Long-term effects of concussion on relevancy-based modulation of somatosensory-evoked potentials

ObjectiveThe purpose of this investigation was to better understand the effects of concussions on the ability to selectively up or down-regulate incoming somatosensory information based on relevance.MethodsMedian nerve somatosensory-evoked potentials (SEPs) were elicited from electrical stimulation and recorded from scalp electrodes while participants completed tasks that altered the relevance of specific somatosensory information being conveyed along the stimulated nerve.ResultsWithin the control group, SEP amplitudes for task-relevant somatosensory information were significantly greater than for non-relevant somatosensory information at the earliest cortical processing potentials (N20-P27). Alternatively, the concussion history group showed similar SEP amplitudes for all conditions at early processing potentials, however a pattern similar to controls emerged later in the processing stream (P100) where both movement-related gating and facilitation of task-relevant information were present.ConclusionsPreviously concussed participants demonstrated impairments in the ability to up-regulate relevant somatosensory information at early processing stages. These effects appear to be chronic, as this pattern was observed on average several years after participants’ most recent concussion.SignificanceGiven the role of the prefrontal cortex in relevancy-based facilitation during movement-related gating, these findings lend support to the notion that this brain area may be particularly vulnerable to concussive forces.     

Spinal interleukin-6 contributes to central sensitisation and persistent pain hypersensitivity in a model of juvenile idiopathic arthritis

Pain is the most debilitating symptom in juvenile idiopathic arthritis. As pain correlates poorly to the extent of joint pathology, therapies that control joint inflammation are often inadequate as analgesics. We test the hypothesis that juvenile joint inflammation leads to sensitisation of nociceptive circuits in the central nervous system, which is maintained by cytokine expression in the spinal cord. Here, transient joint inflammation was induced in postnatal day (P)21 and P40 male Sprague-Dawley rats with a single intra-articular ankle injection of complete Freund’s adjuvant. Hindpaw mechanical pain sensitivity was assessed using von Frey hair and weight bearing tests. Spinal neuron activity was measured using in vivo extracellular recording and immunohistochemistry. Joint and spinal dorsal horn TNFα, IL1β and IL6 protein expression was quantified using western blotting. We observed greater mechanical hyperalgesia following joint inflammation in P21 compared to P40 rats, despite comparable duration of swelling and joint inflammatory cytokine levels. This is mirrored by spinal neuron hypersensitivity, which also outlasted the duration of active joint inflammation. The cytokine profile in the spinal cord differed at the two ages: prolonged upregulation of spinal IL6 was observed in P21, but not P40 rats. Finally, spinal application of anti-IL-6 antibody (30 ng) reduced the mechanical hyperalgesia and neuronal activation. Our results indicate that persistent upregulation of pro-inflammatory cytokines in the spinal dorsal horn is associated with neuronal sensitisation and mechanical hyperalgesia in juvenile rats, beyond the progress of joint pathology. In addition, we provide proof of concept that spinal IL6 is a key target for treating persistent pain in JIA.     

Short-term retention effect of rehabilitation using head position-based electrotactile feedback to the tongue: Influence of vestibular loss and old-age

Our objective was to evaluate whether the severity of vestibular loss and old-age (>65) affect a patient's ability to benefit from training using head-position based, tongue-placed electrotactile feedback. Seventy-one chronic dizzy patients, who had reached a plateau with their conventional rehabilitation, followed six 1-h training sessions during 4 consecutive days (once on days 1 and 4, twice on days 2 and 3). They presented bilateral vestibular areflexia (BVA), bilateral vestibular losses (BVL), unilateral vestibular areflexia or unilateral vestibular losses and were divided into two age-subgroups (≤65 and >65). Posturographic assessments were performed without the device, 4 h before and after the training. Patients were tested with eyes opened and eyes closed (EC) on static and dynamic (passively tilting) platforms. The studied posturographic scores improved significantly, especially under test conditions restricting either visual or somatosensory input. This 4-h retention effect was greater in older compared to younger patients and was proportional to the degree of vestibular loss, patients with increased vestibular losses showing greater improvements. In bilateral patients, who constantly fell under dynamic-EC condition at the baseline, the therapy effect was expressed by disappearance of falls in BVL and significant prolongation in time-to-fall in BVA subgroups.Globally, our data showed that short training with head-position based, tongue-placed electrotactile biofeedback improves balance in chronic vestibulopathic patients some 16.74% beyond that achieved with standard balance physiotherapy. Further studies with longer use of this biofeedback are needed to investigate whether this approach could have long-lasting retention effect on balance and quality of life.     

Age-based normative data for a computerized dynamic posturography system that uses a virtual visual surround environment

Background: Computerized dynamic posturography (CDP) is the gold standard to differentiate between sensory, motor, and central adaptive impairments to postural control.

Objective: To obtain normative values in healthy adults age 20–69 for a CDP system that uses a full-field dynamic visual surround. This is in contrast to the mechanically movable visual surround used in traditional CDP systems.

Methods: Fifty healthy adults divided into five age groups were tested during the three test protocols for CDP: sensory organization test (SOT), motor control test (MCT), and adaptation test (ADT). Outcomes were compared across age groups and to published normative CDP values. Repeatability was assessed in five different subjects (23–30 years old) on 2 days, 1 week apart.

Results: Most outcomes were comparable to published norms with notable differences in SOT condition 4 and ADT. SOT composite and conditions 4–6, all MCT translations, and ADT toes up showed moderate to good repeatability (r?=?0.60 to 0.99). Age group and gender differences were not substantial.

Conclusions: Some but not all CDP outcomes with a virtual visual environment were comparable to published norms. The differences are likely related to the virtual surround having a more compelling effect on balance even in conditions with a stationary surround.     

饮水负荷试验测定胃感觉的临床研究

目的　建立简便易行、非侵入性、符合胃肠生理的检测胃感觉阈值的诊断方法。方法用饮水负荷试验和电子恒压器法分别对 15例健康自愿者和 30例功能性消化不良患者的胃感知和不适阈值进行测定 ,以了解饮水负荷试验测定胃感觉阈值的敏感性、特异性、Kappa值、符合率 ,以及二者之间有无相关性。结果　与电子恒压器法相比较 ,饮水负荷试验测定胃感知阈值的敏感性为85 7% ,特异性为 93 5 % ,Kappa值为 0 82 ,二者的符合率为 91 1% ,两种方法所测得的结果也具有良好的相关性 (P <0 0 1)。饮水负荷试验测定胃不适阈值的敏感性为 81 8% ,特异性为 91 2 % ,Kappa值为 0 79,二者的符合率为 88 9% ,两种方法所测得的结果也具有良好的相关性 (P <0 0 1)。结论　与电子恒压器相比 ,饮水负荷试验测定胃感觉阈值具有较高的特异性、Kappa值和符合率 ,以及良好的相关性 ,可用于消化不良患者胃感觉功能临床辅助诊断和初筛检查 ,在基层医院有广泛的应用前景。     

Rectal compliance in females with obstructed defecation

PURPOSE: This study was designed to investigate whether rectal compliance is altered in females with obstructed defecation. METHODS: Eighty female patients with obstructed defecation and 60 control subjects were studied. Rectal compliance was measured with an infinitely compliant polyethylene bag. This bag was inserted in the rectum and inflated with air to selected pressure plateaus (range, 0–60 mmHg; cumulative steps of 2 mmHg with a duration of ten seconds) using a computer-controlled electromechanical barostat system. Volume changes at the levels of distending pressures were recorded. The distending pressures, needed to evoke first sensation of content in the rectum, earliest urge to defecate, and the maximum tolerable volume were noted. RESULTS: In all cases, the compliance curve had a characteristic triphasic (S-shaped) form. The mean compliance curve obtained from the patients was identical to that of the controls. However, the course of the compliance curve fell above the normal range (mean + 2 SD) in 14 patients. In ten (71 percent) of these patients, a large rectocele was seen at evacuation proctography. Such a rectocele was observed in only five patients (7.6 percent) with a normal compliance curve (P<0.001). Eighty percent of the controls experienced earliest urge to defecate during the second phase of the curve. In 75 percent of the patients, this occurred in the third phase. The mean pressure threshold for first sensation, earliest urge to defecate, and maximum tolerable volume were significantly higher in patients compared with control subjects. Ten of the patients experienced no sensation at all in the pressure range between 0 and 60 mmHg. CONCLUSION: In females with obstructed defection, the compliance of the rectal wall is normal.     

脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理特征的影响

目的探讨脑卒中后肩关节半脱位对偏瘫侧上肢周围神经电生理参数的影响。方法纳入20例脑卒中伴肩关节半脱位的患者,分别对患者双上肢肩胛上神经、腋神经、肌皮神经、桡神经、正中神经、尺神经的运动神经传导及桡神经、正中神经、尺神经的感觉神经传导进行评估,并对偏瘫上肢冈上肌、三角肌、肱二头肌、伸指总肌、拇短展肌和小指展肌进行静息状态下针极肌电图检测;采用Brunnstrom分期对患者的上肢和手功能进行评估,并对患侧神经肌肉复合动作电位(CMAP)波幅的变化率与患者病程、年龄及上肢Brunnstrom分期进行相关性分析。结果与健侧相比,脑卒中后肩关节半脱位侧的肩胛上神经、腋神经、肌皮神经、桡神经、正中神经、尺神经CMAP波幅均显著降低(P<0.01),肩胛上神经和腋神经的潜伏期延长(P<0.05),肌皮神经、桡神经、正中神经和尺神经潜伏期双侧差异无统计学意义(P>0.05)。桡神经、正中神经和尺神经运动传导速度双侧无差异(P>0.05)。偏瘫侧腋神经、肩胛上神经、肌皮神经CMAP波幅变化率明显高于桡神经、正中神经和尺神经(P<0.05)。偏瘫侧桡神经、正中神经和尺神经的感觉神经动作电位(SNAP)较健侧降低(P<0.01),感觉传导速度双侧差异无统计学意义(P>0.05)。偏瘫侧SNAP波幅变化率由高到低依次为正中神经、桡神经和尺神经,但两两对比差异均无统计学意义(P>0.05),感觉神经传导速度变化率两两对比差异亦无统计学意义(P>0.05)。肩关节半脱位后上肢所检肌肉均存在不同程度的自发电位,偏瘫上肢近端出现率高于远端肢体,其中冈上肌自发电位出现率为61.54%,三角肌为84.62%,肱二头肌为69.23%,伸指总肌和拇短展肌为46.15%,小指展肌为30.77%。偏瘫侧CMAP变化率与患者病程、年龄及上肢Brunnstrom分期之间均无明显相关性(P>0.05)。结论脑卒中后肩关节半脱位可导致支配肩和上臂的周围神经损害程度大于支配前臂和手的神经,可能影响患者上肢功能的恢复。