Local subcutaneous and muscle pain impairs detection of passive movements at the human thumb

The relationship between sustained hamstring pain and reorganisation of somatosensory representations: a randomised, controlled study

ABSTRACT

Recurrent hamstring injuries are highly prevalent amongst sporting populations. It has been hypothesised that pain from an initial hamstring injury may induce reorganisation of somatosensory representations that could contribute to reinjury. However, because of the cross-sectional nature of existing research, it remains unknown whether somatosensory changes are a cause or effect of pain or if they are driven by other potentially confounding factors. Here, we explored the effect of experimentally induced sustained hamstring pain on tasks that interrogate somatosensory and spatial representations. Fifty healthy participants were randomly allocated to an experimental group that performed an eccentric exercise protocol on the right hamstring to induce delayed onset muscle soreness or a control group performing a repetition-matched concentric exercise protocol. The tactile cortical representation was assessed using two-point discrimination and tactile localisation, whereas the proprioceptive representation was assessed using a left-right judgement task. Peripersonal spatial representations were assessed using an auditory localisation task. Assessments were performed at baseline and day 2. No between-group differences in tactile acuity were observed. However, improvements in left-right judgments and worsening of auditory localisation occurred in the experimental group compared with the control group. This study provides preliminary evidence showing that somatosensory changes occur in response to sustained hamstring pain. Experimentally induced, sustained hamstring pain elicited enhancements in proprioceptive processing and deficits in peripersonal spatial processing, suggesting a shift in the allocation of attentional resources from the external (peripersonal) to internal (body) environment. These findings may hold important implications for reinjury risk and rehabilitation following hamstring pain.

Development and validation of the Exteroceptive Body Awareness (EBA-q) questionnaire

The conscious processing of body signals influences higher-order psychological and cognitive functions, including self-awareness. Dysfunctions in the processing of these signals has been connected to neurological and psychiatric disorders characterized by altered states of self-consciousness. Studies indicate that perceiving the body through interoceptive signals (e.g., from internal organs such as heartbeat and breathing) is distinct from perceiving the body through exteroceptive signals (e.g., by relying on visual, tactile and olfactory cues). While questionnaires are available for assessing interoception, there are no validated self-report instruments for measuring bodily exterception. To fill this gap, we performed three studies to develop and validate a novel scale designed to assess bodily self-consciousness based on the processing of exteroceptive bodily signals. Exploratory factor analysis (Study 1, N = 302) led to an 18-item questionnaire comprised of four factors. We called this instrument Exteroceptive Body Awareness questionnaire (EBA-q). Confirmatory factor analysis (Study 2, N = 184) run on a second sample showed an acceptable fit for a bifactor model, suggesting researchers may use the questionnaire as a unidimensional scale reflecting exteroceptive bodily self-consciousness, or use each of its four sub-scales, reflecting "visuo-tactile body awareness", "spatial coordination", "awareness of body changes" and "awareness of clothing fit". Overall EBA-q showed good internal consistency. Convergent and divergent validity were assessed via cross-validation with existing body awareness questionnaires (Study 3, N = 366) and behavioral measures (Study 3, N = 64) of exteroceptive and interoceptive bodily self-consciousness. Research applications are discussed within a multi-faceted model of exteroception and interoception as distinct, but at the same time interconnected, dimensions of bodily self-consciousness.

Recovery of pinch force sense after short-term fatigue

The aim of this study was to identify the exact origin of force sense and identify whether it arises centrally or peripherally. The present study was designed to analyze the effects of short-term fatigue on pinch force sense and the duration of these effects. During the fatigue protocol, twenty (10 men and 10 women; Mage = 22.0 years old) young Chinese participants were asked to squeeze maximally until the pinch grip force decreased to 50% of its maximal due to fatigue. Participants were instructed to produce the target force (10% of maximal voluntary isometric contraction) using the same hand before and after fatigue (immediately, 10, 30, 60, 180, 300 s). The results showed significantly higher absolute error immediately after fatigue (1.22 ± 1.06 N) than before fatigue (0.68 ± 0.34 N), and 60 s (0.76 ± 0.69 N), 180 s (0.67 ± 0.42 N), and 300 s (0.75 ± 0.37 N) after fatigue (all P < 0.05) but with no effect on the variable error (P > 0.05). It was also revealed that there was a significant overestimate of the constant error values before (0.32 ± 0.61 N) and immediately after fatigue (0.80 ± 1.38 N, all P < 0.05), while no significant overestimation or underestimation exceeded 300 s after fatigue (P > 0.05). Our study results revealed that short-term fatigue resulted in a significant decrease in force sense accuracy, but it did not affect force sense consistently; however, force sense accuracy recovered to a certain extent within 10 s and 30 s, whereas it recovered fully within 60 s, and force sense directivity improvement exceeded 300 s after fatigue. The present study shows that the sense of tension (peripherally) is also an important factor affecting force sense. Our study supports the view that the periphery is part of the origin of force sense.

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.

Proprioceptive Neuromuscular Facilitation Protocol for Thumb Osteoarthritis: A Pilot Study

BACKGROUND

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint often presents with joint instability and proprioceptive deficits. Proprioception has been found to play an important role in the rehabilitative process. The purpose of this study was to evaluate the effectiveness of a proprioceptive training program on pain and function in individuals with early-stage thumb Carpometacarpal joint OA.

METHODS

A double-blind experimental trial using a 2-group pretest/posttest design was used in this pilot study. Participants had a diagnosis of grade I and II thumb CMC joint OA in their dominant hand and a pain rating of >4/10 on Visual Analogue Scale. Participants received either standard treatment (control group) or standard treatment plus a proprioceptive training program (experimental group). Outcome measures were lateral pinch strength, pain intensity during activities, and proprioceptive response via joint position sense (JPS) testing.

RESULTS

Twelve individuals (average age of 66.25 years) participated. Both groups had a statistically significant decrease in pain and increase in lateral pinch strength, all occurring with a large effect size but no statistically significant difference between groups. The experimental group experienced a large effect size for JPS testing, whereas the control group experienced a trivial effect size, and there was a statistically significant difference between groups for JPS testing.

CONCLUSIONS

Individuals who completed the proprioceptive training program in this study had an improvement in proprioceptive functioning. This program shows potential for routine inclusion in hand therapy for thumb CMC joint OA; however, additional high-level studies with larger sample sizes are required.

Assessing proprioception through time-variability properties of acceleration

Proprioception is a crucial property for movement stability and balance, but its current assessment, based on clinical testing, lacks precision and adequacy in real contexts. This study proposes assessing proprioception and its sensitivity to training effects through acceleration time series recorded during two slackline experiments. In the first experiment, slackliners of different expertise (highly and poorly trained) had to walk on a slackline for 30 s. In the second, twelve beginners had to balance up on the slackline for at least 11 s before and after a training process. Acceleration time series were recorded in body components (legs and centre of mass) and the slackline. The acceleration fluctuations were analysed through Detrended Fluctuation Analysis. The obtained Hurst (H)-exponents were compared between both groups (first experiment) and before and after training (second experiment) using Whitney and Wilcoxon tests, respectively. The values of H-exponents were lower in the highly trained group (Z = -2.15, p = 0.03) (first experiment), and in the post-training conditions (Z = -2.35, p = 0.02) (second experiment). These results suggest better motor and proprioceptive control with training status. Hence, the time-variability structure of acceleration in real contexts, like slackline tasks, is proposed as an objective measure of proprioception and its training effects.

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.

Impaired ankle inversion proprioception during walking is associated with fear of falling in older adults

Background

Ankle proprioception plays a critical role in lower limb movement control. However, the relationship between ankle proprioception and fear of falling (FOF) in older people is still unclear.

Objective

(1) This study aims to develop a new device for measuring ankle inversion proprioceptive discrimination sensitivity during walking, i.e., the Ankle Inversion Discrimination Apparatus–Walking (AIDAW), and assess the test–retest reliability of the AIDAW in both young and older adults; (2) to evaluate the discriminant validity of the measure by comparing ankle proprioception during walking between the two groups; and (3) to explore convergent validity by determining to what extent the AIDAW proprioceptive scores correlate with Fall Efficacy Scale-International (FES-I) scores.

Materials and methods

The AIDAW was purpose-built to test ankle inversion proprioceptive discrimination sensitivity during walking. The area under the receiver operating curve (AUC) was calculated as the proprioceptive discrimination score. In total, 54 adults volunteered. Test–retest reliability was evaluated in 12 young and 12 older adults, and another 15 young and 15 older adults completed the comparison study. FOF was assessed by using the FES-I.

Results

The test–retest reliability intraclass correlation coefficient ICC _(3,1) value for the whole group was 0.76 (95% CI: 0.52–0.89). The ICC values of the young and older groups were 0.81 (95% CI: 0.46–0.94) and 0.71 (95% CI: 0.26–0.91), respectively. The Minimal Detectable Change with 90% confidence (MDC₉₀) values for the young and older groups were 0.03 and 0.11, respectively. There was a significant difference between the AIDAW proprioceptive sensitivity scores for the young and older groups (0.78 ± 0.04 vs. 0.72 ± 0.08, F = 5.06, p = 0.033). Spearman’s correlation analysis showed that the FES-I scores were significantly and negatively correlated with the AIDAW scores (rho = −0.61, p = 0.015), with higher FOF associated with worse ankle proprioception.

Conclusion

The AIDAW is a reliable and valid device for measuring ankle proprioception during walking in both young and older adults. Ankle inversion proprioceptive discrimination sensitivity during walking was found to be impaired in the elderly compared to young adults. This impairment was found to be strongly associated with FOF, suggesting that assessment and intervention for ankle proprioception in this population are needed to reduce the risk of falls.

Correlation analysis of national elite Chinese male table tennis players’ shoulder proprioception and muscle strength

BACKGROUND

Shoulder is the most injured part in table tennis players, and it takes multiple roles in transmitting power and striking the center of the ball during the stroke. Proprioception is strongly correlated with high level of athletic performance. It is customary to assume that there is a correlation between proprioception and muscle strength and therefore proprioceptive assessment and rehabilitation is often neglected.

AIM

To investigate the correlation between isokinetic muscle strength and proprioception in the internal and external rotation muscle groups of elite Chinese male table tennis players, to provide reference for physical training and rehabilitation of elite table tennis players.

METHODS

A total of 19 national elite table tennis players from the Chinese National Table Tennis Team were recruited in this research. All of them had more than 10 years training experience and had participated major competitions such as the National Games and World Youth Championships. IsoMed 2000 was used to test the peak torque of internal and external rotation isokinetic concentric contraction of the athletes' bilateral shoulder joints at low speed (60°/s) and high speed (180°/s) respectively; IsoMed 2000 was used to conduct the Joint Position Reproduction test to evaluate the athletes' proprioceptive ability capacity at low speed (60°/s) and high speed (180°/s) respectively. If the data satisfied the normal distribution, the correlation between the differences in peak torque s and angles in different directions was analyzed using a Pearson simple linear model; otherwise, Spearman correlation analysis was used. The comparison of proprioceptive ability between the table tennis racket-holding hand and non-racket-holding hands was performed using independent samples t-test if the data satisfied a normal distribution; otherwise, the Mann-Whitney U test was used.

RESULTS

There was no direct linear correlation between the strength and proprioceptive correlation analysis at slow speed (60°/s) and fast speed (180°/s) in the racket-holding hand; At the slow speed (60°/s) and fast speed (180°/s), there was no correlation between muscle strength and proprioception in the non-racket-holding hand except for the internal rotation variable error (VE) and external rotation relative peak torque, which showed a moderate positive correlation (r = 0.477, P < 0.05), (r = 0.554, P < 0.05). The internal rotation’s constant error (CE) and VE were 1.06 ± 3.99 and 2.94 ± 2.16, respectively, for the racket-holding hand, and -3.36 ± 2.39 and 1.22 ± 0.93, respectively, for the non-racket-holding hand; the internal rotation’s CE, VE of the racket-holding hand was lower than that of the non-racket-holding hand, and there was a highly significant difference (P < 0.01).

CONCLUSION

There was no correlation between muscle strength and proprioceptive function in the internal and external rotation of the racket-holding hand’s shoulder in elite Chinese male table tennis players. These results may be useful for interventions for shoulder injuries and for the inclusion of proprioceptive training in rehabilitation programs.

Evidence of distorted proprioception and postural control in studies of experimentally induced pain: a critical review of the literature

OBJECTIVES

Deficits in proprioception and postural control are common in patients with different musculoskeletal pain syndromes. It has been proposed that pain can negatively affect proprioception and postural control at a peripheral level, however research is limited to animal studies. Human studies have shown that it is more likely, that the link between pain and proprioceptive deficits, lies within changes in the central nervous system where noxious and non-noxious stimuli may overlap. In clinical studies, causality cannot be determined due to other factors which could confound the assessment such as pathophysiological features of the underlying musculoskeletal disorder and different psycho-social influences especially in patients with chronic pain. On the other hand, experimentally induced pain in healthy participants is able to control most of these confounding factors and perhaps offers an assessment of the effects of pain on proprioception and postural control. The aim of this paper is to critically appraise the literature related to the effect of experimentally induced pain on proprioception and postural control. Results from these studies are discussed and limitations are highlighted for future research.

METHODS

A search of databases (Medline, Scopus, PubMed) was conducted as well as reference check from relevant articles published since 2000. Fifteen studies which explored the effect of experimentally induced pain on postural control and ten studies which explored the effect of experimentally induced pain on proprioception were included.

RESULTS

We found that in the majority of the studies, postural control was negatively affected by experimentally induced pain. Results for proprioception were mixed depending on the body region and the way the painful stimuli were delivered. Kinesthesia was negatively affected in two studies, while in one study kinesthesia was enhanced. Joint position sense was not affected in four out of five studies. Finally, force sense was affected in three out of four studies.

CONCLUSIONS

From a clinical point of view, findings from the available literature suggest that experimentally induced pain impairs postural control and could potentially increases the risk for falls in patients. Interventions aiming to reduce pain in these patients could lead to preservation or improvement of their balance. On the other hand, the same conclusion cannot be drawn for the effect of experimentally induced pain on kinesthesia and joint position sense due to the limited number of studies showing such an effect.

Alteration of Ligamento-Muscular Reflex Patterns After Cutaneous and Periarticular Desensitization of the Basal Thumb Joint: An Electromyographic Study

PURPOSE

Stimulation of the dorsoradial ligament (DRL) of the first carpometacarpal joint (CMC-1) has shown a ligamento-muscular reflex pathway between the DRL and CMC-1 stabilizing muscles in healthy volunteers. However, it remains unclear how this ligamento-muscular reflex pattern is altered after anesthetizing sensory skin receptors and administering a further periarticular block around the CMC-1 joint, which may influence the dynamic aspects of joint stability.

METHODS

Ligamento-muscular reflexes were obtained from the extensor pollicis longus, abductor pollicis longus, abductor pollicis brevis, and the first dorsal interosseous muscles in 10 healthy participants after establishing superficial anesthesia of the skin around the CMC-1. The DRL was stimulated with a fine wire electrode while EMG activities were recorded during isometric tip, key, and palmar pinch. The measurements were repeated after an additional periarticular CMC-1 block using 5 ml of 1% lidocaine. Average EMG values were analyzed to compare the prestimulus and poststimulus activity.

RESULTS

Statistically significant changes in poststimulus EMG activity were observed in all 4 muscles and all 3 tested thumb positions. A markedly reduced activity in all 4 muscles was observed in the palmar position, followed by the tip and key pinch positions. Almost no reactions were observed in the first 20 ms poststimulus for all muscles in all positions.

CONCLUSIONS

Superficial skin anesthesia and an additional periarticular CMC-1 block anesthesia resulted in a reduced ligamento-muscular reflex pattern in all 4 muscles.

CLINICAL RELEVANCE

Ligamento-muscular reflexes play an important role in dynamic CMC-1 joint stability. The elimination of early reactions, those considered joint-protective reflexes, is a potential risk factor for developing osteoarthritis or injury because it results in an inability to adequately protect and stabilize the joint in sudden movements.

Joint position sense impairments in older adults with carpometacarpal osteoarthritis: A descriptive comparative study

STUDY DESIGN

This study has a descriptive-comparative, cross-sectional design.

INTRODUCTION

Sensorimotor (SM) impairments have been observed after common wrist and hand injuries such as distal radius fractures. However, there is a lack of research regarding SM impairments in patients with carpometacarpal (CMC) osteoarthritis (OA).

PURPOSE OF THE STUDY

This study sought to quantify proprioception deficits in older adults with CMC OA as compared with healthy adults using the joint position sense (JPS) test.

METHODS

The active JPS test was used to measure proprioception function in 29 thumbs with CMC OA and their 29 matched-control healthy counterparts. For comparison, participants with unilateral CMC OA were matched against themselves, whereas those with lateral CMC OA were age matched with a healthy participant. Data analysis was performed to compute the mean error of JPS; an unpaired t test was used to compare the mean error of the non-CMC OA group with the healthy control group.

RESULTS

The mean positional error measured from subjects with CMC OA was 9.53° compared with 1.32° for the age-matched healthy subjects. The effect size for the difference in means was D = 1.96.

CONCLUSIONS

Thumb SM impairments were found to be greater in subjects with CMC OA than in their healthy counterparts when using the JPS test to assess proprioception.

The effects of hemiplegic shoulder pain on upper extremity motor function and proprioception

BACKGROUND

Hemiplegic shoulder pain (HSP) after stroke has negative effects on functional use of hemiplegic arm.

OBJECTIVE

This study aimed to investigate the effects of HSP on upper extremity motor function and proprioception.

METHODS

Hundred and twenty-two patients with hemiplegia were included in this study. The patients' shoulder pain was evaluated by Visual Analog Scale. According to pain scores, patients were divided into two groups as group with HSP (Group 1, n = 76) and group without HSP (Group 2, n = 46). Upper extremity motor function level and proprioception were assessed by using Fugl Meyer Motor Function Scale and the Laser-pointer Assisted Angle Reproduction Test for the 45°, 60° and 90° of shoulder flexion.

RESULTS

Upper extremity motor function and shoulder's proprioceptive sense at each angles of group 1 were found significantly worse than group 2's (p≤0.005). Correlation analysis revealed a significant positive correlation between HSP severity, and upper extremity motor dysfunction and proprioceptive impairment (p < 0.005).

CONCLUSIONS

Presence of HSP is one of the main determinators of upper extremity motor function level and proprioceptive ability at different angles. Management of HSP can make a significant contribution to sensorimotor integration by leading to recovery in the motor function and proprioceptive acuity.

Impact of Experimental Tonic Pain on Corrective Motor Responses to Mechanical Perturbations

Movement is altered by pain, but the underlying mechanisms remain unclear. Assessing corrective muscle responses following mechanical perturbations can help clarify these underlying mechanisms, as these responses involve spinal (short-latency response, 20-50 ms), transcortical (long-latency response, 50-100 ms), and cortical (early voluntary response, 100-150 ms) mechanisms. Pairing mechanical (proprioceptive) perturbations with different conditions of visual feedback can also offer insight into how pain impacts on sensorimotor integration. The general aim of this study was to examine the impact of experimental tonic pain on corrective muscle responses evoked by mechanical and/or visual perturbations in healthy adults. Two sessions (Pain (induced with capsaicin) and No pain) were performed using a robotic exoskeleton combined with a 2D virtual environment. Participants were instructed to maintain their index in a target despite the application of perturbations under four conditions of sensory feedback: (1) proprioceptive only, (2) visuoproprioceptive congruent, (3) visuoproprioceptive incongruent, and (4) visual only. Perturbations were induced in either flexion or extension, with an amplitude of 2 or 3 Nm. Surface electromyography was recorded from Biceps and Triceps muscles. Results demonstrated no significant effect of the type of sensory feedback on corrective muscle responses, no matter whether pain was present or not. When looking at the effect of pain on corrective responses across muscles, a significant interaction was found, but for the early voluntary responses only. These results suggest that the effect of cutaneous tonic pain on motor control arises mainly at the cortical (rather than spinal) level and that proprioception dominates vision for responses to perturbations, even in the presence of pain. The observation of a muscle-specific modulation using a cutaneous pain model highlights the fact that the impacts of pain on the motor system are not only driven by the need to unload structures from which the nociceptive signal is arising.

Proprioceptive accuracy in Immersive Virtual Reality: A developmental perspective

Proprioceptive development relies on a variety of sensory inputs, among which vision is hugely dominant. Focusing on the developmental trajectory underpinning the integration of vision and proprioception, the present research explores how this integration is involved in interactions with Immersive Virtual Reality (IVR) by examining how proprioceptive accuracy is affected by Age, Perception, and Environment. Individuals from 4 to 43 years old completed a self-turning task which asked them to manually return to a previous location with different sensory modalities available in both IVR and reality. Results were interpreted from an exploratory perspective using Bayesian model comparison analysis, which allows the phenomena to be described using probabilistic statements rather than simplified reject/not-reject decisions. The most plausible model showed that 4-8-year-old children can generally be expected to make more proprioceptive errors than older children and adults. Across age groups, proprioceptive accuracy is higher when vision is available, and is disrupted in the visual environment provided by the IVR headset. We can conclude that proprioceptive accuracy mostly develops during the first eight years of life and that it relies largely on vision. Moreover, our findings indicate that this proprioceptive accuracy can be disrupted by the use of an IVR headset.

Effect of Adding Proprioceptive Exercise to Balance Training in Older Adults with Diabetes: A Systematic Review

INTRODUCTION

Accidental fall is a serious problem in older adults. The incidence of accidental fall increases by any dysfunction in the proprioceptive system. The function of the proprioceptive system usually is much affected in people with Diabetes Mellitus (DM), particularly in older ages. However, proprioceptive exercise significantly improves the balance control in older adults, no systematic review demonstrated its effectiveness in improving the balance control in older adults with DM. Thus, this systematic review was conducted to examine the effectiveness of adding proprioceptive exercise to any balance training in older adults with DM.

METHODS

A systematic search was performed in five major databases. The inclusion criteria of this search included older adults with DM, peripheral neuropathy, randomized control trial, and proprioceptive dysfunction. The exclusion criterion of this search included any study where participants had a history of a disease that might affect the balance control such as ataxia, stroke, and Parkinsonism. The outcome of interest was the importance of including proprioceptive exercise in increasing the effectiveness of balance training in older adults with DM.

RESULTS

Nine RCTs met the inclusion criteria for this systematic review. Seven studies of these nine studies included randomization details. Only two studies included the blindness, and only one of them included double blindness. The description of the withdrawal of participants was shown in eight studies. All the included studies used a control group and accomplished the homogeny between subjects in the both groups.

CONCLUSION

This systematic review showed that proprioceptive exercise is a vital component that should be included in any balance training to gain short-term improvement in the balance control in older adults with DM.

Ankle proprioception during gait in individuals with incomplete spinal cord injury

INTRODUCTION

Proprioception is known to be affected after a spinal cord injury (SCI). However, it is currently assessed during simple tasks that do not reflect activities of daily living. To better understand how proprioception affects movement, assessing it during a functional sensorimotor task such as walking is therefore of primary importance. Therefore, the objectives of this study were as follows: (a) measure the protocol reliability of a new robotic test in nondisabled controls; (b) evaluate the effect nonlesion-related factors such as sex, age, pain, and gait speed on ankle proprioception; and (c) assess ankle proprioception during walking in individuals with SCI.

METHODS

In the current study, ankle proprioception was assessed during gait in individuals with an incomplete spinal cord injury (iSCI; n = 15) using an electrohydraulic robotized ankle-foot orthosis (rAFO). Ankle proprioceptive threshold was quantified as the participants' ability to detect torque perturbations of varied amplitude applied during swing by the rAFO. In addition, test-retest reliability and the potential effect of nonlesion-related factors (sex, age, pain, and gait speed) were evaluated in nondisabled (ND; n = 65) participants.

RESULTS

During gait, individuals with iSCI had a 53% poorer proprioceptive threshold than ND controls (p < .05). Test-retest reliability was good (ICC = 0.78), and only gait speed affected proprioceptive threshold (p = .018).

CONCLUSION

This study is the first to show that ankle proprioception assessed during gait is impaired in individuals with an iSCI. The developed test can now be used to better characterize proprioception in population with other neurological conditions and has potential to maximize functional recovery during gait training in those populations.

Foam Rolling and Muscle and Joint Proprioception After Exercise-Induced Muscle Damage

CONTEXT

Foam rolling (FR) is considered an effective postexercise modality for reducing delayed-onset muscle soreness and enhancing recovery of muscle function. However, the effects of FR on muscle and joint proprioception have not been investigated.

OBJECTIVE

To examine the effects of FR on muscle and joint proprioception after an intense exercise protocol.

DESIGN

Controlled laboratory study.

SETTING

University-based laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 80 healthy, physically active male students were randomly assigned to either the FR (n = 40; age = 22.8 ± 3.3 years, height = 176.4 ± 5.3 cm, mass = 74.2 ± 6.4 kg) or passive-recovery (PR; n = 40; age = 23.0 ± 3.2 years, height = 178.1 ± 5.5 cm, mass = 74.6 ± 6.2 kg) group.

INTERVENTION(S)

Participants in both groups performed 4 sets of 25 repetitions of voluntary maximal eccentric contractions at 60°/s from 20° to 100° of knee flexion to induce exercise-induced muscle damage. The exercise was followed by either PR or 2 minutes of FR immediately (1 hour) and 24, 48, and 72 hours postexercise.

MAIN OUTCOME MEASURE(S)

Muscle soreness, pressure-pain threshold, quadriceps-muscle strength, joint position sense, isometric force sense, and threshold to detect passive movement at baseline and immediately, 24, 48, and 72 hours postexercise after FR.

RESULTS

Foam rolling resulted in decreased muscle pain, increased pressure-pain threshold, improved joint position sense, attenuated force loss, and reduced threshold to detect passive movement compared with PR at 24 and 48 hours postexercise.

CONCLUSIONS

Foam rolling postexercise diminished delayed-onset muscle soreness and improved recovery of muscle strength and joint proprioception. These results suggested that FR enhanced recovery from exercise-induced damage.

Effect of sustained experimental muscle pain on joint position sense

Introduction:

Joint position sense (JPS) is impaired in clinical musculoskeletal pain conditions, but when this impairment develops in the transition from initial to prolonged pain is not known.

Objectives:

This study assessed whether progressively developing sustained experimentally induced muscle pain impacts JPS in healthy individuals.

Methods:

Twenty-eight healthy individuals received injection of nerve growth factor (NGF) into the right extensor carpi radialis brevis muscle on days 0 and 2 to induce sustained pain and hyperalgesia. Wrist JPS was assessed 2 days before day 0 (day −2), before the injection on days 0 and 2, and on days 4 and 14. Joint position sense was quantified as the ability to return the wrist to a neutral position following movements in the direction of radial and ulnar deviation. A 3-dimensional motion analysis system was used to calculate absolute, relative, and joint-angle repositioning errors. Numerical rating scale scores of pain intensity, body chart pain drawings, and pressure pain thresholds (PPTs) were recorded on each day.

Results:

Compared with baseline, pressure pain thresholds decreased while pain intensity and area increased at day 2 (P < 0.001) and day 4 (P < 0.001) before returning to baseline on day 14 (P > 0.13). Relative to day 0, there was no change in wrist JPS at day 2, 4, and 14 following movements in either target direction (P > 0.05).

Conclusion:

Despite the presence of sustained muscle pain and hyperalgesia for 4 days at the elbow, no statistical change in wrist joint position error was observed. These findings suggest that pain and hyperalgesia lasting as long as 4 days does not impair JPS.

Effect of fatigue and the absence of visual feedback on shoulder motor control in an healthy population during a reaching task

INTRODUCTION

The main role of the upper limb is to position the hand in order to carry out varied activities requiring coordinated multi-joint movement, which requires mobility and stability at the glenohumeral joint. This is made possible by the interaction between active and passive structures as well as the integration of information coming from multiple systems. This interaction can be compromised by factors such as muscle fatigue and lack of visual feedback, leading to decreased performance. Several studies have investigated their isolated effect without looking at their combined effect.

OBJECTIVE

To measure the specific and the combined effects of shoulder muscles fatigue and of lack of visual feedback on shoulder motor control during a reaching task with the arm in an elevated position.

METHODS

60 healthy participants were randomly assigned to one of four experimental groups: 1) control with visual feedback; 2) control without visual feedback; 3) fatigue with visual feedback; 4) fatigue without visual feedback. Subjects had to perform 10 trials of a reaching task in the KINARM robotic arm. Kinematic variables of interest were time taken to complete the task, final error, initial angle of deviation and area under curve. Non-parametric ANOVAs were used.

RESULTS

Analyses showed that there were statistically significant differences (p < 0,01) for the time taken to complete the task (1.15 s compared to 0.70 s), the area under the curve (0.015m² compared to 0.009m²) and the final error (0.025 m compared to 0,011 m) between those who had visual feedback and those who did not. No statistically significant fatigue or feedback X fatigue interaction effects were found for all kinematic variables.

CONCLUSION

Findings show that lack of visual feedback had an impact on the reaching task performance while fatigue did not. In addition, fatigue did not increase the effect of the lack of visual feedback.

Effect of experimental muscle pain on the acquisition and retention of locomotor adaptation: different motor strategies for a similar performance

As individuals with musculoskeletal disorders often experience motor impairments, contemporary rehabilitation relies heavily on the use of motor learning principles. However, motor impairments are often associated with pain. Although there is substantial evidence that muscle pain interferes with motor control, much less is known on its impact on motor learning. The objective of the present study was to assess the effects of muscle pain on locomotor learning. Two groups (Pain and Control) of healthy participants performed a locomotor adaptation task (robotized ankle-foot orthosis perturbing ankle movements during swing) on two consecutive days. On day 1 (acquisition), hypertonic saline was injected in the tibialis anterior (TA) muscle of the Pain group participants, while Control group participants were pain free. All participants were pain free on day 2 (retention). Changes in movement errors caused by the perturbation were assessed as an indicator of motor performance. Detailed analysis of kinematic and electromyographic data provided information about motor strategies. No between-group differences were observed on motor performance measured during the acquisition and retention phases. However, Pain group participants had a residual movement error later in the swing phase and smaller early TA activation than Control group participants, thereby suggesting a reduction in the use of anticipatory motor strategies to overcome the perturbation. Muscle pain did not interfere with global motor performance during locomotor adaptation. The different motor strategies used in the presence of muscle pain may reflect a diminished ability to anticipate the consequences of a perturbation. NEW & NOTEWORTHY This study shows that experimental muscle pain does not influence global motor performance during the acquisition or next-day retention phases of locomotor learning. This contrasts with previous results obtained with cutaneous pain, emphasizing the risk of directly extrapolating from one pain modality to another. Muscle pain affected motor strategies used when performing the task, however: it reduced the ability to use increased feedforward control to overcome the force field.

Pain Induced during Both the Acquisition and Retention Phases of Locomotor Adaptation Does Not Interfere with Improvements in Motor Performance

Cutaneous pain experienced during locomotor training was previously reported to interfere with retention assessed in pain-free conditions. To determine whether this interference reflects consolidation deficits or a difficulty to transfer motor skills acquired in the presence of pain to a pain-free context, this study evaluated the effect of pain induced during both the acquisition and retention phases of locomotor learning. Healthy participants performed a locomotor adaptation task (robotized orthosis perturbing ankle movements during swing) on two consecutive days. Capsaicin cream was applied around participants' ankle on both days for the Pain group, while the Control group was always pain-free. Changes in movement errors caused by the perturbation were measured to assess global motor performance; temporal distribution of errors and electromyographic activity were used to characterize motor strategies. Pain did not interfere with global performance during the acquisition or the retention phases but was associated with a shift in movement error center of gravity to later in the swing phase, suggesting a reduction in anticipatory strategy. Therefore, previously reported retention deficits could be explained by contextual changes between acquisition and retention tests. This difficulty in transferring skills from one context to another could be due to pain-related changes in motor strategy.

Is There a Relationship Between Lumbar Proprioception and Low Back Pain? A Systematic Review With Meta-Analysis

OBJECTIVE

To systematically review the relationship between lumbar proprioception and low back pain (LBP).

DATA SOURCES

Four electronic databases (PubMed, EMBASE, CINAHL, SPORTDiscus) and reference lists of relevant articles were searched from inception to March-April 2014.

STUDY SELECTION

Studies compared lumbar proprioception in patients with LBP with controls or prospectively evaluated the relationship between proprioception and LBP. Two reviewers independently screened articles and determined inclusion through consensus.

DATA EXTRACTION

Data extraction and methodologic quality assessment were independently performed using standardized checklists.

DATA SYNTHESIS

Twenty-two studies (1203 participants) were included. Studies measured lumbar proprioception via active or passive joint repositioning sense (JRS) or threshold to detection of passive motion (TTDPM). Data from 17 studies were pooled for meta-analyses to compare patients with controls. Otherwise, descriptive syntheses were performed. Data were analyzed according to measurement method and LBP subgroup. Active JRS was worse in patients compared with controls when measured in sitting (standard mean difference, .97; 95% confidence interval [CI], .31-1.64). There were no differences between groups measured via active JRS in standing (standard mean difference, .41; 95% CI, -.07 to .89) or passive JRS in sitting (standard mean difference, .38; 95% CI, -.83 to 1.58). Patients in the O'Sullivan flexion impairment subgroup had worse proprioception than the total LBP cohort. The TTDPM was significantly worse in patients than controls. One prospective study found no link between lumbar proprioception and LBP.

CONCLUSIONS

Patients with LBP have impaired lumbar proprioception compared with controls when measured actively in sitting positions (particularly those in the O'Sullivan flexion impairment subgroup) or via TTDPM. Clinicians should consider the relationship between sitting and proprioception in LBP and subgroup patients to guide management. Further studies focusing on subgroups, longitudinal assessment, and improving proprioception measurement are needed.

Assessing proprioception: A critical review of methods

To control movement, the brain has to integrate proprioceptive information from a variety of mechanoreceptors. The role of proprioception in daily activities, exercise, and sports has been extensively investigated, using different techniques, yet the proprioceptive mechanisms underlying human movement control are still unclear. In the current work we have reviewed understanding of proprioception and the three testing methods: threshold to detection of passive motion, joint position reproduction, and active movement extent discrimination, all of which have been used for assessing proprioception. The origin of the methods, the different testing apparatus, and the procedures and protocols used in each approach are compared and discussed. Recommendations are made for choosing an appropriate technique when assessing proprioceptive mechanisms in different contexts.

Reduced Short- and Long-Latency Afferent Inhibition Following Acute Muscle Pain: A Potential Role in the Recovery of Motor Output

OBJECTIVE

Corticomotor output is reduced in response to acute muscle pain, yet the mechanisms that underpin this effect remain unclear. Here the authors investigate the effect of acute muscle pain on short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition to determine whether these mechanisms could plausibly contribute to reduced motor output in pain.

DESIGN

Observational same subject pre-post test design.

SETTING

Neurophysiology research laboratory.

SUBJECTS

Healthy, right-handed human volunteers (n = 22, 9 male; mean age ± standard deviation, 22.6 ± 7.8 years).

METHODS

Transcranial magnetic stimulation was used to assess corticomotor output, short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition before, during, immediately after, and 15 minutes after hypertonic saline infusion into right first dorsal interosseous muscle. Pain intensity and quality were recorded using an 11-point numerical rating scale and the McGill Pain Questionnaire.

RESULTS

Compared with baseline, corticomotor output was reduced at all time points (p = 0.001). Short-latency afferent inhibition was reduced immediately after (p = 0.039), and long-latency afferent inhibition 15 minutes after (p = 0.035), the resolution of pain. Long-interval intra-cortical inhibition was unchanged at any time point (p = 0.36).

CONCLUSIONS

These findings suggest short- and long-latency afferent inhibition, mechanisms thought to reflect the integration of sensory information with motor output at the cortex, are reduced following acute muscle pain. Although the functional relevance is unclear, the authors hypothesize a reduction in these mechanisms may contribute to the restoration of normal motor output after an episode of acute muscle pain.

Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation

In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (-51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (-38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief.

Effect of tonic pain on motor acquisition and retention while learning to reach in a force field

Most patients receiving intensive rehabilitation to improve their upper limb function experience pain. Despite this, the impact of pain on the ability to learn a specific motor task is still unknown. The aim of this study was to determine whether the presence of experimental tonic pain interferes with the acquisition and retention stages of motor learning associated with training in a reaching task. Twenty-nine healthy subjects were randomized to either a Control or Pain Group (receiving topical capsaicin cream on the upper arm during training on Day 1). On two consecutive days, subjects made ballistic movements towards two targets (NEAR/FAR) using a robotized exoskeleton. On Day 1, the task was performed without (baseline) and with a force field (adaptation). The adaptation task was repeated on Day 2. Task performance was assessed using index distance from the target at the end of the reaching movement. Motor planning was assessed using initial angle of deviation of index trajectory from a straight line to the target. Results show that tonic pain did not affect baseline reaching. Both groups improved task performance across time (p<0.001), but the Pain group showed a larger final error (under-compensation) than the Control group for the FAR target (p = 0.030) during both acquisition and retention. Moreover, a Group x Time interaction (p = 0.028) was observed on initial angle of deviation, suggesting that subjects with Pain made larger adjustments in the feedforward component of the movement over time. Interestingly, behaviour of the Pain group was very stable from the end of Day 1 (with pain) to the beginning of Day 2 (pain-free), indicating that the differences observed could not solely be explained by the impact of pain on immediate performance. This suggests that if people learn to move differently in the presence of pain, they might maintain this altered strategy over time.

Ultrastructure and innervation of thumb carpometacarpal ligaments in surgical patients with osteoarthritis

BACKGROUND

The complex configuration of the thumb carpometacarpal (CMC-1) joint relies on musculotendinous and ligamentous support for precise circumduction. Ligament innervation contributes to joint stability and proprioception. Evidence suggests abnormal ligament innervation is associated with osteoarthritis (OA) in large joints; however, little is known about CMC-1 ligament innervation characteristics in patients with OA. We studied the dorsal radial ligament (DRL) and the anterior oblique ligament (AOL), ligaments with a reported divergent presence of mechanoreceptors in nonosteoarthritic joints.

QUESTIONS/PURPOSES

This study's purposes were (1) to examine the ultrastructural architecture of CMC-1 ligaments in surgical patients with OA; (2) to describe innervation, specifically looking at mechanoreceptors, of these ligaments using immunohistochemical techniques and compare the AOL and DRL in terms of innervation; and (3) to determine whether there is a correlation between age and mechanoreceptor density.

METHODS

The AOL and DRL were harvested from 11 patients with OA during trapeziectomy (10 women, one man; mean age, 67 years). The 22 ligaments were sectioned in paraffin and analyzed using immunoflourescent triple staining microscopy.

RESULTS

In contrast to the organized collagen bundles of the DRL, the AOL appeared to be composed of disorganized connective tissue with few collagen fibers and little innervation. Mechanoreceptors were identified in CMC-1 ligaments of all patients with OA. The DRL was significantly more innervated than the AOL. There was no significant correlation between innervation of the DRL and AOL and patient age.

CONCLUSIONS

The dense collagen structure and rich innervation of the DRL in patients with OA suggest that the DRL has an important proprioceptive and stabilizing role.

CLINICAL RELEVANCE

Ligament innervation may correlate with proprioceptive and neuromuscular changes in OA pathophysiology and consequently support further investigation of innervation in disease prevention and treatment strategies.

Does elastic resistance affect finger pinch discrimination?

OBJECTIVE

The sensitivity of pinch movement discrimination between the thumb and index finger was assessed with and without elastic resistance.

BACKGROUND

Researchers have examined the effect of elastic resistance on control of single upper-limb movements; however, no one has explored how elastic resistance affects proprioceptive acuity when using two digits simultaneously in a coordinated movement.

METHOD

For this study, 16 right-handed, healthy young adults undertook an active finger pinch movement discrimination test for the right and left hands, with and without elastic resistance. We manipulated pinch movement distance by varying the size of the object that created the physical stop to end the pinch action.

RESULTS

Adding elastic resistance from a spring to the thumb-index finger pinch task did not affect accuracy of pinch discrimination measured as either the just noticeable difference, F(1, 15) = 1.78, p = .20, or area under the curve, F(1, 15) = 0.07, p = .80.

CONCLUSION

Having elastic resistance to generate lever return in pincers, tweezers, and surgical equipment or in virtual instruments is unlikely to affect pinch movement discrimination.

APPLICATION

Elastic resistance did not affect finger pinch discrimination in the present study, suggesting that return tension on equipment lever arms has a practical but not perceptual function. An active finger pinch movement discrimination task, with or without elastic resistance, could be used for hand proprioceptive training and as a screening tool to identify those with aptitude or decrements in fine finger movement control.

Bimanual proprioceptive performance differs for right- and left-handed individuals

It has been proposed that asymmetry between the upper limbs in the utilization of proprioceptive feedback arises from functional differences in the roles of the preferred and non-preferred hands during bimanual tasks. The present study investigated unimanual and bimanual proprioceptive performance in right- and left-handed young adults with an active finger pinch movement discrimination task. With visual information removed, participants were required to make absolute judgments about the extent of pinch movements made to physical stops, either by one hand, or by both hands concurrently, with the sequence of presented movement extents varied randomly. Discrimination accuracy scores were derived from participants' responses using non-parametric signal detection analysis. Consistent with previous findings, a non-dominant hand/hemisphere superiority effect was observed, where the non-dominant hands of right- and left-handed individuals performed overall significantly better than their dominant hands. For all participants, bimanual movement discrimination scores were significantly lower than scores obtained in the unimanual task. However, the magnitude of the performance reduction, from the unimanual to the bimanual task, was significantly greater for left-handed individuals. The effect whereby bimanual proprioception was disproportionately affected in left-handed individuals could be due to enhanced neural communication between hemispheres in left-handed individuals leading to less distinctive separation of information obtained from the two hands in the cerebral cortex.

The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force

This is a review of the proprioceptive senses generated as a result of our own actions. They include the senses of position and movement of our limbs and trunk, the sense of effort, the sense of force, and the sense of heaviness. Receptors involved in proprioception are located in skin, muscles, and joints. Information about limb position and movement is not generated by individual receptors, but by populations of afferents. Afferent signals generated during a movement are processed to code for endpoint position of a limb. The afferent input is referred to a central body map to determine the location of the limbs in space. Experimental phantom limbs, produced by blocking peripheral nerves, have shown that motor areas in the brain are able to generate conscious sensations of limb displacement and movement in the absence of any sensory input. In the normal limb tendon organs and possibly also muscle spindles contribute to the senses of force and heaviness. Exercise can disturb proprioception, and this has implications for musculoskeletal injuries. Proprioceptive senses, particularly of limb position and movement, deteriorate with age and are associated with an increased risk of falls in the elderly. The more recent information available on proprioception has given a better understanding of the mechanisms underlying these senses as well as providing new insight into a range of clinical conditions.

Functional changes in muscle afferent neurones in an osteoarthritis model: implications for impaired proprioceptive performance

Background

Impaired proprioceptive performance is a significant clinical issue for many who suffer osteoarthritis (OA) and is a risk factor for falls and other liabilities. This study was designed to evaluate weight-bearing distribution in a rat model of OA and to determine whether changes also occur in muscle afferent neurones.

Methodology/Principal Findings

Intracellular recordings were made in functionally identified dorsal root ganglion neurones in acute electrophysiological experiments on the anaesthetized animal following measurements of hind limb weight bearing in the incapacitance test. OA rats but not naïve control rats stood with less weight on the ipsilateral hind leg (P = 0.02). In the acute electrophysiological experiments that followed weight bearing measurements, action potentials (AP) elicited by electrical stimulation of the dorsal roots differed in OA rats, including longer AP duration (P = 0.006), slower rise time (P = 0.001) and slower maximum rising rate (P = 0.03). Depolarizing intracellular current injection elicited more APs in models than in naïve muscle afferent neurones (P = 0.01) indicating greater excitability. Axonal conduction velocity in model animals was slower (P = 0.04).

Conclusions/Significance

The present study demonstrates changes in hind limb stance accompanied by changes in the functional properties of muscle afferent neurones in this derangement model of OA. This may provide a possible avenue to explore mechanisms underlying the impaired proprioceptive performance and perhaps other sensory disorders in people with OA.

Relationship between bodily illusions and pain syndromes

SUMMARY Apart from their contribution to the overall knowledge of perception and related processes, sensory illusions have been used in recent years to treat and better understand pain disorders such as phantom limb pain or complex regional pain syndrome. With the help of modern imaging techniques, we can examine connections between basic processes of integrative perception and the occurrence of chronic pain. This article gives an overview of recent developments in the area of body illusions and pain, and provides suggestions on how they might lead to novel and effective treatments for chronic pain.

Experimental neck muscle pain impairs standing balance in humans

Impaired postural control has been reported in patients with chronic neck pain of both traumatic and non-traumatic etiologies, but whether painful stimulation of neck muscle per se can affect balance control during quiet standing in humans remains unclear. The purpose of the present experiment was thus to investigate the effect of experimental neck muscle pain on standing balance in young healthy adults. To achieve this goal, 16 male university students were asked to stand upright as still as possible on a force platform with their eyes closed in two conditions of No pain and Pain of the neck muscles elicited by experimental painful electrical stimulation. Postural control and postural performance were assessed by the displacements of the center of foot pressure (CoP) and of the center of mass (CoM), respectively. The results showed increased CoP and CoM displacements variance, range, mean velocity, and mean and median frequencies in the Pain relative to the No pain condition. The present findings emphasize the destabilizing effect of experimental neck muscle pain per se, and more largely stress the importance of intact neck neuromuscular function on standing balance.