Biomedical device for spasticity quantification based on the velocity dependence of the Stretch Reflex threshold

The effect of baclofen on walking performance was examined in nine spastic multiple sclerosis patient. In addition, nine healthy subjects were tested as controls. The modulation of the short latency soleus stretch reflex was closer to normal with baclofen compared to the recordings without baclofen, the modulation index being 74% (range: 60-100) with baclofen and 62% (range: 20 -100) without baclofen, P=0.03. In healthy subject the modulation index was 100% (range: 52 -100). In the early swing phase the threshold of the soleus stretch reflex was significantly higher during baclofen medication being 139 degls (range: 63 -302) compared with 93 degls (range: 37-187) with out baclofen, P=0.004. The relation between the stretch velocity (input) and the amplitude of the stretch reflex (output) in early swing phase was unchanged being 0.27 μVs/deg (range: 0.1-1.51) in patient with baclofen and 0.24 μVs/deg (range: 0.08-0.79) without baclofen, P=0.25. Baclofen induced no change in input-output properties of the stretch reflex during walking compared with findings in a sitting position at matched EMG activity. There was a significant correlation between clinical spasticity score and stretch reflex threshold in the early swing phase (p=-0.61, P=0.04) and between clinical spasticity score and the slope of the best linear fit in the early swing phase (p=0.72, P=0.009).

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Tonic Stretch Reflex Threshold as a Measure of Ankle Plantar-Flexor Spasticity After Stroke

Physical Therapy ◽

10.2522/ptj.20140243 ◽

2016 ◽

Vol 96 (5) ◽

pp. 687-695 ◽

Cited By ~ 15

Author(s):

Andreanne K. Blanchette ◽

Aditi A. Mullick ◽

Karina Moïn-Darbari ◽

Mindy F. Levin

Keyword(s):

Stretch Reflex ◽

Regression Line ◽

Intraclass Correlation ◽

Motor Deficits ◽

Plantar Flexor ◽

Study Objective ◽

Promising Alternative ◽

Significant Difference ◽

Dynamic Velocity ◽

Reflex Threshold

Background Commonly used spasticity scales assess the resistance felt by the evaluator during passive stretching. These scales, however, have questionable validity and reliability. The tonic stretch reflex threshold (TSRT), or the angle at which motoneuronal recruitment begins in the resting state, is a promising alternative for spasticity measurement. Previous studies showed that spasticity and voluntary motor deficits after stroke may be characterized by a limitation in the ability of the central nervous system to regulate the range of the TSRT. Objective The study objective was to assess interevaluator reliability for TSRT plantar-flexor spasticity measurement. Design This was an interevaluator reliability study. Methods In 28 people after stroke, plantar-flexor spasticity was evaluated twice on the same day. Plantar-flexor muscles were stretched 20 times at different velocities assigned by a portable device. Plantar-flexor electromyographic signals and ankle angles were used to determine dynamic velocity-dependent thresholds. The TSRT was computed by extrapolating a regression line through dynamic velocity-dependent thresholds to the angular axis. Results Mean TSRTs in evaluations 1 and 2 were 66.0 degrees (SD=13.1°) and 65.8 degrees (SD=14.1°), respectively, with no significant difference between them. The intraclass correlation coefficient (2,1) was .851 (95% confidence interval=.703, .928). Limitations The notion of dynamic stretch reflex threshold does not exclude the possibility that spasticity is dependent on acceleration, as well as on velocity; future work will study both possibilities. Conclusions Tonic stretch reflex threshold interevaluator reliability for evaluating stroke-related plantar-flexor spasticity was very good. The TSRT is a reliable measure of spasticity. More information may be gained by combining the TSRT measurement with a measure of velocity-dependent resistance.

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Stretch Reflex Latencies in Spastic Hemiparetic Subjects are Prolonged After Transcutaneous Electrical Nerve Stimulation

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100047636 ◽

1993 ◽

Vol 20 (2) ◽

pp. 97-106 ◽

Cited By ~ 29

Author(s):

Christina W.Y. Hui-Chan ◽

Mindy F. Levin

Keyword(s):

Nerve Stimulation ◽

Transcutaneous Electrical Nerve Stimulation ◽

Stretch Reflex ◽

Time Course ◽

Dorsal Column ◽

Electrical Nerve Stimulation ◽

Reflex Excitability ◽

Reflex Threshold ◽

Repetitive Electrical Stimulation

ABSTRACT:Low-intensity repetitive electrical stimulation such as dorsal column and transcutaneous electrical nerve stimulation (TENS) reportedly decreases spasticity and improves voluntary motor control. However, the mechanisms mediating these effects are unclear. Recent findings suggest that spasticity may be characterized more appropriately by a decrease in the stretch reflex threshold than by an increase in gain. Our objectives were: (1) to examine possible changes in stretch reflex excitability following 45 min of TENS, (2) to map out the time course of possible post-stimulation effects via both latency and magnitude (amplitude or area) measurements, and (3) to determine the role of segmental versus non-segmental mechanisms involved in mediating these changes. The effects of 45 min of segmentally and heterosegmentally applied TENS on lower limb reflexes in ten spastic hemiparetic subjects were contrasted with those resulting from placebo stimulation. We found that both segmentally and heterosegmentally applied TENS caused an immediate increase in soleus H reflex latencies that was evident for up to 60 minutes post-stimulation in over 75% of the subjects. Similar increases for up to 60 and 40 minutes post-stimulation was noted for the stretch reflex latencies in 50% and 67% of the subjects respectively for segmental and heterosegmental stimulation. These results suggested that manipulation of segmental and heterosegmental afférents for 45 min may lead to a decrease of the otherwise augmented stretch reflex excitability accompanying hemiparetic spasticity.

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Treatment of spasticity with repetitive magnetic stimulation; a double-blind placebo-controlled study

Multiple Sclerosis Journal ◽

10.1177/135245859600200503 ◽

1996 ◽

Vol 2 (5) ◽

pp. 227-232 ◽

Cited By ~ 63

Author(s):

Jorgen F Nielsen ◽

Thomas Sinkjaer ◽

Johannes Jakobsen

Keyword(s):

Multiple Sclerosis ◽

Stretch Reflex ◽

Magnetic Stimulation ◽

Controlled Study ◽

Double Blind ◽

Double Blind Placebo ◽

Future Studies ◽

Sham Stimulation ◽

Repetitive Magnetic Stimulation ◽

Reflex Threshold

The effect of repetitive magnetic stimulation on spasticity was evaluated in 38 patients with multiple sclerosis in a double-blind placebo-controlled study. One group was treated with repetitive magnetic stimulation (n=2l) and the other group with sham stimulation (n=l7). Both groups were seated twice daily for 7 consecutive days. Primary end-points of the study were changes in the patients self-score, in clinical spasticity score, and in the stretch reflex threshold. The self-score of ease of daily day activities improved by 22% (P=0.007) after treatment and by 29% (P=0.004) after sham stimulation. The clinical spasticity score improved 3.3±4.7 arbitrary unit (AU) in treated patients and 0.7±2.5 AU in sham stimulation (P-0.003). The stretch reflex threshold increased 4.3±7.5 degls in treated patients and-3.8±9.7 degls in sham stimulation (P=0.001). The data presented in this study supports the idea that repetitive magnetic stimulation has an antispastic effect in multiple sclerosis. Future studies should darify the optimal treatment regimen.

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