Proprioceptive Acuity Research Articles

Eight weeks of oral iron supplementation improves postural control in young women with iron deficiency anemia.

This study aimed to explore the effect of 8-week oral supplementation on postural control in young women with iron deficiency anemia (IDA). This study involved 15 women with IDA who received 160 mg of elemental iron daily in the form of dried ferrous sulfate capsules (80 mg twice daily) taken in two divided doses for 8 weeks. The mean velocity of oscillations of the center of pressure (CoPv) was recorded to evaluate postural control pre- and post-supplementation. In addition, simple reaction time (SRT) and weight discrimination tests were performed to assess attentional capacity and proprioceptive acuity, respectively. This study revealed significant increases (P < 0.001, mean difference = 1.83, 95% CI: -17.25; -9.42) in proprioceptive acuity values, as well as decreases in CoPv [firm (EO (P < 0.01, mean difference = 0.52, 95% CI: 0.69; 2.92), EC (P < 0.05, mean difference = 0.75, 95% CI: 0.24; 3.45)) and foam (EO (P < 0.001, mean difference = 0.64, 95% CI: 1.71; 4.44) ; EC (P < 0.001, mean difference = 1.04, 95% CI: 3.51; 7.97))] and SRT (P < 0.001, mean difference = 59.31, 95% CI: 103.02; 168.71) values post-supplementation compared to pre-supplementation. This study showed significant improvements in postural control in young women with IDA after 8 weeks of oral iron supplementation. These improvements were probably related to the enhanced bioavailability of iron, which may have influenced neural processes inducing improvements in attention capacity and proprioceptive acuity.

The effect of age and proprioceptive illusion susceptibility on gait

ObjectiveAge-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. MethodsWe 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. ResultsWe 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. ConclusionsOur results suggest that gait impairments observed in those who perceive these proprioceptive illusions are age-independent, potentially rooted in deteriorated proprioception. SignificanceThis is the first study to examine these relations.

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.

Keeping up with ourselves: Multimodal processes underlying body ownership across the lifespan

The sense of a bodily self is thought to depend on adaptive weighting and integration of bodily afferents and prior beliefs. While the physical body changes in shape, size, and functionality across the lifespan, the sense of body ownership remains relatively stable. Yet, little is known about how multimodal integration underlying such sense of ownership is altered in ontogenetic periods of substantial physical changes. We aimed to study this link for the motor and the tactile domain in a mixed-realty paradigm where participants ranging from 7 to 80 years old saw their own body with temporally mismatching multimodal signals. Participants were either stroked on their hand or moved it, while they saw it in multiple trials with different visual delays. For each trial, they judged the visuo-motor/tactile synchrony and rated the sense of ownership for the seen hand. Visual dependence and proprioceptive acuity were additionally assessed. The results show that across the lifespan body ownership decreases with increasing temporal multisensory mismatch, both in the tactile and the motor domain. We found an increased sense of ownership with increasing age independent of delay and modality. Delay sensitivity during multisensory conflicts was not consistently related to age. No effects of age were found on visual dependence or proprioceptive accuracy. The results are at least partly in line with an enhanced weighting of top-down and a reduced weighting of bottom-up signals for the momentary sense of bodily self with increasing age.

Effectiveness of a sensorimotor exercise program on proprioception, balance, muscle strength, functional mobility and risk of falls in older people.

Sensory systems provide the necessary information for a motor response to be provided. In this sense, the objective of this study is to evaluate the effectiveness of a sensorimotor exercise program on proprioceptive acuity, balance, muscle strength, functional mobility and risk of falls in institutionalized elderly. 56 participants (84.6 ± 8.4years) were randomly distributed between the control (CG, n = 28) and intervention groups (IG, n = 28). The CG performed a protocol based on warm-up, muscle strengthening and warm down and the IG performed the same intervention, with the addition of sensorimotor exercises. Joint Position Sensation (JPS) was evaluated in both limbs at angles of 20° and 45°, balance, functional mobility, fear of falling in the elderly and muscle strength of quadriceps, hamstrings, adductors and abductors in both limbs, before and after the 12weeks of intervention. Both groups showed gains in muscle strength. When analyzing functionality through Timed Up and Go (TUG), before and after for each group separately, both showed a significant difference (CG p = 0.002; IG p < 0.001). For the Short Physical Performance Battery (SPPB) variable, there were significant differences in IG in balance (p < 0.001), gait speed time (s) (p = 0.004) and sit-to-stand (p = 0.002). In JPS, significant differences were recorded for Absolute Error 45° Non-Dominant (p = 0.045) and Relative Error 45° Non-Dominant (p = 0.045) in the CG and Relative Error 45° Non-Dominant for IG (p = 0.018). In the Falls Efficacy Scale International (FES-I) variable there were significant improvements in the CG (p = 0.006) and in the GI (p = 0.002). However, only IG showed significant improvements (p = 0.013) for Activities-Specific Balance Confident (ABC) in a comparison between before and after the 12-week research period. When comparing the differences verified with the intervention between CG and IG, only balance SPPB (p < 0.001) and sit-to-stand SPPB (p = 0.022) showed significant values. He effectiveness of sensorimotor exercises provides balance gain in the elderly (p < 0.001) and positively impacts their confidence (p = 0.013) when performing their duties. It is concluded that the protocol presented in its different levels of difficulty is effective and important for the quality of life of the institutionalized sedentary elderly.

Acute effects of Nordic hamstring exercise on hip and knee joints proprioception

Background and objectivesNordic Hamstring Exercise (NHE) is one of the best exercises proposed for injury prevention of hamstring muscles. However, its effects on lower extremity proprioception are unclear. The aim of this study was to investigate the immediate effects of a single bout of NHE on hip and knee joints’ proprioception. MethodsForty collegiate male soccer players participated in this study with a mean age of 22.85 ± 1.82 years and were randomized into either control (n = 20) or experimental (n = 20) groups. Each subject participated in pre-test measurements in which hip and knee active joints position sense (JPS) were assessed in standing and lying tasks using the image-capturing method. The experimental group then performed three sets of NHE with 10 repetitions in each set, while the control group rested for 10 min. Paired and independent t-tests were used for calculating the differences within and between groups on SPSS software, respectively. The level of significance was P ≤ 0.05. ResultsHip JPS in the lying task and knee JPS in both of the standing and lying tasks were impaired significantly after performing a single bout of NHE (P ≤ 0.05). However, the effects of this exercise on hip JPS in the standing task were not significant (P ≥ 0.05). ConclusionsNHE performing with three sets of 10 repetitions can significantly impair hip and knee JPS immediately after exercise and reduce the proprioception acuity of the lower limbs. It is recommended to perform this exercise at a time rather than before training or match sessions.

Relationship Between Postural Stability and Proprioception, Pain, Quadriceps Strength, and Muscle Tightness in Athletes With Patellar Tendinopathy.

Athletes with patellar tendinopathy (PT) have postural stability deficits; however, the underlying mechanisms and factors responsible remain unknown. The effect on postural stability in PT of decreased quadriceps strength, altered proprioception, lower-limb muscle tightness, and knee pain, which explain postural stability deficiency in other populations, is uninvestigated. Proprioceptive acuity, muscle tightness, quadriceps strength, and pain predict postural stability in athletes with PT. Cross-sectional comparative study. Level 2. A total of 43 athletes with PT and 43 healthy athletes were enrolled. Static and dynamic postural stability, proprioceptive acuity, muscle tightness, quadriceps strength, and pain were evaluated using a force platform, Y-balance test (YBT), a weight discrimination protocol, a goniometer, an isometric dynamometer, and a valid questionnaire, respectively. Athletes with PT had significantly worse static and dynamic postural stability in the affected limb (AL) compared with the nonaffected limb (NAL) (P < 0.01) and the control group (P < 0.01). Athletes suffering from PT revealed lower quadriceps strength (P < 0.01), proprioceptive acuity (P = 0.02), and higher muscle tightness in the AL compared with the NAL and controls. Quadriceps weakness of the AL and pain in athletes with PT explained the variance of dynamic postural stability impairment. Athletes with PT have postural stability deficiency compared with healthy peers. Our results demonstrate that quadriceps muscle weakness and pain are the factors that explain postural stability impairment. These results can assist clinicians in the design of therapeutic balance rehabilitation programs by acting not only on pain relief but also on quadriceps strengthening through resistance training to avoid subsequent injuries in athletes with PT.

Proprioceptive acuity for landmarks on the hand and digits.

Previous work using visually guided reaches to localize landmarks on a hidden hand has suggested that proprioceptive acuity for hand targets is low and representation of hand dimensions is highly distorted (e.g., hand width estimated to be 60% wider than actual hand width). We re-examined these issues using a pure proprioceptive task in which 20 blindfolded subjects reached in a single movement without terminal corrections to touch the right index-tip to landmarks of the left hand placed in various locations in 3D space. Subjects were also tested with vision allowed to estimate minimal errors. Based on previous reports of high proprioceptive acuity for some hand landmarks, we hypothesized that the proprioceptive representation of the hand was much less distorted than described previously and that errors were not correlated with target hand location. Mean distance errors in proprioceptively guided reaches to the landmarks averaged less than 3cm and were only 0.5-1.3cm larger than when vision was allowed. Errors were not correlated with hand location in most subjects. Distortions of hand width averaged less than 20% wider than actual width and were not correlated with hand location in most subjects. We conclude that relatively accurate proprioceptive awareness of locations of hand/digit structures and dimensions is available for use in control of hand movements, which are executed largely subconsciously. Studying acuity of proprioception using conscious perceptual tasks and involving vision may not provide accurate measures of proprioceptive acuity as used by the motor system.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study

IntroductionPatellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain. Methods: Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables. ResultsPain intensity was correlated with Y-Balance Test posteromedial component (rs = −0.32, 95%CI = −0.55 to −0.03, p = 0.029) and the composite score (rs = −0.35, 95%CI = −0.58, −0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = −0.23, 95% CI = −0.53 to −0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test. ConclusionPain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Robot-Assisted Training to Improve Proprioception of Wrist.

In recent years, robot-assisted training has been shown to significantly improve motor function and proprioception in people with functional disabilities, but the efficiency of proprioceptive acuity was unclear. To characterize the efficiency of joint proprioceptive acuity improvement in space, we designed a robot-assisted ipsilateral joint position matching experiment using the wrist as the study object. We conducted 2-way repeated measures ANOVA on error data before and after training in 12 healthy subjects and mapped the distribution of wrist proprioceptive learning ability in different workspaces. The results showed significant differences in the proprioceptive acuity of the wrist joint in different workspaces and movement directions before and after training in 12 subjects ( [Formula: see text]), and the proprioceptive acuity of the wrist after training was significantly higher than before training. In addition, the learning ability of wrist proprioceptive acuity showed significant differences in different workspaces and movement directions (Flexion and Extension in habit workspace (HW) ( P=0.037 ); Flexion and Extension in maximum workspace (MW) ( P=0.016 ); Flexion in HW and MW ( P=0.043 )). Robot-assisted training is beneficial for improving the proprioceptive acuity of the wrist. The learning ability of proprioceptive acuity of joints in different movement directions is independently distributed and influenced by usage habits, which accelerate the improvement of proprioceptive acuity. This research hopes to clinically guide the development of highly effective rehabilitation programs to achieve better recovery and help build patient confidence.

Knee osteoarthritis patients assessed during walking for ankle inversion movement discrimination sensitivity.

Background: Knee osteoarthritis (KOA) is a common musculoskeletal condition that affects dynamic balance control and increases the risk of falling during walking. However, the mechanisms underlying this are still unclear. Diminished ankle proprioception during walking has been found to be related to fear of falling in older adults, with a gender difference in incidence of falling. This study aimed to determine 1) whether ankle inversion proprioceptive acuity during walking is impaired in patients with KOA; and 2) whether there is any difference between genders. Methods: Thirty-two patients with KOA (F:M = 17:15, Median age = 52.5, BMI = 22.3 ± 3.0) and 34 healthy controls without KOA (HC) (F:M = 17:17; median age = 49.0, BMI = 22.5 ± 2.7) were recruited. In patients with KOA, ankle inversion proprioceptive acuity was measured on the affected side using the ankle inversion discrimination apparatus for walking (AIDAW), whilst HC were assessed on a randomly selected side. Two-way (2*2) analysis of variance (ANOVA) was performed to determine the main effects and interaction between gender and KOA condition. Results: Two-way ANOVA showed a significant KOA main effect (F = 26.6, p < 0.001, ƞp 2 = 0.3) whereby AIDAW scores during walking for individuals with KOA were significantly lower than those without KOA (KOA vs. HC: 0.746 ± 0.057 vs. 0.807 ± 0.035). There was neither a gender main effect nor interaction (both p > 0.05). Conclusion: Individuals with KOA demonstrated lower ankle proprioception scores during walking compared to their healthy counterparts, with a similar level of impairment in ankle proprioceptive acuity between male and female patients. A low score may contribute to an increased risk of falling in the KOA population. The current findings suggest the need for global concern about lower limb proprioception in the clinical management of KOA.

Effect of a Sensorimotor Training on Pain, Proprioception, and Functional Activities in Participants with Chronic Knee Osteoarthritis: A Randomized Controlled Clinical Trial

Background: Knee osteoarthritis (OA) is a chronic, debilitating condition that significantly impairs functional health status among affected individuals. Key challenges associated with chronic knee OA include persistent pain, diminished functional capabilities, and compromised balance. These factors highlight the critical need for effective intervention strategies. Recent research suggests that sensorimotor training may play a pivotal role in addressing these issues. However, there remains a gap in the literature regarding the specific effects of sensorimotor training on pain perception, proprioception, and overall functional levels in this population. Therefore, the aim of this study was to systematically investigate the impact of sensorimotor training on pain, proprioceptive abilities, and functional performance in individuals with chronic knee OA. Methods: Total 66 patients with chronic knee OA were divided into two equal groups. The control group received a traditional exercise programme and the experimental group received sensorimotor training in addition to traditional exercises. Blind assessment was conducted at the beginning of the study and after 4 weeks of training to measure pain by NPRS, proprioception acuity by passive – active joint position reproduction method, and functional disability by TUG &amp; KOOS scale. Statistical analysis was performed using SPSS 23. Data were presented as mean, standard deviation (SD) and mean difference. Within groups compare we used Paired t test and between groups compare we used Independent t test with post data comparison in SPSS. The significance level was set at (p&lt;0.05). Result: For experimental group and control group statistical significant (p&lt;0.05) improvements were recorded in all measured parameters. Mean difference of KOOS in control group is 5.97% and experimental group is 17.63% and in mean difference of pain in control group is 2.33 and experimental group is 3.88 which shows that SMT is very effective than traditional exercise only. According to MCID of all outcomes, pain, KOSS and TUG test is clinically significant. The sensorimotor group produced significantly better improvement than the traditional group. Conclusion: Sensorimotor training along with traditional exercises is more effective then only traditional exercises for patients with chronic knee OA. The addition of sensorimotor training to traditional strengthening and stretching exercises could provide more motor control and help neuromuscular restoration of balance and subsequently improve the functional level of chronic knee OA subjects.

Hearing Aid Amplification Improves Postural Control for Older Adults With Hearing Loss When Other Sensory Cues Are Impoverished.

Recent studies suggest that sound amplification via hearing aids can improve postural control in adults with hearing impairments. Unfortunately, only a few studies used well-defined posturography measures to assess balance in adults with hearing loss with and without their hearing aids. Of these, only two examined postural control specifically in the elderly with hearing loss. The present study examined the impact of hearing aid use on postural control during various sensory perturbations in older adults with age-related hearing loss. Thirty individuals with age-related hearing impairments and using hearing aids bilaterally were tested. Participants were asked to perform a modified clinical sensory integration in balance test on a force platform with and without hearing aids. The experiment was conducted in the presence of a broadband noise ranging from 0.1 to 4 kHz presented through a loudspeaker. As expected, hearing aid use had a beneficial impact on postural control, but only when visual and somatosensory inputs were both reduced. Data also suggest that hearing aid use decreases the dependence on somatosensory input for maintaining postural control. This finding can be of particular importance in older adults considering the reduction of tactile and proprioceptive sensitivity and acuity often associated with aging. These results provide an additional argument for encouraging early hearing aid fitting for people with hearing loss.

Ab. No. 70 Efficacy of Perturbation Training on Balance and Function in Older Individuals- An Experimental Study

Introduction: Aging involves decline in visual, vestibular and proprioceptive acuity associated with functional limitations and reduced motor function, disturbing balance and increasing risk of fall. The study evaluates the effect of perturbation training in older individuals with mild to moderate risk of fall and its effect on postural stability and balance. Perturbation training has been advocated as an effective intervention for re-educating proprioception and restoring normal neuromuscular coordination. Older adults can quickly adapt to large postural perturbations, altering their biomechanics and preventing falls. Methods: An experimental trial recruited 30 older individuals (65-85 years) with mild to moderate fall risk through purposive sampling. Participants underwent Perturbation Training with tilt-board and conventional balance exercises thrice weekly for four weeks (12 sessions). Modified-CTSIB test on NeuroCom Balance Master® and Timed Up and Go (TUG) Test were taken at baseline and post-completion. Homogeneity of samples was assessed using Shapiro-Wilk’s Test of Normality. Dependent sample t-tests were employed to analyze group data, with means and standard deviations indicating statistical differences in pre and post outcome measures at 95% confidence interval. Results: Pre and post measures on TUG test and M-CTSIB test on NeuroCom Balance Master® shows statistically significant improvement in TUG values(p&lt;0.0001*) and COG sway velocity in all conditions except on Firm surface with eyes open, with FIEO(p&lt;0.1208), FIEC(p&lt;0.0011*), FOEO(P&lt;0.0013*), FOEC(p&lt;0.0001*) and Composite COG sway velocity(p&lt;0.0001*). Conclusion: Perturbation training coupled with conventional balance exercises, showed to be effective intervention to improve balance and postural control in older individuals. The study lacked follow-up, leaving room for future studies into continuity of exercises and retention of its effects. Implications: Given the effectiveness, the study suggests integrating perturbation training in geriatric rehabilitation protocol to enhance physical function, diminish fear of falling, and boost fall-related self-efficacy.

Proprioceptive short-term memory in passive motor learning

A physical trainer often physically guides a learner’s limbs to teach an ideal movement, giving the learner proprioceptive information about the movement to be reproduced later. This instruction requires the learner to perceive kinesthetic information and store the instructed information temporarily. Therefore, (1) proprioceptive acuity to accurately perceive the taught kinesthetics and (2) short-term memory to store the perceived information are two critical functions for reproducing the taught movement. While the importance of proprioceptive acuity and short-term memory has been suggested for active motor learning, little is known about passive motor learning. Twenty-one healthy adults (mean age 25.6 years, range 19–38 years) participated in this study to investigate whether individual learning efficiency in passively guided learning is related to these two functions. Consequently, learning efficiency was significantly associated with short-term memory capacity. In particular, individuals who could recall older sensory stimuli showed better learning efficiency. However, no significant relationship was observed between learning efficiency and proprioceptive acuity. A causal graph model found a direct influence of memory on learning and an indirect effect of proprioceptive acuity on learning via memory. Our findings suggest the importance of a learner’s short-term memory for effective passive motor learning.

Sensory Reweighting for Postural Control in Older Adults with Age-Related Hearing Loss.

There is growing evidence linking hearing impairments and the deterioration of postural stability in older adults. To our knowledge, however, no study to date has investigated the effect of age-related hearing loss on the sensory reweighting process during postural control. In the absence of data, much is unknown about the possible mechanisms, both deleterious and compensatory, that could underly the deterioration of postural control following hearing loss in the elderly. The aim of this study was to empirically examine sensory reweighting for postural control in older adults with age-related hearing loss as compared to older adults with normal hearing. The center of pressure of all participants was recorded using a force platform and the modified clinical test of sensory interaction and balance protocol. The results suggest that individuals with age-related hearing loss displayed increased somatosensory reliance relative to normal hearing younger adults. This increased reliance on somatosensory input does not appear to be effective in mitigating the loss of postural control, probably due to the concomitant deterioration of tactile and proprioceptive sensitivity and acuity associated with aging. Beyond helping to further define the role of auditory perception in postural control, these results further the understanding of sensory-related mechanisms associated with postural instability in older adults.

Proprioception: An evidence-based review

BackgroundProprioception is an essential sensory function of the body. Proprioception is defined as one’s awareness of their body’s position and movement through space. It contributes to both the conscious and unconscious awareness of limb and trunk position and movement. The purpose of this review is to provide an evidence-based review of proprioception and conditions that interfere with proprioceptive acuity. PurposeThe purpose of this review is to provide an evidence-based review of proprioception and conditions that interfere with proprioceptive acuity. Study DesignThis narrative literature review examines studies that determine proprioceptive systems and their implication for rehabilitation. MethodsRelevant study data were extracted as part of this review. ResultsTypes of proprioceptive interventions can include active or passive movement training, somatosensory stimulation training, force reproduction, and somatosensory discrimination training. Joint position sense error is the most widely used objective measure of proprioception. ConclusionsTherapists should consider using a standardized measure to ascertain proprioceptive deficits in their patients following upper extremity injury or disease to determine the deficits and measure change. There are a variety of interventions that can be used in hand rehabilitation to restore proprioceptive acuity, and active movement interventions have been found to be the most effective.

A robot-aided visuomotor wrist training induces motor and proprioceptive learning that transfers to the untrained ipsilateral elbow

BackgroundLearning of a visuomotor task not only leads to changes in motor performance but also improves proprioceptive function of the trained joint/limb system. Such sensorimotor learning may show intra-joint transfer that is observable at a previously untrained degrees of freedom of the trained joint.ObjectiveHere, we examined if and to what extent such learning transfers to neighboring joints of the same limb and whether such transfer is observable in the motor as well as in the proprioceptive domain. Documenting such intra-limb transfer of sensorimotor learning holds promise for the neurorehabilitation of an impaired joint by training the neighboring joints.MethodsUsing a robotic exoskeleton, 15 healthy young adults (18–35 years) underwent a visuomotor training that required them to make continuous, increasingly precise, small amplitude wrist movements. Wrist and elbow position sense just-noticeable‐difference (JND) thresholds and spatial movement accuracy error (MAE) at wrist and elbow in an untrained pointing task were assessed before and immediately after, as well as 24 h after training.ResultsFirst, all participants showed evidence of proprioceptive and motor learning in both trained and untrained joints. The mean JND threshold decreased significantly by 30% in trained wrist (M: 1.26° to 0.88°) and by 35% in untrained elbow (M: 1.96° to 1.28°). Second, mean MAE in untrained pointing task reduced by 20% in trained wrist and the untrained elbow. Third, after 24 h the gains in proprioceptive learning persisted at both joints, while transferred motor learning gains had decayed to such extent that they were no longer significant at the group level.ConclusionOur findings document that a one-time sensorimotor training induces rapid learning gains in proprioceptive acuity and untrained sensorimotor performance at the practiced joint. Importantly, these gains transfer almost fully to the neighboring, proximal joint/limb system.

Proprioceptive Acuity Influences Speech Motor Control in Healthy Adult Talkers.

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

Exercise-induced fatigue affects knee proprioceptive acuity and quadriceps neuromuscular function more in patients with ACL reconstruction or meniscus surgery than in healthy individuals.

To observe how knee proprioceptive acuity and quadriceps neuromuscular function change during and after repeated isokinetic knee-extension exercise in patients with anterior cruciate ligament reconstruction (ACLR) or meniscus surgery. Patients with ACLR or meniscus surgery and matched controls (n = 19 in each group) performed knee-flexion replication at 15° and 75°, and quadriceps peak torque (PT), central activation ratio (CAR) and rate of torque development (RTD) at baseline and immediately after every five sets of isokinetic knee-extension exercise (times 1-5). Compared to the baseline, the ACLR and control groups displayed errors in knee-flexion replication at 75° only at time 5 (115.9-155.6%; p ≤ 0.04, d ≥ 0.97), whereas the meniscus surgery group exhibited errors at all time points (142.5-265.6%; p ≤ 0.0003, d ≥ 1.4). Significant percentage reductions in quadriceps CAR were observed between times 4 and 5 in the ACLR group (-5.8%; p = 0.0002, d = 0.96), but not in the meniscus surgery (-1.4%; n.s.) and control (0.1%; n.s.) groups. Significant percentage reductions in quadriceps RTD were observed between times 4 and 5 in the ACLR (-24.2%; p = 0.007, d = 0.99) and meniscus surgery (-23.0%; p = 0.01, d = 0.85) groups, but not in the control group (-0.2%; n.s.). Patients with ACLR or meniscus surgery displayed a greater loss in knee proprioceptive acuity and quadriceps neuromuscular function during and after exercise than healthy individuals. Evidence-based interventions to enhance exercise-induced fatigue resistance should be implemented following ACLR or meniscus surgery, aiming to prevent proprioceptive and neuromuscular changes within the knee joint and quadriceps. III.