Dishabituation of the flexion reflex in spinal cord-injured man and its application in the restoration of gait

Granat, Malcolm; Nicol, D. J.; Baxendale, R. H.; Andrews, B.J.

doi:10.1016/0006-8993(91)90022-n

Cited by 18 publications

(14 citation statements)

References 8 publications

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“…Similar results were already reported in previous reflex studies, where it was discover that a proper selection of the stimulation parameters, e.g. random inter-stimulus intervals, stimulation of different sites and varying stimulation intensities, can prevent reflexes from habituating ( (Dimitrijević et al, 1972;Granat et al, 1991).…”

Section: Fixed Vs Adjusted Stimulation Intensitiessupporting

confidence: 86%

Introducing the reflex probability maps in the quantification of nociceptive withdrawal reflex receptive fields in humans

Manresa

Jensen

Andersen

2011

Journal of Electromyography and Kinesiology

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Section: Fixed Vs Adjusted Stimulation Intensitiessupporting

confidence: 86%

Introducing the reflex probability maps in the quantification of nociceptive withdrawal reflex receptive fields in humans

Manresa

Jensen

Andersen

2011

Journal of Electromyography and Kinesiology

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“…This variability is seen functionally as loss of effective ground clearance, a stride length that reduces over time and even a complete failure to initiate swing when required. [4][5][6][7] While habituation in flexion reflexes may be the consequence of purely central mechanisms, a number of peripheral factors acting via afferent feedback may also contribute to the variability of flexion reflex magnitude. For example, many studies in human and reduced animal preparations have demonstrated that proprioceptive and cutaneous afferents can influence flexion reflex expression and patterned motor output during locomotion.…”

Section: Introductionmentioning

confidence: 99%

Effects of electrically induced muscle contraction on flexion reflex in human spinal cord injury

Knikou

Conway

2005

Spinal Cord

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Study design: Flexion reflex study in motor complete human spinal cord injury (SCI). Objectives: To examine changes in the magnitude of the flexion reflex following functional electrical stimulation (FES) of the rectus femoris (RF) muscle. Setting: Bioengineering Unit, University of Strathclyde, Glasgow, Scotland, UK. Methods: The flexion reflex was evoked by electrical stimulation of the sural nerve, and was recorded in the tibialis anterior (TA) muscle. RF muscle conditioning stimulation was performed at 0.7, 1, and 2 times motor threshold ( Â MT) over a range of conditioning test intervals.Results: The incidence of the early component of the flexion reflex (o100 ms) was low, suggesting that this reflex component might be suppressed in SCI. The long latency flexion reflex component (4120 ms) was observed in all subjects during control conditions and following sensorimotor conditioning. FES applied to the RF muscle (above and below MT) in the main induced a significant early and long lasting depression of the long latency flexion reflex. Conclusion: The depression of the flexion reflex was a result of multisensory actions on flexion reflex pathways resulting from the direct and indirect (mechanical) consequences of electrically induced muscle contraction on cutaneous and muscle afferents. Our findings emphasize the importance of sensory feedback mechanisms in modulating flexion reflex excitability, and highlight the need for rehabilitation professionals to consider the central actions of FES-induced afferent feedback when incorporating FES into a rehabilitation program. Sponsorship: State Scholarships Foundation (IKY) of Hellas.Spinal Cord (2005) 43, 640-648.

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“…Although habituation of the flexor reflex occurs at short time intervals in human SCI (Dimitrijevic, et al, 1972, Dimitrijevic and Nathan, 1970, Granat, et al, 1991), at the longer intervals similar to those used in this study, habituation is minimal (Fuhrer, 1976). We did observe a drop in the flexor reflex response between the first and second stimulation sequences, but the effect leveled, and the data from the initial 2 stimulation sequences were not included in the analysis.…”

Section: Discussionmentioning

confidence: 69%

“…We did observe a drop in the flexor reflex response between the first and second stimulation sequences, but the effect leveled, and the data from the initial 2 stimulation sequences were not included in the analysis. Note that the application of electrocutaneous stimuli at different locations and bladder distention have both been found to cause a dishabituation of the flexor reflex (Granat, et al, 1991, Griffin and Pearson, 1968), which might account for the increase of the first flexor reflex response that is seen in some subjects shortly after the onset of the conditioning stimulation (Fig. 4).…”

Section: Discussionmentioning

confidence: 97%

Flexor reflex decreases during sympathetic stimulation in chronic human spinal cord injury

Garrison

Schmit

2009

Experimental Neurology

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A better understanding of autonomic influence on motor reflex pathways in spinal cord injury is important to the clinical management of autonomic dysreflexia and spasticity in spinal cord injured patients. The purpose of this study was to examine the modulation of flexor reflex windup during episodes of induced sympathetic activity in chronic human spinal cord injury (SCI). We simultaneously measured peripheral vascular conductance and the windup of the flexor reflex in response to conditioning stimuli of electrocutaneous stimulation to the opposite leg and bladder percussion. Flexor reflexes were quantified using torque measurements of the response to a noxious electrical stimulus applied to the skin of the medial arch of the foot. Both bladder percussion and skin conditioning stimuli produced a reduction (43-67%) in the ankle and hip flexor torques (p<0.05) of the flexor reflex. This reduction was accompanied by a simultaneous reduction in vascular conductance, measured using venous plethysmography, with a time course that matched the flexor reflex depression. While there was an overall attenuation of the flexor reflex, windup of the flexor reflex to repeated stimuli was maintained during periods of increased sympathetic activity. This paradoxical depression of flexor reflexes and minimal effect on windup is consistent with inhibition of afferent feedback within the superficial dorsal horn. The results of this study bring attention to the possible interaction of motor and sympathetic reflexes in SCI above and below the T5 spinal level, and have implications for clinicians in spasticity management and for researchers investigating motor reflexes post SCI.

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Dishabituation of the flexion reflex in spinal cord-injured man and its application in the restoration of gait

Cited by 18 publications

References 8 publications

Introducing the reflex probability maps in the quantification of nociceptive withdrawal reflex receptive fields in humans

Introducing the reflex probability maps in the quantification of nociceptive withdrawal reflex receptive fields in humans

Effects of electrically induced muscle contraction on flexion reflex in human spinal cord injury

Flexor reflex decreases during sympathetic stimulation in chronic human spinal cord injury

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