Proprioceptive acuity assessment via joint position matching: from basic science to general practice

Discrepancies in the Definition and Measurement of Human Interoception: A Comprehensive Discussion and Suggested Ways Forward

Interoception has been the subject of renewed interest over the past 2 decades. The involvement of interoception in a variety of fundamental human abilities (e.g., decision-making and emotional regulation) has led to the hypothesis that interoception is a central transdiagnostic process that causes and maintains mental disorders and physical diseases. However, interoception has been inconsistently defined and conceptualized. In the first part of this article, we argue that the widespread practice of defining interoception as the processing of signals originating from within the body and limiting it to specific physiological pathways (lamina I spinothalamic afferents) is problematic. This is because, in humans, the processing of internal states is underpinned by other physiological pathways generally assigned to the somatosensory system. In the second part, we explain that the consensual dimensions of interoception are empirically detached from existing measures, the latter of which capture loosely related phenomena. This is detrimental to the replicability of findings across measures and the validity of interpretations. In the general discussion, we discuss the main insights of the current analysis and suggest a more refined way to define interoception in humans and conceptualize its underlying dimensions.

The effect of age and proprioceptive illusion susceptibility on gait

OBJECTIVE

Age-related gait decline has been associated with impaired proprioception, one's internal awareness of spatial location and movement. Although impaired proprioception has further been linked to greater susceptibility to proprioceptive illusions, it is unclear the impact such susceptibility has on gait and its interaction with age. The purpose of this study was to address these uncertainties.

METHODS

We measured proprioceptive illusions induced by muscle spindle manipulation and gait in young and older adults. We also compared illusory measures with traditionally used joint position matching to examine if illusory susceptibility can reveal proprioceptive impairments.

RESULTS

We found no effect of age on proprioceptive illusion susceptibility or joint position matching error. Compared to non-perceivers, illusion perceivers across both age groups showed greater joint matching error, suggesting reduced proprioceptive acuity. Consistent with previous studies, older adults had reduced cadence, gait velocity, and step length compared to young adults in both single- and dual-task walking. Interestingly, illusion perceivers, regardless of age, showed reduced cadence and step width compared to non-perceivers.

CONCLUSIONS

Our results suggest that gait impairments observed in those who perceive these proprioceptive illusions are age-independent, potentially rooted in deteriorated proprioception.

SIGNIFICANCE

This is the first study to examine these relations.

Comparing postoperative proprioception of the glenohumeral joint between the open and the arthroscopic Latarjet procedure

BACKGROUND

Shoulder proprioception, in which the anterior glenohumeral capsule plays a major role, is critical to the functioning of the shoulder. Consequently, most surgeons either do not resect or reinsert the anterior capsule in shoulder stabilization surgery. In the original open Latarjet procedure (OLP), the anterior capsule is preserved. However, in the all-arthroscopic Latarjet procedure (ALP), complete anterior capsule resection is recommended for better view and access to the coracoid. This raises the question if there is a postoperative difference in proprioception between these 2 procedures. Therefore, the aims of this study are (1) to assess the difference in postoperative proprioception between the operated and healthy sides after the OLP and ALP and (2) to compare the difference in postoperative proprioception on the operated side between the OLP and ALP.

METHODS

We conducted a retrospective analysis including all patients who underwent a proprioception test after an OLP or ALP at our center. Collected baseline characteristics included sex, age at surgery, operated side, hand dominance, presence of a Hill-Sachs lesion, and time between surgery and the proprioception test. For the test, patients were positioned 1 meter from a wall. They were blindfolded and had to point at a target with a laser pointer taped to their index finger. The laser point was marked and the errors were measured horizontally and vertically and categorized as <4 cm, 4-8 cm, 8-16 cm, and >16 cm.

RESULTS

Between April 2022 and April 2024, a total of 91 cases were identified, of which 24 underwent an OLP and 67 underwent an ALP. No significant difference was found in error distribution between the healthy and operated side after both the OLP (P = .30 horizontally, P = .67 vertically) and ALP (P = .20 horizontally, P = .34 vertically). Moreover, there was no significant difference in error distribution between the operated sides after the OLP vs. ALP (P = .52 horizontally; P = .61 vertically).

CONCLUSION

Our data suggest that postoperative proprioception is not significantly different between the operated and healthy sides after both the OLP and ALP, nor between the operated sides after the OLP vs. after the ALP. This might imply that completely resecting the anterior glenohumeral capsule does not have a detrimental effect on shoulder proprioception. However, these results are multifactorial and prospective studies are needed to better understand the regeneration potential of glenohumeral capsule mechanoreceptors and the importance of the anterior capsule for shoulder proprioception.

Smartphone Proprioception for Ankle Navigation (SPAN): Reliability and Effect of Position Exposure Time

This study investigated ankle discriminative acuity and performance and measurement consistency for tests undertaken with different joint position exposure times (PETs). Twenty-four participants were tested using a novel Smartphone Proprioception for Ankle Navigation (SPAN) under four PETs, i.e., 0.25s, 0.5s, 0.75s and 1s, delivered in a random sequence, and then re-tested within one week. The results indicated a PET main effect (F = 10.12, p = 0.004, partial ƞ2 = 0.14), and limb preference main effect (F = 5.39, p = 0.03, partial ƞ2 = 0.19), without significant interactions (p > 0.05). Ankle proprioception improved with prolonged PET, with the non-dominant side outperforming the dominant side. A PET of 0.25s showed good to excellent reliability, with intraclass correlation coefficients (ICCs) of 0.897 (95%CI: 0.761, 0.955) and 0.885 (95%CI: 0.736, 0.951), with standard errors of measurements (SEM) between 0.030 and 0.035, and minimum detectable change at 90% (MDC90) between 0.070 and 0.082, compared to poor to moderate reliability at the other three longer PETs (ICCs =0.352-0.736). The findings suggested the prolongation of PET can improve ankle proprioceptive performance but can amplify the inter-occasion variability, likely due to increased cognitive analysis with longer stimulus sampling. SPAN may thus be a cost-effective and accessible apparatus for clinical practice.

Balance Control Deficits are Associated With Diminished Ankle Force Sense, Not Position Sense, in Athletes With Chronic Ankle Instability

OBJECTIVES

To compare balance control and ankle proprioception between athletes with and without chronic ankle instability (CAI). A further objective was to explore the relationship between balance control performance and ankle proprioception in athletes with CAI.

DESIGN

Cross-sectional study.

SETTINGS

Sports Rehabilitation Laboratory.

PARTICIPANTS

Eighty-eight recreational athletes (47 CAI and 41 healthy control) were recruited.

INTERVENTIONS

No applicable.

MAIN OUTCOME MEASURES

Balance control performance was assessed using the sway velocity of the center of the pressure during the one-leg standing tasks. Ankle proprioception, including joint position sense and force sense, were tested using absolute error (AE) associated with joint position reproduction and force reproduction tasks in 4 directions, that is, plantarflexion, dorsiflexion, inversion, and eversion.

RESULTS

Athletes with CAI performed significantly worse than those without CAI in balance control tasks. In addition, CAI athletes showed significantly worse joint position sense and force sense in all 3 movement directions tested (plantarflexion, inversion, and eversion). Correlation analysis showed that the AE of the plantarflexion force sense was significantly moderately correlated with medial-lateral sway velocity in the one-leg standing with eyes open and closed conditions (r=.372-.403, P=.006-.012), and the AE of inversion force sense was significantly moderately correlated with medial-lateral sway velocity in the one-leg standing with eyes open (r=.345, P=.018) in athletes with CAI, but the joint position sense measures were not (all P>0.05).

CONCLUSIONS

Athletes with CAI showed significantly impaired balance control performance and diminished ankle proprioception. Deficit in force sense was deemed as a moderate predictor of one-leg standing balance control deficits in athletes with dominant-side injury CAI, whereas ankle position sense may be a small predictor.

The effect of juggling on the proprioceptive and attentional abilities among older women

Background

Age-related changes in attentional abilities can lead to a decline in body segment awareness in space. However, studies have reported that physical activity can improve proprioception among older adults, although proven activities with this potential are limited. Juggling is a promising activity for enhancing proprioception, as it requires high levels of attention and sensory precision. The first hypothesis posited that a juggling intervention would positively impact ipsilateral and contralateral elbow joint position matching without visual input. The second hypothesis suggested a correlation between cognitive abilities and joint position sense efficiency.

Methods

A total of 20 older women (mean age: 69.95 ± 4.58) participated in a repeated-measures study using a Latin square design. Measurements were taken at three time points (baseline, post-juggling, and control). Ipsilateral and contralateral elbow joint position matchings without visual or verbal feedback of accuracy were used to assess proprioception. Attention and reaction time variables were measured using the Vienna Test System protocols.

Results

Although significant changes were observed between baseline and subsequent time points in joint position sense accuracy, no specific effect of juggling was detected. Low and medium correlations were found between decision time and the variability of choice reaction time with contralateral accuracy. For ipsilateral accuracy, a relationship was observed only with handedness. No correlations were found between attention test scores and joint position sense accuracy.

Conclusion

The study did not demonstrate a significant effect of juggling on position-matching ability. However, cognitive abilities such as decision speed and the stability of choice reaction time may play a role in enhancing position-matching in older women.

Clinical trial registration

ClinicalTrials.gov, identifier NCT06108713.

Effectiveness of a home training program on improving pinch force perception in older adults

BACKGROUND

Hand function is reduced with aging which can lead to impairments in the performance of daily activities and eventually loss of independence. The ability to perceive the forces being applied to an object is an important component of hand control that also declines with age. However, the extent to which force perception can be improved through training remains largely unknown.

PURPOSE

This study evaluated the effectiveness of a home-training program focused on improving force perception in older adults.

STUDY DESIGN

Quasi-experimental - Uncontrolled trial.

METHODS

Eleven independent, healthy adults (mean age: 77.2 ± 6.8 years) participated in a home-based sensorimotor hand training program 6 days/week for 6 weeks. Force perception, the primary outcome variable, was measured as the ability to reproduce a pinch force equal to 25% maximum voluntary contraction in the absence of visual feedback using either the ipsilateral remembered or contralateral concurrent (CC) hand. We also measured hand strength, dexterity, tactile acuity, and cognition before and after training.

RESULTS

After the program was completed, participants showed a 35% reduction in absolute (p < 0.01, confidence interval (CI): [7.3, 33.2], effect sizes (ES): 0.87) and constant (p = 0.05, CI: [0.0, 34.9], ES: 0.79) force matching errors in the CC condition. Improvements in dominant hand dexterity (Purdue pegboard test) (p < 0.05, CI: [0.2, 2.4], ES: 0.60) and tactile sensitivity (JVP thresholds) (p < 0.05, CI: [-1.7, -0.1], ES: 0.94), as well as cognition (Trail Making Test B) (p < 0.05, CI: [-24,1. -1.6], ES: 0.30) were also observed post-training.

CONCLUSIONS

The results suggest that home-hand training can be an effective way to improve force perception among older adults.

A multichannel investigation of proprioceptive accuracy

Proprioceptive accuracy (PAc), i.e., the acuity of perception of the state of different parts of the motor system, shows substantial intraindividual differences, and is often considered a general ability. However, it is questionable whether there is an association between accuracies measured with different tests at different body sites. PAc with respect to both knee and elbow joints (joint position reproduction) and the flexors of the upper arms (weight discrimination) was measured in 87 young healthy individuals with regular physical activity across multiple indices. Expected and perceived performance was also assessed for each behavioral task. Frequentist and Bayesian analysis largely supported the idea that PAc with respect to various parts of the motor system are unrelated. No dominant-subdominant differences for actual performance were found; however, PAc for the dominant and subdominant limb were associated in many cases. Finally, perceived performance was related to expected but not to actual performance for all three proprioceptive modalities. In conclusion, actual accuracy of perception of the actual state of a part (i.e., joint, muscle) of the motor system cannot be generalized to other parts. Perceived accuracy, dominantly shaped by expectations, is independent from actual accuracy.

Placebo and nocebo interventions impact perceived but not actual proprioceptive accuracy

Changes in performance caused by positive and negative expectations (i.e., placebo and nocebo responses) were found to play an important role in many aspects of motor performance. This study aimed to test the impact of placebo/nocebo responses and the assumed moderating role of dispositional optimism and anxiety on proprioceptive accuracy, an essential aspect of motor functions. 78 undergraduate university students completed questionnaires assessing dispositional optimism, state anxiety, and motivation to cooperate, then were randomly assigned to three experimental groups. A sham subliminal electric stimulation was applied with claimed positive (placebo group, n = 26), negative (nocebo group, n = 26) or neutral (control group, n = 26) impact on proprioceptive accuracy. Proprioceptive accuracy was measured with active and passive versions of the Joint Position Reproduction task before and after the intervention. Expected and perceived changes in performance were also assessed; changes in state anxiety, optimism, and motivation to cooperate were used as control variables (covariates). Mixed analyses of variance indicated that the experimental manipulation did not affect actual proprioceptive accuracy but impacted expected and perceived performance. Adding the covariates to the models did not substantially change the results. Further, no significant association emerged between actual and perceived change in performance in the active test, and only a weak correlation was found in the passive test. Expected performance did not predict actual performance but predicted perceived performance in both tasks. The results suggest that only perceived (subjective) aspects of proprioceptive accuracy are susceptible to placebo and nocebo interventions.

Differences in biomechanical and metabolic factors between patients with frozen shoulder and asymptomatic individuals. A cross-sectional study

BACKGROUND

the pathogenesis of frozen shoulder (FS) is thought to be one of inflammation and fibrosis possibly influenced by hyperglycemia. Biomechanical changes of the shoulder joint in terms of muscle strength, scapular kinematics and proprioception might occur in FS.

OBJECTIVES

to compare muscle strength, scapular kinematics, proprioception, and blood glucose levels within patients with FS and to asymptomatic individuals.

DESIGN

cross-sectional study.

METHOD

Thirty-five patients with FS and 35 asymptomatic age and gender-matched individuals underwent physical assessment to determine muscle strength (abduction, external and internal rotation), scapular kinematics (both visually and with a plurimeter), proprioception (joint position sense), and blood glucose level.

RESULTS

Patients with FS showed a decrease in muscle strength in their affected shoulder compared to both the unaffected shoulder and asymptomatic individuals. Significant differences were found between the affected and unaffected shoulder in the FS group and between groups (FS versus controls) in scapular upward rotation (plurimeter) at 30° and 60° abduction. No difference in scapular kinematics (visual observation), proprioception, and blood glucose levels was found neither between shoulders in the FS group nor between groups.

CONCLUSION

A clinically relevant difference in muscle strength and increase in scapular upward rotation were found in the affected shoulder of patients with FS compared to their unaffected side and controls. However, no evidence of different levels of scapular kinematics (visual observation), proprioception, and blood glucose levels in the affected shoulder compared to the unaffected shoulder or controls is lacking.

Relationship between Tilt Sensation Ability and Lower Limb Injuries in Junior Athletes

The purpose of this study was to devise a tilt sensation measurement method to evaluate ankle proprioception and to examine its reliability. It was also used to determine the relationship among tilt sensation abilities, physical development, and lower limb injuries in junior athletes. In this study, a step platform created tilt angles. Participants with eye masks answered "yes" or "no" to sensing a tilt, evaluated over nine or seven trials. Experiment 1 involved 22 university students (20.6 ± 0.9 years). The minimum angle at which a tilt could be sensed while standing on both feet was determined, and measurements were taken again to examine reliability. Experiment 2 involved 40 junior athletes (12.3 ± 2.0 years), where the minimum angle for tilt sensation was obtained, and medical checks were conducted to assess injuries in the knee, lower leg, and foot. Reliability studies showed a moderately significant correlation between the first and second sessions (r = 0.504, p = 0.017), suggesting the reliability of the experimental method. The proportion capable of sensing a tilt of 1.1° and 1.6° was significantly higher in junior high school students than in elementary school students (1.1°; χ2 = 8.839, p = 0.003. 1.6°; χ2 = 4.038, p = 0.044). The group unable to sense a tilt of 1.6° and 2.1° had a significantly higher positive rate of knee injuries compared to the sensed group among junior high school students (1.6°; χ2 = 4.622, p = 0.032. 2.1°; χ2 = 4.622, p = 0.032). Our findings suggested that a reduced tilt sensation ability was associated with knee injuries in junior high school students. Utilizing our devised tilt sensation assessment could play a crucial role in preventing and detecting early injuries in junior high school students.

Heart rate-related physiological changes induced by classical music-elicited emotions do not underlie alterations in healthy adults' ankle joint target-matching strategy

Emotions have the potential to modulate human voluntary movement by modifying muscle afferent discharge which in turn may affect kinesthetic acuity. We examined if heart rate (HR)-related physiological changes induced by music-elicited emotions would underlie alterations in healthy young adults' ankle joint target-matching strategy quantified by joint position sense (JPS). Participants (n = 40, 19 females, age = 25.9 ± 2.9 years) performed ipsilateral-, and contralateral ankle target-matching tasks with their dominant and non-dominant foot using a custom-made foot platform while listening to classical music pieces deemed to evoke happy, sad, or neutral emotions (each n = 10). Participants in the 4th group received no music during the task. Absolute (ABS), constant (CONST), and variable (VAR) target-matching errors and HR-related data were analyzed. Participants performed the contralateral target-matching task with smaller JPS errors when listening to sad vs. happy music (ABS: p < 0.001, d = 1.6; VAR: p = 0.010, d = 1.2) or neutral (ABS: p < 0.001, d = 1.6; VAR: p < 0.001, d = 1.4) music. The ABS (d = 0.8) and VAR (d = 0.3) JPS errors were lower when participants performed the task with their dominant vs. non-dominant foot. JPS errors were also smaller during the ipsilateral target-matching task when participants (1) listened to sad vs. neutral (ABS: p = 0.007, d = 1.2) music, and (2) performed the target-matching with their dominant vs. non-dominant foot (p < 0.001, d = 0.4). Although emotions also induced changes in some HR-related data during the matching conditions, i.e., participants who listened to happy music had lower HR-related values when matching with their non-dominant vs. dominant foot, these changes did not correlate with JPS errors (all p > 0.05). Overall, our results suggest that music-induced emotions have the potential to affect target-matching strategy and HR-related metrics but the changes in HR-metrics do not underlie the alteration of ankle joint target-matching strategy in response to classical music-elicited emotions.

Tactile acuity and active joint repositioning sense in individuals with and without chronic low back pain: a cross-sectional study

BACKGROUND

Sensorimotor dysfunction, as measured by tactile acuity and active joint repositioning, has been identified as a contributing factor of chronic low back pain (CLBP). Existing research suggests that further research is necessary to improve the characterization of sensorimotor perception in patients with CLBP.

OBJECTIVES

The main aim is to investigate whether tactile acuity and repositioning errors differ between individuals with CLBP and controls without CLBP. A secondary aim was to investigate the association between age, body mass index (BMI) and physical activity, and tactile acuity and repositioning sense.

METHODS

Cross-sectional study. Sixty-eight participants (36 with, 32 without CLBP) were examined. Two-Point Discrimination (TPD) test (four measures: horizontal and vertical run, left and right side) and Active Joint Reposition Sense (AJRS) test (2 directions: to flexion and to extension) were used.

RESULTS

No differences were found for TPD (right horizontal run: p = .069; left horizontal run: p = .066; right vertical run: p = .933; left vertical run: p = .285) or AJRS (flexion: p = .792; extension: p = .956) between participants with and without CLBP. Older subjects had significantly worse tactile acuity (3 sites, p = .018, p = .004, p = .041) and worse repositioning sense (2 directions, p = .026, p = .040,) than younger subjects. Individuals with BMI ≥ 25 had significantly worse TPD compared to individuals with normal weight (2 sites, p = .028, p = .020).

CONCLUSIONS

Individuals with CLBP did not have impaired tactile and repositioning accuracy when compared to controls without CLBP. Future studies comparing sensorimotor performance should consider age and BMI as potential confounding factors.

Factors that influence the angular error in active knee angle reproduction tests: A systematic review and meta-analysis

Purpose

The systematic review and meta-analysis investigated subject-independent test factors that influence the absolute angle error in active knee angle reproduction tests.

Methods

Five electronic databases were searched to identify relevant studies published before 20 December 2023. Studies were included that were published in either English or German and that investigated joint proprioception in the healthy knee. Included studies were also required to have participants 18-60 years old and free of lower-limb injury, neurological disorders and diseases affecting joint position sense. Risk of bias was assessed using a Cochrane risk-of-bias tool.

Results

Of the 2023 articles identified, 26 studies (1082 participants) were included in the meta-analysis. The meta-analysis showed a significant pooled standard mean difference in the absolute angular error for body orientation, direction of movement and fatigue. Active knee angle reproduction tests were found to have a lower absolute angular error when performed in the sitting position compared to the prone position (SMD = -0.56; 95% CI = -1.00 to -0.12). The absolute angular error was found to be greater in cases of knee flexion compared to knee extension (SMD = 0.71; 95% CI = 0.18-1.24). General and local muscle fatigue were found to result in a higher absolute angular error (SMD = 1.39; 95% CI = 1.04-1.75).

Conclusion

Hence, fatigue, body orientation and direction of movement influence the extent of the absolute angular error in active knee angle reproduction tests. Practitioners should be aware that the test conditions and the patient's level of fatigue can affect the results of such tests and that directly comparing results obtained using different test protocols may not be appropriate. The test protocol should be well documented and applied consistently in the clinical setting.

Level of Evidence

Level III, systematic review with meta-analysis.

Effects of Lower Limb Proprioceptive Training on Balance and Trunk Control Among the Adult Stroke Population

Background and objective Balance and trunk control are major concerns among older adults during stroke rehabilitation. Loss of proprioception in the affected limb has a greater influence on motor learning and reeducation during balance training. Available studies stress the relevance of strength and functional training in regaining balance and trunk control. Proprioception training, in addition to available rehabilitation, can optimize the balance among this population. Our study aimed to find out the effects of proprioceptive training on balance and trunk control among the chronic stroke population. Methodology Out of 45 subjects enrolled at the Indian Head Injury Foundation, New Delhi, India, 30 subjects were selected based on selection criteria and randomized into two groups using the chit method, with 15 subjects in each group. The control group received conventional training, which included a range of motion, stretching, and strengthening exercises, while the intervention group received additional proprioceptive training five days per week for four consecutive weeks. Subjects were assessed on the Berg Balance Scale and Trunk Control Test for balance and trunk control on day one and after four weeks. A paired t-test was used to analyze the difference within the groups, and unpaired t-tests were used between the groups, keeping p < 0.05 as a significance level. Results After four weeks of intervention, statistically significant improvements were seen in the balance and trunk control groups, with p < 0.05 in both groups. However, a significant improvement in balance was observed in the experimental group when compared across groups (p = 0.001), whereas no statistically significant improvement in trunk control was found (p = 0.061). Conclusion We conclude that proprioceptive training and conventional physiotherapy both help to improve balance. Proprioceptive training is better for improving balance, but it has no significant effects on trunk control. It is likely that an extended intervention time or a different form of intervention may be required to achieve substantial gains in these areas. Future research might look at other outcome measures or the impacts of other types of therapies to see which ones are most helpful at increasing trunk control.

Influence of taping on joint proprioception: a systematic review with between and within group meta-analysis

Taping is increasingly used to manage proprioceptive deficits, but existing reviews on its impact have shortcomings. To accurately assess the effects of taping, a separate meta-analyses for different population groups and tape types is needed. Therefore, both between- and within-group meta-analyses are needed to evaluate the influence of taping on proprioception. According to PRISMA guidelines, a literature search was conducted across seven databases (Web of Science, PEDro, Pubmed, EBSCO, Scopus, ERIC, SportDiscus, Psychinfo) and one register (CENTRAL) using the keywords "tape" and "proprioception". Out of 1372 records, 91 studies, involving 2718 individuals, met the inclusion criteria outlined in the systematic review. The meta-analyses revealed a significant between and within-group reduction in repositioning errors with taping compared to no tape (Hedge's g: -0.39, p < 0.001) and placebo taping (Hedge's g: -1.20, p < 0.001). Subgroup and sensitivity analyses further confirmed the reliability of the overall between and within-group analyses. The between-group results further demonstrated that both elastic tape and rigid tape had similar efficacy to improve repositioning errors in both healthy and fatigued populations. Additional analyses on the threshold to detection of passive motion and active movement extent discrimination apparatus revealed no significant influence of taping. In conclusion, the findings highlight the potential of taping to enhance joint repositioning accuracy compared to no tape or placebo taping. Further research needs to uncover underlying mechanisms and refine the application of taping for diverse populations with proprioceptive deficits.

Proprioception, Emotion and Social Responsiveness in Children with Developmental Disorders: An Exploratory Study in Autism Spectrum Disorder, Cerebral Palsy and Different Neurodevelopmental Situations

Proprioception has long been linked with emotional dysregulation in neurotypical adults. Neuropediatric disorders such as autism spectrum disorder (ASD) and cerebral palsy (CP) are distinct entities and yet both present with deficits and challenges in sensory processing and the regulation of emotions. This study aimed to explore the relationship between proprioception and emotional-social performance in children and to compare proprioception and emotional-social performance in different underlying neurodevelopmental conditions. For this purpose, this cross-sectional study included 42 children with ASD, 34 children with CP and 50 typically developing peers. Proprioceptive acuity, proprioceptive reactive behavior as well as emotion regulation and social responsiveness were assessed. The results show a significant correlation between proprioceptive deficits and emotional difficulties in this pediatric sample, with distinct proprioceptive impairment patterns according to the underlying neurological disorder. Children with CP showed significant emotional knowledge deficits, while children with ASD predominantly showed challenges in social responsiveness. These data thus suggest a differentiated impact of proprioception on emotional-social performance in neurodevelopmental disorders and highlight proprioception as a potential therapeutic target for balancing emotion regulation in children with neurodevelopmental conditions.

Balance Control is Sequentially Correlated with Proprioception, Joint Range of Motion, Strength, Pain, and Plantar Tactile Sensation Among Older Adults with Knee Osteoarthritis

BACKGROUND

Patients with knee osteoarthritis (KOA) are at high risk for falls, which is attributed to their impaired balance control. Identifying factors associated with balance control facilitates the development of precise KOA rehabilitation programs. This study was to investigate the correlations of balance control with proprioception, plantar tactile sensation (PTS), pain, joint range of motion (ROM), and strength among older adults with and without KOA, as well as the magnitudes and sequence of correlation of these factors to balance control.

METHODS

A total of 240 older adults with (n = 124, female: 84, age: 68.8 ± 4.0 years) and without (n = 116, female: 64, age: 67.9 ± 3.5 years) KOA were recruited and assigned to the KOA and control groups. Their proprioception, PTS, pain, ROM, and strength were measured. Pearson or Spearman correlations were used to test whether they were significantly related to their Berg Balance Scale (BBS), and factor analysis and multivariate linear regression were used to determine the degrees of correlation between each factor and the BBS.

RESULTS

Compared to the control group, the KOA group had lower BBS score, larger proprioception and PTS thresholds, smaller ROM, and less strength (p: 0.008, < 0.001-0.016, < 0.001-0.005, < 0.001-0.014, and < 0.001-0.002, respectively). In the KOA group, the BBS was weakly to moderately correlated with proprioception, PTS, pain, ROM, and strength (r: 0.332-0.501, 0.197-0.291, 0.340, 0.212-0.508, and 0.236-0.336, respectively). While in the control group, the BBS was correlated with proprioception and strength (r: 0.207-0.379, and 0.212-0.410). In the KOA group, BBS = 54.41+ (0.668*strength) - (0.579*PTS) - (1.141*proprioception) + (1.054* ROM) - (0.339*pain). While in the control group, BBS = 53.85+ (0.441*strength) - (0.677*proprioception).

CONCLUSION

Worse proprioception and PTS, smaller ROM, and less strength were detected among older adults with KOA, and their proprioception, PTS, pain, ROM, and strength were all related to balance control. Proprioception had the strongest correlations, followed by ROM, strength, pain, and PTS. Precise KOA rehabilitation programs may be proposed following the sequence of improving the five factors.

The independence of impairments in proprioception and visuomotor adaptation after stroke

BACKGROUND

Proprioceptive impairments are common after stroke and are associated with worse motor recovery and poor rehabilitation outcomes. Motor learning may also be an important factor in motor recovery, and some evidence in healthy adults suggests that reduced proprioceptive function is associated with reductions in motor learning. It is unclear how impairments in proprioception and motor learning relate after stroke. Here we used robotics and a traditional clinical assessment to examine the link between impairments in proprioception after stroke and a type of motor learning known as visuomotor adaptation.

METHODS

We recruited participants with first-time unilateral stroke and controls matched for overall age and sex. Proprioceptive impairments in the more affected arm were assessed using robotic arm position- (APM) and movement-matching (AMM) tasks. We also assessed proprioceptive impairments using a clinical scale (Thumb Localization Test; TLT). Visuomotor adaptation was assessed using a task that systematically rotated hand cursor feedback during reaching movements (VMR). We quantified how much participants adapted to the disturbance and how many trials they took to adapt to the same levels as controls. Spearman's rho was used to examine the relationship between proprioception, assessed using robotics and the TLT, and visuomotor adaptation. Data from healthy adults were used to identify participants with stroke who were impaired in proprioception and visuomotor adaptation. The independence of impairments in proprioception and adaptation were examined using Fisher's exact tests.

RESULTS

Impairments in proprioception (58.3%) and adaptation (52.1%) were common in participants with stroke (n = 48; 2.10% acute, 70.8% subacute, 27.1% chronic stroke). Performance on the APM task, AMM task, and TLT scores correlated weakly with measures of visuomotor adaptation. Fisher's exact tests demonstrated that impairments in proprioception, assessed using robotics and the TLT, were independent from impairments in visuomotor adaptation in our sample.

CONCLUSION

Our results suggest impairments in proprioception may be independent from impairments in visuomotor adaptation after stroke. Further studies are needed to understand factors that influence the relationship between motor learning, proprioception and other rehabilitation outcomes throughout stroke recovery.

An Overview of the Bodily Awareness Representation and Interoception: Insights and Progress in the Field of Neurorehabilitation Research

In the last two decades, the scientific literature on so-called body representations has been increasing, and the notion of body awareness (BA) is particularly interesting for neurorehabilitation. In this article, we present results derived from recent studies on this representation, considering the different definitions and explicative models proposed as well as the empirical settings used to test it, providing an extensive overview of these issues. This article discusses the challenge of understanding how we integrate the sensory experiences of proprioception (knowing where our body is in space) and interoception (sensing internal bodily sensations, like hunger of thirst) with our perception of self. This is a difficult problem to analyze because our awareness of our body is inherently linked to our perspective, since the body is the means through which we interact with the world. Presenting the different viewpoints offered by recent theories on this concern, we highlighted that the neurorehabilitation and psychiatric settings offer two important fields useful for the study of BA because in them it is possible to analyze bodily representations by inducing/observing a controlled discrepancy between dysfunctional content and sensory inputs.

Joint position sense testing at the wrist and its correlations with kinesiophobia and pain intensity in individuals who have sustained a distal radius fracture: A cross-sectional study

BACKGROUND

Sensorimotor impairment following distal radius fracture (DRF) has been associated with a significant decline in function. Joint position sense (JPS) testing is a meaningful and responsive way to assess sensorimotor impairment for individuals who have sustained a DRF; however, there are factors that may influence the results of JPS testing, including kinesiophobia and pain intensity.

PURPOSE

This study aimed to evaluate the influence kinesiophobia may have on wrist JPS testing and if pain intensity impacts kinesiophobia and JPS in individuals with a DRF.

STUDY DESIGN

This was a cross-sectional study.

METHODS

Participants referred from two medical centers with a diagnosis of DRF treated with at least 3 weeks of immobilization were enrolled in the study. Data were collected at 1 week and 6 weeks postimmobilization period. Demographics were summarized with descriptive statistics, and linear relationships between kinesiophobia, pain intensity, and wrist JPS were examined using Pearson correlation coefficient.

RESULTS

Forty-eight participants were included in this study (mean age 42.9 years). Significant positive correlations were found between the Tampa Scale for Kinesiophobia (TSK) and Numeric Rating Scale (NRS; r = 0.951, p < 0.001), TSK and JPS error (r = 0.942, p < 0.001), as well as NRS and JPS error (r = 0.898, p < 0.001). These correlations indicate that higher levels of kinesiophobia are associated with increased pain intensity and greater JPS error. T-tests reveal no significant difference between male and female for the TSK, NRS, or JPS scores.

CONCLUSIONS

There is an association for individuals with high levels of kinesiophobia and both greater pain and errors with JPS testing.

Test-retest reliability of joint position sense in the elbow among healthy adults

BACKGROUND

Proprioception of the elbow is necessary for daily activities. Proprioception can be impaired with injury or pathology, and rehabilitation efforts seek to improve proprioception for improved upper extremity functioning. In clinical practice, joint position sense (JPS) testing is often utilized to assess conscious proprioception; however, varying methods exist with little evidence of psychometric properties, especially for the elbow.

PURPOSE

The primary aim of this study was to create a standardized elbow JPS test protocol using goniometry measurement to determine the most reliable testing position. The secondary aim was to determine if the elbow JPS test had acceptable test-retest reliability in healthy adults.

STUDY DESIGN

This was a cross-sectional study using a convenience sample of healthy adults.

METHODS

Three elbow positions (45°, 60°, and 75° of elbow flexion) were measured twice on the same day by a single rater using a universal goniometer. We calculated the absolute error in degrees between each position and reposition and the intraclass correlation coefficient (3,1) for relative reliability. We also calculated the standard error of the measurement and visually inspected Bland-Altman plots for absolute reliability.

RESULTS

Sixty-eight healthy adults (mean age 27.9 years, standard deviation 8.59) were assessed. The mean absolute error for all positions for test and retest was 5.7°. The intraclass correlation coefficients were moderate to good (0.57-0.75), and the standard error of the measurement was 2° (rounded) for all positions. The limits of agreement were moderately narrow, and the Bland-Altman plots showed a random distribution of errors for each position, indicating clinically acceptable measurement error.

CONCLUSIONS

The joint position reproduction test for JPS using goniometry demonstrated moderate to good test-retest reliability and acceptable measurement error in healthy adults. The elbow joint angle of 60° flexion was the most reliable for JPS testing, providing insight for JPS assessment in clinical practice.

Test-retest reliability of joint position sense in the carpometacarpal joint among healthy adults

BACKGROUND

Accurate proprioception in the thumb carpometacarpal (CMC) joint is necessary during activities such as performing fine manipulative tasks, such as coin handling, opening doors, using keys, and pressing control buttons.

PURPOSE

The primary aim of the present study was to examine the test-retest reliability of CMC joint position sense (JPS) in healthy subjects. The secondary aim was to determine the most reliable JPS testing position for the thumb CMC joint.

STUDY DESIGN

This was a cross-sectional study of a convenience sample of healthy adults.

METHODS

Three thumb positions (20°, 30°, and 40° of thumb abduction) were measured twice on the same day by a single rater using a universal goniometer. The absolute error in degrees between each position and reposition was calculated. The intraclass correlation coefficient (2,1) was calculated for relative reliability. The standard error of the measurement was calculated.

RESULTS

Sixty-four healthy adults (mean age 27.8 years, standard deviation = 8.7) were assessed. The intraclass correlation coefficients were poor (-0.08 to 0.22), and the standard error of the measurement was 1.4° for all positions.

CONCLUSIONS

The joint position reproduction test for JPS using goniometry demonstrated poor test-retest reliability and acceptable measurement error in healthy adults.

Neural correlates of bilateral proprioception and adaptation with training

Bilateral proprioception includes the ability to sense the position and motion of one hand relative to the other, without looking. This sensory ability allows us to perform daily activities seamlessly, and its impairment is observed in various neurological disorders such as cerebral palsy and stroke. It can undergo experience-dependent plasticity, as seen in trained piano players. If its neural correlates were better understood, it would provide a useful assay and target for neurorehabilitation for people with impaired proprioception. We designed a non-invasive electroencephalography-based paradigm to assess the neural features relevant to proprioception, especially focusing on bilateral proprioception, i.e., assessing the limb distance from the body with the other limb. We compared it with a movement-only task, with and without the visibility of the target hand. Additionally, we explored proprioceptive accuracy during the tasks. We tested eleven Controls and nine Skilled musicians to assess whether sensorimotor event-related spectral perturbations in μ (8-12Hz) and low-β (12-18Hz) rhythms differ in people with musical instrument training, which intrinsically involves a bilateral proprioceptive component, or when new sensor modalities are added to the task. The Skilled group showed significantly reduced μ and low-β suppression in bilateral tasks compared to movement-only, a significative difference relative to Controls. This may be explained by reduced top-down control due to intensive training, despite this, proprioceptive errors were not smaller for this group. Target visibility significantly reduced proprioceptive error in Controls, while no change was observed in the Skilled group. During visual tasks, Controls exhibited significant μ and low-β power reversals, with significant differences relative to proprioceptive-only tasks compared to the Skilled group-possibly due to reduced uncertainty and top-down control. These results provide support for sensorimotor μ and low-β suppression as potential neuromarkers for assessing proprioceptive ability. The identification of these features is significant as they could be used to quantify altered proprioceptive neural processing in skill and movement disorders. This in turn can be useful as an assay for pre and post sensory-motor intervention research.

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.

Pinch force sense test-retest reliability evaluation using contralateral force matching task

A high test-retest reliability in measurement of pinch force sense is required to assess a clinical parameter accurately over a longitudinal study. Ipsilateral reproduction (IR) task and contralateral matching (CM) task have commonly been used for the assessment of force sense. To date, there has been little research on the test-retest reliability of pinch force sense utilizing the contralateral force matching task. This research aimed to explore this phenomenon across a spectrum of reference force levels (10, 30, and 50 percent maximum voluntary isometric contraction (MVIC)) using a contralateral matching task. Every participant in the study was tested twice by the same skilled experts, with each session separated by one week. Although normalized variable error indicated a poor level of reliability (intraclass correlation coefficient (ICC) = - 0.25 to 0.05) for these force sense tests, normalized constant error (ICC = 0.76-0.85) and normalized absolute error (ICC = 0.61-0.81) results indicated a fair to good of reliability. The lower bound of 95% CI of ICC for NAE and NCE indicated fair test-retest reliability (0.41-0.69). These findings suggest that investigators can reasonably obtain a fair to good test-retest reliability when investigating pinch force sense using the contralateral matching task. The Bland-Altman plots, SEM, and MDD95% were lower at these lower reference force level (10% MVIC) compared to the level of higher reference forces (30% and 50% MVIC). Therefore, when the reference force level increases, the participant needs a larger NAE or NCE decrease to show that their pinch force sense has indeed improved.

Reliability and validity of the trunk position sense and modified functional reach tests in individuals after stroke

The psychometric qualities of the proprioception and dynamic trunk control tests have rarely been studied in individuals after stroke.

OBJECTIVE

To investigate the reliability and validity of the Trunk Position Sense Test (TPS) and Modified Functional Reach Test (MFRT) in persons after stroke.

METHODS

Thirty-two participants were included. The TPS and MFRT were assessed by two physiotherapists during a first session. After resting, a second session was conducted. The intraclass correlation coefficient (ICC) was calculated to assess the test-retest (ICC3,k) and inter-rater reliability (ICC2,k). Pearson correlations coefficients were calculated between TPS/MFRT performances and clinical tests (trunk strength, Timed Up and Go and Balance Assessment in Sitting and Standing Positions - BASSP).

RESULTS

The TPS inter-rater reliability was good for vertical error (ICC = 0.75 [0.50-0.88]) while it was moderate for horizontal error (ICC = 0.48 [0.10-0.75]) as well as for test-retest reliability (0.39 ≤ ICC ≤ 0.59). As for the MFRT, inter-rater (0.76 ≤ ICC ≤ 0.90) and test-retest reliability (0.71 ≤ ICC ≤ 0.91) were good to excellent for anterior, paretic et non-paretic displacements. Horizontal errors for the TPS (-0.26 ≤ r ≤ -0.36) and anterior MFRT (0.38 ≤ r ≤ 0.64) values correlated moderately with trunk strength.

CONCLUSION

The MFRT is a reliable test for persons after stroke with trunk control impairments. The TPS does not appear to be relevant for post-stroke individuals. This can be explained by the fact that its procedure is not easily applied for individuals after stroke - who may have significant motor and cognitive impairments.

The Evolution of Hand Proprioceptive and Motor Impairments in the Sub-Acute Phase After Stroke

BACKGROUND

Hand proprioception is essential for fine movements and therefore many activities of daily living. Although frequently impaired after stroke, it is unclear how hand proprioception evolves in the sub-acute phase and whether it follows a similar pattern of changes as motor impairments.

OBJECTIVE

This work investigates whether there is a corresponding pattern of changes over time in hand proprioception and motor function as comprehensively quantified by a combination of robotic, clinical, and neurophysiological assessments.

METHODS

Finger proprioception (position sense) and motor function (force, velocity, range of motion) were evaluated using robotic assessments at baseline (<3 months after stroke) and up to 4 weeks later (discharge). Clinical assessments (among others, Box & Block Test [BBT]) as well as Somatosensory/Motor Evoked Potentials (SSEP/MEP) were additionally performed.

RESULTS

Complete datasets from 45 participants post-stroke were obtained. For 42% of all study participants proprioception and motor function had a dissociated pattern of changes (only 1 function considerably improved). This dissociation was either due to the absence of a measurable impairment in 1 modality at baseline, or due to a severe lesion of central somatosensory or motor tracts (absent SSEP/MEP). Better baseline BBT correlated with proprioceptive gains, while proprioceptive impairment at baseline did not correlate with change in BBT.

CONCLUSIONS

Proprioception and motor function frequently followed a dissociated pattern of changes in sub-acute stroke. This highlights the importance of monitoring both functions, which could help to further personalize therapies.

Proprioceptive Acuity Influences Speech Motor Control in Healthy Adult Talkers

PURPOSE

Somatosensory feedback, including proprioception, is important for speech production. This study evaluates proprioceptive acuity of the tongue using a position-matching task and determining if proprioceptive acuity impacts speech motor control in healthy adult talkers.

METHOD

Twenty-five young adults with no history of speech, language, or hearing disorders had their tongue movements recorded with an electromagnetic articulograph while completing a position-matching task. Participants were also asked to repeat two sentences that differed in the somatosensory feedback obtained. One sentence provided both tactile and proprioceptive feedback, whereas the other primarily provided proprioceptive feedback.

RESULTS

Participants ranged in proprioceptive acuity as measured by the position-matching task. Talkers with smaller position-matching errors and, therefore, higher proprioceptive acuity had smaller movements and slower speeds for both sentences. Talkers with lower proprioceptive acuity had reduced speech movement stability for the sentence that primarily provides proprioceptive feedback.

CONCLUSION

Proprioceptive acuity of the tongue can be evaluated using a position-matching task, and acuity is associated with more efficient speech movements and greater speech movement stability, particularly when producing utterances that provide less tactile feedback.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24293740.

A Systematic Review of the Learning Dynamics of Proprioception Training: Specificity, Acquisition, Retention, and Transfer

OBJECTIVE

We aimed to identify key aspects of the learning dynamics of proprioception training including: 1) specificity to the training type, 2) acquisition of proprioceptive skills, 3) retention of learning effects, and 4) transfer to different proprioceptive skills.

METHODS

We performed a systematic literature search using the database (MEDLINE, EMBASE, Cochrane Library, and PEDro). The inclusion criteria required adult participants who underwent any training program that could enhance proprioceptive function, and at least 1 quantitative assessment of proprioception before and after the intervention. We analyzed within-group changes to quantify the effectiveness of an intervention.

RESULTS

In total, 106 studies with 343 participant-outcome groups were included. Proprioception-specific training resulted in large effect sizes with a mean improvement of 23.4 to 42.6%, nonspecific training resulted in medium effect sizes with 12.3 to 22% improvement, and no training resulted in small effect sizes with 5.0 to 8.9% improvement. Single-session training exhibited significant proprioceptive improvement immediately (10 studies). For training interventions with a midway evaluation (4 studies), trained groups improved by approximately 70% of their final value at the midway point. Proprioceptive improvements were largely maintained at a delayed follow-up of at least 1 week (12 studies). Finally, improvements in 1 assessment were significantly correlated with improvements in another assessment (10 studies).

CONCLUSIONS

Proprioceptive learning appears to exhibit several features similar to motor learning, including specificity to the training type, 2 time constant learning curves, good retention, and improvements that are correlated between different assessments, suggesting a possible, common mechanism for the transfer of training.

The contribution of muscle spindles to position sense measured with three different methods

The sense of limb position is important, because it is believed to contribute to our sense of self-awareness. Muscle spindles, including both primary and secondary endings of spindles, are thought to be the principal position sensors. Passive spindles possess a property called thixotropy which allows their sensitivity to be manipulated. Here, thixotropic patterns of position errors have been studied with three commonly used methods of measurement of position sense. The patterns of errors have been used as indicators of the influence exerted by muscle spindles on a measured value of position sense. In two-arm matching, the blindfolded participant indicates the location of one arm by placement of the other. In one-arm pointing, the participant points to the perceived position of their other, hidden arm. In repositioning, one of the blindfolded participant's arms is placed at a chosen angle and they are asked to remember its position and then, after a delay, reproduce the position. The three methods were studied over the full range of elbow angles between 5° (elbow extension) and 125° (elbow flexion). Different outcomes were achieved with each method; in two-arm matching, position errors were symmetrical about zero and thixotropic influences were large, while in one-arm pointing, errors were biased towards extension. In repositioning, thixotropic effects were small. We conclude that each of the methods of measuring position sense comprises different mixes of peripheral and central influences. This will have to be taken into consideration by the clinician diagnosing disturbances in position sense.

Acute effects of muscle vibration on elbow joint position sense in healthy young men: A randomized trial

BACKGROUND

The study aimed to investigate and compare the acute effects of 2 local vibration frequencies (63 Hz vs 42 Hz frequencies) applied to the biceps brachii muscles on the elbow joint position sense (JPS) in healthy young men.

METHODS

A 3-arm parallel-group design with randomization of participants was used. Forty-five healthy young men aged 19 to 30 years were randomly assigned to 3 groups: to receive 63 Hz (n = 15) in experimental group 1 (EG1) or 42 Hz (n = 15) in experimental group 2 (EG2) or sham vibration in the control group (n = 15). Participants in the EG1 and EG2 received 5 bouts of 1-minute vibration exposure to the biceps brachii muscle, with a 1-minute rest between the bouts. In control group, sham vibration was applied with the same duration and interval as in EG1 and EG2. The active elbow joint position error was selected as an outcome measure to assess elbow JPS. The target angle and the angle reproduced were measured using a Universal Goniometer. The difference between the target and the reproduced angles was calculated to determine active elbow joint position error. Measurements were made before the vibration application and right after it.

RESULTS

No statistically significant difference was observed in the JPS of the elbow joint over time in any group (P = .625). No statistically significant differences were observed between the 33 groups in the JPS of the elbow (P = .075).

CONCLUSION

There was no acute effect of vibration of the biceps brachii muscle at 63 and 42 Hz on active elbow JPS in healthy adults.

Grip force makes wrist joint position sense worse

Background

The purpose of this study was to investigate how grip force affects wrist joint position sense.

Methods

Twenty-two healthy participants (11 men and 11 women) underwent an ipsilateral wrist joint reposition test at 2 distinct grip forces [0 and 15% of maximal voluntary isometric contraction (MVIC)] and 6 different wrist positions (pronation 24°, supination 24°, radial deviation 16°, ulnar deviation 16°, extension 32°, and flexion 32°).

Results

The findings demonstrated significantly elevated absolute error values at 15% MVIC (3.8 ± 0.3°) than at 0% MVIC grip force [3.1 ± 0.2°, t(20) = 2.303, P = 0.032].

Conclusion

These findings demonstrated that there was significantly worse proprioceptive accuracy at 15% MVIC than at 0% MVIC grip force. These results may contribute to a better comprehension of the mechanisms underlying wrist joint injuries, the development of preventative measures to lower the risk of injuries, and the best possible design of engineering or rehabilitation devices.

Ageing and joint position sense of the asymptomatic shoulder: An observational study

PURPOSE

This study aimed to quantify the extent to which age was associated with joint position sense (JPS) of the asymptomatic shoulder as measured by joint position reproduction (JPR) tasks and assess the reproducibility of these tasks.

METHODS

120 Asymptomatic participants aged 18-70 years each performed 10 JPR-tasks. Both contralateral and ipsilateral JPR-tasks were evaluated on accuracy of JPR under active- and passive conditions at two levels within the shoulder forward flexion trajectory. Each task was performed three times. In a subgroup of 40 participants, the reproducibility of JPR-tasks was assessed one week after initial measurement. Reproducibility of JPR-tasks was evaluated by both reliability (intra-class correlation coefficients (ICC's)) and agreement (standard error of measurement (SEM)) measures.

RESULTS

Age was not associated with increased JPR-errors for any of the contralateral or ipsilateral JPR-tasks. ICC's ranged between 0.63 and 0.80 for contralateral JPR-tasks, and from 0.32 to 0.48 for ipsilateral tasks, except for one ipsilateral task where the reliability was similar to contralateral tasks (0.79). The SEM was comparable and small for all JPR-tasks, ranging between 1.1 and 2.1.

CONCLUSION

No age-related decline in JPS of the asymptomatic shoulder was found, and good agreement between test and re-test measurements for all JPR-tasks as indicated by the small SEM.

Somatosensory Information in Skilled Motor Performance: A Narrative Review

Historically, research aimed at improving motor performance has largely focused on the neural processes involved in motor execution due to their role in muscle activation. However, accompanying somatosensory and proprioceptive sensory information is also vitally involved in performing motor skills. Here we review research from interdisciplinary fields to provide a description for how somatosensation informs the successful performance of motor skills as well as emphasize the need for careful selection of study methods to isolate the neural processes involved in somatosensory perception. We also discuss upcoming strategies of intervention that have been used to improve performance via somatosensory targets. We believe that a greater appreciation for somatosensation's role in motor learning and control will enable researchers and practitioners to develop and apply methods for the enhancement of human performance that will benefit clinical, healthy, and elite populations alike.

Perception of Torque is Impacted by a Subset of Features Related to the Motor Command

Accurate perception of one's self-generated torques is integral to sensorimotor control. Here, we examined how features of the motor control task, specifically the variability, duration, muscle activation pattern, and magnitude of torque generation, relate to one's perception of torque. Nineteen participants generated and perceived 25% of their maximum voluntary torque (MVT) in elbow flexion while simultaneously abducting at their shoulder to 10%, 30%, or 50% of their MVT in shoulder abduction (MVT[Formula: see text]). Subsequently, participants matched the elbow torque without feedback and without activating their shoulder. The shoulder abduction magnitude affected the time to stabilize the elbow torque (p 0.001), but did not significantly impact the variability of generating the elbow torque (p = 0.120) or the co-contraction between the elbow flexor and extensor muscles (p = 0.265). The shoulder abduction magnitude influenced perception (p = 0.001) in that the error in matching the elbow torque increased with an increased shoulder abduction torque. However, the torque matching errors neither correlated with the time to stabilize and variability in generating the elbow torque, nor the co-contraction of the elbow muscles. These findings suggest that the total torque generated during a multi-joint task impacts the perception of a torque about a single joint; yet, effective and efficient generation of the torque about a single joint does not impact the torque percept.

The retention of proprioceptive information is suppressed by competing verbal and spatial task

Proprioceptive information makes us able to perceive the position of our joints from an internal point of view. In the certain cases, proprioceptive information has to be stored in short-term memory, for example, during the learning of new motor skills or the assessment of proprioceptive accuracy. However, there are contradictory findings about the modality-specific storage of proprioceptive information in working memory. In this preregistered study, we applied the interference paradigm, assessing proprioceptive memory capacity in the subdominant elbow joint for 35 young individuals in five different experimental conditions: (a) without competing task/interference (baseline condition), (b) with motor interference, (c) with spatial interference, (d) with visual interference, and (e) with verbal interference. Proprioceptive span was lower in the verbal and spatial interference condition than in the baseline condition, whereas no significant differences were found for the motor and visual conditions. These results indicate that individuals use verbal and spatial strategies to encode proprioceptive information in short-term memory, and, in contrast to our expectation, the motor subsystem of working memory is not substantially involved in this process.

μ-band desynchronization in the contralateral central and central-parietal areas predicts proprioceptive acuity

Introduction

Position sense, which belongs to the sensory stream called proprioception, is pivotal for proper movement execution. Its comprehensive understanding is needed to fill existing knowledge gaps in human physiology, motor control, neurorehabilitation, and prosthetics. Although numerous studies have focused on different aspects of proprioception in humans, what has not been fully investigated so far are the neural correlates of proprioceptive acuity at the joints.

Methods

Here, we implemented a robot-based position sense test to elucidate the correlation between patterns of neural activity and the degree of accuracy and precision exhibited by the subjects. Eighteen healthy participants performed the test, and their electroencephalographic (EEG) activity was analyzed in its μ band (8–12 Hz), as the frequency band related to voluntary movement and somatosensory stimulation.

Results

We observed a significant positive correlation between the matching error, representing proprioceptive acuity, and the strength of the activation in contralateral hand motor and sensorimotor areas (left central and central-parietal areas). In absence of visual feedback, these same regions of interest (ROIs) presented a higher activation level compared to the association and visual areas. Remarkably, central and central-parietal activation was still observed when visual feedback was added, although a consistent activation in association and visual areas came up.

Conclusion

Summing up, this study supports the existence of a specific link between the magnitude of activation of motor and sensorimotor areas related to upper limb proprioceptive processing and the proprioceptive acuity at the joints.

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.

The use of machine learning and deep learning techniques to assess proprioceptive impairments of the upper limb after stroke

BACKGROUND

Robots can generate rich kinematic datasets that have the potential to provide far more insight into impairments than standard clinical ordinal scales. Determining how to define the presence or absence of impairment in individuals using kinematic data, however, can be challenging. Machine learning techniques offer a potential solution to this problem. In the present manuscript we examine proprioception in stroke survivors using a robotic arm position matching task. Proprioception is impaired in 50-60% of stroke survivors and has been associated with poorer motor recovery and longer lengths of hospital stay. We present a simple cut-off score technique for individual kinematic parameters and an overall task score to determine impairment. We then compare the ability of different machine learning (ML) techniques and the above-mentioned task score to correctly classify individuals with or without stroke based on kinematic data.

METHODS

Participants performed an Arm Position Matching (APM) task in an exoskeleton robot. The task produced 12 kinematic parameters that quantify multiple attributes of position sense. We first quantified impairment in individual parameters and an overall task score by determining if participants with stroke fell outside of the 95% cut-off score of control (normative) values. Then, we applied five machine learning algorithms (i.e., Logistic Regression, Decision Tree, Random Forest, Random Forest with Hyperparameters Tuning, and Support Vector Machine), and a deep learning algorithm (i.e., Deep Neural Network) to classify individual participants as to whether or not they had a stroke based only on kinematic parameters using a tenfold cross-validation approach.

RESULTS

We recruited 429 participants with neuroimaging-confirmed stroke (< 35 days post-stroke) and 465 healthy controls. Depending on the APM parameter, we observed that 10.9-48.4% of stroke participants were impaired, while 44% were impaired based on their overall task score. The mean performance metrics of machine learning and deep learning models were: accuracy 82.4%, precision 85.6%, recall 76.5%, and F1 score 80.6%. All machine learning and deep learning models displayed similar classification accuracy; however, the Random Forest model had the highest numerical accuracy (83%). Our models showed higher sensitivity and specificity (AUC = 0.89) in classifying individual participants than the overall task score (AUC = 0.85) based on their performance in the APM task. We also found that variability was the most important feature in classifying performance in the APM task.

CONCLUSION

Our ML models displayed similar classification performance. ML models were able to integrate more kinematic information and relationships between variables into decision making and displayed better classification performance than the overall task score. ML may help to provide insight into individual kinematic features that have previously been overlooked with respect to clinical importance.

A Randomized, Double-Blind Placebo Control Study on the Effect of a Blood Flow Restriction by an Inflatable Cuff Worn around the Arm on the Wrist Joint Position Sense in Healthy Recreational Athletes

The number of blood flow restriction (BFR) training practitioners is rapidly increasing, so understanding the safety issues associated with limb occlusion is strongly needed. The present study determined the effect of BFR by an inflatable cuff worn around the arm on the wrist joint position sense (JPS) in healthy recreational athletes. In the prospective randomized, double-blind placebo control study, sixty healthy right-handed recreational athletes aged x = 22.93 ± 1.26 years were assigned to groups of equal size and gender rates: BFR, placebo, and control. The active wrist JPS was assessed in two separate sessions using an isokinetic dynamometer. The first assessment was performed with no cuffs. In the second session, a cuff with a standardized pressure was worn on the examined limb in the BFR group. In the placebo group, the cuff was uninflated. A between-session comparison in each group of collected angular errors expressed in degrees was carried out. The angular error in the BFR group was larger during the second measurement than the first one (p = 0.011-0.336). On the contrary, in the placebo (p = 0.241-0.948) and control (p = 0.093-0.904) groups, the error value in the second session was comparable or smaller. It was determined that BFR by an inflatable cuff around the arm impairs the wrist position sense. Hence, BFR training should be performed with caution.

Reliability of the active knee joint position sense test and influence of limb dominance and sex

The output of a sensorimotor performance can be measured with the joint position sense (JPS) test. However, investigations of leg dominance, sex and quality measures on this test are limited. Therefore, these potential influencing factors as well as reliability and consistency measures were evaluated for angular reproduction performance and neuromuscular activity during the active knee JPS test in healthy participants. Twenty healthy participants (10 males; 10 females; age 29 ± 8 years; height 165 ± 39 cm; body mass 69 ± 13 kg) performed a seated knee JPS test with a target angle of 50°. Measurements were conducted in two sessions separated by two weeks and consisted of two blocks of continuous angular reproduction (three minutes each block). The difference between reproduced and target angle was identified as angular error measured by an electrogoniometer. During reproduction, the neuromuscular activity of the quadriceps muscle was assessed by surface electromyography. Neuromuscular activity was normalized to submaximal voluntary contraction (subMVC) and displayed per muscle and movement phase. Differences between leg dominance and sex were calculated using Friedman-test (α = 0.05). Reliability measures including intraclass correlation coefficient (ICC), Bland-Altman analysis (bias ± limits of agreement (LoA)) and minimal detectable change (MDC) were analysed. No significant differences between leg dominance and sex were found in angular error and neuromuscular activity. Angular error demonstrated inter-session ICC scores of 0.424 with a bias of 2.4° (± 2.4° LoA) as well as MDC of 6.8° and moderate intra-session ICC (0.723) with a bias of 1.4° (± 1.65° LoA) as well as MDC of 4.7°. Neuromuscular activity for all muscles and movement phases illustrated inter-session ICC ranging from 0.432 to 0.809 with biases between - 2.5 and 13.6% subMVC and MDC from 13.4 to 63.9% subMVC. Intra-session ICC ranged from 0.705 to 0.987 with biases of - 7.7 to 2.4% subMVC and MDC of 2.7 to 46.5% subMVC. Leg dominance and sex seem not to influence angular reproduction performance and neuromuscular activity. Poor to excellent relative reliability paired with an acceptable consistency confirm findings of previous studies. Comparisons to pathological populations should be conducted with caution.

Assessment of grip force sense test-retest reliability in healthy male participants

There has been a lack of research to date regarding the test-retest reliability of grip force sense in healthy adult males. This study was therefore designed to explore this topic across a series of target force levels using an ipsilateral force reproduction task. The same experienced research staff conducted two testing sessions for each study participant, with 1 week between test sessions. Intraclass correlation coefficient values indicated that these force sensing tests exhibited good to fair reliability with respect to both absolute error (0.42-0.63) and constant error (0.49-0.60), although variable error was indicative of poor reliability (-0.85 to 0.14). Together, these results suggest that researchers can achieve a fair level of test-retest reliability when analysing grip force sense in healthy adult males, with results being most reliable at force levels of 20 N and 50 N, as determined based upon measured constant error and absolute error. Practitioner summary: To ensure that grip force sense can be accurately interpreted over time, it is important to assess the test-retest reliability. It is recommended that practitioners measure the absolute error and constant error at force levels of 20 N and 50 N when assessing grip force sense in a clinical setting.

Effect of Different Landing Heights and Loads on Ankle Inversion Proprioception during Landing in Individuals with and without Chronic Ankle Instability

Proprioception is essential for neuromuscular control in relation to sport injury and performance. The effect of landing heights and loads on ankle inversion proprioceptive performance in individuals with or without chronic ankle instability (CAI) may be important but are still unclear. Forty-three participants (21 CAI and 22 non-CAI) volunteered for this study. The Ankle Inversion Discrimination Apparatus for Landing (AIDAL), with one foot landing on a horizontal surface and the test foot landing on an angled surface (10°, 12°, 14°, 16°), was utilized to assess ankle proprioception during landing. All participants performed the task from a landing height of 10 cm and 20 cm with 100% and 110% body weight loading. The four testing conditions were randomized. A repeated measures ANOVA was used for data analysis. The result showed that individuals with CAI performed significantly worse across the four testing conditions (p = 0.018). In addition, an increased landing height (p = 0.010), not loading (p > 0.05), significantly impaired ankle inversion discrimination sensitivity. In conclusion, compared to non-CAI, individuals with CAI showed significantly worse ankle inversion proprioceptive performance during landing. An increased landing height, not loading, resulted in decreased ankle proprioceptive sensitivity. These findings suggest that landing from a higher platform may increase the uncertainty of judging ankle positions in space, which may increase the risk of ankle injury.

Human Perception of Wrist Flexion and Extension Torque During Upper and Lower Extremity Movement

Real-world application of haptic feedback from kinesthetic devices is implemented while the user is in motion, but human wrist torque magnitude discrimination has previously only been characterized while users are stationary. In this study, we measured wrist torque discrimination in conditions relevant to activities of daily living, using a previously developed backdrivable wrist exoskeleton capable of applying wrist flexion and extension torque. We implemented a torque comparison test using a two-alternative forced-choice paradigm while participants were both seated and walking on a treadmill, with both a stationary and a moving wrist. Like most kinesthetic haptic devices, the wrist exoskeleton output torque is commanded in an open-loop manner. Thus, the study design was informed by Monte Carlo simulations to verify that the errors in the wrist exoskeleton output torque would not significantly affect the results. Results from ten participants show that although both walking and moving wrist conditions result in higher Weber Fractions (worse perception), participants were able to detect relatively small changes in torque of 12-19% on average in all grouped conditions. The results provide insight regarding the torque magnitudes necessary to make wrist-worn kinesthetic haptic devices noticeable and meaningful to the user in various conditions relevant to activities of daily living.

Testing Precision and Accuracy of an Upper Extremity Proprioceptive Targeting Task Assessment

Objective

To develop and test an assessment measuring extended physiological proprioception (EPP). EPP is a learned skill that allows one to extend proprioception to an external tool, which is important for controlling prosthetic devices. The current study examines the ability of this assessment to measure EPP in a nonamputee population for translation into the affected population.

Design

Measuring precision and accuracy of an upper extremity (UE) proprioceptive targeting task assessment. Participants completed 2 sessions of a targeting task while seated at a table. The targeting was completed with the dominant and nondominant hand and with eyes open and eyes closed during the task. Participants completed 2 sessions of the clinical test with a 1-week washout period to simulate reasonable time between clinical visits.

Setting

Research laboratory.

Participants

Twenty right-handed participants (N=20) with no neurologic or orthopedic deficits that would interfere with proprioception, median age of 25 years (range, 19-33 years), completed the assessment (10 men, 10 women).

Interventions

Not applicable.

Main Outcome Measures

Precision (consistency in targeting) and accuracy (distance between the intended target and participant result) in UE targeting task using EPP; test-retest repeatability between sessions.

Results

Both precision and accuracy were significantly decreased in the eyes-closed condition compared with the eyes-open condition regardless of targeting with dominant or nondominant hand (all P<.001). In the eyes-open condition, there was a dominance effect relating to the accuracy; however, in the eyes-closed condition, accuracy between dominant and nondominant hands was statistically equivalent. Based on minimum detectable change with 95% confidence, there was no change in either metric between the first and second sessions.

Conclusions

The results of this study support the feasibility of using this assessment to measure EPP-based on the definition of EPP as a learned skill that indicates control over an external, simple tool-because they demonstrate reliance on proprioception in the eyes-closed condition, symmetry in proprioceptive accuracy between hands for within-participant control, and test-retest reliability for longitudinal measurements. The results also establish normative values for this assessment in young, healthy adults. Further research is required in a clinical population to evaluate the UE proprioceptive targeting task assessment further and collect objective data on EPP.

Transcranial direct current stimulation over the posterior parietal cortex improves visuomotor performance and proprioception in the lower extremities

The purpose of this study was to examine whether anodal transcranial direct current stimulation (a-tDCS) over the posterior parietal cortex (PPC) could affect visuomotor performance and proprioception in the lower extremities. We evaluated visuomotor performance in 15 healthy volunteers using a visuomotor control task by plantar dorsiflexion of the ankle joint, and calculated the absolute difference between the target and measured angle. In addition, we evaluated proprioception using a joint position matching task. During the task, the subject reproduced the ankle joint plantar dorsiflexion angle presented by the examiner. We calculated the absolute difference between the presented and measured angles (absolute error) and the variation of measured angles (variable error). Simultaneously, a-tDCS (1.5 mA, 15 min) or sham stimulation was applied to the right PPC. We observed that the absolute error of the visuomotor control task and the variable error of the joint position matching task significantly decreased after a-tDCS. However, the absolute error of the joint position matching task was not affected. This study suggests that a-tDCS over the PPC improves visuomotor performance and reduces the variable error in the joint position matching task.

Body representation underlies response of proprioceptive acuity to repetitive peripheral magnetic stimulation

Proprioceptive acuity is of great significance in basic research exploring a possible neural mechanism of fine motor control and in neurorehabilitation practice promoting motor function recovery of limb-disabled people. Moreover, body representation relies on the integration of multiple somatic sensations, including proprioception that is mainly generated in muscles and tendons of human joints. This study aimed to examine two hypotheses: First, different extension positions of wrist joint have different proprioceptive acuities, which might indicate different body representations of wrist joint in the brain. Second, repetitive peripheral magnetic stimulation (rPMS) applied peripherally to the forearm radial nerve and extensors could change proprioceptive acuity at the wrist joint. Thirty-five healthy participants were recruited then randomly divided into the real stimulation group (n = 15) and the sham stimulation group (n = 20). The participants’ non-dominant side wrist joint position sense was tested at six extension positions within the physiological joint motion range (i.e., 10°, 20°, 30°, 40°, 50°, 60°) both before stimulation and after stimulation. Results showed that proprioceptive bias (arithmetic difference of target position and replicated position) among six extension positions could be divided into lower-extension position (i.e., 10°, 20°, 30°) and higher-extension position (i.e., 40°, 50°, 60°). One session rPMS could influence proprioceptive bias in lower-extension position but not in higher-extension position. However, proprioceptive precision (standard deviation within lower-extension position and higher-extension position) was not influenced. To conclude, proprioceptive bias may vary between different wrist extension positions due to different hand postures being related to changes in body representation, and different functions relating to proprioceptive bias and proprioceptive precision may underlie two aspects of body representation.

Assessing proprioceptive acuity in people with multiple sclerosis

Background

Proprioceptive acuity and impairments in proprioceptively guided reaches have not been comprehensively examined in people with multiple sclerosis (MS).

Objective

To examine proprioceptive acuity in people with MS who self-report and who do not self-report upper limb (UL) impairment, and to determine how people with MS reach proprioceptive targets.

Methods

Twenty-four participants with MS were recruited into two groups based on self-reported UL impairment: MS-R (i.e. report UL impairment; n  =  12) vs. MS-NR (i.e. do not report UL impairment; n  =  12). Proprioception was assessed using ipsilateral and contralateral robotic proprioceptive matching tasks.

Results

Participants in the MS-R group demonstrated worse proprioceptive acuity compared to the MS-NR group on the ipsilateral and contralateral robotic matching tasks. Analyses of reaches to proprioceptive targets further revealed that participants in the MS-R group exhibited deficits in movement planning, as demonstrated by greater errors at peak velocity in the contralateral matching task in comparison to the MS-NR group.

Conclusion

Our findings suggest that people with MS who self-report UL impairment demonstrate worse proprioceptive acuity, as well as poorer movement planning in comparison to people with MS who do not report UL impairment.