ABSTRACT
@#Objective:To explore the kinematics characteristics of articulators (including lips, tongue and jaw) during articulation in dysarthric individuals post brain injury by using electromagnetic articulography (electromagnetic articulography, EMA). Methods:From October, 2017 to October, 2018, six eligible individuals with dysarthria were recruited as dysarthria group, and ten age-gender matched healthy adults were recruited as healthy control group. Both groups received EMA assessment, and the dysarthria group was assessed with Chinese modified version of Frenchay Dysarthria Assessment before EMA assessment. To track and record kinematic parameters data (including duration, velocity, acceleration, distance) and displacement movement trajectories, a series of sensors were attached on the participant's lips, tongue (tip, blade and back of tongue) and jaw, the reference sensor was attached on the bridge of nose, all of the sensors were along midsagittal plane. During EMA assessment, each participant was received syllable repetition task, which containing consonants (/d/, /t/, /j/, /q/, /g/, /k/, /b/, /p/) at word initial position and vowels (/a/, /ia/, /iu/), to produce the single word with the Chinese linguistic meaning, every syllable produced was repeated three times. Then Praat software and Matlab software were used to process acoustic and kinematic data, so as to compare the differences of articulatory kinematic performance between two groups. Results:The outcome of the Frenchay Dysarthria Assessment indicated that the severity of dysarthria was from moderate to extreme severe. EMA assessment demonstrated that, compared with the healthy control group, the dysarthria group showed a reduction of velocity, acceleration and distance of tongue and lip movement (<italic>t</italic> > 2.422, <italic>P</italic> < 0.05), and longer duration of tongue tip, tongue back and jaw movement (<italic>t</italic> > 3.369, <italic>P</italic> < 0.05). There was no statistical difference in duration of tongue blade and lip movement (<italic>t</italic> < 2.146, <italic>P</italic> > 0.05), the same as the velocity, acceleration and distance of jaw movement between two groups (<italic>t</italic> < 1.016, <italic>P</italic> > 0.05). Image analysis of kinematics parameters and synchronous audio data showed that, compared with the healthy control group, the dysarthria group varied unstably in velocity and acceleration, and the audio data showed that, when repeated /da/ three times, the duration of each syllable was not equal. The coordination of articulation movement displacement in the anterior-posterior dimension and inferior-superior dimension was poor, there were significant differences in visual inspection of movement trajectories between two groups, and a smaller displacement was found in the anterior-posterior dimension in the dysarthric group. Conclusion:EMA assessment has significant advantages in evaluating kinematics parameters quantitatively, which could reveal the kinematics characteristics of articulators.
ABSTRACT
Objective To obtain the ratcheting strain of articular cartilage under different loading conditions, and construct the theoretical model so as to predict the ratcheting strain of cartilage. Methods The fresh articular cartilage obtained from the trochlear of distal femur was used as experimental subject. The ratcheting strain of articular cartilage was tested under cyclic compressive loads by applying the non-contact digital image correlation technique. The theoretical model was constructed to predict the ratcheting strain of articular cartilage with different stress amplitudes and stress rates. The results from predictions were compared with the experimental results. Results The ratcheting strain of cartilage increased rapidly at initial stage and then showed the slower increase with cycles increasing. The ratcheting strain increased with stress amplitude increasing when the stress rate was constant. However, the ratcheting strain decreased with stress rate increasing when the stress amplitude was constant. When the stress rate increased, the ratcheting stain decreased. The prediction results of the established theoretical model were in good agreement with experimental results. Conclusions The ratcheting strain of articular cartilage is proportional to the stress amplitude, and inversely proportional to the stress rate. The established theoretical model can predict the ratcheting strain of articular cartilage and provide guidance for the construction of tissue engineered artificial cartilage.
ABSTRACT
Objective To obtain the ratcheting strain of articular cartilage under different loading conditions,and construct the theoretical model so as to predict the ratcheting strain of cartilage.Methods The fresh articular cartilage obtained from the trochlear of distal femur was used as experimental subject.The ratcheting strain of articular cartilage was tested under cyclic compressive loads by applying the non-contact digital image correlation technique.The theoretical model was constructed to predict the ratcheting strain of articular cartilage with different stress amplitudes and stress rates.The results from predictions were compared with the experimental results.Results The ratcheting strain of cartilage increased rapidly at initial stage and then showed the slower increase with cycles increasing.The ratcheting strain increased with stress amplitude increasing when the stress rate was constant.However,the ratcheting strain decreased with stress rate increasing when the stress amplitude was constant.When the stress rate increased,the ratcheting stain decreased.The prediction results of the established theoretical model were in good agreement with experimental results.Conclusions The ratcheting strain of articular cartilage is proportional to the stress amplitude,and inversely proportional to the stress rate.The established theoretical model can predict the ratcheting strain of articular cartilage and provide guidance for the construction of tissue engineered artificial cartilage.
ABSTRACT
Objective To obtain the ratcheting strain of articular cartilage under different loading conditions,and construct the theoretical model so as to predict the ratcheting strain of cartilage.Methods The fresh articular cartilage obtained from the trochlear of distal femur was used as experimental subject.The ratcheting strain of articular cartilage was tested under cyclic compressive loads by applying the non-contact digital image correlation technique.The theoretical model was constructed to predict the ratcheting strain of articular cartilage with different stress amplitudes and stress rates.The results from predictions were compared with the experimental results.Results The ratcheting strain of cartilage increased rapidly at initial stage and then showed the slower increase with cycles increasing.The ratcheting strain increased with stress amplitude increasing when the stress rate was constant.However,the ratcheting strain decreased with stress rate increasing when the stress amplitude was constant.When the stress rate increased,the ratcheting stain decreased.The prediction results of the established theoretical model were in good agreement with experimental results.Conclusions The ratcheting strain of articular cartilage is proportional to the stress amplitude,and inversely proportional to the stress rate.The established theoretical model can predict the ratcheting strain of articular cartilage and provide guidance for the construction of tissue engineered artificial cartilage.