White matter microstructural alterations in patients with neuropathic pain after spinal cord injury: a diffusion tensor imaging study

BackgroundThrough contrastive analysis, we aimed to identify the white matter brain regions that show microstructural changes in patients with neuropathic pain (NP) after spinal cord injury (SCI).MethodsWe categorized patients with SCI into NP (n = 30) and non-NP (n = 15) groups. We extracted diffusion tensor maps of fractional anisotropy (FA) and mean (MD), axial (AD), and radial (RD) diffusivity. A randomization-based method in tract-based spatial statistics was used to perform voxel-wise group comparisons among the FA, MD, AD, and RD for nonparametric permutation tests.ResultsAtlas-based analysis located significantly different regions (p < 0.05) in the appointed brain atlas. Compared to the non-NP group, the NP group showed higher FA in the posterior body and splenium of the corpus callosum and higher AD in the corpus callosum, internal capsule, corona radiata, posterior thalamic radiation, sagittal stratum, external capsule, cingulum, fornix/stria terminalis, superior longitudinal fasciculus, and uncinate fasciculus.ConclusionThe results demonstrated that compared with the non-NP group, NP pathogenesis after SCI was potentially related to higher values in FA that are associated with microstructural changes in the posterior body and splenium of the corpus callosum, which could be regarded as central sensitization or network hyperexcitability

Comparison between esophageal and intestinal temperature responses to upper-limb exercise in individuals with spinal cord injury

Objective: Individuals with spinal cord injuries (SCI) may present with impaired sympathetic control over thermoregulatory responses to environmental and exercise stressors, which can impact regional core temperature (Tcore) measurement. The purpose of this study was to investigate whether regional differences in Tcore responses exist during exercise in individuals with SCI. Setting: Rehabilitation centre in Wakayama, Japan. Methods: We recruited 12 men with motor-complete SCI (7 tetraplegia, 5 paraplegia) and 5 able-bodied controls to complete a 30-minute bout of arm-cycling exercise at 50% V̇ O2peak. Tcore was estimated using telemetric pills (intestinal temperature; Tint) and esophageal probes (Teso). Heat storage was calculated from baseline to 15 and 30 minutes of exercise. Results: At 15 minutes of exercise, elevations in Teso (Δ0.39±0.22°C; P<0.05), but not Tint (Δ0.04±0.18°C; P=0.09), were observed in able-bodied men. At 30 minutes of exercise, men with paraplegia and able-bodied men both exhibited increases in Teso (paraplegia: Δ0.56±0.30°C, P<0.05; able-bodied men: Δ0.60±0.31°C, P<0.05) and Tint (paraplegia: Δ0.38±0.33°C, P<0.05; able-bodied men: Δ0.30±0.30°C, P<0.05). Teso began rising 7.2 min earlier than Tint (pooled, P<0.01). Heat storage estimated by Teso was greater than heat storage estimated by Tint at 15 minutes (P=0.02) and 30 minutes (P=0.03) in men with paraplegia. No elevations in Teso, Tint, or heat storage were observed in men with tetraplegia. Conclusions: While not interchangeable, both Teso and Tint are sensitive to elevations in Tcore during arm-cycling exercise in men with paraplegia, although Teso may have superior sensitivity to capture temperature information earlier during exercise

The inflammatory response to a wheelchair half-marathon in people with a spinal cord injury - the role of autonomic function

This study investigates the relationship between autonomic function and the inflammatory response to a wheelchair half-marathon in people with a spinal cord injury (SCI). Seventeen wheelchair athletes with a cervical SCI (CSCI, N = 7) and without CSCI (NON-CSCI, N = 10) participated in a wheelchair half-marathon. Blood was taken prior, post and 1 h post-race to determine the concentrations of adrenaline, noradrenaline, extracellular heat shock protein 72 (eHsp72) and interleukin-6 (IL-6). A sit-up tilt test was performed to assess autonomic function at rest. CSCI showed a lower supine ratio of the low and high frequency power of the variability in RR intervals (LF/HF RRI, p = 0.038), total and low frequency power of the systolic blood pressure variability (TP SBP, p 81%, p < 0.012). In summary, the dampened acute inflammatory response to a wheelchair half-marathon in CSCI was strongly associated with the autonomic dysfunction present in this group

A comparison of static and dynamic cerebral autoregulation during mild whole-body cold stress in individuals with and without cervical spinal cord injury: a pilot study

Study design: Experimental study. Objectives: To characterize static and dynamic cerebral autoregulation (CA) of individuals with cervical spinal cord injury (SCI) compared to able-bodied controls in response to moderate increases in mean arterial pressure (MAP) caused by mild whole-body cold stress. Setting: Japan Methods: Five men with complete autonomic cervical SCI (sustained>5y) and six age-matched able-bodied men participated in hemodynamic, temperature, catecholamine and respiratory measurements for 60 min during three consecutive stages: baseline (10 min; 330C water through a thin-tubed whole-body suit), mild cold stress (20 min; 250C water) and post-cold recovery (30 min; 330C water). Static CA was determined as the ratio between mean changes in middle cerebral artery blood velocity and MAP, dynamic CA as transfer function coherence, gain and phase between spontaneous changes in MAP to middle cerebral artery blood velocity. Results: MAP increased in both groups during cold and post-cold recovery (mean differences: 5 to 10 mm Hg; main effect of time: p=0.001). Static CA was not different between the able-bodied vs the cervical SCI group (mean [95% CI] of between-group difference: -4 [-11 to 3] and -2 [-5 to 1] cm/s/mmHg for cold (p=0.22) and post-cold (p=0.24), respectively). At baseline, transfer function phase was shorter in the cervical SCI group (mean [95% CI] of between-group difference: 0.6 [0.2 to 1.0] rad; p=0.006), while between-group differences in changes in phase were not different in response to the cold stress (interaction term: p=0.06). Conclusions: This pilot study suggests that static CA is similar between individuals with cervical SCI and able-bodied controls in response to moderate increases in MAP, while dynamic CA may be impaired in cervical SCI due to disturbed sympathetic control

The prevalence of ulnar neuropathy at the elbow and ulnar nerve dislocation in recreational wheelchair marathon athletes.

BackgroundUlnar neuropathy at the elbow is an entrapment neuropathy, while ulnar nerve dislocation might also be involved in its incidence and severity. Wheelchair marathon athletes may be at an increased risk for Ulnar Neuropathy. However, there is a paucity of research into the prevalence of Ulnar Neuropathy and ulnar nerve dislocation in this population.ObjectiveTo investigate the prevalence of ulnar neuropathy at the elbow and ulnar nerve dislocation in wheelchair marathon athletes.ParticipantsWheelchair marathon athletes (N = 38) who participated in the 2017, 2018, and 2019 Oita International Wheelchair Marathon. 2 athletes participated only one time, 36 athletes repeatedly. Data from athletes`latest assessment were used.MethodsThe day before the race, questionnaires, physical examinations, and ultrasonography were conducted to screen for Ulnar Neuropathy in both upper limbs. Ulnar nerve dislocation was confirmed by physical examination and ultrasonography.Results11 (29%) athletes were diagnosed with Ulnar Neuropathy. There were no significant differences in age, height, weight, Body Mass Index, or history of primary illness between athletes with and without Ulnar Neuropathy. In the group without Ulnar Neuropathy, 44% of athletes reported to have been engaging in other wheelchair sports, compared to 9% in the group with Ulnar Neuropathy (p = 0.037). Ulnar nerve dislocation was diagnosed in 15 (39%) athletes by ultrasonography. Out of the 14 elbows of 11 athletes diagnosed with Ulnar Neuropathy, 9 (64%) elbows had ulnar nerve dislocation.ConclusionThe prevalence of Ulnar Neuropathy in wheelchair marathon athletes was higher than previously reported in able-bodied, non-athlete individuals and lower than in non-athletes with lower limb dysfunction. Therefore, while wheelchair sports may provide some protection against Ulnar Neuropathy, this study further supports the importance of screening for Ulnar Neuropathy, as well as for ulnar nerve dislocation as a potential risk factor for the development of Ulnar Neuropathy