Persistence of locomotor-related interlimb reflex networks during walking after stroke

Zehr, E. Paul; Loadman, Pamela M.

doi:10.1016/j.clinph.2011.07.049

Cited by 51 publications

(64 citation statements)

References 43 publications

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“…Our results add to existing evidence that portions of the neural circuitry regulating rhythmic motor output for the arms remain acces- sible after stroke (Ferris et al 2006;Zehr and Loadman 2012;Zehr et al 2004aZehr et al , 2009). This preservation of neural regulation is seen for both the MA and LA arms; however, the regulation of the MA arm is reduced compared with the LA arm or to the control data.…”

Section: Rhythmic Background Motor Output During Arm Cycling After Stsupporting

confidence: 79%

“…Alterations in descending supraspinal inputs induced by the lesion can allow spinal cord circuits that are exquisitely regulated by interneuronal connections (Jankowska and Hammar 2002) to operate in an unregulated fashion. As a result, activity in spinal pathways may be changed including cutaneous reflexes (Jones and Yang 1994;Zehr and Loadman 2012;Zehr et al 1998).…”

mentioning

confidence: 99%

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Neural control of rhythmic arm cycling after stroke

Zehr

Loadman

Hundza

2012

Journal of Neurophysiology

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Disordered reflex activity and alterations in the neural control of walking have been observed after stroke. In addition to impairments in leg movement that affect locomotor ability after stroke, significant impairments are also seen in the arms. Altered neural control in the upper limb can often lead to altered tone and spasticity resulting in impaired coordination and flexion contractures. We sought to address the extent to which the neural control of movement is disordered after stroke by examining the modulation pattern of cutaneous reflexes in arm muscles during arm cycling. Twenty-five stroke participants who were at least 6 mo postinfarction and clinically stable, performed rhythmic arm cycling while cutaneous reflexes were evoked with trains (5 × 1.0-ms pulses at 300 Hz) of constant-current electrical stimulation to the superficial radial (SR) nerve at the wrist. Both the more (MA) and less affected (LA) arms were stimulated in separate trials. Bilateral electromyography (EMG) activity was recorded from muscles acting at the shoulder, elbow, and wrist. Analysis was conducted on averaged reflexes in 12 equidistant phases of the movement cycle. Phase-modulated cutaneous reflexes were present, but altered, in both MA and LA arms after stroke. Notably, the pattern was "blunted" in the MA arm in stroke compared with control participants. Differences between stroke and control were progressively more evident moving from shoulder to wrist. The results suggest that a reduced pattern of cutaneous reflex modulation persists during rhythmic arm movement after stroke. The overall implication of this result is that the putative spinal contributions to rhythmic human arm movement remain accessible after stroke, which has translational implications for rehabilitation.

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Section: Rhythmic Background Motor Output During Arm Cycling After Stsupporting

confidence: 79%

mentioning

confidence: 99%

Neural control of rhythmic arm cycling after stroke

Zehr

Loadman

Hundza

2012

Journal of Neurophysiology

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“…Interlimb cutaneous reflex pathways from the LA hand (SR n.) and foot (superficial peroneal n.) remain viable and modulated during walking after stroke [21], a result complimentary to observations within the MA leg [22]. Interestingly, there is a potential enhancement in transmission from LA arm to MA leg as compared to control participants.…”

Section: Persistent Somatosensory and Locomotor-activated Linkages Bementioning

confidence: 69%

“…Interlimb networks of cutaneous reflexes also remain active during gait after stroke [21]. Interlimb cutaneous reflex pathways from the LA hand (SR n.) and foot (superficial peroneal n.) remain viable and modulated during walking after stroke [21], a result complimentary to observations within the MA leg [22].…”

Section: Persistent Somatosensory and Locomotor-activated Linkages Bementioning

confidence: 90%

Neuromechanical Interlimb Interactions and Rehabilitation of Walking after Stroke

Zehr

Barss

Kaupp

et al. 2014

Biosystems &Amp; Biorobotics

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Abstract. Bipedal humans operate using elements of quadrupedal neuronal limb control during locomotion. This has significant implications for supporting transfer of the huge body of quadrupedal animal literature to human rehabilitation. In particular, this has translational applications for neurological rehabilitation after stroke where interlimb coordination is compromised. The data supports including arm activity in addition to leg activity as a component of gait retraining after stroke. An additional component is to consider strength training of the less affected limb to improve motor output of the more affected limb when that limb is too weak to be initially incorporated in functional rehabilitation. The major concept is to use activity related to the less affected limbs to modulate output of the more affected limbs after stroke. A key example is to incorporate arm activity into rehabilitation of leg motion in stepping after stroke.

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“…If the changes in threshold were related to local denervation effects on the side of the ankle sprain one would not have expected changes in the contralateral leg. Bilateral effects on the uninjured side may be explained, by cortical suppression (or facilitation) due to injury-related neuroplastic changes as often seen in patients with SCI or stroke (Norton et al, 2008;Zehr and Loadman, 2012). Alternatively, the loss of sensation may have been the cause rather than the result of the ankle sprain (see above).…”

Section: Cutaneous Afferents and Faimentioning

confidence: 99%