"Teaching somebody else makes you a better person:" A phenomenological exploration of the importance of informal peer support for individuals with spinal cord injury.

BACKGROUND: Peer support is widely recognized as an important aspect of health promotion for individuals with spinal cord injury (SCI). Reports indicate positive effects for the recipients of either informal and formal peer support. The experience can also be meaningful to the person(s) providing support, although the value to providers is not well studied. OBJECTIVE: This study examines the experience of provision of and receipt of informal peer support for individuals with SCI through semi-structured interviews. METHODS: Data were analysed using a qualitative phenomenological approach. 16 participants with SCI participated in the study. RESULTS: Three main themes were developed, each describing different benefits of peer support from the perspective of both members of the peer support dyad. First, participants found personal satisfaction from using their own experiences to help others adjust to their disability. Participants also noted that they learned how to complete activities of daily living as well as how to be autonomous in travel from others with SCI. Finally, participants spoke of the intrinsic benefit in teaching others with SCI. CONCLUSIONS: This study provides a novel understanding of the importance of informal peer support for individuals with SCI. Practitioners should provide opportunities for individuals with SCI to develop informal peer relationships with others who have sustained SCI.

"It Helps Me With Everything": A Qualitative Study of the Importance of Exercise for Individuals With Spinal Cord Injury.

Background: The influence of exercise after spinal cord injury (SCI) is a topic important to both clinicians and researchers. The impact of exercise for individuals with SCI is often studied quantitively, with a large focus on the physiological adaptations to exercise intervention. Objectives: This study explores individualized experiences of exercise for people with SCI. Methods: A phenomenological approach was utilized to qualitatively study the experiences of exercise for 16 individuals with SCI. Results: Participants described multiple benefits of exercise, including increased independence, improved mental health, and increased engagement in social activity. Conclusion: This study provides novel information about attitudes toward exercise held by individuals with SCI and a more thorough understanding of concepts that are well researched.

What Did We Learn from the Animal Studies of Body Weight-Supported Treadmill Training and Where Do We Go from Here?

Body weight-supported treadmill training (BWSTT) developed from animal studies of spinal cord injury (SCI). Evidence that spinal cats (i.e., cats that have a complete surgical transection of the cord) could regain the ability to step on a moving treadmill indicated a vast potential for spinal circuits to generate walking without the brain. BWSTT represented a means to unlock that potential. As the technique was adapted as a rehabilitation intervention for humans with SCI, shortcomings in the translation to walking in the real world were exposed. Evidence that BWSTT has not been as successful for humans with SCI leads us to revisit key animal studies. In this short review, we describe the task-specific nature of BWSTT and discuss how this specificity may pose limits on the recovery of overground walking. Also discussed are more recent studies that have introduced new strategies and tools that adapt BWSTT ideas to more functionally-relevant tasks. We introduce a new device for weight-supported overground walking in rats called Circular BART (Body weight supported Ambulatory Rat Trainer) and demonstrate that it is relatively easy and inexpensive to produce. Future animal studies will benefit from the development of simple tools that facilitate training and testing of overground walking.

Energy expenditure and heart rate responses to increased loading in individuals with motor complete spinal cord injury performing body weight-supported exercises.

OBJECTIVE: To examine acute metabolic and heart rate responses in individuals with motor complete spinal cord injury (SCI) during stepping and standing with body weight support (BWS). DESIGN: Cohort study. SETTING: Therapeutic exercise research laboratory. PARTICIPANTS: Nonambulatory individuals with chronic, motor complete SCI between T5 and T12 (n=8) and healthy, able-bodied controls (n=8). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Oxygen consumption (V˙o2) and heart rate. RESULTS: Individuals with motor complete SCI performed standing and stepping exercises in a BWS system with manual assistance of lower body kinematics. V˙o2 and heart rate responses were assessed in relation to level of BWS. Weight support was provided by an overhead lift at high (≥50% BWS) or low (20%-35% BWS) levels during stepping and standing. Although participants with motor complete SCI were unable to stand or step without assistance, levels of V˙o2 and heart rate were elevated by 38% and 37%, respectively, when load was maximized during stepping (ie, low BWS). Participants without an SCI (able-bodied group) had a similar acute response to exercise. None of the participants met the target range for V˙o2 response in any of the tasks. However, stepping was sufficient to enable half of the participants in the SCI group to attain the target range for heart rate response to exercise. CONCLUSIONS: Individuals with motor complete SCI exhibit cardiovascular responses during body weight-supported exercise. Findings indicate that body weight-supported stepping provides a minimal cardiovascular challenge for individuals with paraplegia. Emphasis on low weight support during locomotor training can trigger additional heart rate adaptations.

Spinal segment-specific transcutaneous stimulation differentially shapes activation pattern among motor pools in humans.

Transcutaneous and epidural electrical spinal cord stimulation techniques are becoming more valuable as electrophysiological and clinical tools. Recently, we observed selective activation of proximal and distal motor pools during epidural spinal stimulation. In the present study, we hypothesized that the characteristics of recruitment curves obtained from leg muscles will reflect a relative preferential activation of proximal and distal motor pools based on their arrangement along the lumbosacral enlargement. The purpose was to describe the electrophysiological responses to transcutaneous stimulation in leg muscles innervated by motoneurons from different segmental levels. Stimulation delivered along the rostrocaudal axis of the lumbosacral enlargement in the supine position resulted in a selective topographical recruitment of proximal and distal leg muscles, as described by threshold intensity, slope of the recruitment curves, and plateau point intensity and magnitude. Relatively selective recruitment of proximal and distal motor pools can be titrated by optimizing the site and intensity level of stimulation to excite a given combination of motor pools. The slope of the recruitment of particular muscles allows characterization of the properties of afferents projecting to specific motoneuron pools, as well as to the type and size of the motoneurons. The location and intensity of transcutaneous spinal electrical stimulation are critical to target particular neural structures across different motor pools in investigation of specific neuromodulatory effects. Finally, the asymmetry in bilateral evoked potentials is inevitable and can be attributed to both anatomical and functional peculiarities of individual muscles or muscle groups.

Phase-dependent modulation of percutaneously elicited multisegmental muscle responses after spinal cord injury.

Phase-dependent modulation of monosynaptic reflexes has been reported for several muscles of the lower limb of uninjured rats and humans. To assess whether this step-phase-dependent modulation can be mediated at the level of the human spinal cord, we compared the modulation of responses evoked simultaneously in multiple motor pools in clinically complete spinal cord injury (SCI) compared with noninjured (NI) individuals. We induced multisegmental responses of the soleus, medial gastrocnemius, tibialis anterior, medial hamstring, and vastus lateralis muscles in response to percutaneous spinal cord stimulation over the Th11-Th12 vertebrae during standing and stepping on a treadmill. Individuals with SCI stepped on a treadmill with partial body-weight support and manual assistance of leg movements. The NI group demonstrated phase-dependent modulation of evoked potentials in all recorded muscles with the modulation of the response amplitude corresponding with changes in EMG amplitude in the same muscle. The SCI group demonstrated more variation in the pattern of modulation across the step cycle and same individuals in the SCI group could display responses with a magnitude as great as that of modulation observed in the NI group. The relationship between modulation and EMG activity during the step cycle varied from noncorrelated to highly correlated patterns. These findings demonstrate that the human lumbosacral spinal cord can phase-dependently modulate motor neuron excitability in the absence of functional supraspinal influence, although with much less consistency than that in NI individuals.

Facilitation of stepping with epidural stimulation in spinal rats: role of sensory input.

We investigated the role of afferent information during recovery of coordinated rhythmic activity of the hindlimbs in rats with a complete spinal cord section (approximately T8) and unilateral deafferentation (T12-S2) to answer the following questions: (1) Can bilateral stepping be generated with only afferent projections intact on one side? (2) Can the sensory input from the non-deafferented side compensate for the loss of the afferent input from the deafferented side through the crossed connections within the lumbosacral spinal cord? (3) Which afferent projections to the spinal cord from the non-deafferented side predominantly mediate the effect of epidural stimulation to facilitate stepping? Recovery of stepping ability was tested under the facilitating influence of epidural stimulation at the S1 spinal segment, or epidural stimulation plus quipazine, a 5-HT agonist. All chronic spinal rats were able to generate stepping-like patterns on a moving treadmill on the non-deafferented, but not deafferented, side from 3 to 7 weeks after surgery when facilitated by epidural stimulation. Adaptation to the loss of unilateral afferent input was evident at 7 weeks after surgery, when some movements occurred on the deafferented side. Spinal-cord-evoked potentials were observed on both sides, although middle (monosynaptic) and late (long latency) responses were more prominent on the non-deafferented side. The afferent information arising from the non-deafferented side, however, eventually could mediate limited restoration of hindlimb movements on the deafferented side. These data suggest that facilitation of stepping with epidural stimulation is mediated primarily through ipsilateral afferents that project to the locomotor networks.

Epidural stimulation induced modulation of spinal locomotor networks in adult spinal rats.

The importance of the in vivo dynamic nature of the circuitries within the spinal cord that generate locomotion is becoming increasingly evident. We examined the characteristics of hindlimb EMG activity evoked in response to epidural stimulation at the S1 spinal cord segment in complete midthoracic spinal cord-transected rats at different stages of postlesion recovery. A progressive and phase-dependent modulation of monosynaptic (middle) and long-latency (late) stimulation-evoked EMG responses was observed throughout the step cycle. During the first 3 weeks after injury, the amplitude of the middle response was potentiated during the EMG bursts, whereas after 4 weeks, both the middle and late responses were phase-dependently modulated. The middle- and late-response magnitudes were closely linked to the amplitude and duration of the EMG bursts during locomotion facilitated by epidural stimulation. The optimum stimulation frequency that maintained consistent activity of the long-latency responses ranged from 40 to 60 Hz, whereas the short-latency responses were consistent from 5 to 130 Hz. These data demonstrate that both middle and late evoked potentials within a motor pool are strictly gated during in vivo bipedal stepping as a function of the general excitability of the motor pool and, thus, as a function of the phase of the step cycle. These data demonstrate that spinal cord epidural stimulation can facilitate locomotion in a time-dependent manner after lesion. The long-latency responses to epidural stimulation are correlated with the recovery of weight-bearing bipedal locomotion and may reflect activation of interneuronal central pattern-generating circuits.

Modulation of multisegmental monosynaptic responses in a variety of leg muscles during walking and running in humans.

Motor responses evoked by stimulating the spinal cord percutaneously between the T11 and T12 spinous processes were studied in eight human subjects during walking and running. Stimulation elicited responses bilaterally in the biceps femoris, vastus lateralis, rectus femoris, medial gastrocnemius, soleus, tibialis anterior, extensor digitorum brevis and flexor digitorum brevis. The evoked responses were consistent with activation of Ia afferent fibres through monosynaptic neural circuits since they were inhibited when a prior stimulus was given and during tendon vibration. Furthermore, the soleus motor responses were inhibited during the swing phase of walking as observed for the soleus H-reflex elicited by tibial nerve stimulation. Due to the anatomical site and the fibre composition of the peripheral nerves it is difficult to elicit H-reflex in leg muscles other than the soleus, especially during movement. In turn, the multisegmental monosynaptic responses (MMR) technique provides the opportunity to study modulation of monosynaptic reflexes for multiple muscles simultaneously. Phase-dependent modulation of the MMR amplitude throughout the duration of the gait cycle period was observed in all muscles studied. The MMR amplitude was large when the muscle was activated whereas it was generally reduced, or even suppressed, when the muscle was quiescent. However, during running, there was a systematic anticipatory increase in the amplitude of the MMR at the end of swing in all proximal and distal extensor muscles. The present findings therefore suggest that there is a general control scheme by which the transmission in the monosynaptic neural circuits is modulated in all leg muscles during stepping so as to meet the requirement of the motor task.

Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5-10 years after chemotherapy.

PURPOSE: To explore the relationship of regional cerebral blood flow and metabolism with cognitive function and past exposure to chemotherapy for breast cancer. PATIENTS AND METHODS: Subjects treated for breast cancer with adjuvant chemotherapy remotely (5-10 years previously) were studied with neuropsychologic testing and positron emission tomography (PET), and were compared with control subjects who had never received chemotherapy. [O-15] water PET scans was acquired during performance of control and memory-related tasks to evaluate cognition-related cerebral blood flow, and [F-18] fluorodeoxyglucose (FDG) PET scans were acquired to evaluate resting cerebral metabolism. PET scans were analyzed by statistical parametric mapping and region of interest methods of analysis. RESULTS: During performance of a short-term recall task, modulation of cerebral blood flow in specific regions of frontal cortex and cerebellum was significantly altered in chemotherapy-treated subjects. Cerebral activation in chemotherapy-treated subjects differed most significantly from untreated subjects in inferior frontal gyrus, and resting metabolism in this area correlated with performance on a short-term memory task previously found to be particularly impaired in chemotherapy-treated subjects. In examining drug-class specific effects, metabolism of the basal ganglia was significantly decreased in tamoxifen + chemotherapy-treated patients compared with chemotherapy-only breast cancer subjects or with subjects who had not received chemotherapy, while chemotherapy alone was not associated with decreased basal ganglia activity relative to untreated subjects. CONCLUSION: Specific alterations in activity of frontal cortex, cerebellum, and basal ganglia in breast cancer survivors were documented by functional neuroimaging 5-10 years after completion of chemotherapy.

Spinal cord reflexes induced by epidural spinal cord stimulation in normal awake rats.

Motor responses in hindlimb muscles to epidural spinal cord stimulation in normal awake rats during bipedal standing were studied. Stimulation at L2 or S1 induced simultaneous and bilateral responses in the vastus lateralis, semitendinosus, tibialis anterior, and medial gastrocnemius muscles. Stimulation at S1 evoked an early (ER), middle (MR) and late (LR) response: stimulation at L2 elicited only a MR and LR. Vibration and double epidural stimulation testing suggests that the ER is a direct motor response, whereas the MR and LR are mediated synaptically. MR has properties of a monosynaptic reflex, i.e., inhibited during vibration and depressed during the second pulse of a double stimulation. Some components of the LR seem to be mediated by afferents associated with the flexor reflex and probably involve group II afferents. During bipedal treadmill stepping, the MR was modulated in extensors, whereas the LR was modulated in flexors. These results show differential modulation of monosynaptic and polysynaptic reflexes in flexor and extensor motor pools during locomotion. Monosynaptic responses to stimulation at either L2 or S1 generally were amplified in extensors during the stance phase and in flexors during the swing phase of the step cycle. No correlation was found between the ER and the EMG background during stepping, whereas both the MR and LR were closely correlated with the changes in the EMG activity level of the corresponding muscle. These data demonstrate the feasibility of using epidural stimulation for examining monosynaptic and polysynaptic pathways to motor pools associated with multiple muscles during movement and over a prolonged period.

Dissociable correlates of recollection and familiarity within the medial temporal lobes.

Regions in the medial temporal lobes (MTL) have long been implicated in the formation of new memories for events, however, it is unclear whether different MTL subregions support different memory processes. Here, we used event-related functional magnetic resonance imaging (fMRI) to examine the degree to which two recognition memory processes-recollection and familiarity-were supported by different MTL subregions. Results showed that encoding activity in the rhinal cortex selectively predicted familiarity-based recognition, whereas, activity in the hippocampus and posterior parahippocampal cortex selectively predicted recollection. Collectively, these results support the view that different subregions within the MTL memory system implement unique encoding processes that differentially support familiarity and recollection.