Correlations of Postural Stability to Proprioception, Tactile Sensation, and Strength Among People With Chronic Ankle Instability.

OBJECTIVES: The static and dynamic correlations of postural stability to its three potential contributors, namely, proprioception, tactile sensation, and strength remain unclear among people with chronic ankle instability (CAI). This study aimed to compare static and dynamic postural stability, along with proprioception, tactile sensation, and strength between people with and without CAI and explore their correlations. METHODS: Sixty-seven participants with CAI and 67 participants without CAI were enrolled in this study. Ankle proprioception, plantar tactile sensation, and lower limb strength were measured by a proprioception test device, a set of monofilaments, and a strength testing system, respectively. Static and dynamic postural stability were measured during standing and jump landing on a force plate and indicated by the root mean square of center of pressure and time to stability. RESULTS: Compared to people without CAI, people with CAI had poorer postural stability, proprioception, tactile sensation, and strength. Both groups demonstrated correlation between proprioception and static postural stability, but only people without CAI showed correlation between proprioception and dynamic postural stability. Both groups demonstrated a correlation between tactile sensation and static postural stability, but not with dynamic stability. Both groups demonstrated a correlation between strength and both static and dynamic postural stability. CONCLUSIONS: People with CAI had deficits in static and dynamic postural stability, proprioception, tactile sensation, and strength. Among people with CAI, proprioception, tactile sensation, and strength can help maintain static postural stability; strength can help maintain dynamic postural stability, whereas proprioception may not provide sufficient information for dynamic postural stability.

Imprecise perception of hand position during early motor adaptation.

Localizing one's body parts is important for movement control and motor learning. Recent studies have shown that the precision with which people localize their hand places constraints on motor adaptation. Although these studies have assumed that hand localization remains equally precise across learning, we show that precision decreases rapidly during early motor learning. In three experiments, healthy young participants (n = 92) repeatedly adapted to a 45° visuomotor rotation for a cycle of two to four reaches, followed by a cycle of two to four reaches with veridical feedback. Participants either used an aiming strategy that fully compensated for the rotation (experiment 1), or always aimed directly at the target, so that adaptation was implicit (experiment 2). We omitted visual feedback for the last reach of each cycle, after which participants localized their unseen hand. We observed an increase in the variability of angular localization errors when subjects used a strategy to counter the visuomotor rotation (experiment 1). This decrease in precision was less pronounced in the absence of reaiming (experiment 2), and when subjects knew that they would have to localize their hand on the upcoming trial, and could thus focus on hand position (experiment 3). We propose that strategic reaiming decreases the precision of perceived hand position, possibly due to attention to vision rather than proprioception. We discuss how these dynamics in precision during early motor learning could impact on motor control and shape the interplay between implicit and strategy-based motor adaptation.NEW & NOTEWORTHY Recent studies indicate that the precision with which people localize their hand limits implicit visuomotor learning. We found that localization precision is not static, but decreases early during learning. This decrease is pronounced when people apply a reaiming strategy to compensate for a visuomotor perturbation and is partly resistant to allocation of attention to the hand. We propose that these dynamics in position sense during learning may influence how implicit and strategy-based motor adaption interact.

Influence of compression garments on proprioception: A systematic review and meta-analysis.

Compression garments (CGs) are commonly used in rehabilitation and sports contexts to enhance performance and speed up recovery. Despite the growing use of CGs in recent decades, there is no unanimous consensus on their overall influence on joint proprioception. In this current meta-analysis, we aim to fill this knowledge gap by assessing the impact of CGs on joint proprioception. We conducted a literature search across seven databases and one registry. Ultimately, we included 27 studies with 671 participants. The meta-analysis revealed that wearing CGs resulted in a significant reduction in absolute error during joint position sensing (Hedges' g: -0.64, p = 0.006) as compared to no CGs. However, further analyses of variables such as constant error (p = 0.308), variable error (p = 0.541) during joint position sense tests, threshold to detect passive motion (p = 0.757), and active movement extent discrimination (p = 0.842) did not show a significant impact of CGs. The review also identified gaps in the reporting of certain outcomes, such as parameters of CGs, reporting of performance, individual-reported outcomes, and lack of placebo comparators. Consequently, this review provides guidelines for future studies that may facilitate evidence-based synthesis and ultimately contribute to a better understanding of the overall influence of CGs on joint proprioception.

Deficits in proprioception and strength may contribute to the impaired postural stability among individuals with functional ankle instability.

Purpose: The correlations of postural stability with proprioception and strength may explain the recurrent sprains among individuals with functional ankle instability (FAI). This study aimed to compare anterior-posterior (AP) and medial-lateral (ML) postural stability, along with ankle proprioception and strength between individuals with and without FAI and investigated their correlations. Methods: Forty participants with FAI and another 40 without FAI were recruited. Their postural stability, represented by time to stabilization (TTS) in the AP (TTSAP) and ML (TTSML) directions, was calculated by the ground reaction force during jumping onto a force plate. Their ankle proprioception and strength during plantarflexion/dorsiflexion and inversion/eversion were measured using a proprioception device and a strength testing system, separately. Results: Individuals with FAI had longer TTSAP (p = 0.015) and TTSML (p = 0.006), larger ankle proprioception thresholds (p = 0.000-0.001), and less strength (p = 0.001-0.017) than those without FAI. Correlations between strength and TTSAP were detected among individuals with (ankle plantarflexion, r = -0.409, p = 0.009) and without FAI (ankle plantarflexion, r = -0.348, p = 0.028; ankle dorsiflexion, r = -0.473, p = 0.002). Correlations of proprioception (ankle inversion, r = 0.327, p = 0.040; ankle eversion, r = 0.354, p = 0.025) and strength (ankle eversion, r = -0.479, p = 0.002) with TTSML were detected among individuals without FAI but not among those with FAI. Conclusion: Individuals with FAI have worse postural stability and proprioception and less strength. Their proprioception and strength decreased to a point where they could not provide sufficient functional assistance to the ML postural stability. Improvements in proprioception and strength may be keys to prevent recurrent ankle sprains among individuals with FAI.

Multi-joint Assessment of Proprioception Impairments Poststroke.

OBJECTIVES: To investigate shoulder, elbow and wrist proprioception impairment poststroke. DESIGN: Proprioceptive acuity in terms of the threshold detection to passive motion at the shoulder, elbow and wrist joints was evaluated using an exoskeleton robot to the individual joints slowly in either inward or outward direction. SETTING: A university research laboratory. PARTICIPANTS: Seventeen stroke survivors and 17 healthy controls (N=34). Inclusion criteria of stroke survivors were (1) a single stroke; (2) stroke duration <1 year; and (3) cognitive ability to follow simple instructions. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Threshold detection to passive motion and detection error at the shoulder, elbow and wrist. RESULTS: There was significant impairment of proprioceptive acuity in stroke survivors as compared to healthy group at all 3 joints and in both the inward (shoulder horizontal adduction, elbow and wrist flexion, P<.01) and outward (P<.01) motion. Furthermore, the distal wrist joint showed more severe impairment in proprioception than the proximal shoulder and elbow joints poststroke (P<.01) in inward motion. Stroke survivors showed significantly larger detection error in identifying the individual joint in motion (P<.01) and the movement direction (P<.01) as compared to the healthy group. There were significant correlations among the proprioception acuity across the shoulder, elbow and wrist joints and 2 movement directions poststroke. CONCLUSIONS: There were significant proprioceptive sensory impairments across the shoulder, elbow and wrist joints poststroke, especially at the distal wrist joint. Accurate evaluations of multi-joint proprioception deficit may help guide more focused rehabilitation.

The effects of periodic and noisy tendon vibration on a kinesthetic targeting task.

Tendon vibration is used extensively to assess the role of peripheral mechanoreceptors in motor control, specifically, the muscle spindles. Periodic tendon vibration is known to activate muscle spindles and induce a kinesthetic illusion that the vibrated muscle is longer than it actually is. Noisy tendon vibration has been used to assess the frequency characteristics of proprioceptive reflex pathways during standing; however, it is unknown if it induces the same kinesthetic illusions as periodic vibration. The purpose of the current study was to assess the effects of both periodic and noisy tendon vibration in a kinesthetic targeting task. Participants (N = 15) made wrist extension movements to a series of visual targets without vision of the limb, while their wrist flexors were either vibrated with periodic vibration (20, 40, 60, 80, and 100 Hz), or with noisy vibration which consisted of filtered white noise with power between ~ 20 and 100 Hz. Overall, our results indicate that both periodic and noisy vibration can induce robust targeting errors during a wrist targeting task. Specifically, the vibration resulted in an undershooting error when moving to the target. The findings from this study have important implications for the use of noisy tendon vibration to assess proprioceptive reflex pathways and should be considered when designing future studies using noisy vibration.

Ankle proprioception in children with cerebral palsy.

PURPOSE: There is no established clinical standard to evaluate ankle proprioception in children with cerebral palsy (CP). This study compared ankle position sense of children with CP to age-matched children who are typically developing (TD). METHODS: Children aged 6-17 years participated (15 CP, 58 TD). Using a custom-built device, the ankle was passively rotated to two positions for 25 trials. Using a psychophysical forced-choice paradigm, participants indicated which position was more plantarflexed. A psychometric function was fitted to the response data to determine the just noticeable difference (JND) threshold and the associated uncertainty (random error) for ankle position sense. RESULTS: Median JND thresholds for the CP group were elevated (CP: 4.3°, TD: 3.0°). Three children with CP exceeded the 95th percentile of TD. No differences in random error were found. CONCLUSION: This method assessed ankle proprioception relative to norm data and identified position sense impairments in children with CP. Using this method can provide data on proprioceptive status in CP, augmenting the assessment of motor impairment.

Motion sense sensitivity of the ankle is abnormal and correlated with motor performance in children with and without a probable developmental coordination disorder.

This study systematically examined ankle motion sense sensitivity and its relation to motor functions in children with and without a probable developmental coordination disorder (pDCD). Seventy-two children aged 10-11 years were recruited, including thirty-six children with pDCD and 36 age- and sex-matched typically developing (TD) children. Children placed their dominant foot on a passive ankle motion apparatus that induced plantar flexion of the ankle under nine constant velocities ranging between 0.15 and 1.35°/s. The adjusted movement detection time (ADT) to passive ankle motion was obtained to measure ankle motion sense sensitivity. The results showed that, in comparison to that in the TD group, ankle ADT was significantly increased by 22-59% for the range of velocities in the pDCD group. A correlation analysis showed that mean ADTs were significantly correlated with the manual dexterity (r = -0.33, p = 0.005) and balance (r = -0.24, p = 0.046) scores on the Movement Assessment Battery for Children (MABC-2) in the combined group. Similar correlations were found between the ADTs and the manual dexterity (r = -0.37, p = 0.028) and total motor (r = -0.34, p = 0.047) scores in the TD group. This study documents that ankle motion sense sensitivity to passive foot motion is reduced and is likely to contribute to poor motor performance in children with and without pDCD.

Assessment of proprioception, muscle strength and endurance during dynamic isokinetic test in patients with breast cancer-related lymphedema.

BACKGROUND: Breast cancer-related lymphedema is a common complication after breast cancer treatment.This study examined isokinetic proprioception, muscular strength, and endurance by comparing extremity with lymphedema and the extremity without lymphedema in women with breast cancer-related lymphedema. METHODS: A total of 15 individuals aged between 35 and 70 years participated in this study. Cybex Humac NORM Isokinetic dynamometer (CSMi, Stoughton, MA) were used to assess upper extremity passive proprioception, active proprioception, kinesthesia, muscle strength, and muscle endurance. The upper extremity lymphedema was measured with the water displacement arm volumetry test using a volumeter. FINDINGS: All isokinetic measurements demonstrated a statistically significant difference between the extremity with lymphedema and the extremity without lymphedema, suggesting lower scores in the extremity with lymphedema (p < .05). There was a positive correlation between passive internal rotation in the extremity with lymphedema and the time after mastectomy (r= 0.628, p = .012) and a moderate positive relationship was found between the time after lymphedema and passive internal rotation (r = 0.577; p = .024), and active external rotation position sense (r = 0.540; p = .038) in the extremity with lymphedema. Also, a unidirectional positive moderate (r = 0.594; p = .020) relationship was found between the lymphedema stage and passive external rotation in the extremity with lymphedema. INTERPRETATION: The difference in proprioception, muscle strength, and endurance between the extremity with lymphedema and the extremity without lymphedema in women with breast cancer-related lymphedema will provide valuable information in terms of prioritizing these parameters in treatment.

Superimposed electromyostimulation of the thigh muscles during passive isokinetic cycling increases muscle strength without effort.

Objectives: This study was designed to investigate the effects of a completely passive isokinetic cycle (PIC) exercise with electromyostimulation (EMS) on improving muscle strength and the changes in kinesthesia during daily activities. Methods: Twenty-nine sedentary females were divided into three groups. The EMS anterior and whole groups performed the PIC exercise without EMS 3 times a week for 3 weeks, followed by a 1-week break, and then performed it with EMS applied to the anterior and entire thigh muscles, respectively, 3 times a week for 3 weeks. The control group did not perform any training. Results: The PIC exercise with EMS significantly increased the 30s chair stand test scores by 12-16% and the maximum isometric knee extension and flexion torques by 38-68% in both EMS-applied groups. The participants found its exercise easy and felt more comfortable with daily physical activities. The exercise without EMS did not show similar improvements. Muscle soreness was significantly greater in the EMS anterior group than in the EMS whole group; however, it was not severe. Conclusions: The PIC exercise with EMS resulted in significant increases in muscle strength, facilitating a perceived ease of daily physical activities, while minimizing difficulties, effort, and notable muscle soreness.

Submaximal fatiguing eccentric contractions of knee flexors alter leg extrapersonal representation.

This study assessed the immediate and prolonged effects of eccentric-induced fatigue on position sense, utilizing position-pointing tasks, which had not been previously implemented for this purpose. Fifteen healthy adults underwent a fatiguing eccentric protocol that entailed sets of unilateral submaximal contractions of knee flexor muscles until reaching a 20% decrease in maximal isometric torque production. Evaluations of knee flexor neuromuscular function as well as position-pointing tasks at 40° and 70° of knee flexion were conducted prior to the fatiguing eccentric protocol, immediately after (POST), and 24 h after (POST24) exercise termination. To assess neuromuscular fatigue etiology, electrical myostimulations were administered during and after maximal voluntary isometric contractions. At POST, the voluntary activation level and evoked potentiated doublet amplitude at 100 Hz were significantly reduced. In addition, position-pointing errors exhibited a significant increase at POST regardless of the tested angle, with participants positioning the pointer in a more extended position compared to their hidden exercised limb. At POST24, neuromuscular function and position sense parameters had reverted to their baseline levels. The findings of this experiment demonstrate that position-pointing accuracy was impaired immediately after the fatiguing eccentric protocol, manifesting in the presence of both central and peripheral fatigue. As position-pointing accuracy relies heavily on extrapersonal representation of the body at the brain level, acute changes in exercised limb's extrapersonal representation might have resulted from central fatigue-related mechanisms altering the cognitive processes responsible for converting kinesthetic signals into extrapersonal coordinates.

Knee joint repositioning error in different trunk positions among females with chronic nonspecific low back pain: A cross-sectional study.

PURPOSE: Proprioception is a self-perceived sense of position and movement of one's body and its deficits can lead to motor control problems such as delayed muscle reflexes. Previous studies have confirmed lumbar proprioception impairments among individuals with Low Back Pain (LBP), which can afflict the normal central sensory-motor control and hence increases the risk of abnormal loading on the lumbar spine. Although the local investigation of proprioception is important, its influence on other joints in a kinetic chain particularly between extremities and spine should not be ignored. Therefore, the aim of this study was to compare the proprioception of knee joint in different trunk positions among females with chronic nonspecific low back pain (CNSLBP) and healthy females. DESIGN: The study included 24 healthy subjects and 25 patients with CNSLBP participated in this study. Repositioning error of knee joint in four different lumbar positions including flexion, neutral position, 50% ROM of left rotation and 50% ROM right rotation was evaluated using an inclinometer. Absolute error and constant error were obtained and analyzed. RESULTS: Absolute error in flexion and neutral positions in the individuals with CNSLBP were significantly higher than in healthy individuals; whereas, there was no significant difference in absolute and constant error between the two groups in 50% rotation to either side. CONCLUSION: This study showed that knee joint repositioning accuracy was reduced in patients with CNSLBP compared to healthy ones.

Effects of a Novel Web-Based Sensorimotor Exercise Program for Patients With Subacute Whiplash-Associated Disorders: Protocol for a Randomized Clinical Trial.

INTRODUCTION: Whiplash-associated disorder (WAD) often becomes a persistent problem and is one of the leading causes of disability in the world. It is a costly condition for individuals, for insurance companies, and for society. Guidelines for the management of WAD have not been updated since 2014, and the use of computer-based sensorimotor exercise programs in treatment for this patient group has not been well documented. The purpose of this randomized clinical trial is to explore the degree of association between self-reported and clinical outcome measures in WAD. METHODS: Individuals (n = 180) with subacute WAD grades I and II will be randomized into 3 groups using block randomization. The 2 primary intervention groups (A and B) will receive physical therapy involving manual therapy and either a remote, novel, computer-based cervical kinesthetic exercise (CKE) program starting at visit 2 (Group A) or neck exercises provided by the corresponding physical therapist (Group B). These groups will be compared to a "treatment as usual" Group C. Movement control, proprioception, and cervical range of motion will be measured. Neck disability and pain intensity, general health, self-perceived handicap, and physical, emotional, and functional difficulties due to dizziness will be measured using questionnaires. The short-term effects will be measured 10 to 12 weeks after the baseline measurements, and the long-term effects will be measured 6 to 12 months after the baseline measurements. IMPACT: The successful completion of this trial will help guide clinicians in the selection of outcome measures for patients with subacute WAD in the assessment of the short- and long-term effectiveness of treatment combining manual therapy with computer-based CKE compared with manual therapy and non-computer-based exercises. This trial will also demonstrate the potential of using a computer-based intervention to increase the exercise dose for this patient group and how this influences outcomes such as levels of pain and disability in the short and long term.

Does visual experience influence arm proprioception and its lateralization? Evidence from passive matching performance in congenitally-blind and sighted adults.

In humans, body segments' position and movement can be estimated from multiple senses such as vision and proprioception. It has been suggested that vision and proprioception can influence each other and that upper-limb proprioception is asymmetrical, with proprioception of the non-dominant arm being more accurate and/or precise than proprioception of the dominant arm. However, the mechanisms underlying the lateralization of proprioceptive perception are not yet understood. Here we tested the hypothesis that early visual experience influences the lateralization of arm proprioceptive perception by comparing 8 congenitally-blind and 8 matched, sighted right-handed adults. Their proprioceptive perception was assessed at the elbow and wrist joints of both arms using an ipsilateral passive matching task. Results support and extend the view that proprioceptive precision is better at the non-dominant arm for blindfolded sighted individuals. While this finding was rather systematic across sighted individuals, proprioceptive precision of congenitally-blind individuals was not lateralized as systematically, suggesting that lack of visual experience during ontogenesis influences the lateralization of arm proprioception.

When proprioceptive feedback enhances visual perception of self-body movement: rehabilitation perspectives.

Introduction: Rehabilitation approaches take advantage of vision's important role in kinesthesia, using the mirror paradigm as a means to reduce phantom limb pain or to promote recovery from hemiparesis. Notably, it is currently applied to provide a visual reafferentation of the missing limb to relieve amputees' pain. However, the efficiency of this method is still debated, possibly due to the absence of concomitant coherent proprioceptive feedback. We know that combining congruent visuo-proprioceptive signals at the hand level enhances movement perception in healthy people. However, much less is known about lower limbs, for which actions are far less visually controlled in everyday life than upper limbs. Therefore, the present study aimed to explore, with the mirror paradigm, the benefit of combined visuo-proprioceptive feedback from the lower limbs of healthy participants. Methods: We compared the movement illusions driven by visual or proprioceptive afferents and tested the extent to which adding proprioceptive input to the visual reflection of the leg improved the resulting movement illusion. To this end, 23 healthy adults were exposed to mirror or proprioceptive stimulation and concomitant visuo-proprioceptive stimulation. In the visual conditions, participants were asked to voluntarily move their left leg in extension and look at its reflection in the mirror. In the proprioceptive conditions, a mechanical vibration was applied to the hamstring muscle of the leg hidden behind the mirror to simulate an extension of the leg, either exclusively or concomitantly, to the visual reflection of the leg in the mirror. Results: (i) Visual stimulation evoked leg movement illusions but with a lower velocity than the actual movement reflection on the mirror; (ii) proprioceptive stimulation alone provided more salient illusions than the mirror illusion; and (iii) adding a congruent proprioceptive stimulation improved the saliency, amplitude, and velocity of the illusion. Conclusion: The present findings confirm that visuo-proprioceptive integration occurs efficiently when the mirror paradigm is coupled with mechanical vibration at the lower limbs, thus providing promising new perspectives for rehabilitation.

Effects of elastic kinesiology taping on shoulder proprioception: a systematic review.

BACKGROUND: Shoulder injuries are associated with proprioceptive deficits. Elastic kinesiology tape (KT) is used for treating musculoskeletal disorders, including shoulder injuries, as it arguably improves proprioception. OBJECTIVE: To synthesize the evidence on the effects of elastic KT on proprioception in healthy and pathological shoulders. METHODS: Four databases (PubMed, WoS, CINAHL, SPORTDiscus) were searched for studies that investigated the effects of elastic KT on shoulder proprioception. Outcome measures were active joint position sense (AJPS), passive joint position sense (PJPS), kinesthesia, sense of force (SoF), and sense of velocity (SoV). Risk of bias (RoB) was assessed using the Cochrane Collaboration RoB tool for randomized controlled trials (RCTs), and the ROBINS-1 for non-RCTs, while the certainty of evidence was determined using GRADE. RESULTS: Eight studies (5 RCTs, 3 non-RCTs) were included, yielding 187 shoulders (102 healthy and 85 pathological shoulders). RoB ranged from low (2 studies), moderate (5 studies), to high (1 study). Elastic KT has a mixed effect on AJPS of healthy shoulders (n=79) (low certainty). Elastic KT improves AJPS (subacromial pain syndrome and rotator cuff tendinopathy, n=52) and PJPS (chronic hemiparetic shoulders, n=13) among pathological shoulders (very low certainty). Elastic KT has no effect on kinesthesia among individuals with subacromial pain syndrome (n=30) (very low certainty). CONCLUSION: There is very low to low certainty of evidence that elastic KT enhances shoulder AJPS and PJPS. The aggregate of evidence is currently so low that any recommendation on the effectiveness of elastic KT on shoulder proprioception remains speculative.

Cervical Proprioception Assessed through Targeted Head Repositioning: Validation of a Clinical Test Based on Optoelectronic Measures.

Neck proprioception is commonly assessed with head repositioning tests. In such a test, an operator rotates the head of a blindfolded individual to a target position. After returning to the rest position, the participant actively repositions the head to the target. Joint Position Error (JPE) is the angular difference between the target angle (however oriented in a 3D space) and the actively reached positions (the smaller the difference, the better the proprioception). This study aimed to validate a head-to-target (HTT) repositioning test using an optoelectronic system for also measuring the components of the JPE in the horizontal, frontal, and sagittal planes. The head movements requested by the operator consisted of 30° left-right rotations and 25° flexion-extension. The operators or subjects could not obtain these movements without modest rotations in other planes. Two operators were involved. Twenty-six healthy participants (13 women) were recruited (mean (SD): 33.4 (6.3) years). The subjects' JPE in the requested (intended) plane of motion (JPEint-component) was a few degrees only and smaller for flexion-extensions than for left-right rotations (right rotation: 5.39° (5.29°); left rotation: 5.03° (4.51°), extension: 1.79° (3.94°); flexion: 0.54° (4.35°)). Participants' average error in unintended planes was around 1° or less. Inter-operator consistency and agreement were high. The smallest detectable change, at p < 0.05, for JPEint-component ranged between 4.5° and 6.98°. This method of optoelectronic measurement in HTT repositioning tests provides results with good metric properties, fostering application to clinical studies.

Acuity of Proprioceptive Localization Varies with Body Region.

We accurately sense locations of objects touching various points on the body and, if they are irritants, make accurate rapid movements to remove them. Such movements require accurate proprioception of orientation and motion of the reaching limb and of the target. However, it is unknown whether acuity of these sensations is similar for different points on the body. We investigated accuracy of comfortable speed reaching movements of the right index-tip by 10 subjects (five females) to touch 12 different body locations with and without vision with the body part stationary in different locations and moving in different directions. Reaching movements to points on the face/head and trunk had mean errors averaging less than 0.2 cm greater than under vision conditions. Mean errors for reaches to touch points on the left arm and digits were less accurate (p < 0.05), but average less than 1 cm relative to vision conditions. Mean errors for reaches to touch points on the left lower limb were least accurate (p < 0.05), with mean errors averaging 1.5-3.1 cm relative to movements made with vision. We conclude that there is high proprioceptive acuity for locations of points on axial structures and the left upper limb including the digits, which contrasts with previous reports of greatly distorted proprioceptive maps of the face/head and hand. Apparently low proprioceptive acuity for points on the leg may be task sensitive as many lower limb motor tasks can be performed accurately without vision.

Proprioceptive response strength in the primary sensorimotor cortex is invariant to the range of finger movement.

Proprioception is the sense of body position and movement that relies on afference from the proprioceptors in muscles and joints. Proprioceptive responses in the primary sensorimotor (SM1) cortex can be elicited by stimulating the proprioceptors using evoked (passive) limb movements. In magnetoencephalography (MEG), proprioceptive processing can be quantified by recording the movement evoked fields (MEFs) and movement-induced beta power modulations or by computing corticokinematic coherence (CKC) between the limb kinematics and cortical activity. We examined whether cortical proprioceptive processing quantified with MEF peak strength, relative beta suppression and rebound power and CKC strength is affected by the movement range of the finger. MEG activity was measured from 16 right-handed healthy volunteers while movements were applied to their right-index finger metacarpophalangeal joint with an actuator. Movements were either intermittent, every 3000 ± 250 ms, to estimate MEF or continuous, at 3 Hz, to estimate CKC. In both cases, 4 different ranges of motion of the stimuli were investigated: 15, 18, 22 and 26 mm for MEF and 6, 7, 9 and 13 mm for CKC. MEF amplitude, relative beta suppression and rebound as well as peak CKC strength at the movement frequency were compared between the movement ranges in the source space. Inter-individual variation was also compared between the MEF and CKC strengths. As expected, MEF and CKC responses peaked at the contralateral SM1 cortex. MEF peak, beta suppression and rebound and CKC strengths were similar across all movement ranges. Furthermore, CKC strength showed a lower degree of inter-individual variation compared with MEF strength. Our result of absent modulation by movement range in cortical responses to passive movements of the finger indicates that variability in movement range should not hinder comparability between different studies or participants. Furthermore, our data indicates that CKC is less prone to inter-individual variability than MEFs, and thus more advantageous in what pertains to statistical power.

The measurement of proprioceptive accuracy: A systematic literature review.

BACKGROUND: Proprioceptive accuracy refers to the individual's ability to perceive proprioceptive information, that is, the information referring to the actual state of the locomotor system, which originates from mechanoreceptors located in various parts of the locomotor system and from tactile receptors located in the skin. Proprioceptive accuracy appears to be an important aspect in the evaluation of sensorimotor functioning; however, no widely accepted standard assessment exists. In this systematic review, our goal was to identify and categorize different methods that are used to assess different aspects of proprioceptive accuracy. METHODS: A literature search was conducted in 5 different databases (PubMed, SPORTDiscus, PsycINFO, ScienceDirect, and SpringerLink). RESULTS: Overall, 1139 scientific papers reporting 1346 methods were included in this review. The methods assess 8 different aspects of proprioception: (a) the perception of joint position, (b) movement and movement extent, (c) trajectory, (d) velocity, and the sense of (e) force, (f) muscle tension, (g) weight, and (h) size. They apply various paradigms of psychophysics (i.e., the method of adjustment, constant stimuli, and limits). CONCLUSION: As the outcomes of different tasks with respect to various body parts show no associations (i.e., proprioceptive accuracy is characterized by site-specificity and method-specificity), the appropriate measurement method for the task needs to be chosen based on theoretical considerations and/or ecological validity.