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Anatomical Record (Hoboken, N.J. : 2007) Jun 2024It is presumed that the unusual central location of mesencephalic trigeminal neurons is a specialization that allows them to receive synaptic input. However, relatively...
It is presumed that the unusual central location of mesencephalic trigeminal neurons is a specialization that allows them to receive synaptic input. However, relatively few synaptic terminals were observed on the somata of mesencephalic trigeminal neurons in macaque monkeys via electron microscopy. This leaves the question of dendritic synaptic terminals open. Unlike the pseudounipolar neurons found in the trigeminal ganglion, some mesencephalic trigeminal neurons have been reported to be multipolar cells exhibiting a number of dendritic processes in non-primate species. To examine whether this morphological feature was also present in macaque monkeys, we retrogradely filled these cells with biotinylated dextran amine by injecting it into the trigeminal nerve entry zone. A portion of the mesencephalic trigeminal neurons exhibited short, poorly branched, dendritic processes. They also exhibited very fine, short processes believed to be somatic spines. Thus, primate trigeminal mesencephalic neurons appear to have specializations aimed at increasing the membrane surface area available for synaptic input.
PubMed: 38924671
DOI: 10.1002/ar.25523 -
PloS One 2024Generalized Joint hypermobility (GJH) is predominantly non-symptomatic. In fact, individuals with joint flexibility usually perform better than their non-hypermobile...
BACKGROUND
Generalized Joint hypermobility (GJH) is predominantly non-symptomatic. In fact, individuals with joint flexibility usually perform better than their non-hypermobile counterparts during physical activities. Notwithstanding, strength and balance are essential to maintain the control of the extra range of motion during activities and to prevent musculoskeletal complications. There are limited and conflicting pieces of evidence in literature regarding the association between strength and balance in children with GJH.
OBJECTIVES
The purpose of this study was to examine differences in functional strength, dynamic balance, proprioception, and isometric strength in children with and without joint hypermobility and determine the association between strength outcomes and dynamic balance.
METHOD
A cross-sectional study was conducted among children aged 6 to 11. Hypermobility was determined using the Beighton Score, with scores ≥6 representing hypermobility. Functional strength was assessed with the Functional Strength Measure (FSM), isometric strength was determined with a handheld dynamometer (HHD), the Y-Balance Test (YBT) was used to assess dynamic balance and the Wedges test to measure proprioception.
RESULTS
This study included 588 participants (age: 7.97 ± 1.3 years; height: 128±10.1 cm; mass: 27.18 ± 7.98 kg). 402 children were classified as having normal mobility and 186 as being hypermobile. Hypermobile children had better functional strength in the lower extremities than children with normal range mobility but lower reach distance in the YBT. No differences in proprioception, functional strength of the upper extremity or isometric strength in the hands were found. However, isometric lower extremity force was less in hypermobile children than children with normal range mobility. Irrespective of their joint mobility, a fair significant correlation existed between total Y-balance distance and FSM items r = 0.16-0.37, p = 0.01. Correlations between total Y-balance distance and isometric strength of knee and ankle muscles ranged between r = 0.26-0.42, p = 0.001.
CONCLUSION
Hypermobile joints seem to co-occur with lower extremity isometric strength, more functional strength in the lower extremities and less reaching distance in dynamic balance. The opposing direction of the results on functional and isometric strength tests highlights the importance of the type of outcome measures used to describe the association of strength and the range of motion.
Topics: Humans; Child; Joint Instability; Male; Female; Postural Balance; Cross-Sectional Studies; Muscle Strength; Range of Motion, Articular; Proprioception
PubMed: 38923950
DOI: 10.1371/journal.pone.0302218 -
The International Journal of Medical... Jun 2024Up to 20% of patients remain unsatisfied after total knee arthroplasty (TKA), prompting the development of new implants. Bi-Cruciate Retaining (BCR) TKA preserves both... (Comparative Study)
Comparative Study
BACKGROUND
Up to 20% of patients remain unsatisfied after total knee arthroplasty (TKA), prompting the development of new implants. Bi-Cruciate Retaining (BCR) TKA preserves both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), with the ACL beneficial for its proprioceptive qualities. The Bi-Cruciate Stabilised (BCS) TKA substitutes the ACL and PCL with a unique dual cam-post mechanism. Robotics improve accuracy and facilitate technically demanding TKA.
METHODS
This was a retrospective case-control study recruited from two centres. Measured outcomes included kinematic analysis, proprioception, and functional outcomes.
RESULTS
There was a significantly larger maximum flexion angle and range of flexion to extension in sit-to-stand and stairs in BCR when compared to BCS. Further analysis revealed more similarities between BCR and normal native knees. Proprioception and functional scores did not have any statistical difference.
CONCLUSION
BCR TKA demonstrated better knee flexion in weight-bearing active range of motion and showed similarities with normal knee kinematics.
Topics: Humans; Arthroplasty, Replacement, Knee; Robotic Surgical Procedures; Biomechanical Phenomena; Male; Female; Retrospective Studies; Range of Motion, Articular; Middle Aged; Aged; Posterior Cruciate Ligament; Case-Control Studies; Knee Joint; Anterior Cruciate Ligament; Knee Prosthesis; Treatment Outcome; Proprioception
PubMed: 38922786
DOI: 10.1002/rcs.2655 -
Journal of Functional Morphology and... Jun 2024This review aims to reveal the effectiveness of myofunctional speech therapy on facial rejuvenation and/or improvement of orofacial function. A systematic review of four... (Review)
Review
This review aims to reveal the effectiveness of myofunctional speech therapy on facial rejuvenation and/or improvement of orofacial function. A systematic review of four medical electronic databases (Medline, Google Scholar, SciELO, and LILACS) was conducted between January and March 2023. The research question was defined using the PICO model: Population (P): adult subjects with signs of physiological aging of facial skin. Intervention (I): aesthetic speech therapy (facial exercises and/or myofunctional therapy). Control (C): absence of treatment. Outcome (O): facial rejuvenation. Through the search process, a total of 472 potentially relevant articles were identified. A total of 21 studies were included in the review. Most of the studies required the participants to perform exercises learned during the weekly session on a daily basis. The subjects underwent an integrated treatment with facial exercises and worked on the stomatognathic functions for different durations. Many differences were found in the evaluation tools used to investigate the starting situation and the effects obtained following the treatment. At the diagnostic level, there was no concordance in the choice of the most appropriate scales and assessment tools, but great heterogeneity was observed. Indeed, forty-eight percent of the studies collected objective data through the use of various instruments (oral devices, electromyographs, cutometers, muscle ultrasound scans, and laser scans of the face). The observed improvements included not only a reduction in wrinkles and frown lines but also decreased muscle tension and slackness, enhanced facial symmetry and lip competence, improved skin elasticity, and restored stomatognathic function. These changes led to myofunctional restoration and facial rejuvenation, resulting in increased satisfaction with self-image and proprioception.
PubMed: 38921635
DOI: 10.3390/jfmk9020099 -
Infection and Drug Resistance 2024Tabes dorsalis is a late manifestation of neurosyphilis, characterized by progressive ataxia, lightning pains, loss of proprioception, and urinary incontinence. The...
BACKGROUND
Tabes dorsalis is a late manifestation of neurosyphilis, characterized by progressive ataxia, lightning pains, loss of proprioception, and urinary incontinence. The absence of a definitive diagnostic standard and the non-specific clinical manifestations have led to a significant rate of misdiagnoses.
METHODS
Hospitalized patients with tabes dorsalis at Peking Union Medical College Hospital between January 2010 and December 2023 were reviewed.
RESULTS
A total of 13 patients were included, with 10 males and 3 females. The median age was 50 years (range, 34-64). The most frequent initial symptoms were limb numbness (30.8%) and lightning pains (30.8%). Eleven patients (84.6%) received misdiagnoses prior to the final diagnosis. The most frequently observed physical sign was positive Romberg's sign (84.6%). Notably, Argyll Robertson pupil was presented in 7 subjects (53.8%). Serological tests revealed positive rapid plasma regain (RPR) and particle agglutination (TPPA) for all patients. All CSF samples were TPPA-reactive. Intramedullary hyperintensity on T2-weighted imaging of spinal MRI was found in 5 patients (38.5%). All patients received anti-syphilitic treatment, with effective treatment recorded in five cases.
CONCLUSION
This study underscores the importance of neurological symptoms and signs in diagnosing tabes dorsalis. Individuals with progressive ataxia and positive Romberg's sign should be closely monitored for potential neurosyphilis. Integrating clinical features, laboratory tests, and neuroimaging could reduce misdiagnosis and expedite the initiation of anti-syphilitic therapy.
PubMed: 38919834
DOI: 10.2147/IDR.S464581 -
The Iowa Orthopaedic Journal 2024Walking is a vital activity often compromised in individuals with neuropathic conditions. Charcot-Marie-Tooth (CMT) disease and Cerebral Palsy (CP) are two common...
BACKGROUND
Walking is a vital activity often compromised in individuals with neuropathic conditions. Charcot-Marie-Tooth (CMT) disease and Cerebral Palsy (CP) are two common neurodevelopmental disabilities affecting gait, predisposing to the risk of falls. With guiding scientific evidence limited, there is a critical need to better understand how surgical correction affects mobility, balance confidence, and gait compared to ankle foot orthosis (AFO) bracing. A systematic approach will enable rigorous collaborative research to advance clinical care.
METHODS
Key elements of this vision include 1) prospective studies in select patient cohorts to systematically compare conservative vs. surgical management, 2) objective laboratory-based evaluation of patient mobility, balance, and gait using reliable methods, and 3) use of patient-centric outcome measures related to health and mobility.
RESULTS
Valid and reliable standardized tests of physical mobility and balance confidence have been described in the literature. They include 1) the four-square step test, a widely used test of balance and agility that predicts fall risk, 2) the self-selected walking velocity, a measure of general mobility able to detect function change with orthosis use, and 3) the activity specific balance confidence scale, a survey instrument that assesses an individual's level of balance confidence during activity. Additionally, motion capture and ground reaction force data can be used to evaluate whole-body motion and loading, with discriminative biomechanical measures including toe clearance during the swing phase of gait, plantarflexion at 50% of swing, peak ankle plantarflexor moment, and peak ankle push-off power.
CONCLUSION
The tools needed to support evidence-based practice and inform clinical decision making in these challenging patient populations are all available. Research must now be conducted to better understand the potential benefits and limitations of AFO use in the context of mobility and balance during gait for individuals with neuropathic conditions, particularly relative to those offered by surgical correction.
CLINICAL RELEVANCE
Following this path of research will provide comparative baseline data on mobility, balance confidence, and gait that can be used to inform an objective criterion-based approach to AFO prescription and the impact of surgical intervention.
Topics: Humans; Postural Balance; Charcot-Marie-Tooth Disease; Foot Orthoses; Cerebral Palsy; Orthotic Devices; Gait Disorders, Neurologic; Gait; Walking
PubMed: 38919344
DOI: No ID Found -
Journal of Neurophysiology Jun 2024Previous research has shown that action effects of self-generated movements are internally predicted before outcome feedback becomes available. To test whether these...
Previous research has shown that action effects of self-generated movements are internally predicted before outcome feedback becomes available. To test whether these sensorimotor predictions are used to facilitate visual information uptake for feedback processing, we measured eye movements during the execution of a goal-directed throwing task. Participants could fully observe the effects of their throwing actions (ball trajectory, and either hitting or missing a target) in most of the trials. In a portion of the trials, the ball trajectory was not visible, and participants only received static information about the outcome. We observed a large proportion of predictive saccades, shifting gaze toward the goal region before the ball arrived and outcome feedback became available. Fixation locations after predictive saccades systematically covaried with future ball positions in trials with continuous ball flight information, but notably also in trials with static outcome feedback and only efferent and proprioceptive information about the movement that could be used for predictions. Fixation durations at the chosen positions after feedback onset were modulated by action outcome (longer durations for misses than for hits) and outcome uncertainty (longer durations for narrow vs. clear outcomes). Combining both effects, durations were longest for narrow errors and shortest for clear hits, indicating that the chosen locations offer informational value for feedback processing. Thus, humans are able to use sensorimotor predictions to direct their gaze toward task-relevant feedback locations. Outcome-dependent saccade latency differences (miss vs. hit) indicate that also predictive valuation processes are involved in planning predictive saccades.
PubMed: 38919149
DOI: 10.1152/jn.00052.2024 -
Journal of the Royal Society, Interface Jun 2024Virtual balancing tasks facilitate the study of human motion control: human reaction to the change of artificially introduced parameters can be studied in a computer...
Virtual balancing tasks facilitate the study of human motion control: human reaction to the change of artificially introduced parameters can be studied in a computer environment. In this article, the dynamics of human stick balancing are generalized using fractional-order derivatives. Reaction delay sets a strong limitation on the length of the shortest stick that human subjects can balance. Human processing of visual input also exhibits a memory effect, which can be modelled by fractional-order derivatives. Therefore, we hypothesize a delayed fractional-order PD control of the unstable fractional-order process. The resulting equation of motion is investigated in a dimensionless framework, and stabilizability limits are determined as a function of the dynamics's order. These theoretical limits are then compared with the results of a systematic series of virtual balancing tests performed by 18 subjects. The comparison shows that the theoretical stabilizability limits for controllers with fixed fractional order correspond to the measured data points. The best fit is obtained if the fractional order of the underlying control law is 0.475.
Topics: Humans; Female; Male; Adult; Postural Balance; Models, Biological; Reaction Time
PubMed: 38919061
DOI: 10.1098/rsif.2023.0685 -
Experimental Brain Research Jun 2024The purpose of the present study was to elucidate whether an external reference frame contributes to tactile localization in blindfolded healthy humans. In a session,...
The purpose of the present study was to elucidate whether an external reference frame contributes to tactile localization in blindfolded healthy humans. In a session, the right forearm was passively moved until the elbow finally reached to the target angle, and participants reached the left index finger to the right middle fingertip. The locus of the right middle fingertip indicated by the participants deviated in the direction of the elbow extension when vibration was provided to the biceps brachii muscle during the passive movement. This finding indicates that proprioception contributes to the identification of the spatial coordinate of the specific body part in an external reference frame. In another session, the tactile stimulus was provided to the dorsal of the right hand during the passive movement, and the participants reached the left index finger to the spatial locus at which the tactile stimulus was provided. Vibration to the biceps brachii muscle did not change the perceived locus of the tactile stimulus indicated by the left index finger. This finding indicates that an external reference frame does not contribute to tactile localization during the passive movement. Humans may estimate the spatial coordinate of the tactile stimulus based on the time between the movement onset and the time at which the tactile stimulus is provided.
PubMed: 38918211
DOI: 10.1007/s00221-024-06877-w -
Journal of Athletic Training Jun 2024
Topics: Humans; Foot; Postural Balance; Electric Stimulation; Male; Biomechanical Phenomena; Young Adult; Female
PubMed: 38918008
DOI: 10.4085/1062-6050-1004.24