System identification of tendon reflex dynamics (original) (raw)
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Identification of Patellar Tendon Reflex Based on Simple Kinematic Measurement
Journal of Biomechanical Science and Engineering, 2009
This paper presents a method for quantifying tendon reflex dynamics addressing kinematical characteristics of the patellar tendon reflex. The method uses a limb-mounted three-dimensional motion sensor and an instrumented hammer to assess input-output relations of the patellar tendon reflex. A healthy adult male subject participated in our experiment. A simple rigid-body physical model was introduced to obtain viscoelastic and inertial responses of kinetic motion of the lower leg. This model is used to estimate knee extension torque by indicating the reflex responses of the muscle. A system identification method was then applied to describe the reflex responses to the hammer tapping by considering a second-order mathematical model with a delay term. Iterative prediction-error minimization was applied to the cascaded data for three tapping conditions: weak, medium, and strong. Good consistency was obtained between the analysis from the model and the measurement results. The results suggest that the proposed method was sufficiently feasible to characterize the reflex responses with a few characterized system parameters, which will be useful to provide additional quantitative assessment capability for neuromuscular diagnosis.
Quantification of patellar tendon reflex by motion analysis
5th Kuala Lumpur International Conference on Biomedical Engineering, BIOMED 2011, Held in Conjunction with the 8th Asian Pacific Conference on Medical and Biological Engineering, APCMBE 2011, 2011
This study collected quantitative measurements of the patellar tendon reflex using 3-dimensional motion analysis. The study was conducted in the Motion Analysis Laboratory, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia. Patellar tendon reflex of a group of healthy subjects involving 28 males and 22 females was examined. The left and right patellar tendons were tapped by a Queen Square reflex hammer with three different angles where the reflex hammer was released. The phenomenon of Jendrassik maneuver was tested by tapping on the tendon with the hammer raised to an angle of 60°. The purpose of this was to investigate the effect of reinforcement method on reflex responses. Results of the study showed that the patellar tendon reflex response of male subjects were higher at higher tapping force. Reflex response of the left and the right side did not show any significant difference. The study of tapping force on reflex response showed greater response at increasing tapping force. The reinforcement method named Jendrassik maneuver increased patellar tendon reflex response for both legs. © 2011 Springer-Verlag. http://link.springer.com/chapter/10.1007/978-3-642-21729-6\_52
Motion Analysis of Normal Patellar Tendon Reflex
The Canadian Journal of Neurological Sciences, 2013
Background:Reflex assessment, an essential element in the investigation of the motor system, is currently assessed through qualitative description, which lacks of normal values in the healthy population. This study quantified the amplitude and latency of patellar tendon reflex in normal subjects using motion analysis to determine the factors affecting the reflex amplitude.Methods:100 healthy volunteers were recruited for patellar tendon reflex assessments which were recorded using a motion analysis system. Different levels of input strength were exerted during the experiments.Results:A linear relationship was found between reflex input and reflex amplitude (r = 0.50, P <0.001). The left knee was found to exhibit 26.3% higher reflex amplitude than the right (P <0.001). The Jendrassik manoeuvre significantly increased reflex amplitude by 34.3% (P = 0.001); the effect was especially prominent in subjects with weak reflex response. Reflex latency normality data were established, w...
The Validity and Reliability of Motion Analysis in Patellar Tendon Reflex Assessment
PLoS ONE, 2013
Background: The deep tendon reflex assessments that are essential to the accurate diagnosis of neurological or neuromuscular disorders are conducted subjectively in clinical neurology. Our aim was to assess deep tendon reflexes objectively with a new reflex quantification method. Methodology/Principal Findings: The present study used a motion analysis technique to collect quantitative measurements for both the input and output of normal patellar tendon reflex. Reflex responses were measured as knee angles. The patellar tendon reflexes of 100 healthy subjects were examined using 6 levels of tendon taps, where all the assessments were captured using motion capture system. A linear relationship was found between the experimental maximum tapping velocity and tapping angle (coefficient of determination = 0.989), which was consistent with the theoretical values. Tapping velocities were predictable according to tapping angles. The findings proved the reproducibility of tapping method in producing consistent input. The reflex amplitude was consistent between two randomly assigned groups, and linearly proportionate to the tapping velocity. Conclusions/Significance: The findings on reflex amplitude indicate that motion analysis is a valid and reliable method of assessing and measuring deep tendon reflexes. © 2013 Tham et al. http://www.ncbi.nlm.nih.gov/pubmed/23409022
Assessment of Patellar Tendon Reflex Responses Using Second-Order System Characteristics
Applied Bionics and Biomechanics, 2016
Deep tendon reflex tests, such as the patellar tendon reflex (PTR), are widely accepted as simple examinations for detecting neurological disorders. Despite common acceptance, the grading scales remain subjective, creating an opportunity for quantitative measures to improve the reliability and efficacy of these tests. Previous studies have demonstrated the usefulness of quantified measurement variables; however, little work has been done to correlate experimental data with theoretical models using entire PTR responses. In the present study, it is hypothesized that PTR responses may be described by the exponential decay rate and damped natural frequency of a theoretical second-order system. Kinematic data was recorded from both knees of 45 subjects using a motion capture system and correlation analysis found that the meanR2value was 0.99. Exponential decay rate and damped natural frequency ranges determined from the sample population were −5.61 to −1.42 and 11.73 rad/s to 14.96 rad/s...
Investigation to predict patellar tendon reflex using motion analysis technique
Medical Engineering & Physics, 2011
The investigation of patellar tendon reflex involves development of a reflex hammer holder, kinematic data collection and analysis of patellar reflex responses using motion analysis techniques. The main aim of this research is to explore alternative means of assessing reflexes as a part of routine clinical diagnosis. The motion analysis system was applied to provide quantitative data which is a more objective measure of the patellar tendon reflex. Kinematic data was collected from 28 males and 22 females whilst subjected to a knee jerk test. Further analysis of kinematic data was performed to predict relationships which might affect the patellar tendon reflex. All subjects were seated on a high stool with their legs hanging freely within the capture volume of the motion analysis system. Knee jerk tests were applied to all subjects, on both sides of the leg, by eliciting hypo, hyper, and normal reflexes. An additional reinforcement technique called the Jendrassik manoeuvre was also performed under the same conditions to elicit a normal patellar tendon reflex. The comparison of reflex response between genders showed that female subjects generally had a greater response compared to males. However, the difference in reflex response between the left leg and the right leg was not significant. Tapping strength to elicit a hyper-reflex produced greater knee-jerk compared to the normal clinical tapping strength. All results were in agreement with clinical findings and results found by some early researchers. (C) 2010 IPEM. Published by Elsevier Ltd. All rights reserved. http://ac.els-cdn.com/S1350453310002705/1-s2.0-S1350453310002705-main.pdf?\_tid=8773f9fe-a018-11e3-83e4-00000aab0f26&acdnat=1393551476\_59ec0bbc6ca1368b2d6cbac16e3cb683 http://www.ncbi.nlm.nih.gov/pubmed/21146440 http://www.sciencedirect.com/science/article/pii/S1350453310002705
BMC musculoskeletal disorders, 2005
It has been postulated that muscle contraction is slower in patients with osteoarthritis of the knee than asymptomatic individuals, a factor that could theoretically impair joint protection mechanisms. This study investigated whether patients with osteoarthritis of the knee took longer than asymptomatic participants to generate force during reflex quadriceps muscle contraction. This was an exploratory study to inform sample size for future studies. An exploratory observational cross sectional study was carried out. Two subject groups were tested, asymptomatic participants (n = 17), mean (SD) 56.7 (8.6) years, and patients with osteoarthritis of the knee, diagnosed by an orthopaedic surgeon, (n = 16), age 65.9 (7.8) years. Patellar tendon reflex responses were elicited from participants and measured with a load cell. Force latency, contraction time, and force of the reflex response were determined from digitally stored data. The Mann-Whitney U test was used for the between group comp...