Paired corticospinal-motoneuronal stimulation and exercise after spinal cord injury

CONTEXT

Rehabilitation after spinal cord injury (SCI) relies on the use of exercise training, which has limited functional gains. There is a need to develop more efficient approaches to facilitate recovery after SCI.

METHODS

This review focuses on a neuromodulation method where transcranial magnetic stimulation (TMS) over the primary motor cortex is paired with transcutaneous electrical stimulation over a peripheral nerve to induce plasticity at corticospinal-motoneuronal synapses. These two stimuli are applied at precise inter-stimulus intervals to reinforce corticospinal synaptic transmission using principles of spike-timing-dependent plasticity applied alone or in combination with exercise training.

RESULTS

Transmission in residual corticospinal axons, assessed using TMS and maximal voluntary motor output, increased after stimulation combined with exercise training in persons with SCI. There were also significant improvements in functional outcomes, including walking speed and grasping function, which persisted after 6-9 months post stimulation. Moreover, the data suggested that the effects of the stimulation protocol can be augmented with a higher number of sessions and with multiple stimulation sites in the spinal cord.

CONCLUSIONS

Voluntary movement is enhanced in people with SCI through the strengthening of corticospinal-motoneuronal synapses using paired stimulation. This neuromodulation technique represents a novel powerful strategy to facilitate functional recovery after SCI.

Acute intermittent hypoxia boosts spinal plasticity in humans with tetraplegia

Paired corticospinal-motoneuronal stimulation (PCMS) elicits spinal synaptic plasticity in humans with chronic incomplete cervical spinal cord injury (SCI). Here, we examined whether PCMS-induced plasticity could be potentiated by acute intermittent hypoxia (AIH), a treatment also known to induce spinal synaptic plasticity in humans with chronic incomplete cervical SCI. During PCMS, we used 180 pairs of stimuli where corticospinal volleys evoked by transcranial magnetic stimulation over the hand representation of the primary motor cortex were timed to arrive at corticospinal-motoneuronal synapses of the first dorsal interosseous (FDI) muscle ~1-2 ms before the arrival of antidromic potentials elicited in motoneurons by electrical stimulation of the ulnar nerve. During AIH, participants were exposed to brief alternating episodes of hypoxic inspired gas (1 min episodes of 9% O₂) and room air (1 min episodes of 20.9% O₂). We examined corticospinal function by measuring motor evoked potentials (MEPs) elicited by cortical and subcortical stimulation of corticospinal axons and voluntary motor output in the FDI muscle before and after 30 min of PCMS combined with AIH (PCMS+AIH) or sham AIH (PCMS+sham-AIH). The amplitude of MEPs evoked by magnetic and electrical stimulation increased after both protocols, but most after PCMS+AIH, consistent with the hypothesis that their combined effects arise from spinal plasticity. Both protocols increased electromyographic activity in the FDI muscle to a similar extent. Thus, PCMS effects on spinal synapses of hand motoneurons can be potentiated by AIH. The possibility of different thresholds for physiological vs behavioral gains needs to be considered during combinatorial treatments.

Implementing a patient education intervention about Methicillin-resistant Staphylococcus aureus prevention and effect on knowledge and behavior in veterans with spinal cord injuries and disorders: a pilot randomized controlled trial

OBJECTIVES

To assess the feasibility and effect of a nurse-administered patient educational intervention about Methicillin-resistant Staphylococcus aureus (MRSA) prevention on knowledge and behavior of Veterans with spinal cord injuries and disorders (SCI/D).

DESIGN

Blinded, block-randomized controlled pilot trial.

SETTING

Two Department of Veterans Affairs (VA) SCI Centers.

PARTICIPANTS

Veterans were recruited March-September 2010 through referral by a healthcare provider from inpatient, outpatient, and residential care settings.

INTERVENTION

Thirty participants were randomized to the nurse-administered intervention and 31 to the usual care group. The intervention included a brochure and tools to assist nurses in conducting the education.

OUTCOME MEASURES

Pre- and post-intervention measurement of knowledge and behaviors related to MRSA and prevention strategies and feasibility measures related to implementation.

RESULTS

Participants were primarily male (95.1%), white (63.9%), with tetraplegia (63.9%) and mean age and duration of injury of 64.3 and 20.5 years, respectively. The intervention groups mean knowledge score significantly increased between pre- and post-test (mean change score = 1.70, 95% confidence interval, CI 0.25-3.15) while the usual care groups score did not significantly change (mean change score = 1.45, 95% CI -0.08-2.98). However, the mean knowledge change between intervention and usual care groups was not significantly different (P = 0.81). Overall behavior scores did not significantly differ between treatment groups; however, the intervention group was more likely to report intentions to clean hands (90.0% vs. 64.5%, P = 0.03) and asking providers about MRSA status (46.7% vs. 16.1%, P = 0.01). Nurse educators reported that the quality of the intervention was high and could be implemented in clinical care.

CONCLUSIONS

A targeted educational strategy is feasible to implement in SCI/D clinical practices and may improve some participants' knowledge about MRSA and increase intentions to improve hand hygiene and engagement with providers about their MRSA status.