Irregularity of instantaneous gamma frequency in the motor control network characterize visuomotor and proprioceptive information processing.

Objective.The study aims to characterize movements with different sensory goals, by contrasting the neural activity involved in processing proprioceptive and visuo-motor information. To accomplish this, we have developed a new methodology that utilizes the irregularity of the instantaneous gamma frequency parameter for characterization.Approach.In this study, eight essential tremor patients undergoing an awake deep brain stimulation implantation surgery repetitively touched the clinician's finger (forward visually-guided/FV movement) and then one's own chin (backward proprioceptively-guided/BP movement). Neural electrocorticographic recordings from the motor (M1), somatosensory (S1), and posterior parietal cortex (PPC) were obtained and band-pass filtered in the gamma range (30-80 Hz). The irregularity of the inter-event intervals (IEI; inverse of instantaneous gamma frequency) were examined as: (1) auto-information of the IEI time series and (2) correlation between the amplitude and its proceeding IEI. We further explored the network connectivity after segmenting the FV and BP movements by periods of accelerating and decelerating forces, and applying the IEI parameter to transfer entropy methods.Main results.Conceptualizing that the irregularity in IEI reflects active new information processing, we found the highest irregularity in M1 during BP movement, highest in PPC during FV movement, and the lowest during rest at all sites. Also, connectivity was the strongest from S1 to M1 and from S1 to PPC during FV movement with accelerating force and weakest during rest.Significance. We introduce a novel methodology that utilize the instantaneous gamma frequency (i.e. IEI) parameter in characterizing goal-oriented movements with different sensory goals, and demonstrate its use to inform the directional connectivity within the motor cortical network. This method successfully characterizes different movement types, while providing interpretations to the sensory-motor integration processes.

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

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

The effects of remnant-preserving anterior cruciate ligament reconstruction on proprioception: A prospective comparative study.

OBJECTIVE: The aim of this study was to investigate the effects of anterior cruciate ligament reconstruction performed by preserving remnant tissue on proprioception and to assess the effects it has on isokinetic quadriceps and hamstring muscle strength, as well as on range of motion and functional scores. METHODS: A prospective study was conducted with 44 patients who underwent either anterior cruciate ligament reconstruction with remnant preservation (study group, n=22) or with remnant excision (control group, n=22) with the use of a 4-strand hamstring allograft. The mean follow-up time was 20.2 ± 1.4 months after surgery. Using an isokinetic dynamometer, proprioception was evaluated with passive joint position perception at 150, 450, and 600, and quadriceps femoris, and hamstring muscle strength were evaluated at speeds of 900, 1800, and 2400 per second. Range of motion was measured using a goniometer. Functional outcomes were assessed using International Knee Documentation Committee subjective knee evaluation score and Lysholm knee scoring questionnaires. RESULTS: It was only at 15° of knee flexion that there was a statistically significant difference in proprioception; the median of the difference in the amount of deviation from the target angle between the healthy knee and the operated side was 1.7 (range, 0.7-20.7) in those with remnant preserved, and 2.7 (range, 1-26) in those with remnant excised (P=.016). At 2400/s speed, the mean quadriceps femoris strength was 77.2 ± 24.3 Nm in those with remnant preserved and 67.6 ± 24.2 Nm in those with remnant excised. (P=.048) There was no difference between the 2 groups in terms of range of motion, International Knee Documentation Committee, and Lysholm knee scoring. (P > .05) Conclusion: The present study has demonstrated that better proprioception and higher quadriceps femoris muscle strength can be obtained by remnant-preserving anatomical single-bundle anterior cruciate ligament reconstruction using a hamstring autograft. LEVEL OF EVIDENCE: Level II, Therapeutic study.

Reliability, validity and clinical usability of a robotic assessment of finger proprioception in persons with multiple sclerosis.

BACKGROUND: Multiple sclerosis often leads to proprioceptive impairments of the hand. However, it is challenging to objectively assess such deficits using clinical methods, thereby also impeding accurate tracking of disease progression and hence the application of personalized rehabilitation approaches. OBJECTIVE: We aimed to evaluate test-retest reliability, validity, and clinical usability of a novel robotic assessment of hand proprioceptive impairments in persons with multiple sclerosis (pwMS). METHODS: The assessment was implemented in an existing one-degree of freedom end-effector robot (ETH MIKE) acting on the index finger metacarpophalangeal joint. It was performed by 45 pwMS and 59 neurologically intact controls. Additionally, clinical assessments of somatosensation, somatosensory evoked potentials and usability scores were collected in a subset of pwMS. RESULTS: The test-retest reliability of robotic task metrics in pwMS was good (ICC=0.69-0.87). The task could identify individuals with impaired proprioception, as indicated by the significant difference between pwMS and controls, as well as a high impairment classification agreement with a clinical measure of proprioception (85.00-86.67%). Proprioceptive impairments were not correlated with other modalities of somatosensation. The usability of the assessment system was satisfactory (System Usability Scale ≥73.10). CONCLUSION: The proposed assessment is a promising alternative to commonly used clinical methods and will likely contribute to a better understanding of proprioceptive impairments in pwMS.

Effects of functional training on proprioception in sport athletes / Efeitos do treinamento funcional na propriocepção física de atletas esportivos / Efectos del entrenamiento funcional en la propiocepción física de los deportistas

ABSTRACT Introduction Physical training is a well-known training method in competitive sports. However, in the majority of the physical training classes, the focus is still on the traditional exercises of physical conditioning as strength, speed, resistance, etc., directed for young athletes that are in the growth and development phase, without a literary base to assure actual effectiveness in the load increases for the athletic performance facing the risks in the athletes' physical proprioception. Objective Explores the effect of functional training on the physical sensibility of sports athletes. Methods The data collection method is used in the daily training of six notable athletes in a district sports school: judo, martial arts, wrestling, tennis team, swimming team, and table tennis team, adding the functional training protocol in body movement. Results The average performance of the groups before and after the experiment was collected and confronted, the difference test was performed, and the test result found P>0.05. The athletes in the experimental group not only improved the footwork speed and physical coordination, the movement speed of the footwork and the speed of the connection between movements increased significantly in the sixth week, reflecting more excellent stability and motor coordination in the movements. Proprioception is one of the essential sports qualities of the human body; it is directly related to physical qualities such as speed and strength and is also closely related to the different neural pathways. Conclusion Functional training can improve athletes' physical flexibility and motor coordination; it can also stimulate body proprioceptors, increase athletes' confidence, and make training more efficient and effective. Evidence level II; Therapeutic Studies - Investigating the results.

RESUMO Introdução O treinamento físico é um método de treinamento bastante conhecido em esportes competitivos. Porém, na maioria das aulas de treinamento físico, o foco ainda está nos exercícios tradicionais de condicionamento físico como força, velocidade, resistência, etc., voltados para jovens atletas que estão em fase de crescimento e desenvolvimento, sem embasamento literário para assegurar uma real eficácia nos aumentos de carga para o desempenho atlético frente aos riscos na propriocepção física dos atletas. Objetivo Explorar o efeito do treinamento funcional na sensibilidade física de atletas esportivos. Métodos O método de coleta de dados é utilizado no treinamento diário de seis diferentes atletas especiais em uma escola de esportes distrital: judô, artes marciais, luta livre, equipe de tênis, equipe de natação e equipe de tênis de mesa, agregando o protocolo de treino funcional em movimento corporal. Resultados O desempenho médio dos grupos antes e depois do experimento foram coletados e confrontados, o teste de diferença foi realizado, sendo o resultado do teste encontrado P>0,05. Os atletas do grupo experimental não apenas melhoraram a velocidade de trabalho com os pés e a coordenação física, a velocidade do movimento do trabalho com os pés e a velocidade da conexão entre os movimentos aumentaram significativamente na sexta semana, refletindo maior estabilidade e coordenação motora nos movimentos. A propriocepção é uma das qualidades esportivas essenciais do corpo humano, não está apenas diretamente relacionada às qualidades físicas, como velocidade e força, mas também está intimamente relacionada as diferentes vias neurais. Conclusão O treinamento funcional pode melhorar a flexibilidade física e a coordenação motora dos atletas; também pode estimular os proprioceptores corporais, aumentar a confiança dos atletas e tornar o treinamento mais eficiente e eficaz. Nível de evidência II; Estudos terapêuticos - Investigação de resultados.

RESUMEN Introducción El entrenamiento físico es un método de entrenamiento muy conocido en los deportes de competición. Sin embargo, en la mayoría de las clases de entrenamiento físico, el enfoque sigue siendo los ejercicios tradicionales de acondicionamiento físico como fuerza, velocidad, resistencia, etc., dirigidos para jóvenes atletas que están en fase de crecimiento y desarrollo, sin base literaria para asegurar una eficacia real en los aumentos de carga para el rendimiento atlético frente a los riesgos en la propiocepción física de los atletas. Objetivo Explorar el efecto del entrenamiento funcional en la sensibilidad física de los deportistas. Métodos El método de recogida de datos se utiliza en el entrenamiento diario de seis atletas especiales diferentes en una escuela deportiva distrital: judo, artes marciales, lucha, equipo de tenis, equipo de natación y equipo de tenis de mesa, añadiendo el protocolo de entrenamiento funcional en el movimiento corporal. Resultados Se recogió el rendimiento medio de los grupos antes y después del experimento y se confrontó, se realizó la prueba de la diferencia y el resultado de la prueba fue P>0,05. Los atletas del grupo experimental no sólo mejoraron la velocidad del trabajo de pies y la coordinación física, sino que la velocidad del movimiento de pies y la velocidad de la conexión entre los movimientos aumentaron significativamente en la sexta semana, lo que refleja una mayor estabilidad y coordinación motora en los movimientos. La propiocepción es una de las cualidades deportivas esenciales del cuerpo humano, no sólo está directamente relacionada con cualidades físicas como la velocidad y la fuerza, sino que también está estrechamente relacionada con las diferentes vías neuronales. Conclusión El entrenamiento funcional puede mejorar la flexibilidad física y la coordinación motora de los atletas; también puede estimular los propioceptores corporales, aumentar la confianza de los atletas y hacer que el entrenamiento sea más eficiente y eficaz. Nivel de evidencia II;Estudios terapéuticos - Investigación de resultados.

Factors Influencing Treatment Outcome and Proprioception after Electrocoagulation of the Femoral Insertion of the Anterior Cruciate Ligament.

(1) Background: Studies have established that exercises shaping the sense of deep sensation are an important element of medical rehabilitation of patients after vaporization of the femoral insertion of the anterior cruciate ligament and affect the restoration of correct movement patterns, thus reducing the risk of injuries. The aim of this study was to determine the factors influencing the treatment outcome and deep-feeling function after applying a specific rehabilitation scheme 12 weeks after anterior cruciate ligament electrocoagulation surgery. (2) Methods: The study group consisted of 41 patients after partial rupture of the anterior cruciate ligament, who underwent electrocoagulation of the femoral cruciate ligament attachment and microfracture of the femoral attachment area. All patients were operated on by the same surgeon and then rehabilitated according to the same medical rehabilitation protocol. The anthropometric and clinical data were collected through an anterior drawer test, Lachman test, assessment of the range of movements in the knee joint, muscle strength test, Unterberger test and Lysholm questionnaire. The assessment was performed before the surgery, and then on days 7-10, after 6 and 12 weeks of rehabilitation treatment. (3) Results: Statistical improvement of the parameters was demonstrated by strength of the quadriceps and hamstrings muscle, the Unterberger test, and the Lysholm scale after surgery. A negative correlation was found between the Unterberger test and Lysholm scale at the end of the research period and it differed depending on the gender and the dominant limb. The Lysholm scale and muscle strength were independent of sex, dominant extremity and associated damage of the meniscus and cartilage. The Lysholm scale 6 weeks after surgery negatively correlated with BMI. (4) Conclusions: Stability of the knee joint and improvement of proprioception were demonstrated 12 weeks after treatment with an ACL electrocoagulation and rehabilitation regimen. The factors contributing to a better treatment outcome were greater muscle strength, less thigh asymmetry, better sense of depth, younger age and lower body weight.

Ankle Inversion Proprioception Impairment in Persons with Chronic Ankle Instability Is Task-Specific.

While investigators have often compared ankle proprioception between groups with and without chronic ankle instability (CAI), findings have been inconsistent. Possibly this is because ankle proprioceptive impairment in this population is task-specific. Thus, we aimed to compare ankle inversion proprioception in individuals with and without CAI in two task conditions: (i) when standing (not challenging) and (ii) when on a step-down landing (minimally-challenging). Ankle inversion proprioception was measured in both conditions for 38 recreational sport player volunteers with CAI (n = 19) and without CAI (n = 19). We used the Active Movement Extent Discrimination Apparatus (AMEDA) for the standing condition and the Ankle Inversion Discrimination Apparatus-Landing (AIDAL) for step-down landing. From analysis of variance (ANOVA) tests, CAI and non-CAI participants performed equally well on the AMEDA when standing; but the CAI group performed significantly worse than the non-CAI group on the AIDAL step-down landing task (p = 0.03). Within the non-CAI group, the AIDAL proprioceptive scores, as area under the receiver operating characteristics curve (AUC), were significantly higher than their AMEDA AUC scores (p = 0.03), while there was no significant difference between AIDAL and AMEDA AUC scores in the CAI group. Cumberland Ankle Instability Tool CAIT scores were significantly correlated with AIDAL scores (Spearman's rho = 0.391, p = 0.015), but not with the AMEDA scores; and there was no significant correlation between the AIDAL and AMEDA scores. Thus, an ankle inversion proprioceptive deficit was evident for persons with CAI on the step-down AIDAL, and in a dose-response way, but not evident on the standing AMEDA, suggesting that ankle proprioceptive impairment is task-specific. Selected proprioceptive tests must present some minimal degree of challenge to the ankle joint in a functional task in order to differentiate CAI from non-CAI participants.

Cancer survivors post-chemotherapy exhibit unique proprioceptive deficits in proximal limbs.

BACKGROUND: Oxaliplatin (OX) chemotherapy for colorectal cancer is associated with adverse neurotoxic effects that can contribute to long-term sensorimotor impairments in cancer survivors. It is often thought that the sensorimotor impairments are dominated by OX-induced dying-back sensory neuropathy that primarily affects the distal regions of the limb. Recent preclinical studies have identified encoding dysfunction of muscle proprioceptors as an alternative mechanism. Unlike the dying-back sensory neuropathy affecting distal limbs, dysfunction of muscle proprioceptors could have more widespread effects. Most investigations of chemotherapy-induced sensorimotor impairments have considered only the effects of distal changes in sensory processing; none have evaluated proximal changes or their influence on function. Our study fills this gap by evaluating the functional use of proprioception in the shoulder and elbow joints of cancer survivors post OX chemotherapy. We implemented three multidirectional sensorimotor tasks: force matching, target reaching, and postural stability tasks to evaluate various aspects of proprioception and their use. Force and kinematic data of the sensorimotor tasks were collected in 13 cancer survivors treated with OX and 13 age-matched healthy controls. RESULTS: Cancer survivors exhibited less accuracy and precision than an age-matched control group when they had to rely only on proprioceptive information to match force, even for forces that required only torques about the shoulder. There were also small differences in the ability to maintain arm posture but no significant differences in reaching. The force deficits in cancer survivors were significantly correlated with self-reported motor dysfunction. CONCLUSIONS: These results suggest that cancer survivors post OX chemotherapy exhibit proximal proprioceptive deficits, and that the deficits in producing accurate and precise forces are larger than those for producing unloaded movements. Current clinical assessments of chemotherapy-related sensorimotor dysfunction are largely limited to distal symptoms. Our study suggests that we also need to consider changes in proximal function. Force matching tasks similar to those used here could provide a clinically meaningful approach to quantifying OX-related movement dysfunction during and after chemotherapy.

Proprioceptive and Clinical Outcomes after Remnant Preserved Anterior Cruciate Ligament Reconstruction: Assessment with Minimal Confounding Factors.

OBJECTIVE: To evaluate the proprioceptive and clinical function of the knee joint after anterior cruciate ligament reconstruction (ACLR) with various amounts of remnant preserved with as few confounding factors as possible. METHODS: This retrospective study included 46 patients who underwent ACLR with remnant preservation between March 2013 and February 2019. These patients had less than 6 months injury-to-surgery interval and no concomitant injuries. The researchers divided these subjects into two groups based on the length of the remnant preserved after ACLR, with group A defined as having more than 1/3 of the original length preserved and group B defined as less than 1/3 of the original length preserved. Clinical scores were obtained using the Lysholm knee scoring scale and the Tegner activity scale. The Lysholm score was calculated preoperatively, at 3, 6, and 12 months postoperatively, and at the last follow up. The Tegner score was calculated preoperatively, at 12 months postoperatively and at the last follow up. Anterior laxity was measured using the KT2000 arthrometer preoperatively and at 12 months postoperatively. Proprioceptive function was evaluated through reproduction of passive positioning (RPP) and threshold to detection of passive motion (TDPM). Both RPP and TDPM were measured at the angle of 15° at 3, 6, and 12 months postoperatively. Unpaired t-tests were performed to investigate the difference in each parameters between the two groups. RESULTS: In the present study, 20 patients were classified into group A and 26 into group B. All patients were followed up for an average of 34.70 ± 12.79 months. All 46 patients were satisfied with the outcome of the surgery and no complications were reported at the end of the study. No significant differences were found between the two groups in terms of the Lysholm score and anterior laxity by KT2000 at all time points. The Tegner score was significantly higher in group A at 12 months postoperatively and at the final follow-up. In addition, group A's RPP was significantly better than that of group B's when tested at the angles of 15° and 30° at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively. Group A's TDPM was also significantly better than that of group B's at all three tested angles at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively. CONCLUSION: Patients with ACLR with more than 1/3 of the original length preserved demonstrated a higher activity level 12 months postoperatively and better proprioceptive function at 15° of extension at 3 and 6 months postoperatively.

Efectos del autoinjerto hueso-tendón patelar-hueso sobre la posición articular y la fuerza en pacientes con reconstrucción del ligamento cruzado anterior / Effects of bone-patellar tendon-bone autograft on joint position and strength in patients with anterior cruciate ligament reconstruction

RESUMEN: El objetivo del estudio fue comparar el déficit propioceptivo a través del Joint position sense (JPS) y Force steadiness en pacientes con reconstrucción del ligamento cruzado anterior (LCA) injerto hueso-tendón patelar-hueso (HTH) 6 a 12 meses postcirugía. Participaron 15 pacientes (13 hombres y 2 mujeres, 25,5 ± 1,3 años) con reconstrucción de LCA con autoinjerto HTH y 20 personas sin lesión del LCA (19 hombres y 1 mujer, 24,1 ± 0,8 años). Para evaluar la sensación de posición de la articulación de la rodilla se midió la Joint position sense (JPS) en tres rangos: 0°-30°, 31°-60° y 61°-90° y la sensación de fuerza del cuádriceps fue evaluada con la prueba Force steadiness (FS) al 15 % de la contracción voluntaria máxima (CVM), ambas pruebas realizadas 6 a 12 meses post cirugía. Los resultados mostraron que no hubo diferencias estadísticamente significativas en la sensación de la posición articular (JPS 0°-30°) (p=0.564) y 31°-60° (p=0.681), mientras que en el rango 61°-90° (p=0.003) existieron diferencias estadísticamente significativas. En las mediciones de sensación de fuerza del cuádriceps (FS al 15 % CVM) entre los pacientes operados de LCA técnica HTH y el grupo control no hubo diferencias estadísticas (p= 0.987) La sensación de la fuerza del cuádriceps medida con la prueba FS al 15 % CVM no presentaría déficit entre los 6 a 12 meses en pacientes post operados de LCA al ser comparados con sujetos sin lesión ni cirugía de este ligamento. Se concluye que la sensación de la posición articular medida con la prueba JPS en en tres rangos articulares de pacientes con reconstrucción de LCA injerto HTH 6 a 12 meses post cirugía sólo mostró alteraciones en el rango de 61°- 90° al ser comparado con el grupo control, lo cual indica que la sensación de la posición articular presenta un déficit en este rango específico.

SUMMARY: The aim of the study was to compare the proprioceptive deficit through the Joint position sense (JPS) and Force steadiness in patients with anterior cruciate ligament (ACL) bone-patellar tendon-bone graft (PTH) reconstruction 6 to 12 months post-surgery. Fifteen patients (13 men and 2 women, 25.5 ± 1.3 years) with ACL reconstruction with HTH autograft and 20 persons without ACL injury (19 men and 1 woman, 24.1 ± 0.8 years) participated. To assess knee joint position sensation, Joint position sense (JPS) was measured in three ranges: 0°-30°, 31°- 60° and 61°-90° and quadriceps strength sensation was assessed with the Force steadiness (FS) test at 15 % of maximal voluntary contraction (MVC), both tests performed 6 to 12 months post surgery. The results showed that there were no statistically significant differences in joint position sensation (JPS 0°-30°) (p=0.564) and 31°-60° (p=0.681), while in the range 61°-90° (p=0.003) there were statistically significant differences. In the quadriceps strength sensation measurements (FS at 15 % CVM) between the patients operated on ACL HTH technique and the control group there were no statistical differences (p= 0.987). The quadriceps strength sensation measured with the FS test at 15 % CVM would not present a deficit between 6 to 12 months in post- operated ACL patients when compared to subjects without injury or surgery of this ligament. It is concluded that the joint position sensation measured with the JPS test in three joint ranges of patients with ACL reconstruction HTH graft 6 to 12 months post surgery only showed alterations in the range of 61°- 90° when compared to the control group, indicating that the joint position sensation presents a deficit in this specific range.

Dual modulatory effects on feedback from a proprioceptor in the crustacean stomatogastric nervous system.

Neuromodulatory actions that change the properties of proprioceptors or the muscle movements to which they respond necessarily affect the feedback provided to the central network. Here we further characterize the responses of the gastropyloric receptor 1 (GPR1) and gastropyloric receptor 2 (GPR2) neurons in the stomatogastric nervous system of the crab Cancer borealis to movements and contractions of muscles, and we report how neuromodulation modifies those responses. We observed that the GPR1 response to contractions of the gastric mill 4 muscle (gm4) was absent, or nearly so, when the neuron was quiescent but robust when it was spontaneously active. We also found that the effects of four neuromodulatory substances (GABA, serotonin, proctolin, and TNRNFLRFamide) on the GPR1 response to muscle stretch were similar to those previously reported for GPR2. Finally, we showed that an excitatory action on gm4 due to proctolin combined with an inhibitory action on GPR2 due to GABA can allow for larger muscle contractions without increased proprioceptive feedback.NEW & NOTEWORTHY We report that the combination of GABA and the peptide proctolin increases contraction of a stomatogastric muscle while decreasing the corresponding response of the proprioceptor that reports on it. These results suggest a general mechanism by which muscle movements can be modified while sensory feedback is conserved, one that may be particularly well suited for providing flexibility to central pattern generator networks.

Distinct subtypes of proprioceptive dorsal root ganglion neurons regulate adaptive proprioception in mice.

Proprioceptive neurons (PNs) are essential for the proper execution of all our movements by providing muscle sensory feedback to the central motor network. Here, using deep single cell RNAseq of adult PNs coupled with virus and genetic tracings, we molecularly identify three main types of PNs (Ia, Ib and II) and find that they segregate into eight distinct subgroups. Our data unveil a highly sophisticated organization of PNs into discrete sensory input channels with distinct spatial distribution, innervation patterns and molecular profiles. Altogether, these features contribute to finely regulate proprioception during complex motor behavior. Moreover, while Ib- and II-PN subtypes are specified around birth, Ia-PN subtypes diversify later in life along with increased motor activity. We also show Ia-PNs plasticity following exercise training, suggesting Ia-PNs are important players in adaptive proprioceptive function in adult mice.

Comparison of proprioception between osteoarthritic and age-matched unaffected knees: a systematic review and meta-analysis.

PURPOSE: Theoretically, proprioceptive acuity could decrease in patients with knee osteoarthritis. However, there have been conflicting results in terms of proprioceptive deficit in osteoarthritic knees. The purpose of this systematic review and meta-analysis was to compare knee proprioception between osteoarthritic and healthy control knees. METHODS: Studies comparing proprioception in osteoarthritic and healthy knees of age-matched control group using thresholds to detect passive motion (TTDPM) or joint position sense (JPS) tests were identified. JPS was assessed by measuring the reproduction of passive positioning (RPP) or active positioning (RAP) of the knees. RESULTS: Seventeen studies were finally included in this meta-analysis. The pooled results of the analyses of the TTDPM for both 30° and 45° knee flexion showed that the mean angle of error was 0.83° greater (95% confidence interval: 0.44 to 1.23°; p < 0.001) in the osteoarthritic knees than in control knees. The pooled data of the RAP and RPP also showed that the mean angle of error was 1.89° greater in the osteoarthritic knees than in the control group. The mean difference in the angle of error between the osteoarthritic knees and control group was 1.06° greater in the JPS test than in the TTDPM (p < 0.001). CONCLUSION: The knee proprioceptive acuity of the patients with knee osteoarthritis was poorer than that of the patients with unaffected knees in the age-matched control group both in terms of the TTDPM and JPS; clinical relevance of these deficits needs to be clarified in further studies. LEVEL OF EVIDENCE: Meta-analysis, Level II.

Alterated ligamento-muscular reflex pattern after stimulation of the anterior talofibular ligament in functional ankle instability.

PURPOSE: Ligamento-muscular reflex pattern following stimulation of the anterior talofibular ligament (ATFL) was examined. METHODS: The peroneus longus (PL), the tibialis anterior (TA), and tibialis posterior (TP) muscles were investigated in sixteen patients with functional ankle instability (FAI) and 16 age- and gender-matched controls. The ATFL was stimulated with a fine wire electrode while electromyographic (EMG) activities were recorded during isometric foot contraction of 20% maximal force in plantarflexion, dorsiflexion, supination and pronation. The complete measurement was repeated after a peroneal block anesthesia. RESULTS: Statistically significant changes in post-stimulus EMG activity were observed in all three muscles and all four tested foot positions. In supination, the PL showed no reactions in both groups before and after anesthesia. The post-stimulus inhibition of the TA seen after 80 and 180 ms disappeared in controls after anesthesia. The TP had similar inhibitory responses in both groups. CONCLUSION: Ligamento-muscular reflex pattern is alterated in FAI. While early reactions are essential in protecting the ankle joint in sudden movements, the later responses indicate a supraspinal control of neuromuscular stability of the ankle joint. Proprioceptive rehabilitation of the PL, TA, and TP is crucial in FAI to compensate for post-traumatic ligamentomuscular reflex deficiencies. LEVEL OF EVIDENCE: II.

Topography of sensory receptors within the human glenohumeral joint capsule.

BACKGROUND AND HYPOTHESES: Sensory receptors in the joint capsule are critical for maintaining joint stability. However, the distribution of sensory receptors in the glenohumeral joint of the shoulder, including mechanoreceptors and free nerve endings, has not been described yet. This study aimed to describe the distributions of different sensory receptor subtypes in the glenohumeral joint capsule. Our hypotheses were as follows: (1) Sensory receptor subtypes would differ in density but follow a similar distribution pattern, and (2) the anterior capsule would have the highest density of sensory receptors. METHODS: Six glenohumeral joint capsules were harvested from the glenoid to the humeral attachment. The capsule was divided into 4 regions of interest (anterior, posterior, superior, and inferior) and analyzed using modified gold chloride stain. Sensory receptors as well as free nerve endings were identified and counted under a light microscope from sections of each region of interest. The density of each sensory receptor subtype was calculated relative to capsule volume. RESULTS: Sensory receptors were distributed in the glenohumeral joint capsule with free nerve endings. The anterior capsule exhibited the highest median density of all 4 sensory receptors examined, followed by the superior, inferior, and posterior capsules. The median densities of these sensory receptor subtypes also significantly differed (P = .007), with type I (Ruffini corpuscles) receptors having the highest density (2.97 U/cm3), followed by type IV (free nerve endings, 2.25 U/cm3), type II (Pacinian corpuscles, 1.40 U/cm3), and type III (Golgi corpuscles, 0.24 U/cm3) receptors. CONCLUSION: Sensory receptor subtypes are differentially expressed in the glenohumeral joint capsule, primarily type I and IV sensory receptors. The expression of sensory receptors was dominant in the anterior capsule, stressing the important role of proprioception feedback for joint stability. The surgical procedure for shoulder instability should consider the topography of sensory receptors to preserve or restore the proprioception of the shoulder joint.

Proprioceptive training on the recovery of total knee arthroplasty patients: A meta-analysis protocol of randomized controlled trial.

BACKGROUND: Total knee arthroplasty is a common surgery for end-stage of knee osteoarthritis. Proprioceptive training has become an important part in athletes training programmes in different sports. However, the effects of proprioceptive training on the recovery of total knee arthroplasty were unknown. This meta-analysis, with its comprehensive and rigorous methodology, will provide better insight into this problem. METHODS AND ANALYSIS: Electronic databases including PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI) database, Wanfang Database and Chinese Biomedical Literature Database (CBM) were searched from its inception to October 21, 2020. We only included proprioceptive training vs placebo in patients after total knee arthroplasty and pooled results were summarized by STATA 12.0 software. Two researchers independently selected the study and assessed the quality of the included studies. The heterogeneity was measured by I2 tests (I2 < 50 indicates little heterogeneity, I2 ≥ 50 indicates high heterogeneity). Publication bias was ruled out by funnel plot and statistically assessed by Beggs test (P > .05 as no publication bias). RESULTS: Results will be published in relevant peer-reviewed journals. CONCLUSION: Our study aims to systematically present the clinical effects of proprioceptive training after total knee arthroplasty patients, which will be provide clinical guidance for total knee arthroplasty patients.

Efficacy of proprioceptive training on the recovery of total joint arthroplasty patients: a meta-analysis.

BACKGROUND: Optimal balance control is of paramount importance for function recovery after total joint arthroplasty (TJA). The study objective of this meta-analysis was to assess the short- and mid-term effects of proprioceptive and balance training for patients undergoing TJA. METHODS: Electronic searches were conducted from PubMed, Cochrane library, and Embase databases to identify eligible RCTs through May 2020. Standard mean difference (SMD) with 95% confidence interval (95%CI) was applied to calculate pooled effect estimates between proprioceptive and balance training and control group. Main outcomes were self-reported functionality, balance, pain, quality of life, and function (range of motion). RESULTS: Seven randomized controlled trials were finally included in this meta-analysis. Pooled results found that balance and proprioceptive trainings have a positive role in improving self-reported functionality at short-term after TJA. Moreover, balance and proprioceptive trainings were associated with an increase of the balance at short- and mid-term after TJA. These results were further confirmed by subgroup analysis between preoperative and postoperative administration of balance and proprioceptive trainings. CONCLUSION: Our meta-analysis suggests that balance and proprioceptive trainings after TJA improved self-reported functionality and balance. These improvements were maintained at mid-terms. More research is needed to confirm balance and proprioceptive trainings for pain and quality of life for TJA.

Piezo2 expressed in proprioceptive neurons is essential for skeletal integrity.

In humans, mutations in the PIEZO2 gene, which encodes for a mechanosensitive ion channel, were found to result in skeletal abnormalities including scoliosis and hip dysplasia. Here, we show in mice that loss of Piezo2 expression in the proprioceptive system recapitulates several human skeletal abnormalities. While loss of Piezo2 in chondrogenic or osteogenic lineages does not lead to human-like skeletal abnormalities, its loss in proprioceptive neurons leads to spine malalignment and hip dysplasia. To validate the non-autonomous role of proprioception in hip joint morphogenesis, we studied this process in mice mutant for proprioceptive system regulators Runx3 or Egr3. Loss of Runx3 in the peripheral nervous system, but not in skeletal lineages, leads to similar joint abnormalities, as does Egr3 loss of function. These findings expand the range of known regulatory roles of the proprioception system on the skeleton and provide a central component of the underlying molecular mechanism, namely Piezo2.

The effects of partial meniscectomy and meniscal repair on the knee proprioception and function.

PURPOSE: Aim of our study was to compare the effects of partial meniscectomy and meniscus repair on knee proprioception and function. METHODS: The study included 46 patients with clinical and radiological diagnosis of meniscal tear and accompanying anterior cruciate ligament (ACL) rupture. The patients were evaluated under two groups: group 1: partial meniscectomy and ACL reconstruction, and group 2: meniscal repair and ACL reconstruction. Proprioceptive and functional evaluation of all patients was performed prior to surgery and on postoperative 12th month. RESULTS: Group 1 consists of 18 male and 1 female patients with an average age of 28.78 ± 3.50. Group 2 consists of 23 male and 4 female patients with an average age of 27.14 ± 3.65. Preoperative evaluation revealed significant differences in knee joint position sense values on wide range of knee motion (15°, 30°, 45°, 60°, and 75°) in both groups. The statistically significant difference was observed in only the range of knee motion of 60° in patients underwent meniscal repair (group 2), whereas in the range of knee motion of 45°, 60°, and 75° in patients underwent partial meniscectomy (group 1) at 12th-month control. According to Lysholm knee scoring system, significantly better results were achieved with meniscal repair compared to the partial meniscectomy at 12th-month control. CONCLUSION: In case of ACL rupture accompanied by meniscal tear, the meniscal repair should be sutured, if possible, in order to obtain better results in terms of knee function and proprioception.