OBJECTIVE: We designed this study to evaluate muscle tone by using a biomechanical method and to provide data for the future studies about muscle tone. METHOD: We evaluated 29 subjects without known neuromuscalar diseases using the biomechanical method. Both plantar flexors of each subject were passively stretched by isokinetic dynamometer from 30degrees plantar flexion position to 10degrees dorsiflexion position. Peak eccentric torque (PET) and torque threshold angle (TTA) were calculated at angular velocity of 10degrees/sec, 90degrees/sec and 300degrees/sec. Regression lines from torque/position curve at 10degrees/sec and 300degrees/sec were considered an intrinsic stiffness index (ISI) and total stiffness index (TSI). Stretch reflex threshold speed (SRTS) was defined as the minimum speed of plantar flexion movement in which EMG reflex activity in plantar flexor muscles is induced. RESULTS: The mean of TTA was higher in 10o/sec than in 300degrees/sec. The means of ISI and TSI were 0.11+/-0.08, and 0.18+/-0.04. The mean of SRTS was 125.2+/-48.3degrees. No statistical difference in each parameter was found according to the side or gender. CONCLUSION: ISI, TSI, PET, TTA and SRTS using a biomechanical method are thought to be useful parameters for the quantitative assessment of muscle tone change of ankle plantar flexors.
Ankle* ; Muscles ; Reflex ; Reflex, Stretch ; Torque

Adie's syndrome is characterized by a delayed or diminished direct and consensual reaction to light in a pupil larger than normal associated with loss of tendon reflexes. The authors experienced two female patients at our hcspital whom we feel to have Adie's syndrome and report them with related literature findings.
Adie Syndrome* ; Female ; Humans ; Pupil ; Reflex, Stretch

A 38-year-old man developed weakness in all limbs 3 days prior to admission. Motor examination showed decreased strength in the limbs, but sensory examination was normal. Deep tendon reflexes were hyperactive. Electrophysiological examination showed conduction blocks with nearly normal conduction velocities and terminal latencies in the motor nerves and normal amplitudes and velocities in the sensory nerves. Acute motor conduction block neuropathy with hyperreflexia may be another variant of Guillain-Barre syndrome.
Adult ; Extremities ; Guillain-Barre Syndrome ; Humans ; Reflex, Abnormal ; Reflex, Stretch

OBJECTIVE: There has been some existing problems with the electrical reflex hammer. The occurrence of pressure build up with percussion and change of hammering points is one example. In order to make improvements on this device, we conducted studies with a newly designed percussion instrumental stimulator. METHOD: The data collected from the first group was based on the manual percussion of electrical reflex hammer on the patella ligament. The data collected from the second group by usage of a newly designed instrumental stimulator maintained steady pressure and time and target position on the electrical reflex hammer. Comparisons were made between the two group. RESULTS: Our single measure of latency and amplitude on the manual and instrumental percussion group resulted in the reliability of 84.67%, 91.23%, 73.63%, and 83.29%. The 10 repeated measure of latency and amplitude on the manual and instrumental percussion group resulted in the reliability of 99.95%, 99.97%, 99.90%, and 99.94%. CONCLUSION: From our experiment on the tendon reflex, we found out that it is important to have an instrumental stimulator that can maintain steady pressure while it is applying percussion to accurate data. On manual percussion, it is important to obtain data based on mean value of repeated measurements.
Ligaments ; Patella ; Patellar Ligament* ; Percussion* ; Reflex* ; Reflex, Stretch

OBJECTIVE: To investigate the effects of Jendrassik maneuver on latency and amplitude of the T-reflex and H-reflex of the soleus muscle in normal adults. METHOD: The T-reflex and H-reflex tests were performed on sixty normal adults with standardized technique using the soleus muscle. The shortest latency and the largest peak-to-peak amplitude were chosen for representative values. RESULTS: The results were as follows: 1) There was a significant difference in latency of the T-reflex between with and without Jendrassik maneuver. 2) The increment ratio of the amplitude with Jendrassik maneuver was 88% in the T-reflex and 18% in the H-reflex. There were a significant difference in the amplitude of both reflexes between with and without Jendrassik maneuver. 3) A high correlation was present between the latency of H- & T-reflex and the length. CONCLUSION: According to these results, we suggest that Jendrassik maneuver primarily increases the sensitivity of muscle spindles and decreases the presynaptic inhibition of the Ia terminals at cortical, subcortical and spinal levels. Jendrassik maneuver can be a useful tool in cases of clinically decreased or absent deep tendon reflex.
Adult ; H-Reflex* ; Humans ; Muscle Spindles ; Muscle, Skeletal* ; Reflex ; Reflex, Stretch

OBJECTIVE: To establish a correlation between the modified Ashworth scale (MAS) and amplitude and latency of T-reflex and to demonstrate inter-rater and intra-rater reliability of the T-reflex of the biceps muscle for assessing spasticity after stroke. METHOD: A total of 21 patients with hemiplegia and spasticity after ischemic stroke were enrolled for this study. The spasticity of biceps muscle was evaluated by an occupational therapist using the MAS. The mean value of manual muscle test of biceps muscles was 2.3+/-0.79. Latency and amplitude of T-reflex were recorded from biceps muscles by two physicians. The onset latency and peak to peak amplitude of the mean of 5 big T-reflex were measured. The examinations were carried out by two physicians at the same time to evaluate the inter-rater reliability. Further, one of the physicians performed the examination again after one week to evaluate the intra-rater reliability. The correlations between MAS and T-reflex, and the intra- and inter-rater reliability of biceps T-reflex were established by calculating the Spearman correlation coefficients and the intra-class correlation coefficients (ICCs). RESULTS: Amplitude of the biceps T-reflex increased with increasing level of MAS (rs=0.464 and 0.573, respectively, p<0.01). ICCs of latency and amplitude of biceps T-reflex were 0.914 and 0.822. The Spearman correlation coefficients of latency and amplitude of biceps T-reflex were 0.937 and 0.635, respectively (p<0.01). CONCLUSION: Biceps T-reflex demonstrates a good quantitative measurement and correlation tool with MAS for spasticity, and also shows acceptable inter- and intra-rater reliability, which can be used for patients with spasticity after stroke.
Hemiplegia ; Humans ; Muscle Spasticity ; Muscles ; Reflex, Stretch ; Stroke

Spasticity is a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex. As one component of the upper motor neuron syndrome, spasticity remains a vexing problem for both clinicians and patients. Although several medications have been approved for clinical use in patients with spasticity, the literature has yielded no clear standard of care. The aims of this article are to review the mechanisms of spasticity, factors to consider when choosing and starting antispastic drugs in clinical settings, and the typical characteristics and effects of commonly used agents. This review will focus only on enteral medications, not neurolytic or intrathecal therapy.
Humans ; Motor Neurons ; Muscle Spasticity ; Reflex, Stretch ; Standard of Care ; Tendons

OBJECTIVE: This study was designed to evaluate the usefulness of stretch reflex threshold speed (SRTS) in biomechanical assesment of spasticity of hemiplegic patients. METHOD: Thirty-eight hemiplegic patients and twenty-seven control subjects were studied. The spasticity of ankle plantar flexor muscles were assessed both clinically and biomechanically. Modified Ashworth scale (MAS) and Brunnstrom stage were used in clinical assessment. For biomechanical assessment, ankle plantar flexor muscles were stretched isokinetically while EMG signals were recorded simultaneously. SRTS was defined as a minimum angular velocity in which EMG signals evoked by stretch reflex were recorded. RESULTS: SRTSs of ankle plantar flexors were 128.1 47.1o/sec in control group, 163.7 79.7o/sec in intact legs, and 83.4 69.1o/sec in involved legs of hemiplegic group. STRS was significantly lower in involved legs of hemiplegic group than in intact legs of hemiplegic group and control group. Significant reverse correlation was observed between SRTS and MAS. There was significant difference in SRTS between MAS 0 group and other groups. The patients with Brunnstrom stage 3 and 4 groups showed decreased SRTS compared to the patients with other groups. CONCLUSION: SRTS is thought to reflect increased excitability of stretch reflex and seems to be one of useful parameters in quantitative assessment of spasticity.
Ankle ; Equidae ; Hemiplegia ; Humans ; Leg ; Muscle Spasticity* ; Muscles ; Reflex, Stretch*

OBJECTIVE: The aim of this study was to develop objective evaluation method of spasticity which reflects the characteristics of lengthening velocity-dependent stretch reflex of spasticity. METHOD: Kinematic analysis for knee angle and rectus femoris muscle lengthening parameters, and dynamic EMG were performed simultaneously during pendular movement of spastic lower leg for thirty two patients with spasticity and ten normal control subjects. Angular parameters consist of angular relaxation index (ARI), maximal angular velocity (MAV), angular threshold (AT) and angular velocity threshold (AVT). And lengthening parameters consist of lengthening relaxation index (LRI), maximal lengthening velocity (MLV), lengthening threshold (LT) and lengthening velocity threshold (LVT). RESULTS: 1) ARI, MAV, AT, and AVT according to Modified Ashworth scale (MAS) were 1.32+/-0.11, 303.84+/-45.11 deg/sec, 44.19+/-13.81 deg, 262.15+/-33.54 deg/sec in MAS I, 1.16+/-0.16, 279.92+/-42.94 deg/sec, 30.33+/-6.02 deg, 247.65+/-35.92 deg/sec in MAS II, and 0.95+/-0.14, 241.31+/-19.98 deg/sec, 20.55+/-2.68 deg, 209.11+/-48.11 deg/sec in MAS III (P<0.05). 2) LRI, MLV, LT, and LVT according to MAS were 1.27+/-0.11, 0.58+/-0.07, 1.164+/-0.14, 0.53+/-0.05 in MAS I, 1.12+/-0.09, 0.53+/-0.05, 1.150+/-0.08, 0.42+/-0.04 in MAS II, and 0.99+/-0.10, 0.44+/-0.01, 1.137+/-0.15, 0.36+/-0.02 in MAS III (P<0.05). 3) There were significant correlation between various pendulum test parameters and MAS. CONCLUSION: Muscle lengthening parameters as well as knee angular parameters were sensitive parameters reflecting the degree of spasticity. LVT is the most sensitive parameter among all parameters (p<0.01).
Humans ; Knee ; Leg ; Muscle Spasticity* ; Quadriceps Muscle ; Reflex, Stretch ; Relaxation

OBJECTIVE: This study was performed to investigate the effect of experimental muscle pain on the stretch reflex through electrophysiologic measuring of H-reflex and ankle tendon reflex. METHOD: Muscle pain was produced by the continuous infusion of 5% hypertonic saline into the soleus and tibialis anterior muscles respectively in the fourteen healthy, male volunteers. Control was made with infusion of 0.9% isotonic saline. H-reflex and ankle tendon reflex were recorded at the soleus before, during and 30 minutes after infusion of saline. RESULTS: The amplitude of ankle tendon reflex increased significantly during soleus and tibialis anterior muscle pain by the infusion of hypertonic saline as compared with those of before and after injection. But the H-reflex showed no significant changes during the infusion in either muscles. CONCLUSION: These results have demonstrated a muscle pain increased the amplitude of the stretch reflex without a corresponding increase of the H-reflex amplitude. One explanation could be an increased dynamic sensitivity of the muscle spindles during muscle pain caused by an increased firing of the dynamic gamma-motor neurons.
Ankle ; Fires ; H-Reflex ; Humans* ; Male ; Muscle Spindles ; Muscles ; Myalgia* ; Neurons ; Reflex, Stretch* ; Volunteers