducted for validation. Repeated simulations were performed to investigate the different parameters and evaluate inter-experimental variability. An equivalence statistical test and the Bland-Altman method were used to observe the significance between the simulated and experimental data. Simulated and experimentally recorded data had high similarity for the three measures: maximal power of power spectral density (p < 0.0001), root mean square of surface electromyogram (p < 0.0001) and force recorded at the footplate (p < 0.03). Inter-subject variability in the experimental results was in-line with the variability in the repeated simulation results. This experimentally validated computational model for the surface electromyogram and force of the Tibialis Anterior muscle is significant as it allows the examination of three important muscular factors associated with ageing and disease: size, fibre type and number of motor units.


Assuntos
Simulação por Computador , Eletromiografia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Humanos
5.
Biosensors (Basel) ; 10(1)2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31861890

RESUMO

In this paper, we have investigated the differences in the voices of Parkinson's disease (PD) and age-matched control (CO) subjects when uttering three phonemes using two complexity measures: fractal dimension (FD) and normalised mutual information (NMI). Three sustained phonetic voice recordings, /a/, /u/ and /m/, from 22 CO (mean age = 66.91) and 24 PD (mean age = 71.83) participants were analysed. FD was first computed for PD and CO voice recordings, followed by the computation of NMI between the test groups: PD-CO, PD-PD and CO-CO. Four features reported in the literature-normalised pitch period entropy (Norm. PPE), glottal-to-noise excitation ratio (GNE), detrended fluctuation analysis (DFA) and glottal closing quotient (ClQ)-were also computed for comparison with the proposed complexity measures. The statistical significance of the features was tested using a one-way ANOVA test. Support vector machine (SVM) with a linear kernel was used to classify the test groups, using a leave-one-out validation method. The results showed that PD voice recordings had lower FD compared to CO (p < 0.008). It was also observed that the average NMI between CO voice recordings was significantly lower compared with the CO-PD and PD-PD groups (p < 0.036) for the three phonetic sounds. The average NMI and FD demonstrated higher accuracy (>80%) in differentiating the test groups compared with other speech feature-based classifications. This study has demonstrated that the voices of PD patients has reduced FD, and NMI between voice recordings of PD-CO and PD-PD is higher compared with CO-CO. This suggests that the use of NMI obtained from the sample voice, when paired with known groups of CO and PD, can be used to identify PD voices. These findings could have applications for population screening.


Assuntos
Técnicas Biossensoriais , Doença de Parkinson/diagnóstico , Máquina de Vetores de Suporte , Voz , Idoso , Humanos , Fonética
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 3523-3526, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31946638

RESUMO

This study has investigated the use of inter-personnel mutual information computed from the phonetic sound recordings to differentiate between Parkinson's disease (PD) and control subjects. The normalized mutual information (NMI) denotes the amount of information shared between the voice recordings of people within the same group: PD and Control. The hypothesis of this study was that within group NMI will be significantly different when compared with inter- group NMI. For each phonetic sound, the NMI was computed for every pairing of recordings for both the PD and control groups. Pearson correlation coefficient analysis was used to determine the association of NMI with clinical parameters including Unified Parkinson's Disease Rating Scale (UPDRS), Montreal cognitive assessment (MoCA) and disease duration. ANOVA test for the three phonetic sounds of control and PD subjects showed that there is significant difference between the intra-group mean NMI for the two groups (p <; 0.003) and also showed significant association with the UPDRS motor examination score, MoCA and disease duration.


Assuntos
Doença de Parkinson , Fonética , Distúrbios da Fala , Interpretação Estatística de Dados , Humanos , Doença de Parkinson/diagnóstico , Som , Fala , Distúrbios da Fala/diagnóstico
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 2325-2328, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440872

RESUMO

In this study we developed a technique for identifying noisy electrodes in high density surface electromyography (HD-sEMG). The technique finds the spatial similarity of each electrode in the electrode array by counting the number of interactions the electrode has. Using this information the technique identifies noisy electrodes by finding electrodes that are significantly dissimilar to the other electrodes. The HD-sEMG recordings used in this study were taken from three participants who performed two isometric contractions of their biceps at 40% and 80% of their maximum voluntary contraction (MVC) force. White Gaussian noisy was added to a varying number of recorded signals before being digital filtering to generate a variety of recordings to test the technique with. In the recordings, groups of 2, 4, 8, and 16 electrodes had noise added such that the signal to noise ratios (SNR) were 0, 5, 10, 15, and 20dB. The results show that the technique can reliably identify groups of 2, 4, and 8 noisy electrodes with SNRs of 0, 5, and 10dB.


Assuntos
Eletromiografia , Contração Isométrica , Músculo Esquelético/fisiologia , Eletrodos , Humanos , Razão Sinal-Ruído
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 5656-5659, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441619

RESUMO

Modelling and analysis of surface Electromyogram (sEMG) signal has gained increasing attention in bio-signal processing for medical and healthcare applications. This research reports the study to examine the complexity in surface electromyogram signal measured from different muscles to identify the properties of muscles. Experiments were conducted to study the properties of the four muscle groups representing four sizes in length and complexities: Zygomaticus (facial), biceps, quadriceps and flexor digitorum superficialis (FDS). Complexity of the sEMG signal was computed using Higuchi's Fractal dimension. The relationship between FD and the muscle properties was investigated. Experimental results demonstrate that for a small variation in muscle contraction, there is very small change in the value of complexity (measured using Fractal dimension $\sim 0.1$%) and indicates that the larger and more complex muscles having a higher complexity at MVC. It is observed that the change in FD with muscle contraction is a result of changes in the properties of the particular muscle and its associated movement or change in length.


Assuntos
Fractais , Contração Muscular , Eletromiografia , Antebraço , Humanos , Contração Isométrica , Músculo Esquelético
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 5938-5941, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441688

RESUMO

Convolutional neural networks have been widely used for identifying diabetic retinopathy on color fundus images. For such application, we proposed a novel framework for the convolutional neural network architecture by embedding a preprocessing layer followed by the first convolutional layer to increase the performance of the convolutional neural network classifier. Two image enhancement techniques i.e. 1- Contrast Enhancement 2- Contrast-limited adaptive histogram equalization were separately embedded in the proposed layer and the results were compared. For identification of exudates, hemorrhages and microaneurysms, the proposed framework achieved the total accuracy of 87.6%, and 83.9% for the contrast enhancement and contrast-limited adaptive histogram equalization layers, respectively. However, the total accuracy of the convolutional neural network alone without the prreprocessing layer was found to be 81.4%. Consequently, the new convolutional neural network architecture with the proposed preprocessing layer improved the performance of convolutional neural network.


Assuntos
Retinopatia Diabética/diagnóstico , Aumento da Imagem , Redes Neurais de Computação , Algoritmos , Exsudatos e Transudatos , Fundo de Olho , Hemorragia , Humanos , Microaneurisma
10.
IEEE Trans Neural Syst Rehabil Eng ; 26(3): 675-686, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29522411

RESUMO

Surface electromyography (sEMG) data acquired during lower limb movements has the potential for investigating knee pathology. Nevertheless, a major challenge encountered with sEMG signals generated by lower limb movements is the intersubject variability, because the signals recorded from the leg or thigh muscles are contingent on the characteristics of a subject such as gait activity and muscle structure. In order to cope with this difficulty, we have designed a three-step classification scheme. First, the multichannel sEMG is decomposed into activities of the underlying sources by means of independent component analysis via entropy bound minimization. Next, a set of time-domain features, which would best discriminate various movements, are extracted from the source estimates. Finally, the feature selection is performed with the help of the Fisher score and a scree-plot-based statistical technique, prior to feeding the dimension-reduced features to the linear discriminant analysis. The investigation involves 11 healthy subjects and 11 individuals with knee pathology performing three different lower limb movements, namely, walking, sitting, and standing, which yielded an average classification accuracy of 96.1% and 86.2%, respectively. While the outcome of this study per se is very encouraging, with suitable improvement, the clinical application of such an sEMG-based pattern recognition system that distinguishes healthy and knee pathological subjects would be an attractive consequence.


Assuntos
Eletromiografia/classificação , Traumatismos do Joelho/fisiopatologia , Extremidade Inferior/fisiologia , Movimento/fisiologia , Algoritmos , Fenômenos Biomecânicos , Análise Discriminante , Eletromiografia/estatística & dados numéricos , Entropia , Voluntários Saudáveis , Humanos , Extremidade Inferior/fisiopatologia , Masculino , Músculo Esquelético/fisiologia , Caminhada/fisiologia , Adulto Jovem
11.
IEEE J Biomed Health Inform ; 22(5): 1648-1652, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29028217

RESUMO

BACKGROUND: Change of handwriting can be an early marker for severity of Parkinson's disease but suffers from poor sensitivity and specificity due to inter-subject variations. AIM: This study has investigated the group-difference in the dynamic features during sketching of spiral between PD and control subjects with the aim of developing an accurate method for diagnosing PD patients. METHOD: Dynamic handwriting features were computed for 206 specimens collected from 62 Subjects (31 Parkinson's and 31 Controls). These were analyzed based on the severity of the disease to determine group-difference. Spearman rank correlation coefficient was computed to evaluate the strength of association for the different features. RESULTS: Maximum area under ROC curve (AUC) using the dynamic features during different writing and spiral sketching tasks were in the range of 0.67 to 0.79. However, when angular features ($\boldsymbol{\varphi }$ and ${\boldsymbol{p}_{\boldsymbol{n}}}$) and count of direction inversion during sketching of the spiral were used, AUC improved to 0.933. Spearman correlation coefficient was highest for ϕ and ${\boldsymbol{p}_{\boldsymbol{n}}}$. CONCLUSION: The angular features and count of direction inversion which can be obtained in real-time while sketching the Archimedean guided spiral on a digital tablet can be used for differentiating between Parkinson's and healthy cohort.


Assuntos
Escrita Manual , Destreza Motora/fisiologia , Doença de Parkinson/diagnóstico , Doença de Parkinson/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Doença de Parkinson/classificação
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 2434-2437, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060390

RESUMO

This study has investigated the stride, swing, stance and double support intervals of gait for Parkinson's disease (PD) patients with different levels of severity. Self-similar properties of the gait signal were analyzed to investigate the changes in the gait pattern of the healthy and PD patients. To understand the self-similar property, detrended fluctuation analysis was performed. The analysis shows that the PD patients have less defined gait when compared to healthy. The study also shows that among the stance and swing phase of stride interval, the self-similarity is less for swing interval when compared to the stance interval of gait and decreases with the severity of gait. Also, PD patients show decreased self-similar patterns in double support interval of gait. This suggest that there are less rhythmic gait intervals and a sense of urgency to remain in support phase of gait by the PD patients.


Assuntos
Doença de Parkinson , Marcha , Transtornos Neurológicos da Marcha , Humanos , Periodicidade
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 3461-3464, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29060642

RESUMO

In this study we investigated a technique for estimating the progression of localized muscle fatigue. This technique measures the dependence between motor units using high density surface electromyogram (HD-sEMG) and is based on the Normalized Mutual Information (NMI) measure. The NMI between every pair combination of the electrode array is computed to measure the interactions between electrodes. Participants in the experiment had an array of 64 electrodes (16 by 4) placed over the TA of their dominate leg such that the columns of the array ran parallel with the muscle fibers. The HD-sEMG was recorded whilst the participants maintained an isometric dorsiflexion with their dominate foot until task failure at 40% and 80% of their maximum voluntary contraction (MVC). The interactions between different locations over the muscle were computed using the recorded HD-sEMG signals. The results show that the average interactions between various locations over the TA significantly increased during fatigue at both levels of contraction. This can be attributed to the dependence in the motor units.


Assuntos
Fadiga Muscular , Eletromiografia , Contração Muscular , Fibras Musculares Esqueléticas , Músculo Esquelético
14.
Biomed Tech (Berl) ; 61(6): 607-610, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27023317

RESUMO

The protocol for estimating force of contraction by triceps surae (TS) muscles requires the immobilization of the ankle during dorsiflexion and plantar flexion. However, large variability in the results has been observed. To identify the cause of this variability, experiments were conducted where ankle dorsiflexion force and electromyogram (EMG) of the TS were recorded under two conditions: (i) toes were strapped and (ii) toes were unstrapped, with all other conditions such as immobilization of the ankle remaining unchanged. The root mean square (RMS) of the EMG and the force were analyzed and one-tail Student's t-test was performed for significance between the two conditions. The RMS of the EMG from TS muscles was found to be significantly higher (~55%) during dorsiflexion with toes unstrapped compared with when the toes were strapped. The torque corresponding to dorsiflexion was also higher with toes unstrapped. Our study has shown that it is important to strap the toes when measuring the torque at the ankle and EMG of the TS muscles.


Assuntos
Eletromiografia , Perna (Membro)/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Dedos do Pé/fisiologia , Humanos , Torque
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 3638-3641, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28324992

RESUMO

Age-associated changes in the surface electromyogram (sEMG) of Tibialis Anterior (TA) muscle can be attributable to neuromuscular alterations that precede strength loss. We have used our sEMG model of the Tibialis Anterior to interpret the age-related changes and compared with the experimental sEMG. Eighteen young (20-30 years) and 18 older (60-85 years) performed isometric dorsiflexion at 6 different percentage levels of maximum voluntary contractions (MVC), and their sEMG from the TA muscle was recorded. Six different age-related changes in the neuromuscular system were simulated using the sEMG model at the same MVCs as the experiment. The maximal power of the spectrum, Gaussianity and Linearity Test Statistics were computed from the simulated and experimental sEMG. A correlation analysis at α=0.05 was performed between the simulated and experimental age-related change in the sEMG features. The results show the loss in motor units was distinguished by the Gaussianity and Linearity test statistics; while the maximal power of the PSD distinguished between the muscular factors. The simulated condition of 40% loss of motor units with halved the number of fast fibers best correlated with the age-related change observed in the experimental sEMG higher order statistical features. The simulated aging condition found by this study corresponds with the moderate motor unit remodelling and negligible strength loss reported in literature for the cohorts aged 60-70 years.


Assuntos
Eletromiografia/métodos , Músculo Esquelético/fisiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Pé/fisiologia , Pé/fisiopatologia , Humanos , Contração Isométrica/fisiologia , Perna (Membro)/fisiologia , Perna (Membro)/fisiopatologia , Masculino , Músculo Esquelético/fisiopatologia , Distribuição Normal , Processamento de Sinais Assistido por Computador
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 876-879, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28268463

RESUMO

In this study, we have analyzed the accelerometer data recorded during gait analysis of Parkinson disease patients for detecting freezing of gait (FOG) episodes. The proposed method filters the recordings for noise reduction of the leg movement changes and computes the wavelet coefficients to detect FOG events. Publicly available FOG database was used and the technique was evaluated using receiver operating characteristic (ROC) analysis. Results show a higher performance of the wavelet feature in discrimination of the FOG events from the background activity when compared with the existing technique.


Assuntos
Algoritmos , Transtornos Neurológicos da Marcha/diagnóstico , Doença de Parkinson/fisiopatologia , Acelerometria/métodos , Idoso , Bases de Dados Factuais , Feminino , Marcha/fisiologia , Transtornos Neurológicos da Marcha/fisiopatologia , Humanos , Perna (Membro)/fisiologia , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Doença de Parkinson/diagnóstico , Curva ROC
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 3654-3657, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28269086

RESUMO

In this study we have tested the hypothesis regarding the increase in synchronization with the onset of muscle fatigue. For this aim, we have investigated the difference in the synchronicity between high density surface electromyogram (sEMG) channels of the rested muscles and when at the limit of endurance. Synchronization was measured by computing and normalizing the mutual information between the sEMG signals recorded from the high-density array electrode locations. Ten volunteers (Age range: 21 and 35 years; Mean age = 26 years; Male = 6, Female = 4) participated in our experiment. The participants performed isometric dorsiflexion of their dominate foot at two levels of contraction; 40% and 80% of their maximum voluntary contraction (MVC) until task failure. During the experiment an array of 64 electrodes (16 by 4) placed over the TA parallel to the muscle fiber was used to record the HD-sEMG. Normalized Mutual Information (NMI) between electrodes was calculated using the HD-sEMG data and then analyzed. The results show that that the average NMI of the TA significantly increased during fatigue at both levels of contraction. There was a statistically significant difference between NMI of the rested muscle compared with it being at the point of task failure.


Assuntos
Eletromiografia/métodos , Fadiga Muscular/fisiologia , Adulto , Eletrodos , Eletromiografia/instrumentação , Desenho de Equipamento , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/fisiologia
18.
MethodsX ; 2: 107-11, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26150978

RESUMO

It is important to accurately estimate the electromyogram (EMG)/force relationship of triceps surae (TS) muscle for detecting strength deficit of tibalis anterior (TA) muscle. In literature, the protocol for recording EMG and force of dorsiflexion have been described, and the necessity for immobilizing the ankle has been explained. However, there is a significant variability of the results among researchers even though they report the fixation of the ankle. We have determined that toe extension can cause significant variation in the dorsiflexion force and EMG of TS and this can occur despite following the current guidelines which require immobilizing the ankle. The results also show that there was a large increase in the variability of the force and the RMS of EMG of TS when the toes were not strapped compared with when they were strapped. Thus, with the current guidelines, where there are no instructions regarding the necessity of strapping the toes, the EMG/force relationship of TS could be incorrect and give an inaccurate assessment of the dorsiflexor TA strength. In summary, •Current methodology to estimate the dorsiflexor TA strength with respect to the TS activity, emphasizing on ankle immobilization is insufficient to prevent large variability in the measurements.•Toe extension during dorsiflexion was found to be one source of variability in estimating the TA strength.•It is recommended that guidelines for recording force and EMG from TA and TS muscles should require the strapping of the toes along with the need for immobilizing the ankle.

19.
Biomed Eng Online ; 14: 30, 2015 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-25889735

RESUMO

BACKGROUND: Myoelectric controlled prosthetic hand requires machine based identification of hand gestures using surface electromyogram (sEMG) recorded from the forearm muscles. This study has observed that a sub-set of the hand gestures have to be selected for an accurate automated hand gesture recognition, and reports a method to select these gestures to maximize the sensitivity and specificity. METHODS: Experiments were conducted where sEMG was recorded from the muscles of the forearm while subjects performed hand gestures and then was classified off-line. The performances of ten gestures were ranked using the proposed Positive-Negative Performance Measurement Index (PNM), generated by a series of confusion matrices. RESULTS: When using all the ten gestures, the sensitivity and specificity was 80.0% and 97.8%. After ranking the gestures using the PNM, six gestures were selected and these gave sensitivity and specificity greater than 95% (96.5% and 99.3%); Hand open, Hand close, Little finger flexion, Ring finger flexion, Middle finger flexion and Thumb flexion. CONCLUSION: This work has shown that reliable myoelectric based human computer interface systems require careful selection of the gestures that have to be recognized and without such selection, the reliability is poor.


Assuntos
Membros Artificiais , Eletromiografia , Gestos , Mãos , Músculo Esquelético/fisiologia , Reconhecimento Automatizado de Padrão/métodos , Interface Usuário-Computador , Algoritmos , Antebraço/fisiologia , Humanos , Aprendizado de Máquina , Desenho de Prótese , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2015: 2900-3, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26736898

RESUMO

With age, there is a change in functional connectivity of motor units in muscle. This leads to reduced muscle strength. This study has investigated the effect of age on the changes in the motor unit recruitment by measuring the mutual information between multiple channels of surface electromyogram (sEMG) of biceps brachii muscle. It is hypothesised that with ageing, there is a reduction in number of motor units, which can lead to an increase in the dependency of remaining motor units. This increase can be observed in the mutual information between the multiple channels of the muscle activity. Two channels of sEMG were recorded during the maximum level of isometric contraction. 28 healthy subjects (Young: age range 20-35years and Old: age range - 60-70years) participated in the experiments. The normalized mutual information (NMI), a measure of dependency factor, was computed for the sEMG recordings. Statistical analysis was performed to test the effect of age on NMI. The results show that the NMI among the older cohort was significantly higher when compared with the young adults.


Assuntos
Neurônios Motores , Adulto , Idoso , Braço , Eletromiografia , Humanos , Contração Isométrica , Pessoa de Meia-Idade , Contração Muscular , Músculo Esquelético , Recrutamento Neurofisiológico , Adulto Jovem
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