Position sense testing: influence of starting position and type of displacement

Adaptive walking performance is related to the hip joint position sense during active hip flexion rather than during passive hip flexion

The purpose of this study was to investigate the relationship between hip joint position sense during active or passive hip flexion and adaptive walking performance across obstacles. After screening, 30 young men with the right dominant leg (age, 21 ± 2 years) participated in the experiment. To measure adaptive walking performance on the first day, the participants stepped over an obstacle underfoot with the left leg just high enough to avoid touching the obstacle. The difference between the height of the knee joint at the moment of crossing the obstacle and the height of the obstacle was normalized to the lower limb length and used to evaluate performance. To measure hip joint position sense on the second day, the participants adjusted their left hip joint angle to the target angle (range of joint motion: 80° of hip flexion) by active or passive hip flexion using a dynamometer. Although the absolute error in hip joint position sense during active hip flexion (6.3° ± 4.4°) significantly correlated with that during passive hip flexion (23.2° ± 11.0°) (r = 0.507, P < 0.001), a notable difference was observed between the two (P < 0.001). The normalized knee joint height was significantly correlated with the absolute error of hip joint position sense during active hip flexion (r = 0.477, P < 0.001) but not during passive hip flexion. The results of this study suggest a strong association between hip joint position sense under conditions that closely resemble actual walking behavior and adaptive walking performance, such as crossing over obstacles.

Investigating the Effect of Elevation and Sex-Based Differences on Shoulder Proprioceptive Accuracy

Background

Evaluating shoulder proprioception provides functional data that supplement imaging for the diagnosis/rehabilitation of rotator cuff injuries. There is a need for a system capable of establishing normal ranges for proprioceptive accuracy in healthy shoulders during unrestricted 3-dimensional motion.

Purpose

To conduct passive joint position sense (JPS) testing in men and women with no history of shoulder injury using a novel testing system, identifying differences in proprioceptive accuracy based on sex, shoulder elevation, and crossbody position.

Study Design

Controlled laboratory study.

Methods

We recruited 20 (10 male and 10 female) healthy participants aged between 18 and 25 years for JPS testing. Participants used a single wrist-worn sensor, and our primary outcome was errors in position matching (first guiding a participant's dominant arm from a neutral starting position to a target position and then having participants independently return from the start position to the same target) across 12 targets comprised of all possible combinations of shoulder elevation angles (EAs) (30°, 60°, 90°, and 120°) and crossbody angles (CAs) (0°, 45°, and 90°). A linear mixed model was employed to evaluate sex- and position-based differences in JPS accuracy.

Results

Position-matching accuracy increased in both males and females as target EAs increased from 30° to 120° (P < .001). The greatest EA position-matching accuracy in both sexes was observed at EAs of 90° and 120° (P < .0001). A change in the direction of error was observed in both males and females as target EAs increased from 90° to 120°, transitioning from positive (overshooting) to negative (undershooting) error (P < .005). A sex-based difference was observed at EAs of 60°, 90°, and 120° in the 90° CA plane, where females exhibited more negative CA matching error compared with males (P < .01).

Conclusion

Proprioceptive accuracy increased in both sexes at higher shoulder elevations. In the 90° CA plane, females demonstrated greater CA undershoot than males.

Clinical Relevance

While magnetic resonance imaging and ultrasound are effective tools for determining the size/age of rotator cuff tears, they do not provide functional prognostic insight for pain or mobility. Proprioceptive testing, as a functional metric based on free shoulder motion, may assist in clinically characterizing a patient's shoulder injury and rehabilitative success at multiple time points.

Normative values and the influence of sex, hand dominance, and direction of movement on active wrist joint position sense in young healthy adults

BACKGROUND

Active wrist joint position sense (JPS) is a feasible method for determining wrist proprioception. However, the normative values and factors affecting wrist JPS are not known.

OBJECTIVES

To identify normative values of active wrist JPS in young healthy adults and explore the influence of sex, hand dominance and direction of wrist movement.

DESIGN

Cross-sectional study.

METHOD

JPS of 100 individuals aged 18-40 years, (male: female = 51:49) were measured at two wrist positions (20° flexion/extension) using the active wrist JPS test. Absolute error (in degrees) was calculated and summarized using descriptive measures. Kruskal-Wallis analysis of variance was performed to determine the differences in JPS error based on sex, dominance and direction of wrist movement.

RESULTS

Mean absolute JPS flexion error on the dominant side was 3.47°(SD = 3.91°), and non-dominant side was 3.26°(SD = 3.23°). Mean absolute JPS extension error on the dominant side was 3.35°(SD = 3.43°), and non-dominant side was 4.59°(SD = 4.82°). Compared to males, females had more absolute error for flexion and extension on the dominant side. No significant difference was found in the absolute error between the dominant and non-dominant sides or between flexion and extension.

CONCLUSION

These normative values of active JPS in young healthy adults can help clinicians while assessing proprioceptive impairments of the wrist. Differences in JPS errors due to sex were found, but not due to dominance or direction of movement. These findings can guide future research on mechanisms involved in wrist JPS.

Known-group validity of passive knee joint position sense: a comparison between individuals with unilateral anterior cruciate ligament reconstruction and healthy controls

BACKGROUND

Knee joint position sense (JPS) might be negatively affected after injuries to the anterior cruciate ligament (ACL). Recent systematic reviews suggest further investigation of psychometric properties, including validity, of knee JPS tests following ACL reconstruction (ACLR). This study investigated the known-group validity by comparing knee JPS errors between individuals who underwent unilateral ACLR and healthy controls.

METHODS

This cross-sectional study involved 36 men, including 19 after ACLR (ACLR group) and 17 healthy controls (control group). In both groups, the absolute error (AE), constant error (CE) and variable error (VE) of passive knee JPS were calculated in the flexion and extension directions, for two target angles (30° and 60° flexion) per direction. Discriminative validity was evaluated by comparing JPS errors between the operated and non-operated knees in the ACLR group. Known-group validity was evaluated by comparing JPS errors between the operated knees in the ACLR group and the asymptomatic non-dominant knees of healthy controls.

RESULTS

Mean AE, CE and VE for all tests were 4.1°, - 2.3° and 3.6° for the operated knees in the ACLR group, 5.5°, - 2.6° and 3.3° for the non-operated knees in the ACLR group and 4.6°, - 2.6° and 3.3° for the non-dominant knees in the control group, respectively, regardless of the test direction and target angle. The operated knees in the ACLR group did not show significantly greater JPS errors compared to the contralateral knees in the ACLR group and to the non-dominant knees in the control group (p ≥ 0.05). On the other hand, the non-operated knees showed significantly greater AE for the 0°-60° flexion test (p = 0.025) and CE for the 0°-30° flexion test (p = 0.024) than the operated knees in the ACLR group. JPS errors did not significantly differ in the operated knees in the ACLR group based on the direction of movement and the target angle. However, the errors were significantly higher when the knee was moved through a greater range compared to that of a lesser range between the starting and target angles.

CONCLUSION

The ACLR knees did not show greater passive JPS errors than the contralateral or control knees. The direction of movement and target angle did not influence the JPS acuity after ACLR. However, higher JPS errors were evident when the knee was moved through a greater range compared to a lesser range of motion. Further studies investigating the psychometric properties of standardized JPS tests following ACLR are warranted.

Neck Muscle Vibration Alters Upper Limb Proprioception as Demonstrated by Changes in Accuracy and Precision during an Elbow Repositioning Task

Upper limb control depends on accurate internal models of limb position relative to the head and neck, accurate sensory inputs, and accurate cortical processing. Transient alterations in neck afferent feedback induced by muscle vibration may impact upper limb proprioception. This research aimed to determine the effects of neck muscle vibration on upper limb proprioception using a novel elbow repositioning task (ERT). 26 right-handed participants aged 22.21 ± 2.64 performed the ERT consisting of three target angles between 80−90° (T1), 90−100° (T2) and 100−110° (T3). Controls (CONT) (n = 13, 6F) received 10 min of rest and the vibration group (VIB) (n = 13, 6F) received 10 min of 60 Hz vibration over the right sternocleidomastoid and left cervical extensor muscles. Task performance was reassessed following experimental manipulation. Significant time by group interactions occurred for T1: (F1,24 = 25.330, p < 0.001, ηp2 = 0.513) where CONT improved by 26.08% and VIB worsened by 134.27%, T2: (F1,24 = 16.157, p < 0.001, ηp2 = 0.402) where CONT improved by 20.39% and VIB worsened by 109.54%, and T3: (F1,24 = 21.923, p < 0.001, ηp2 = 0.447) where CONT improved by 37.11% and VIB worsened by 54.39%. Improvements in repositioning accuracy indicates improved proprioceptive ability with practice in controls. Decreased accuracy following vibration suggests that vibration altered proprioceptive inputs used to construct body schema, leading to inaccurate joint position sense and the observed changes in elbow repositioning accuracy.

Effects of Whole-Body Vibration and Balance Training on Female Athletes with Chronic Ankle Instability

We explored the effects of 6-week whole-body vibration (WBV) and balance training programs on female athletes with chronic ankle instability (CAI). This randomized controlled study involved female athletes with dominant-leg CAI. The participants were randomly divided into three groups: WBV training (Group A), balance training (Group B), and nontraining (control group; Group C). Groups A and B performed three exercise movements (double-leg stance, one-legged stance, and tandem stance) in 6-week training programs by using a vibration platform and balance ball, respectively. The Star Excursion Balance Test (SEBT), a joint position sense test, and an isokinetic strength test were conducted. In total, 63 female athletes with dominant-leg CAI were divided into three study groups (all n = 21). All of them completed the study. We observed time-by-group interactions in the SEBT (p = 0.001) and isokinetic strength test at 30°/s of concentric contraction (CON) of ankle inversion (p = 0.04). Compared with the control group, participants of the two exercise training programs improved in dynamic balance, active repositioning, and 30°/s of CON and eccentric contraction of the ankle invertor in the SEBT, joint position sense test, and isokinetic strength test, respectively. Furthermore, the effect sizes for the assessed outcomes in Groups A and B ranged from very small to small. Female athletes who participated in 6-week training programs incorporating a vibration platform or balance ball exhibited very small or small effect sizes for CAI in the SEBT, joint position sense test, and isokinetic strength test. No differences were observed in the variables between the two exercise training programs.

Investigation of how accurately individuals with hemiparetic stroke can mirror their forearm positions

Current literature suggests that greater than 50% of survivors of a stroke cannot accurately perceive where their upper extremity is positioned. Our recent work demonstrates that the extent to which this perception is affected can depend on how the task is performed. For example, individuals with stroke who have a deficit in mirroring the position of their passively-placed paretic forearm during a between-arms task may accurately reproduce the position of their actively-controlled paretic forearm during a single-arm task. Moreover, the ability of individuals with various types of unilateral lesions to locate their thumb can depend on whether they reach for their paretic thumb or non-paretic thumb. Consequently, we investigated to what extent the accuracy of individuals post-hemiparetic stroke in mirroring forearm positions on a between-arms task is influenced by various conditions. Eighteen participants with hemiparetic stroke rotated their reference forearm to a target position, and then rotated their opposite forearm to concurrently mirror the position of their reference forearm. This task was performed when participants referenced each forearm (paretic, non-paretic) at two target positions (extension, flexion) for two modes of limb control (passive, active). We quantified for every testing scenario of each participant their position-mirroring error. The number of times for which participants were classified as having a deficit was least when mirroring forearm positions at the flexed position when referencing their non-paretic forearm. Additionally, the difference in the magnitude of errors when participants referenced each arm was greater during active than passive movements. Findings from this study provide further evidence that the accuracy with which individuals post stroke perceive the position of their limbs can depend on how a task is performed. Factors to consider include whether movements are active versus passive, which limb is referenced, and where the limb is positioned.

Adaptation of reach action to a novel force-field is not predicted by acuity of dynamic proprioception in either older or younger adults

Healthy ageing involves degeneration of the neuromuscular system which impacts movement control and proprioception. Yet the relationship between these sensory and motor deficits in upper limb reaching has not been examined in detail. Recently, we reported that age-related proprioceptive deficits were unrelated to accuracy in rapid arm movements, but whether this applied in motor tasks more heavily dependent on proprioceptive feedback was not clear. To address this, we have tested groups of younger and older adults on a force-field adaptation task under either full or limited visual feedback conditions and examined how performance was related to dynamic proprioceptive acuity. Adaptive performance was similar between the age groups, regardless of visual feedback condition, although older adults showed increased after-effects. Physically inactive individuals made larger systematic (but not variable) proprioceptive errors, irrespective of age. However, dynamic proprioceptive acuity was unrelated to adaptation and there was no consistent evidence of proprioceptive recalibration with adaptation to the force-field for any group. Finally, in spite of clear age-dependent loss of spatial working memory capacity, we found no relationship between memory capacity and adaptive performance or proprioceptive acuity. Thus, non-clinical levels of deficit in dynamic proprioception, due to age or physical inactivity, do not affect force-field adaptation, even under conditions of limited visual feedback that might require greater proprioceptive control.

Upper Limb Proprioceptive Acuity Assessment Based on Three-Dimensional Position Measurement Systems

The aim of the current work was to verify three-dimensional directional effects on the reproduction error precision of the human upper limb position. Thirty male subjects without history of upper limb pathology were recruited from Renmin University of China. A three-dimensional position reproduction task in six directions (up, down, left, right, far, and near) was performed by each subject. The results suggested that the proprioceptive sense of upper limb position depends on the direction, with smaller absolute errors in Directions 4 (right) and 5 (far) than in Directions 1 (up), 2 (down), 3 (left), and 6 (near). Proprioception near the end of the elbow joint range of motion may be more reliable and sensitive. Subjects reproduced fewer ranges in the horizontal plane (Directions 3, 5, and 6) and they overshot the target position along the z-axis (vertical direction) except for Direction 6. Overestimations of position in the z-axis may be caused by overestimations of force.

Effect of Force Level and Gender on Pinch Force Perception in Healthy Adults

This study investigated the effects of both force level and gender on pinch force reproduction errors in normal participants during an ipsilateral force reproduction task. In total, 20 healthy participants were asked to generate a range of levels of reference forces ranging from 5% to 60% maximal voluntary isometric contraction (MVIC) in increments of 5% MVIC using the tip pinch and to reproduce these forces using the same hand. The results showed that the males more accurately and consistently reproduced the forces than did the females, and the most accurate estimation occurred at approximately 20% to 35% MVIC. This finding can help us better understand the reasons for the higher rate of musculoskeletal disorders in females than in males and to develop tools and preventive strategies to decrease the rate of hand injuries in both genders.

Evaluation of proprioception in denervated and healthy wrist joints

We recruited 25 patients after complete wrist denervation and 60 healthy adults to investigate conscious and unconscious proprioception of the wrist. Ipsi- and contralateral joint-position sense, force sense, and wrist reflexes were measured. The latter were triggered by a trapdoor, recording electromyographic signals from the extensor carpi radialis brevis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris muscles. No significant differences were found for joint position sense, force sense, and wrist reflexes between both groups, except for reflex time of the flexor carpi ulnaris after denervation of the left wrist as compared with the left flexor carpi ulnaris in controls or in right operated wrists. At a mean follow-up of 32 months (range 8 to 133), we found no proprioceptive deficit of the conscious proprioceptive qualities of joint position sense, force sense, and the unconscious proprioceptive neuromuscular control of wrist reflex time for most muscles after complete wrist denervation. We conclude from this study that complete wrist denervation does not affect the proprioceptive senses of joint position, force sense, and reflex time of the wrist.

Test-retest reliability of tip, key, and palmar pinch force sense in healthy adults

Background

No previous studies have investigated the test–retest reliability of tip, key, and palmar pinch force sense in healthy adults. The present study explores the test-retest reliability of tip, key, and palmar pinch force sense for different force levels in healthy adults during an ipsilateral force reproduction task.

Methods

Fifty-six healthy subjects were instructed to produce varying levels of reference forces (10, 30, and 50% maximal voluntary isometric contraction (MVIC)) using three types of pinches (tip pinch, palmar pinch, and key pinch) and to reproduce these forces using the same hand. The subjects were tested twice by the same experienced testers, 1 week apart.

Results

Based on the high values of the intraclass correlation coefficient (ICC), the tip pinch (0.783–0.895) and palmar pinch (0.752–0.903) force sense tests demonstrated good reliability for all the variables. The ICCs for the key pinch (0.712–0.881) indicated fair to good relative test-retest reliability.

Conclusion

1) This study demonstrates that high test-retest reliability of tip, key, and palmar pinch force sense in healthy adults can be achieved using standardized positioning and the proposed approach. 2) According to the reliability measurements, 30 and 50% maximal voluntary isometric contraction (MVIC) are the most reliable pinch force sense levels.

Variability of shoulder girdle proprioception in 44 healthy volunteers

BACKGROUND

Improved knowledge of normal shoulder girdle proprioception should benefit the treatment and rehabilitation of shoulder disorders. Whereas many of the available methods for assessing joint position sense (JPS) are costly and complex, Balke et al. have described a simple test. The primary objective of this study was to use this test to identify factors that influence shoulder-girdle JPS evaluation in healthy individuals. The secondary objective was to determine reference values based on the values obtained and on the factors associated with their variability.

HYPOTHESIS

Age and dominant limb influence the results of shoulder girdle JPS evaluation, creating a need for reference values that take these factors in account.

PATIENTS AND METHODS

A single-centre prospective study of healthy volunteers was performed between September 2012 and January 2013. In each volunteer, shoulder repositioning accuracy was assessed bilaterally as described by Balke et al. A line was drawn on the floor parallel to and 1 metre away from a wall. A target on the wall showed marks corresponding to three angles of arm elevation: 55°, 90°, and 125°. The volunteer was asked to raise the arm to the three positions, in abduction and in flexion, while memorising the joint positions, then to replicate the same positions with the eyes closed. The absolute differences between the replicated positions and the reference positions, designated angle deviations, were measured in degrees. Age, sex, and dominant upper limb were recorded.

RESULTS

The 88 shoulders of 44 healthy volunteers were studied. No significant difference was found between males and females (p>0.05). The only significant difference between sides was better replication by the dominant arm of flexion at 55° (p=0.03). By univariate analysis, age was the only factor significantly associated with repositioning errors (p=0.003); neither dominant limb nor sex were significant (p=0.29 and p=0.59, respectively). In flexion, the angle deviation increased significantly with movement amplitude. The measurements were used to create a chart of expected angle deviations in healthy individuals according to age and to plane and amplitude of movement.

DISCUSSION

The test described by Balke et al. is simple and feasible in everyday practice. Age, dominance, and plane of movement should be considered when evaluating abnormal shoulders. Further studies in larger numbers of individuals are needed to better define normal angle deviations related to these factors.

LEVEL OF EVIDENCE

IV.

The long-term effect of complex regional pain syndrome type 1 on disability and quality of life after foot injury

PURPOSE

To study the long-term evolution of patients with lower-limb Complex Regional Pain Syndrome (CRPS), focusing on functional and proprioceptive aspects and quality of life.

METHODS

In 20 patients suffering from chronic distal lower-limb CRPS diagnosed using Budapest criteria, we assessed joint position sense and strength of the knee muscles at the CRPS and unaffected leg, functional exercise capacity, pain, CRPS severity score, quality of life and kinesiophobia. Similar assessments were performed in 20 age-matched controls.

RESULTS

The joint position performance (at 45°) was significantly lower for the CRPS leg as compared to controls. The knee extensor strength of the CRPS leg was significantly reduced as compared to the unaffected leg (-27%) and controls (-42%). CRPS patients showed significantly reduced performance at the 6 min-walk test as compared to their age group predicted value and controls. Patients suffering from CRPS for 3.8 years in average still exhibit high pain, severity and kinesiophobia scores.

CONCLUSIONS

Long-term deficits in strength and proprioceptive impairments are observed at the knee joint of the CRPS leg. This persistent functional disability has significant repercussions on the quality of life. We highlight the importance of including strength and proprioceptive exercises in the therapeutic approaches for CPRS patients.IMPLICATIONS FOR REHABILITATIONThe long-term evolution of patients suffering from lower-limb Complex Regional Pain Syndrome is associated with persistent disability, pain and impacts the quality of life.Strength, proprioceptive, functional and subjective assessments are necessary to better identify deficits.Rehabilitation should focus on the overall deficit of the affected and contralateral limb.

Bilateral Tactile Feedback-Enabled Training for Stroke Survivors Using Microsoft KinectTM

Rehabilitation and mobility training of post-stroke patients is crucial for their functional recovery. While traditional methods can still help patients, new rehabilitation and mobility training methods are necessary to facilitate better recovery at lower costs. In this work, our objective was to design and develop a rehabilitation training system targeting the functional recovery of post-stroke users with high efficiency. To accomplish this goal, we applied a bilateral training method, which proved to be effective in enhancing motor recovery using tactile feedback for the training. One participant with hemiparesis underwent six weeks of training. Two protocols, “contralateral arm matching” and “both arms moving together”, were carried out by the participant. Each of the protocols consisted of “shoulder abduction” and “shoulder flexion” at angles close to 30 and 60 degrees. The participant carried out 15 repetitions at each angle for each task. For example, in the “contralateral arm matching” protocol, the unaffected arm of the participant was set to an angle close to 30 degrees. He was then requested to keep the unaffected arm at the specified angle while trying to match the position with the affected arm. Whenever the two arms matched, a vibration was given on both brachialis muscles. For the “both arms moving together” protocol, the two arms were first set approximately to an angle of either 30 or 60 degrees. The participant was asked to return both arms to a relaxed position before moving both arms back to the remembered specified angle. The arm that was slower in moving to the specified angle received a vibration. We performed clinical assessments before, midway through, and after the training period using a Fugl-Meyer assessment (FMA), a Wolf motor function test (WMFT), and a proprioceptive assessment. For the assessments, two ipsilateral and contralateral arm matching tasks, each consisting of three movements (shoulder abduction, shoulder flexion, and elbow flexion), were used. Movements were performed at two angles, 30 and 60 degrees. For both tasks, the same procedure was used. For example, in the case of the ipsilateral arm matching task, an experimenter positioned the affected arm of the participant at 30 degrees of shoulder abduction. The participant was requested to keep the arm in that position for ~5 s before returning to a relaxed initial position. Then, after another ~5-s delay, the participant moved the affected arm back to the remembered position. An experimenter measured this shoulder abduction angle manually using a goniometer. The same procedure was repeated for the 60 degree angle and for the other two movements. We applied a low-cost Kinect to extract the participant’s body joint position data. Tactile feedback was given based on the arm position detected by the Kinect sensor. By using a Kinect sensor, we demonstrated the feasibility of the system for the training of a post-stroke user. The proposed system can further be employed for self-training of patients at home. The results of the FMA, WMFT, and goniometer angle measurements showed improvements in several tasks, suggesting a positive effect of the training system and its feasibility for further application for stroke survivors’ rehabilitation.

Shoulder and elbow joint position sense assessment using a mobile app in subjects with and without shoulder pain - between-days reliability

OBJECTIVES

To determine between-days reliability and the minimal detectable change for shoulder and elbow joint position sense assessment using a validated mobile app, in subjects with and without shoulder pain.

DESIGN

Reliability study.

SETTING

Clinical measurement.

PARTICIPANTS

Subjects with (n = 25) and without shoulder pain (n = 29).

MAIN OUTCOME MEASURES

Subjects were assessed by the same examiner in two sessions, with one-week interval. Active joint repositioning tests of shoulder flexion and scaption and elbow flexion were assessed at the target-angles of 50°, 70°, 90° and 110°. Intra-class correlation coefficient, standard error of measurement and minimal detectable change were calculated for constant, absolute, total and variable errors.

RESULTS

Good to excellent reliability was found for constant, absolute and total errors at the target-angle of 50° of scaption for healthy subjects; at 110° of shoulder flexion and all target-angles for elbow for both groups.

CONCLUSIONS

The mobile app is a reliable tool and may be useful for assessing shoulder joint position sense mainly at 110° of flexion and for elbow between 50° and 110° of flexion in subjects with and without shoulder pain. Minimal detectable changes were demonstrated and may help clinicians to follow-up rehabilitation and researchers to interpret findings of studies.

Proprioceptive deficits in inactive older adults are not reflected in fast targeted reaching movements

During normal healthy ageing there is a decline in the ability to control simple movements, characterised by increased reaction times, movement durations and variability. There is also growing evidence of age-related proprioceptive loss which may contribute to these impairments. However, this relationship has not been studied in detail for the upper limb. We recruited 20 younger adults (YAs) and 31 older adults (OAs) who each performed 2 tasks on a 2D robotic manipulandum. The first assessed dynamic proprioceptive acuity using active, multi-joint movements constrained by the robot to a pre-defined path. Participants made perceptual judgements of the lateral position of the unseen arm. The second task required fast, accurate and discrete movements to the same targets in the absence of visual feedback of the hand, and without robotic intervention. We predicted that the variable proprioceptive error (uncertainty range) assessed in Task 1 would be increased in physically inactive OAs and would predict increased movement variability in Task 2. Instead we found that physically inactive OAs had larger systematic proprioceptive errors (bias) than YAs (t[33] = 2.8, p = 0.009), and neither proprioceptive uncertainty nor bias was related to motor performance in either age group (all regression model R2 ≤ 0.06). We suggest that previously reported estimates of proprioceptive decline with ageing may be exaggerated by task demands and that the extent of these deficits is unrelated to control of discrete, rapid movement. The relationship between dynamic proprioceptive acuity and movement control in other tasks with greater emphasis on online feedback is still unclear and warrants further investigation.

Ability of individuals with chronic hemiparetic stroke to locate their forearms during single-arm and between-arms tasks

BACKGROUND

According to between-arms assessments, more than 50% of individuals with stroke have an impaired position sense. Our previous work, which employed a clinical assessment and slightly differing tasks, indicates that individuals who have a deficit on a between-forearms position-localization task do not necessarily have a deficit on a single-forearm position-localization task.

OBJECTIVE

Our goal here was to, using robotics tools, determine whether individuals with stroke who have a deficit when matching forearm positions within an arm also have a deficit when mirroring forearm positions between arms, independent of the arm that leads the task.

METHODS

Eighteen participants with chronic hemiparetic stroke and nine controls completed a single-arm position-matching experiment and between-arms position-mirroring experiment. For each experiment, the reference forearm (left/right) passively rotated about the elbow joint to a reference target location (flexion/extension), and then the participant actively rotated their same/opposite forearm to match/mirror the reference forearm's position. Participants with stroke were classified as having a position-matching/-mirroring deficit based on a quantitative threshold that was derived from the controls' data.

RESULTS

On our single-arm task, one participant with stroke was classified as having a position-matching deficit with a mean magnitude of error greater than 10.7° when referencing their paretic arm. Position-matching ability did not significantly differ for the controls and the remaining seventeen participants with stroke. On our between-arms task, seven participants with stroke were classified as having a position-mirroring deficit with a mean magnitude of error greater than 10.1°. Position-mirroring accuracy was worse for these participants with stroke, when referencing their paretic arm, than the controls.

CONCLUDING REMARK

Findings underscore the need for assessing within-arm position-matching deficits, in addition to between-arms position-mirroring deficits when referencing each arm, to comprehensively evaluate an individual's ability to locate their forearm(s).

High obsessive-compulsive individuals may have attenuated access to internal cues associated with active movement: Evidence from a head repositioning study

BACKGROUND AND OBJECTIVES

The Seeking Proxies for Internal States model of OCD posits that obsessive-compulsive (OC) individuals have attenuated access to their internal states. Consequently, they seek and rely on discernible substitutes for these internal states. Previous research has supported these conjectures. Other studies, using a variety of measures, reported a reduced sense of agency (SoA) in OCD. The current study aimed to connect these two bodies of research by focusing on internal signals associated with active movement, which are related to the SoA. We hypothesized that the performance accuracy of high OC participants would be similar for active and passive movements, while that of low OC participants would be higher when the movement is acquired actively.

METHOD

Participants with high vs. low OC tendencies were asked to reposition their head to a target angle that was acquired actively or passively. This was repeated with eyes blindfolded to evaluate reliance on visual information. Accuracy of repositioning was measured with a cervical range-of-motion device.

RESULTS

As predicted, while low OC participants presented a significant decrease in their accuracy after passive (compared to active) acquisition, high OC participants' accuracy did not differ between acquisition types. Contrary to our predictions, reliance on vision was similar across groups.

LIMITATIONS

The generalization of our findings to OCD requires replication with a clinical sample.

CONCLUSIONS

This study implies that high OC individuals have a deficient access to internal cues involved in active movement. This might contribute to their doubt regarding their actions and to their reduced SoA.

Reliability, validity, and clinical feasibility of a rapid and objective assessment of post-stroke deficits in hand proprioception

BACKGROUND

Proprioceptive function can be affected after neurological injuries such as stroke. Severe and persistent proprioceptive impairments may be associated with a poor functional recovery after stroke. To better understand their role in the recovery process, and to improve diagnostics, prognostics, and the design of therapeutic interventions, it is essential to quantify proprioceptive deficits accurately and sensitively. However, current clinical assessments lack sensitivity due to ordinal scales and suffer from poor reliability and ceiling effects. Robotic technology offers new possibilities to address some of these limitations. Nevertheless, it is important to investigate the psychometric and clinimetric properties of technology-assisted assessments.

METHODS

We present an automated robot-assisted assessment of proprioception at the level of the metacarpophalangeal joint, and evaluate its reliability, validity, and clinical feasibility in a study with 23 participants with stroke and an age-matched group of 29 neurologically intact controls. The assessment uses a two-alternative forced choice paradigm and an adaptive sampling procedure to identify objectively the difference threshold of angular joint position.

RESULTS

Results revealed a good reliability (ICC(2,1) = 0.73) for assessing proprioception of the impaired hand of participants with stroke. Assessments showed similar task execution characteristics (e.g., number of trials and duration per trial) between participants with stroke and controls and a short administration time of approximately 12 min. A difference in proprioceptive function could be found between participants with a right hemisphere stroke and control subjects (p<0.001). Furthermore, we observed larger proprioceptive deficits in participants with a right hemisphere stroke compared to a left hemisphere stroke (p=0.028), despite the exclusion of participants with neglect. No meaningful correlation could be established with clinical scales for different modalities of somatosensation. We hypothesize that this is due to their low resolution and ceiling effects.

CONCLUSIONS

This study has demonstrated the assessment's applicability in the impaired population and promising integration into clinical routine. In conclusion, the proposed assessment has the potential to become a powerful tool to investigate proprioceptive deficits in longitudinal studies as well as to inform and adjust sensorimotor rehabilitation to the patient's deficits.

Test–retest reliability of wrist joint position sense in healthy adults in a clinical setting

Introduction

Proprioceptive assessments of the wrist inform clinical decision making. In wrist rehabilitation, joint position sense has emerged as one way of assessing conscious proprioception with varying methods and minimal psychometric analysis reported. The purpose of this study was to standardise the wrist joint position sense test method for clinical use and to determine its test–retest reliability in a healthy population.

Methods

Four wrist positions (20° and 45° flexion, 20° and 45° extension) were measured twice in a random order, by a single rater, using a universal goniometer on the same day. The absolute error in degrees between each position and reposition was calculated. For relative reliability analysis, the intraclass correlation coefficient (3,1) was calculated. For absolute reliability the standard error of the measurement was calculated and Bland–Altman plots visually inspected.

Results

Fifty-five healthy volunteers (mean age 31.1 SD±10.25 years) were assessed. The mean absolute error, summarised for all positions for test and retest, was 3.98°. The intraclass correlation coefficients were poor to fair (0.07–0.47), and standard error of the measurement was 2° (rounded) for all positions. The limits of agreement were fairly narrow, and the Bland–Altman plots showed random distribution of errors for each position, therefore the measurement error was clinically acceptable.

Conclusions

The active wrist joint position sense test using goniometry demonstrated poor to fair test–retest reliability and acceptable measurement error in healthy volunteers. The wrist joint position sense angle of 20° flexion was the most reliable.

Auditory Proprioceptive Integration: Effects of Real-Time Kinematic Auditory Feedback on Knee Proprioception

The purpose of the study was to assess the influence of real-time auditory feedback on knee proprioception. Thirty healthy participants were randomly allocated to control (n = 15), and experimental group I (15). The participants performed an active knee-repositioning task using their dominant leg, with/without additional real-time auditory feedback where the frequency was mapped in a convergent manner to two different target angles (40 and 75°). Statistical analysis revealed significant enhancement in knee re-positioning accuracy for the constant and absolute error with real-time auditory feedback, within and across the groups. Besides this convergent condition, we established a second divergent condition. Here, a step-wise transposition of frequency was performed to explore whether a systematic tuning between auditory-proprioceptive repositioning exists. No significant effects were identified in this divergent auditory feedback condition. An additional experimental group II (n = 20) was further included. Here, we investigated the influence of a larger magnitude and directional change of step-wise transposition of the frequency. In a first step, results confirm the findings of experiment I. Moreover, significant effects on knee auditory-proprioception repositioning were evident when divergent auditory feedback was applied. During the step-wise transposition participants showed systematic modulation of knee movements in the opposite direction of transposition. We confirm that knee re-positioning accuracy can be enhanced with concurrent application of real-time auditory feedback and that knee re-positioning can modulated in a goal-directed manner with step-wise transposition of frequency. Clinical implications are discussed with respect to joint position sense in rehabilitation settings.

Codification mechanisms of wrist position sense

Proprioceptive signals from cutaneous, joint, tendon and muscle receptors create the basis for bodily perception and are known to be essential for motor control. However, which are the mechanisms underlying the proprioceptive signals and which are the variables that affect them is still a matter of debate. In particular, what is worth to investigate is, namely, the codification of proprioceptive information related to pointing movements of the wrist towards kinesthetic targets. In this work we asked 10 healthy adults to perform with their wrist a robot-aided proprioceptive matching task, in which the starting position of the matching movements was shifted forward or backward, in order to ascertain to which extent such shifts cause target over/under estimation and how important is movement's length on task performance. Results indicate that accuracy and precision of performance are highly correlated with the starting position and targets tended to be undershot when the active matching movements were longer. Moreover, further analysis revealed a consistent decrement of movement speed for shorter movements and conversely, faster displacement in case of backward of starting position.

Impact of motor task execution on an individual's ability to mirror forearm positions

This work is motivated by our goal of determining why individuals with stroke are impaired when locating their arms in space. We assessed the ability of individuals without neurological impairments to mirror their forearms during various motor tasks so that we could identify baseline performance in an unimpaired population. Nine right-hand dominant participants without neurological impairments mirrored forearm positions bi-directionally (i.e., right forearm mirrors left forearm, vice versa) for three motor tasks (i.e., passive, passive/active, and active) and two position identification modes (i.e., mirroring to a position stored in working memory versus concurrently felt by the opposite arm). During each trial, the participant's reference forearm moved to a flexion ([Formula: see text]) or extension ([Formula: see text]) position, and then, their opposite forearm mirrored the position of their reference forearm. The main finding across all tested conditions is that participants mirrored forearm positions with an average magnitude of error [Formula: see text]. When controlling their forearms' movements (active motor task), participants mirrored forearm positions more accurately by up to, on average, [Formula: see text] at the flexion location than at the extension location. Moreover, participants mirrored forearm positions more accurately by up to, on average, [Formula: see text] when their forearms were moved for them rather than when they controlled their forearms' movements. Task directionality and position identification mode did not significantly affect participant arm mirroring accuracy. These findings are relevant for interpreting in future work the reason why impairments occur, on similar tasks, in individuals with altered motor commands, working memory, and arm impedance, e.g., post-stroke hemiparesis.

The effects of age and amplitude on wrist proprioceptive acuity

This study examined wrist proprioception in a cross-sectional sample of 44 children aged between 8-to 14-years and a control group of 10 neurologically and physically healthy adults. Using a 3-degrees of freedom robotic device, participants performed an ipsilateral joint position matching task in which target amplitude (40% or 80% functional range of motion [fRoM]) and degrees-of-freedom (Flexion/Extension [FE], Radial/Ulnar deviation [RUD], Pronation/Supination [PS]) were manipulated. Results indicated that proprioceptive function became more accurate and consistent over the developmental spectrum, but that the ability to utilize proprioceptive feedback did not reach adult levels till the age of 10-11 years. Furthermore, proprioceptive acuity was influenced by target amplitude, such that movements were more accurate for the 80% fROM compared to the 40% fROM target for both the RUD and PS DoFs, independently of age. The present results provide critical information about the typical development of wrist proprioception that will enable clinicians to chart the course of development and dysfunction in neurological disorders in children, and help establish protocols for the robotic diagnosis and assessment of neurodevelopmental disorders.

Reliable and Rapid Robotic Assessment of Wrist Proprioception Using a Gauge Position Matching Paradigm

Quantitative assessments of position sense are essential for the investigation of proprioception, as well as for diagnosis, prognosis and treatment planning for patients with somatosensory deficits. Despite the development and use of various paradigms and robotic tools, their clinimetric properties are often poorly evaluated and reported. A proper evaluation of the latter is essential to compare results between different studies and to identify the influence of possible confounds on outcome measures. The aim of the present study was to perform a comprehensive evaluation of a rapid robotic assessment of wrist proprioception using a passive gauge position matching task. Thirty-two healthy subjects undertook six test-retests of proprioception of the right wrist on two different days. The constant error (CE) was 0.87°, the absolute error (AE) was 5.87°, the variable error (VE) was 4.59° and the total variability (E) was 6.83° in average for the angles presented in the range from 10° to 30°. The intraclass correlation analysis provided an excellent reliability for CE (0.75), good reliability for AE (0.68) and E (0.68), and fair reliability for VE (0.54). Tripling the assessment length had negligible effects on the reliabilities. Additional analysis revealed significant trends of larger overestimation (constant errors), as well as larger absolute and variable errors with increased flexion angles. No proprioceptive learning occurred, despite increased familiarity with the task, which was reflected in significantly decreased assessment duration by 30%. In conclusion, the proposed automated assessment can provide sensitive and reliable information on proprioceptive function of the wrist with an administration time of around 2.5 min, demonstrating the potential for its application in research or clinical settings. Moreover, this study highlights the importance of reporting the complete set of errors (CE, AE, VE, and E) in a matching experiment for the identification of trends and subsequent interpretation of results.

The effects of knee direction, physical activity and age on knee joint position sense

BACKGROUND

Previous research has suggested a decline in knee proprioception with age. Furthermore, regular participation in physical activity may improve proprioceptive ability. However, there is no large scale data on uninjured populations to confirm these theories. The aim of this study was to provide normative knee joint position data (JPS) from healthy participants aged 18-82years to evaluate the effects of age, physical activity and knee direction.

METHODS

A sample of 116 participants across five age groups was used. The main outcome measures were knee JPS absolute error scores into flexion and extension, Tegner activity levels and General Practitioner Physical Activity Questionnaire results.

RESULTS

Absolute error scores in to knee flexion were 3.6°, 3.9°, 3.5°, 3.7° and 3.1° and knee extension were 2.7°, 2.5°, 2.9°, 3.4° and 3.9° for ages 15-29, 30-44, 45-59, 60-74 and 75 years old respectively. Knee extension and flexion absolute error scores were significantly different when age group data were pooled. There was a significant effect of age and activity level on joint position sense into knee extension. Age and lower Tegner scores were also negatively correlated to joint position sense into knee extension.

CONCLUSIONS

The results provide some evidence for a decline in knee joint position sense with age. Further, active populations may have heightened static proprioception compared to inactive groups. Normative knee joint position sense data is provided and may be used by practitioners to identify patients with reduced proprioceptive ability.

Effects of hip abductor muscle fatigue on gait control and hip position sense in healthy older adults

We experimentally investigated whether unilateral hip abductor muscle fatigue affected gait control and hip position sense in older adults. Hip abductor muscles were fatigued unilaterally in side-lying position in 17 healthy older adults (mean age 73.2 SD 7.7 years). Hip joint position sense was assessed by an active-active repositioning test while standing and was expressed as absolute and relative errors. Participants walked on a treadmill at their preferred walking speed, while 3D linear accelerations were collected by an inertial sensor at the lower back. Gait parameters, including step and stride time, local divergence exponents and harmonic ratio were quantified. In fatigued gait, stride time variability and step-to-step asymmetry in the frontal plane were significantly increased. Also a significantly slower mediolateral trunk movement in fatigued leg late stance toward the non-fatigued leg was observed. Despite these temporal and symmetry changes, gait stability in terms of the local divergence exponents was not affected by fatigue. Hip position sense was also affected by fatigue, as indicated by an increased relative error of 0.7° (SD 0.08) toward abduction. In conclusion, negative effects of fatigue on gait variability, step-to-step symmetry, mediolateral trunk velocity control and hip position sense indicate the importance of hip abductor muscles for gait control.

Bimanual elbow robotic orthoses: preliminary investigations on an impairment force-feedback rehabilitation method

Modern rehabilitation practices have begun integrating robots, recognizing their significant role in recovery. New and alternative stroke rehabilitation treatments are essential to enhance efficacy and mitigate associated health costs. Today's robotic interventions can play a significant role in advancing rehabilitation. In addition, robots have an inherent ability to perform tasks accurately and reliably and are typically well suited to measure and quantify performance. Most rehabilitation strategies predominantly target activation of the paretic arm. However, bimanual upper-limb rehabilitation research suggests potential in enhancing functional recovery. Moreover, studies suggest that limb coordination and synchronization can improve treatment efficacy. In this preliminary study, we aimed to investigate and validate our user-driven bimanual system in a reduced intensity rehab practice. A bimanual wearable robotic device (BWRD) with a Master-Slave configuration for the elbow joint was developed to carry out the investigation. The BWRD incorporates position and force sensors for which respective control loops are implemented, and offers varying modes of operation ranging from passive to active training. The proposed system enables the perception of the movements, as well as the forces applied by the hemiparetic arm, with the non-hemiparetic arm. Eight participants with chronic unilateral stroke were recruited to participate in a total of three 1-h sessions per participant, delivered in a week. Participants underwent pre- and post-training functional assessments along with proprioceptive measures. The post-assessment was performed at the end of the last training session. The protocol was designed to engage the user in an assortment of static and dynamic arm matching and opposing tasks. The training incorporates force-feedback movements, force-feedback positioning, and force matching tasks with same and opposite direction movements. We are able to suggest identification of impairment patterns in the position-force plot results. In addition, we performed a proprioception evaluation with the system. We set out to design innovative and user immersive training tasks that utilize the BWRD capabilities, and we demonstrate that the subjects were able to cooperate and accomplish the protocol. We found that the Fugl-Meyer and Wolf Motor Function Test (pre to post) measured improvements (15 and 19%, respectively). Recognizing the brevity of the training, we focus our report primarily on the proprioception testing (32% significant improvement, p prop = 0.033) and protocol distinctive features and results. This paper presents the electromechanical features and performance of the BWRD, the testing protocol, and the assessments utilized. Outcome measures and results are presented and demonstrate the successful application and operation of the system.

Sensorimotor function of the cervical spine in healthy volunteers

BACKGROUND

Sensorimotor mechanisms are important for controlling head motion. However, relatively little is known about sensorimotor function in the cervical spine. This study investigated how age, gender and variations in the test conditions affect measures of position sense, movement sense and reflex activation in cervical muscles.

METHODS

Forty healthy volunteers (19M/21F, aged 19-59 years) participated. Position sense was assessed by determining repositioning errors in upright and flexed neck postures during tests performed in 25%, 50% and 75% cervical flexion. Movement sense was assessed by detecting thresholds to passive flexion and extension at velocities between 1 and 25°s(-1). Reflexes were assessed by determining the latency and amplitude of reflex activation in trapezius and sternocleidomastoid muscles. Reliability was evaluated from intraclass correlation coefficients.

FINDINGS

Mean repositioning errors ranged from 1.5° to 2.6°, were greater in flexed than upright postures (P=0.006) and in people aged over 25 years (P=0.05). Time to detect head motion decreased with increasing velocity (P<0.001) and was lower during flexion than extension movements (P=0.002). Reflexes demonstrated shorter latency (P<0.001) and greater amplitude (P=0.009) in trapezius compared to sternocleidomastoid, and became slower and weaker with age. None of the measures were influenced by gender. Reliability was good for movement sense measures, but was influenced by the test conditions when assessing position sense.

INTERPRETATION

Increased repositioning errors and slower reflexes in older subjects suggest that sensorimotor function in the cervical spine becomes impaired with age. In position sense tests, reliability was influenced by the test conditions with mid-range flexion movements, performed in standing, providing the most reliable measurements.

Semi-rigid brace and taping decrease variability of the ankle joint position sense

The present study investigated the effect of taping and the semi-rigid ankle brace on ankle joint position sense. Sixteen healthy women (20.8 ± 2.3 years old) actively placed the ankle in a target position. The experimental conditions were: 1) wearing no orthosis device, 2) using semi-rigid brace, and 3) wearing ankle taping. Absolute error (AE) and variable error (VE) were calculated to obtain the joint position sense. We found an interaction effect between condition and target angle at 15o of plantar flexion for the variable VE, which showed smaller errors during the use of taping and semi-rigid brace. In conclusion, the use of ankle joint orthoses, whether taping or semi-rigid brace, decrease the variability of the position sense at 15o of plantar flexion, potentially decreasing ankle sprains occurrence.

Systematic changes in position sense accompany normal aging across adulthood

Background

Development of clinical neurological assessments aimed at separating normal from abnormal capabilities requires a comprehensive understanding of how basic neurological functions change (or do not change) with increasing age across adulthood. In the case of proprioception, the research literature has failed to conclusively determine whether or not position sense in the upper limb deteriorates in elderly individuals. The present study was conducted a) to quantify whether upper limb position sense deteriorates with increasing age, and b) to generate a set of normative data that can be used for future comparisons with clinical populations.

Methods

We examined position sense in 209 healthy males and females between the ages of 18 and 90 using a robotic arm position-matching task that is both objective and reliable. In this task, the robot moved an arm to one of nine positions and subjects attempted to mirror-match that position with the opposite limb. Measures of position sense were recorded by the robotic apparatus in hand-and joint-based coordinates, and linear regressions were used to quantify age-related changes and percentile boundaries of normal behaviour. For clinical comparisons, we also examined influences of sex (male versus female) and test-hand (dominant versus non-dominant) on all measures of position sense.

Results

Analyses of hand-based parameters identified several measures of position sense (Variability, Shift, Spatial Contraction, Absolute Error) with significant effects of age, sex, and test-hand. Joint-based parameters at the shoulder (Absolute Error) and elbow (Variability, Shift, Absolute Error) also exhibited significant effects of age and test-hand.

Conclusions

The present study provides strong evidence that several measures of upper extremity position sense exhibit declines with age. Furthermore, this data provides a basis for quantifying when changes in position sense are related to normal aging or alternatively, pathology.

The role of differential delays in integrating transient visual and proprioceptive information

Many actions involve limb movements toward a target. Visual and proprioceptive estimates are available online, and by optimally combining (Ernst and Banks, 2002) both modalities during the movement, the system can increase the precision of the hand estimate. The notion that both sensory modalities are integrated is also motivated by the intuition that we do not consciously perceive any discrepancy between the felt and seen hand's positions. This coherence as a result of integration does not necessarily imply realignment between the two modalities (Smeets et al., 2006). For example, the two estimates (visual and proprioceptive) might be different without either of them (e.g., proprioception) ever being adjusted after recovering the other (e.g., vision). The implication that the felt and seen positions might be different has a temporal analog. Because the actual feedback from the hand at a given instantaneous position reaches brain areas at different times for proprioception and vision (shorter for proprioception), the corresponding instantaneous unisensory position estimates will be different, with the proprioceptive one being ahead of the visual one. Based on the assumption that the system integrates optimally and online the available evidence from both senses, we introduce a temporal mechanism that explains the reported overestimation of hand positions when vision is occluded for active and passive movements (Gritsenko et al., 2007) without the need to resort to initial feedforward estimates (Wolpert et al., 1995). We set up hypotheses to test the validity of the model, and we contrast simulation-based predictions with empirical data.

Joint position sense during a reaching task improves at targets located closer to the head but is unaffected by instruction

The purpose of the present study was twofold. Our first purpose was to test whether joint position sense is similar under instructions to memorize hand position and instructions to memorize shoulder and elbow angles. We hypothesized that instructions to memorize hand position would produce smaller errors due to evidence suggesting that the CNS directly determines hand position but indirectly determines joint angles from proprioceptive information. Our second purpose was to assess biases in joint position sense at various joint angles in a sagittal workspace. We hypothesized that akin to previous single-joint investigations, the shoulder and elbow would demonstrate better joint position sense as joint angles approached 90° during our multi-joint task. Sixteen healthy and right-hand-dominant subjects participated in the present investigation. Subjects were required to actively position their right upper extremity to one of three targets for a memorization period. After returning to the rest position, subjects then actively repositioned back into the target. We did not find evidence of a substantial difference in joint position sense between instructions to memorize the hand position or joint angle. This finding, when considered in conjunction with other evidence, suggests that studies employing either a joint angle protocol or a hand estimation protocol likely produce results that are similar enough to be compared. Proprioception has been shown to be non-uniform across a two-dimensional horizontal workspace. The present investigation provides evidence that proprioception is also non-uniform across a two-dimensional sagittal workspace. Specifically, angular errors decrease as upper extremity joint angles approach 90° of flexion and endpoint errors decrease as targets are located increasingly closer to the head.

Reach endpoint errors do not vary with movement path of the proprioceptive target

Previous research has shown that reach endpoints vary with the starting position of the reaching hand and the location of the reach target in space. We examined the effect of movement direction of a proprioceptive target-hand, immediately preceding a reach, on reach endpoints to that target. Participants reached to visual, proprioceptive (left target-hand), or visual-proprioceptive targets (left target-hand illuminated for 1 s prior to reach onset) with their right hand. Six sites served as starting and final target locations (35 target movement directions in total). Reach endpoints do not vary with the movement direction of the proprioceptive target, but instead appear to be anchored to some other reference (e.g., body). We also compared reach endpoints across the single and dual modality conditions. Overall, the pattern of reaches for visual-proprioceptive targets resembled those for proprioceptive targets, while reach precision resembled those for the visual targets. We did not, however, find evidence for integration of vision and proprioception based on a maximum-likelihood estimator in these tasks.

Three-dimensional repositioning tasks show differences in joint position sense between active and passive shoulder motion

Proprioception is important in maintaining shoulder joint stability. Previous studies investigated the effects of unconstrained multiplanar motion, with subjects able to move freely in space, on repositioning tasks for active shoulder motion but not passive motion. We sought to further explore joint position sense with 3D passive, robot-guided motions. We hypothesized that target repositioning error would be greater in the case of passively placed targets than for actively placed targets. To investigate, 15 healthy individuals participated (8 female, 7 male), who were at most 6 ft (183 cm) tall to accommodate the equipment, and who had no history of shoulder injury, surgery, or significant participation in throwing sports. Target orientations were centered at 44° of elevation and 32° of horizontal rotation from the frontal plane. Two sets of 10 trials were performed. The first set involved active placement followed by active replacement, and the second set involved passive, robot-guided, placement followed by active replacement. Repositioning error was greater following passive placement than active placement (p < 0.001). These results further our understanding of the differences between active and passive joint position sense at the shoulder.

Joint position sense is not altered during shoulder medial and lateral rotations in female assembly line workers with shoulder impingement syndrome

This study evaluated joint position sense (JPS) during medial and lateral rotations of the shoulder in female workers with and without shoulder impingement syndrome (SIS). Three groups were assessed. The case group consisted of 15 female assembly line workers (35.5, SD 5.8 years) with unilateral SIS. Control group 1 consisted of 15 female assembly line workers asymptomatic for SIS (34.4, SD 5.5 years) and control group 2 consisted of 15 female subjects (33.1, SD 6.2 years) asymptomatic for SIS and with no exposure to activities with the upper limbs. The JPS was evaluated bilaterally during passive (2°/sec) and active (5°/sec) repositioning tests using an isokinetic dynamometer. The target angles were 45° of lateral rotation (achieved by medially rotating the shoulder from 90° of lateral rotation) and 75° of lateral rotation (achieved by laterally rotating the shoulder from neutral rotation). There were no differences between sides for all groups (p  >  0.05). There were no differences in any of the variables between the case group and the control groups (p  >  0.05). The results of this study suggest that JPS during medial and lateral rotations of the shoulder is not altered in female assembly line workers with SIS.

Shoulder position sense during passive matching and active positioning tasks in individuals with anterior shoulder instability

BACKGROUND

Altered neuromuscular control due to compromised joint position sense may contribute to recurrent shoulder instability.

OBJECTIVE

The purpose of the present study was to examine whether individuals with anterior shoulder instability exhibit larger shoulder position sense errors than those with healthy shoulders in both passive matching and active positioning.

DESIGN

This was a between-groups study with repeated measures.

METHODS

Ten people with anterior shoulder instability and 15 people with healthy shoulders participated in the study. Shoulder position sense was examined with 3 different protocols (passive motion to remembered shoulder rotation angles and active shoulder abduction and rotation to verbally specified positions) in positions of both mid-range and end-range of motion.

RESULTS

Participants with unstable shoulders exhibited significantly larger errors (by 1.8° on average) in perception of shoulder position compared with those with healthy shoulders during passive matching. During active positioning, participants with unstable shoulders were able to voluntarily move the shoulder to verbally specified angles as accurately as those with healthy shoulders in both abduction (0.85° difference) and rotation (0.99° difference) tasks.

CONCLUSIONS

Results of this study indicate that people with unstable shoulders can perceive shoulder angles as accurately as people with healthy shoulders in activities with voluntary arm movements. Compared with passive matching, better information from muscle spindles and other sources during voluntary arm movements may compensate for the potential joint position sense deficits after the injury. Therefore, individuals with an unstable shoulder may have adequate neuromuscular control to engage proper protective mechanisms to stabilize the shoulder joint during functional activities.

Measurement of active shoulder proprioception: dedicated system and device

Proprioception is an essential part of shoulder stability and neuromuscular control. The purpose of the study was the development of a precise system of shoulder proprioception assessment in the active mode (Propriometr). For that purpose, devices such as the electronic goniometer and computer software had been designed. A pilot study was carried out on a control group of 27 healthy subjects, the average age being 23.8 (22–29) in order to test the system. The result of the assessment was the finding of the error of active reproduction of the joint position (EARJP). EARJP was assessed for flexion, abduction, external and internal rotation. For every motion, reference positions were used at three different angles. The results showed EARJP to range in 3–6.1°. The proprioception evaluation system (propriometr) allows a precise measurement of active joint position sense. The designed system can be used to assess proprioception in both shoulder injuries and treatment. In addition, all achieved results of normal shoulders may serve as reference to be compared with the results of forthcoming studies.

The laser-pointer assisted angle reproduction test for evaluation of proprioceptive shoulder function in patients with instability

INTRODUCTION

Over the last decade, proprioceptive function gained increasing attention in joint disorders such as instability of the shoulder. Common tests for evaluation of proprioception are limited by their complexity and high technical demands. Thus, they are hardly applicable during daily routine. Our hypothesis was that the simplified "laser-pointer assisted angle reproduction test" (LP-ART) presented here allows for clinically feasible assessment of proprioceptive shoulder function.

METHODS

Active angle reproduction capability as an aspect of sensorimotor function was evaluated with the new method in patients with shoulder instability (n = 24) and healthy controls (n = 24). 15 patients had traumatic, 9 non-traumatic anterior instability (6 bilateral), 17 were treated surgically, 13 non-operatively. Tests were performed in flexion and abduction in different angles (55°, 90°, 125°) in randomized order.

RESULTS

Angle reproduction capability was worst below shoulder level (55°) in all groups. Best results were achieved at shoulder level (90°). Healthy controls showed overall better results than patients with instability. Patients after surgical stabilization had better results in 55° and 90° abduction compared to instability patients before surgery.

CONCLUSIONS

The new LP-ART presented here is a technically simple, yet effective instrument for evaluation of the proprioceptive function of the shoulder. In contrast to former test setups it is feasible in daily routine. Compared to healthy controls, patients with unstable shoulder joints show significant proprioceptive disorders that can be quantified by the LP-ART.

Correlation analysis of proprioceptive acuity in ipsilateral position-matching and velocity-discrimination

In order to plan and control movements the central nervous system (CNS) needs to continuously keep track of the state of the musculoskeletal system. Therefore the CNS constantly uses sensory input from mechanoreceptors in muscles, joints and skin to update information about body configuration on different levels of the CNS. On the conscious level, such representations constitute proprioception. Different tests for assessment of proprioceptive acuity have been described. However, it is unclear if the proprioceptive acuity measurements in these tests correlate within subjects. By using both uni- and multivariate analysis we compared proprioceptive acuity in different variants of ipsilateral active and passive limb position-matching and ipsilateral passive limb movement velocity-discrimination in a group of healthy subjects. The analysis of the position-matching data revealed a higher acuity of matching for active movements in comparison to passive ones. The acuity of matching was negatively correlated to movement extent. There was a lack of correlation between proprioceptive acuity measurements in position-matching and velocity-discrimination.

Comparison of trunk proprioception between patients with low back pain and healthy controls

OBJECTIVE

To determine whether proprioceptive impairments exist in patients with low back pain (LBP). We hypothesized that patients with LBP would exhibit larger trunk proprioception errors than healthy controls.

DESIGN

Case-control study.

SETTING

University laboratory.

PARTICIPANTS

24 patients with nonspecific LBP and 24 age-matched healthy controls.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We measured trunk proprioception in all 3 anatomical planes using motion perception threshold, active repositioning, and passive repositioning tests.

RESULTS

LBP patients had significantly greater motion perception threshold than controls (P<.001) (1.3+/-0.9 degrees vs 0.8+/-0.6 degrees ). Furthermore, all subjects had the largest motion perception threshold in the transverse plane (P<.001) (1.2+/-0.7 degrees vs 1.0+/-0.8 degrees for all other planes averaged). There was no significant difference between LBP and healthy control groups in the repositioning tasks. Errors in the active repositioning test were significantly smaller than in the passive repositioning test (P=.032) (1.9+/-1.2 degrees vs 2.3+/-1.4 degrees ).

CONCLUSIONS

These findings suggest that impairments in proprioception may be detected in patients with LBP when assessed with a motion perception threshold measure.

New method of measuring wrist joint position sense avoiding cutaneous and visual inputs

BACKGROUND

Aspects of afferent inputs, generally termed proprioception, are being increasingly studied. Extraneous factors such as cutaneous inputs can dramatically interfere while trying to design studies in order to determine the participation of the different structures involved in proprioception in the wrist position sense. We tried to determine validity and repeatability of a new wrist joint position measurement device using methodology designed to minimize extraneous factors and isolate muscle and joint inputs.

METHODS

In order to test the reliability of the system, eighty young-adult subjects without musculoskeletal or neurologic impairments affecting the right upper extremity were tested using a custom made motion tracking system. Testing consisted of two conditions: active reproduction of active placement and passive reproduction of passive placement. Subjects performed two repetitions of each target position (10, 20, and 30 degrees of flexion and extension) presented in a random order. Test- retest reliability was then tested.

RESULTS

The average constant error in the passive condition was -0.7 degrees +/- 4.7 degrees as compared to the active condition at 3.7 degrees +/- 5.1 degrees. Average absolute error in the passive condition was 4.9 degrees +/- 2.9 degrees compared to the active condition in which absolute error was 5.9 degrees +/- 3.5 degrees.

DISCUSSION

Test-retest repeatability in both conditions was less than the 5 degrees magnitude typical of clinical goniometry. Errors in the active condition (less than 2 degrees ) were slightly smaller than the passive condition, and the passive condition was also associated with poorer consistency between apparatus sensors and skin sensors.

CONCLUSIONS

The current system for measurement of wrist joint proprioception allows the researcher to decrease extraneous influences that may affect joint position sense awareness, and will help in future study aiming to determine precisely the role of the different structure involved in proprioception.

Quantitative assessment of limb position sense following stroke

BACKGROUND

Impairment of position sense of the upper extremity (UE) may impede activities of daily living and limit motor gains after stroke. Most clinical assessments of position sense rely on categorical or ordinal ratings by clinicians that lack sensitivity to change or the ability to discriminate subtle deficits.

OBJECTIVE

Use robotic technology to develop a reliable, quantitative technique with a continuous scale to assess UE position sense following stroke.

METHODS

Forty-five patients recruited from an inpatient stroke rehabilitation service and 65 age-matched healthy controls performed an arm position matching task. Each UE was fitted in the exoskeleton of a KINARM device. One UE was passively placed in one of 9 positions, and the subject was told to match his or her position with the other UE. Patients were compared with statistical distributions of control data to identify those with deficits in UE position sense. Test-retest sessions using 2 raters established interrater reliability.

RESULTS

Two thirds of left hemiparetic and one third of right hemiparetic patients had deficits in limb position sense. Left-affected stroke subjects demonstrated significantly more trial-to-trial variability than right-affected or control subjects. The robotic assessment technique demonstrated good interrater reliability but limited agreement with the clinical thumb localizing test.

CONCLUSIONS

Robotic technology can provide a reliable quantitative means to assess deficits in limb position sense following stroke.

The assessment of the cervical spine. Part 1: Range of motion and proprioception

Neck pain and headache of cervical origin are complaints affecting an increasing number of the general population. Mechanical factors such as sustained neck postures or movements and long-term "abnormal" physiologic loads on the neck are believed to affect the cervical structures and compromise neck function. A comprehensive assessment of neck function requires evaluation of its physical parameters such as range of motion, proprioception, strength and endurance/fatigue. The complicated structure of the cervical spine however, makes it difficult for any clinician to obtain reliable and valid results. The aim of the first part of this systematic critical review is to identify the factors influencing the assessment of range of motion and proprioception of the cervical spine.