Impaired joint proprioception at higher shoulder elevations in chronic rotator cuff pathology

Anderson VB, Wee E. Impaired joint proprioception at higher shoulder elevations in chronic rotator cuff pathology.

Objectives

To assess the degree of impairment of shoulder proprioceptive acuity in individuals with chronic rotator cuff pathology (CRCP), and to examine the effect of impingement-related shoulder pain on acuity using a reliable laboratory technique.

Design

Case-control study.

Setting

University human movement laboratory.

Participants

A volunteer sample of individuals with CRCP (n=26) were recruited and screened, and compared with age-, sex-, and limb dominance–matched individuals (n=30) who acted as controls. Ten participants with CRCP underwent repeat assessment after 2 days to determine the intrarater reliability of proprioceptive measurement.

Interventions

Not applicable.

Main Outcome Measures

Each participant underwent assessment of joint position sense at 40° and 100° of scapular plane abduction using an active position-matching task. Movements were recorded with reflective skin markers and a multidimensional motion analysis system. Self-reported pain intensity associated with the procedure was recorded with a visual analog scale.

Results

Intraclass correlation coefficients (model 3,5) between repeat assessments ranged from .54 to .99. On average, those with CRCP demonstrated reduced acuity at 40° and 100° test angles. In comparison with the control group, proprioceptive acuity was significantly impaired (P<.01) at the 100° test angle, where the pain intensity was significantly greater (P<.01).

Conclusions

This study demonstrated impairment of shoulder joint position sense in CRCP. The degree of proprioceptive impairment was greatest at higher elevations in the setting of increased shoulder impingement and pain, which may serve to perpetuate the pathology. These findings provide a theoretic rationale for the continued implementation of proprioceptive rehabilitation programs in managing CRCP.     

The rubber hand illusion and its application to clinical neuroscience

The rubber hand illusion (RHI) is a perceptual experience which often occurs when an administered tactile stimulation of a person's real hand hidden from view, occurs synchronously with a corresponding visual stimulation of an observed rubber hand placed in full vision of the person in a position corresponding to where their real hand might normally be. The perceptual illusion is that the person feels a sense of "ownership" of the rubber hand which they are looking at. Most studies have focused on the underlying neural properties of the illusion and the experimental manipulations that lead to it. The illusion could also be used for exploring the sense of limb and prosthetic ownership for people after amputation. Cortical electrodes such as those used in sensorimotor stimulation surgery for pain may provide an opportunity to further understand the cortical representation of the illusion and possibly provide an opportunity to modulate the individual's sense of body ownership. Thus, the RHI might also be a critical tool for development of neurorehabilitative interventions that will be of great interest to the neurosurgical and rehabilitation communities.     

Principles of postoperative anterior cruciate ligament rehabilitation

It is known that anterior cruciate ligament (ACL) reconstruction needs to be combined with detailed postoperative rehabilitation in order for patients to return to their pre-injury activity levels, and that the rehabilitation process is as important as the reconstruction surgery. Literature studies focus on how early in the postoperative ACL rehabilitation period rehabilitation modalities can be initiated. Despite the sheer number of studies on this topic, postoperative ACL rehabilitation protocols have not been standardized yet. Could common, “ossified” knowledge or modalities really prove themselves in the literature? Could questions such as “is postoperative brace use really necessary?”, “what are the benefits of early restoration of the range of motion (ROM)?”, “to what extent is neuromuscular electrical stimulation (NMES) effective in the protection from muscular atrophy?”, “how early can proprioception training and open chain exercises begin?”, “should strengthening training start in the immediate postoperative period?” be answered for sure? My aim is to review postoperative brace use, early ROM restoration, NMES, proprioception, open/closed chain exercises and early strengthening, which are common modalities in the very comprehensive theme of postoperative ACL rehabilitation, on the basis of several studies (Level of Evidence 1 and 2) and to present the commonly accepted ways they are presently used. Moreover, I have presented the objectives of postoperative ACL rehabilitation in tables and recent miscellaneous studies in the last chapter of the paper.     

膝骨关节炎患者本体感觉、肌力及关节功能的相关性研究

目的 通过研究膝骨关节炎患者的膝关节本体感觉、屈伸肌群峰力矩及膝关节功能,探索三者之间的相关性。方法 本研究共纳入56例膝骨关节炎患者。本体感觉评估和膝关节屈伸肌群肌力评估均采用Isomed 2000等速肌力测试训练仪。个体本体感觉功能以膝关节的被动运动感知阈为评价指标,膝关节屈伸肌群肌力以膝关节屈伸肌群的峰力矩及峰力矩体质量比为评价指标。膝关节功能评估采用WOMAC问卷量表。同时对上述三者的相关性进行分析。再以膝骨关节炎患者关节功能WOMAC评分为因变量,年龄、体质量指数、 VAS疼痛评分、双侧Kellgren-Lawrance分级均值、双侧股四头肌肌力均值、双侧腘绳肌肌力均值、双侧本体感觉误差均值作为自变量进行多元逐步回归分析。结果 膝关节左、右侧本体感觉与股四头肌肌力及腘绳肌肌力均存在负相关（ Pr=0.659, Pr分别为－0.511、－0.408, PB）=0.385, P=0.007〕、VAS疼痛评分（B=0.347, P=0.014）与WOMAC评分呈正相关。结论 膝骨关节炎患者本体感觉-被动运动感知阈的低下与关节屈伸肌群肌力下降及关节功能下降有关。膝骨关节炎患者疼痛程度、本体感觉功能一定程度上参与影响膝骨关节炎患者的关节功能。     

Localization in the frontal plane is not susceptible to manipulation of afferent feedback via the Jendrassik Maneuver

We have previously shown that registered vergence eye position is altered while participants perform the Jendrassik Maneuver (JM). We proposed that the altered eye position signal registration is due to the effect of the JM which changes the gain of the sensory feedback from the eye muscles, possibly via the activity of non-twitch motoneurons. We conducted two studies to further extend and clarify one of our previous findings by examining whether the JM also affects registered eye position during localization in the frontal plane. Since the non-twitch motoneurons do not receive premotor input from areas involved in the programming of saccades, we hypothesized that localization responses associated with the saccadic system should not be affected by the JM. The data confirmed our prediction. We propose that the non-twitch motoneurons are involved in parametric adjustment of the proprioceptive feedback loops of the vergence but not the version eye movements.     

Neuronal mechanisms of visual stability

Human vision is stable and continuous in spite of the incessant interruptions produced by saccadic eye movements. These rapid eye movements serve vision by directing the high resolution fovea rapidly from one part of the visual scene to another. They should detract from vision because they generate two major problems: displacement of the retinal image with each saccade and blurring of the image during the saccade. This review considers the substantial advances in understanding the neuronal mechanisms underlying this visual stability derived primarily from neuronal recording and inactivation studies in the monkey, an excellent model for systems in the human brain. For the first problem, saccadic displacement, two neuronal candidates are salient. First are the neurons in frontal and parietal cortex with shifting receptive fields that provide anticipatory activity with each saccade and are driven by a corollary discharge. These could provide the mechanism for a retinotopic hypothesis of visual stability and possibly for a transsaccadic memory hypothesis, The second neuronal mechanism is provided by neurons whose visual response is modulated by eye position (gain field neurons) or are largely independent of eye position (real position neurons), and these neurons could provide the basis for a spatiotopic hypothesis. For the second problem, saccadic suppression, visual masking and corollary discharge are well established mechanisms, and possible neuronal correlates have been identified for each.     

Internally driven control of reaching movements: a study on a proprioceptively deafferented subject

We investigated the possibility of controlling reaching movements on the sole basis of central mechanisms, i.e., without peripheral feedback on hand and target positions. A deafferented subject (GL) and control subjects reached with the unseen hand for a straight-ahead target that could be displaced laterally at movement onset. The shifted target was continuously or briefly lit, or not visible. In this latter condition, a beep from either side of subjects' head single-handedly signaled the change in the movement goal, so that movements could only be controlled through an internal representation of the memorised target position. Compared to controls, GL showed quantitatively similar corrections (77% of the target displacement, on an average) and similar reaction times to the target shift (mean = 516 ms), regardless of target visual information. These results highlight a remarkable capacity for controlling reaching movements on the sole basis of internally driven processes. On the other hand, trajectories in double-step trials differed drastically between GL and controls. Controls' trajectories were composed of two segments, the second of which brought the hand directly toward the displaced target. The patient produced three-segment, stair-like trajectories. The first and third segments were mainly in the sagittal plane and the second segment was a vector-image of the lateral target shift. A control experiment showed that GL's trajectories were not the result of a voluntary strategy used to adjust movement trajectory in the absence of peripheral information on hand position. We suggest that GL's trajectories reflect a deficit in interjoint coordination in the absence of proprioception.     

Test–retest reliability of muscle vibration effects on postural sway

The effect of alterations in the processing of proprioceptive signals, on postural control, has been studied using muscle vibration effects. However, reliability and agreement of muscle vibration have still to be addressed.This study aimed to assess intra- and interday reliability and agreement of vibration effects of lumbar paraspinal and triceps surae muscles in a non-selected sample of 20 subjects, standing on solid surface and on foam. We used mean position and velocity of Centre of Pressure (CoP), during and after vibration to quantify the effect of muscle vibration. We also calculated the ratio of vibration effects on the lumbar paraspinal and triceps surae muscles (proprioceptive weighting).Displacement of the CoP during vibration showed good reliability (ICCs > 0.6), and proprioceptive weighting of displacement fair to good reliability (0.52–0.73). Agreement measures were poor, with most CV's ranging between 18% and 36%. Change in CoP velocity appeared not to be reliable. Balance recovery, when based on CoP position and calculated a short period after cessation of vibration, showed good reliability. According to this study, displacement during vibration, proprioceptive weighting and selected recovery variables are the most reliable indicators of the response to muscle vibration.     

Chronic ankle instability affects learning rate during repeated proprioception testing

Objectives1. To determine whether individuals with chronic ankle instability (CAI) have lower proprioception sensitivity scores from a test on the Active Movement Extent Discrimination Apparatus (AMEDA). 2. To determine whether individuals with CAI can improve proprioception sensitivity scores with repeated active movement testing using the AMEDA. 3. To assess the test-retest reliability of the AMEDA.DesignA cohort study comparing those with CAI or healthy ankles.SettingUniversity clinical laboratory.Participants61 healthy university students, 36 with CAI, 25 with stable ankles.Main outcome measuresA 2-way ANOVA was conducted to compare performance of CAI and stable ankle groups, over 3 test repetitions on the AMEDA. The reliability intra-class correlation coefficient (ICC) was obtained for test repetitions.ResultsThe scores improved in both groups when the AMEDA test was repeated (p = <0.001). The rates of improvement in proprioception test scores differed, with the CAI group showing a slower learning rate than the stable ankle group (p = 0.047). The ICC for the whole group across the three trials was 0.80 (95% CI = 0.69 to 0.87, p = <0.001).ConclusionsCAI participants improve their proprioception scores more slowly upon repeated AMEDA testing, suggesting differences in learning strategies.     

Effect of ankle taping on angle and force matching and strength of the plantar flexors

ObjectiveInvestigate the effect of ankle taping on plantar-flexion strength, angle matching and force matching.DesignSingle group, repeated measures.SettingLaboratory of an educational institution.ParticipantsTwenty uninjured females (22.9 ± 3.6 years).Main Outcome MeasuresTape was applied to the ankle using a conventional hindfoot technique. Angle and force matching, and plantar-flexor strength were assessed using the purpose built dual ankle dynamometer, and measures were taken prior to and following taping. Angle matching was assessed passively and actively at 10, 15 and 20° of plantar-flexion. Participants were required to match the angle of the reference leg with the contralateral leg. Force matching was assessed at 10° of plantar-flexion and participants matched the torque of the reference leg with the contralateral leg.ResultsTaping had no effect on absolute errors during active or passive angle matching. Regardless of taping, the ankle angle tested had a significant effect on passive angle matching (p < 0.001); subjects were most accurate at matching a plantar-flexion angle of 20°. Ankle taping had no effect on force matching. Taping significantly improved peak plantar-flexion strength by 20% (p = 0.028).ConclusionAnkle taping has little effect on contralateral force and angle matching, but it can enhance peak plantar-flexion strength.