Separate Quantification of Reflex and Nonreflex Components of Spastic Hypertonia in Chronic Hemiparesis (original) (raw)
Related papers
Journal of Electromyography and Kinesiology, 2000
Spasticity after a stroke is usually assessed in a score form by subjectively determining the resistance of a joint to an externally imposed passive movement. This work presents a spasticity measurement system for on-line quantifying the stretch reflex of paretic limbs. Four different constant stretch velocities in a ramp-and-hold mode are used to elicit the stretch reflex of the elbow joint in spastic subjects. The subjects are tested at supine position with the upper limb stretched towards the ground, in contrast with the horizontally stretched movement used in other studies. By subtracting the baseline torque, reflex torque measured at a selected low stretch velocity of 5 deg/sec, the influence of gravity torque and inertial in vertical stretching mode can be minimized. The averaged speed-dependent reflex torque (ASRT), defined as the measured torque deviated from the baseline torque, is used for quantifying the spastic hypertonia. Four subjects having incurred cerebrovascular accident (CVA) are recruited for time-course study in which the measurements are taken at 72 hours, one week, one month, three months, and six months after onset of stroke. During the development of spasticity, the changes of ASRT and velocity sensitivity of ASRT of the involved and the intact elbow joints are discussed.
Clinical Rehabilitation, 2008
Objective: To quantify agreement between three clinically usable methods of measuring spasticity. Methods: Patients with a first stroke who had no useful functional movement in the upper limb within six weeks from stroke onset were eligible to participate. Spasticity at the wrist joint was simultaneously measured using three methods, during an externally imposed passive stretch at two (uncontrolled) displacement velocities. The measures used were a common clinical measure (modified Ashworth Scale), a biomechanical measure (resistance to passive movement) and a neurophysiological measure (muscle activity). Results: One hundred patients (54 men and 46 women) with a median age of 74 years (range 43-91) participated. Median time since stroke was three weeks (range 1-6), the right side was affected in 52 patients and the left in 48 patients. Based on muscle activity measurement, 87 patients had spasticity. According to the modified Ashworth score 44 patients had spasticity. Sensitivity of modified Ashworth score, when compared with muscle activity recordings, was 0.5 and specificity was 0.92. Based on muscle activity patterns, patients could be classified into five subgroups. The biomechanical measures showed no consistent relationship with the other measures. Conclusion: The presentations of spasticity are variable and are not always consistent with existing definitions. Existing clinical scales that depend on the quantification of muscle tone may lack the sensitivity to quantify the abnormal muscle activation and stiffness associated with common definitions of spasticity. Neurophysiological measures may provide more clinically useful information for the management and assessment of spasticity.
Biomechanical examination of a commonly used measure of spasticity
Clinical Biomechanics, 2001
Background. An increase in the prevalence of neurological disability puts pressure on service providers to restrict costs associated with rehabilitation. Spasticity is an important neurological impairment for which many novel and expensive treatment options now exist. The antispastic eects of these techniques remain unexplored due to a paucity of valid outcome measures. Aim. To develop a biomechanical measure of resistance to passive movement, which could be used in routine clinical practice, and to examine the validity of the modi®ed Ashworth scale. Study design. Repeated measure cross-section study on 16 subjects who had a unilateral stroke one-week previously and had no elbow contractures. Outcome measures. Simultaneous measurement of resistance to passive movement using a custom built measuring device and the modi®ed Ashworth scale. Passive range of movement and velocity were also measured. The``catch'', a phenomenon associated with the modi®ed Ashworth scale, was identi®ed by the assessor using a horizontal visual analogue scale and biomechanically quanti®ed using the residual calculated from a linear regression technique. Results. Half the study population had a modi®ed Ashworth score greater than zero. The association between the two measures was poor (j 0:366). The speed and range of passive movement were greater in subjects with modi®ed Ashworth score``0'' (P < 0:05). Resistance to passive movement was higher in the impaired arm (P < 0:05) and tended to decrease with repeated measures and increasing speeds. Conclusions. A device to measure resistance to passive movement at the elbow was developed. The modi®ed Ashworth scale may not provide a valid measure of spasticity but a measure of resistance to passive movement in an acute stroke population. Relevance Spasticity is an important neurological impairment for which many novel and expensive treatment options are being made available. There is a paucity of clinically usable outcomes to measure spasticity. A device to measure resistance to passive movement at the elbow, which was more reliable than the modi®ed Ashworth scale was developed. This device may provide a much needed objective clinical measure to evaluate the ecacy of antispasticity treatment.
Indian Journal of Physiotherapy and Occupational Therapy—An International Journal, 2020
Background : Stroke or cerebrovascular accident is the sudden loss of neurological function caused by an interruption of the blood flow to the brain. Stroke leads to various signs and symptoms, which includes alteration in tone (commonly spasticity), loss of superficial and deep sensations, muscle weakness, abnormal synergy patterns, abnormal reflexes, gait abnormality, altered coordination, etc. Modified Modified Ashworth scale and Modified Tardieu scale both are tools to assess spasticity in stroke patients. Modified Ashworth Scale was less reliable than Modified Tardieu scale hence Ansari et al. developed Modified Modified Tardieu scale. Aim: The aim of the study is to correlate Modified Modified Ashworth Scale with H-reflex and Modified Tardieu Scale with H-reflex to assess Planterflexor spasticity in Chronic post-Stroke patients. Method: This Observational study which included 40 chronic post- stroke patients whose age was between 45-60 years and having stroke since at least 1 ...
Spasticity-assessment: a review
Spinal Cord, 2006
Study design: Review of the literature on the validity and reliability of assessment of spasticity and spasms. Objectives: Evaluate the most frequently used methods for assessment of spasticity and spasms, with particular focus on individuals with spinal cord lesions.
2011
The Modified Modified Ashworth Scale (MMAS) is a clinical instrument for measuring spasticity. Few studies have been performed on the reliability of the MMAS. The aim of the present study was to investigate the intrarater reliability of the MMAS for the assessment of spasticity in the lower limb. We conducted a test-retest study on spasticity in the hip adductors, knee extensors, and ankle plantar flexors. Each patient was measured by a hospital-based clinical physiotherapist. Twenty-three patients with stroke or multiple sclerosis (fourteen women, nine men) and a mean +/-standard deviation age of 37.3 +/-14.1 years participated. The weighted kappa was moderate for the hip adductors (weighted kappa = 0.45, standard error [SE] = 0.16, p = 0.007), good for the knee extensors (weighted kappa = 0.62, SE = 0.12, p < 0.001), and very good for the ankle plantar flexors (weighted kappa = 0.85, SE = 0.05, p < 0.001). The kappa value for overall agreement was very good (weighted kappa = 0.87, SE = 0.03, p < 0.001). The reliability for the ankle plantar flexors was significantly higher than that for the hip adductors. The intrarater reliability of the MMAS in patients with lower-limb muscle spasticity was very good, and it can be used as a measure of spasticity over time.
Journal of Neurophysiology, 2013
This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping. Tendon reflex was characterized with reflex gain and threshold. Reflexively, tonic reflex gain was increased in spastic ankles at rest ( P < 0.038) and was not regulated with muscle contraction, indicating impaired tonic stretch reflex. Phasic-reflex gain in spastic plantar flexors was higher and increased faster with plantar flexor contraction ( P < 0.012) than controls ( P < 0.023) and higher in dorsi-flexors at lower torques ( P < 0.038), primarily because of its increase at rest ( P = 0.045), indicating exaggerated phasic stretch reflex especially in more spastic plantar flex...
Frontiers in Bioengineering and Biotechnology
Background: Despite recent developments in the methodology for measuring spasticity, the discriminative capacity of clinically diagnosed spasticity has not been well established. This study aimed to develop a simple device for measuring velocity-dependent spasticity with improved discriminative capacity based on an analysis of clinical maneuver and to examine its reliability and validity.Methods: This study consisted of three experiments. First, to determine the appropriate motion of a mechanical device for the measurement of velocity-dependent spasticity, the movement pattern and the angular velocity used by clinicians to evaluate velocity-dependent spasticity were investigated. Analysis of the procedures performed by six physical therapists to evaluate spasticity were conducted using an electrogoniometer. Second, a device for measuring the resistance force against ankle dorsiflexion was developed based on the results of the first experiment. Additionally, preliminary testing of va...
Clinical and Electromechanical Methods of Spasticity Assessment: A Review
Zenodo (CERN European Organization for Nuclear Research), 2018
Spasticity is a neurological disorder which results in disordered sensorimotor control owing to an upper motor neuron lesion. The muscles are continuously contracted which causes stiffness in the muscle which hinders the movement of muscle from their natural movement. It is mainly caused due to an injury to the central nervous system. Commonly used assessment methods of spasticity like the Ashworth and modified Ashworth scales do not quantify the degree of spasticity in the patients as they simply make available a semi quantitative degree of the force applied by the foot as resistance to passive movement with restricted inter-rater reliability. Electromechanical methods like isokinetic dynamometers can be used only when an objective quantitative weigh is available for the resistance to passive motion. Electrophysiological methods are valuable for the understanding of the pathophysiological procedures tangled in spasticity. But none of the methods are easy and reliable.