Table 2 shows all of the tested combinations and the classification accuracy of each classifier. In each case, principal component analysis PCA is applied to the input features to perform feature transformation but results are only shown for the case in which PCA improved the performance of at least one classifier.
The points are labeled to show the correctly classified sample from each group, using a different mark for each NINDS level and the misclassified samples as well. The dark round markers shows misclassified tests by naive Bayes classifier, and all other points were correctly classified into their respective groups.
The dynamic behavior of the leg during the patellar reflex creates movement patterns that can be automatically classified in the NINDS scale with a useful degree of accuracy. This is shown to be possible using a straightforward feature extraction procedure and pattern recognition techniques. However, despite the good performance by the proposed system, discordance between clinical measurements and the current measurements might still be considered high in some scenarios.
Moreover, the proposed approach should be verified using observations from different neurologists to determine how well this approach generalized across experts. Nonetheless, the proposed system might lead to the full automatization of this test by integrating these future improvements, along with other promising technical enhancements, such as wireless sensors to increase a patient's comfort or edge computing to simplify the data processing and transmission process.
The authors declare that there are no conflicts of interest regarding the publication of this article. National Center for Biotechnology Information , U. Journal List J Healthc Eng v. J Healthc Eng. Published online Jul 9. Blanca E. Luis A. Author information Article notes Copyright and License information Disclaimer.
Corresponding author. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article has been cited by other articles in PMC. Associated Data Data Availability Statement The data used to support the findings of this study are available from the corresponding author upon request.
Abstract Clinical evaluation of the patellar reflex is one of the most frequent diagnostic methods used by physicians and medical specialists. Introduction The observation of the patellar reflex is one of the clinical trials performed most frequently for neurological tests, making it an essential tool for the diagnosis of many neuromuscular diseases [ 1 ]. Materials and Methods 2. Mechanical Controlled Force System The mechanical controlled force system consists of a hammer designed as a Charpy pendulum.
Volunteer Selection In this work, we use a group of healthy volunteers to evaluate our proposed system. Measurement Procedure Experimental tests were performed under the supervision of the physician. Open in a separate window. Figure 1. Data Treatment and Features The data stored by the system contain three time series.
Figure 2. Figure 3. Classification To achieve the classification of the realized patellar reflex tests based on the number of crossings in the NINDS scale, basic pattern recognition and machine learning methods are used [ 25 , 26 ]. Figure 4. Figure 5. Figure 6. Figure 7.
Figure 8. Conclusion The dynamic behavior of the leg during the patellar reflex creates movement patterns that can be automatically classified in the NINDS scale with a useful degree of accuracy. Acknowledgments G. Data Availability The data used to support the findings of this study are available from the corresponding author upon request.
Conflicts of Interest The authors declare that there are no conflicts of interest regarding the publication of this article. References 1. Merck Manual of Medical Information. The reflex that the doctor checks by tapping your knee is called the patellar, or knee-jerk, reflex. It is also known as a deep tendon reflex DTR because the doctor is actually tapping on a tendon called the patellar say: puh-TEL-ur tendon.
This tap stretches the tendon and the muscle in the thigh that connects to it. A message then gets sent to the spinal cord that the muscle has been stretched. The spinal cord very quickly sends a message back to the muscle telling it to contract. The contraction of the muscle causes your lower leg to kick out.
You might wonder why such a reflex exists. Because of this and the complexity of conscious reactions, they take more time to complete than a reflex.
On average, humans have a reaction time of 0. Reaction times vary from individual to individual. Because of the higher degree of neural processing, reaction times can be influenced by a variety of factors. Reaction times can decrease with practice, as often times athletes have faster reaction times than non-athletes. Sleepiness, emotional distress, or consumption of alcohol can also impact reaction time.
Stretch reflexes are a special type of muscle reflex which protect the muscle against increases in length which may tear or damage muscle fibers.
Stretch reflexes are very important in maintaining your upright posture in humans. Consider the patellar reflex -- a very familiar reflex for those of us who have visited the doctor's office over the years. The primary purpose of the patellar reflex, which is the stretch reflex of the quadriceps femoris muscle in your anterior thigh, is to prevent the stretching of the quadriceps.
The patellar reflex is illustrated in Figure 2. The patellar tendon attaches the quadriceps muscle to the tibia bone of the lower leg. The quadriceps is an extensor muscle because when it contracts it extends the angle of the knee joint by raising the lower leg. Tapping the patellar tendon stretches the quadriceps muscle and causes the sensory receptor of the muscle, called a spindle fiber, to send a signal along the afferent neuron to the spinal cord.
This causes the efferent neuron to return a signal to the quadriceps muscle to contract and lift the lower leg. This action resists the initial stretch and is a classic example of negative feedback. To consider more carefully the events which results of in the "sensation" of muscle stetch, we have to define a few more muscle fiber types. Muscle spindles, called intrafusal fibers, are innervated by sensory neurons and are arranged in parallel to normal muscle fibers extrafusal.
Intrafusal fibers respond to tension by depolarizing a sensory neuron. The sensory neuron synapses with a motor neuron in the spinal cord that innervates extrafusal fibers.
The contraction of the extrafusal fibers releases tension on the intrafusal fibers, decreasing stimulation to neuron. The extensor muscle of the knee quadriceps femoris is attached just below the knee to the anterior part of the tibia by the patellar tendon. Hitting the patellar tendon with a rubber mallet stretches the spindles in the quadriceps muscle, causing contraction Sherwood, The patellar tendon reflex tests the function of the femoral nerve and spinal cord segments L2-L4.
The absence or decrease of this reflex is known as Westphal's sign. That term knee-jerk was coined by Sir Michael Foster in his textbook of physiology in "Striking the tendon below the patella gives rise to a sudden extension of the leg, known as the knee-jerk.
The term began to be used figuratively from the early 20th century onwards. And gets only an occasional knee-jerk.
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