Impaired Proprioception Research Articles

The accuracy of restoration of femoral head centre of rotation in the anteroposterior plane after uncemented total hip arthroplasty

AimsHip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane.MethodsPostoperative CT scans of 40 patients who underwent unilateral uncemented total hip arthroplasty were analyzed. Anteroposterior offset (APO) and femoral anteversion were measured on both the operated and non-operated sides. Sagittal tilt of the femoral stem was also measured. APO measured on axial slices was defined as the perpendicular distance between a line drawn from the anterior most point of the proximal femur (anterior reference line) to the centre of the femoral head. The anterior reference line was made parallel to the posterior condylar axis of the knee to correct for rotation.ResultsOverall, 26/40 hips had a centre of rotation displaced posteriorly compared to the contralateral hip, increasing to 33/40 once corrected for sagittal tilt, with a mean posterior displacement of 7 mm. Linear regression analysis indicated that stem anteversion needed to be increased by 10.8° to recreate the head centre in the AP plane. Merely matching the native version would result in a 12 mm posterior displacement.ConclusionThis study demonstrates the significant incidence of posterior displacement of the head centre in uncemented hip arthroplasty. Effects of such displacement include a reduction in impingement free range of motion, potential alterations in muscle force vectors and lever arms, and impaired proprioception due to muscle fibre reorientation.Cite this article: Bone Joint Res 2022;11(3):180–188.

The effect of cryotherapy on postural stabilization assessed by standardized horizontal perturbations of a movable platform

BackgroundCryotherapy is a frequently used therapy in the acute treatment of sports injuries, although it has possible negative effects on dynamic postural stabilization. Research questionWhat is the effect of cryotherapy on the postural stabilization assessed by imposed platform perturbations? MethodsTwenty-four healthy participants (15 male, 9 female) performed 2 test sessions (before and after cryotherapy) consisting of 4 trials each. Each trial included 30 s single leg stance (SLS) on both legs and 4 testing blocks (2 for each leg) of 30 s for the dynamic testing. A single testing block comprised 4 perturbations. After the first session, cryotherapy was applied to the right leg by placing it in ice water at a temperature between 10 °C and 12 ° for 20 min. Outcome measuresWe assessed the Center of Pressure speed (CoPs) and the mean force variation for both static and dynamic tests. Additionally, the Time To Stability (TTS) was calculated for the perturbations. ResultsIn the static trials there was an interaction between leg and session present for the mean force variation (p = 0.01) with a large η2 of 0.24, which shows higher variation of vertical force after application of the cryotherapy on the right leg. During the dynamic trials we found an interaction between leg and session for the TTS suggesting increase of the TTS due to the cryotherapy (p = 0.04), with a large η2 of 0.17. No interaction effect was present for the CoPs in the mediolateral and anteroposterior direction (p = 0.62 and p = 0.12, respectively). SignificanceCryotherapy applied to the lower extremity results in a worse postural stabilization when assessed by platform perturbations. This might be the result of an altered balance strategy, due to impaired proprioception from the affected body part. More research is needed to examine the duration of this effect. Level of evidenceLevel 3, associative study

Impairments in trunk muscles performance and proprioception in older adults with hyperkyphosis

ABSTRACT Background and objectives Thoracic hyperkyphosis is one of the most common postural deformities in the geriatric population. This study investigated whether trunk proprioception, muscle strength, and endurance differ between older adults with hyperkyphosis and the age-matched control group. This study also aimed to explore the association of kyphotic posture with muscle performance, position sense, and force sense. Methods Ninety-seven elderly volunteers (61 with hyperkyphosis and 36 normal controls) participated in this cross-sectional study. The kyphosis degree, trunk position sense, force sense, back muscle strength, and endurance were assessed in all participants. Results The results showed lower back extensor strength and endurance, also higher force and position sense error in the hyperkyphotic group than the control group. In addition, the findings revealed that back extensor strength and endurance, as well as trunk position sense, were associated with kyphotic posture in older adults. Discussion and Implications This study suggests that back extensor strength and endurance and trunk position sense and force sense are potentially modifiable impairments associated with thoracic kyphosis in older adults with hyperkyphosis. It seems monitoring these potentially contributing factors would be helpful in the assessment and treatment of hyperkyphotic older individuals.

The Relationship Between Generalised Joint Hypermobility and Autism Spectrum Disorder in Adults: A Large, Cross-Sectional, Case Control Comparison.

Autism spectrum disorder (ASD) and generalised joint hypermobility (GJH) share a number of clinical manifestations including proprioceptive impairment, motor difficulties, sensory hypersensitivity, and autonomic dysfunction. Clinical observations suggest that GJH is overrepresented in ASD. However, there are currently few systematic studies available. Knowledge about comorbidities may unfold common aetiopathological pathways underlying the association and improve the clinical management. The aim of this large, cross-sectional comparative study is to evaluate the relationship between ASD and GJH in adults. Data on joint hypermobility, symptoms associated with both hypermobility spectrum disorders (HSD) and hypermobile Ehlers-Danlos syndrome (hEDS), lifetime psychiatric diagnoses, psychiatric rating scales for ASD and attention deficit hyperactivity disorder (ADHD), and socio-demographics was collected for 199 individuals with ASD and 419 non-ASD community controls. Logistic regression models adjusting for covariates (age, sex, ethnicity) revealed a significant relationship between ASD and GJH and between ASD and symptomatic GJH, with adjusted odds ratios of 3.1 (95% CI: 1.9, 5.2; p < 0.001) and 4.9 (95% CI: 2.6, 9.0; p < 0.001), respectively. However, the high prevalence of comorbid ADHD in the study sample reduces the generalizability of the results among individuals with ASD without comorbid ADHD. Possibly, an additional ADHD phenotype is the primary driver of the association between ASD and GJH. Furthermore, GJH with additional self-reported symptoms, suggestive of HSD/hEDS, showed a stronger association with ASD than did non-specified GJH, indicating that symptomatic GJH plays a greater role in the relationship than non-specified GJH does. Therefore, the current study underscores the need of careful sample subclassifications. ASD with GJH may represent a novel subgroup of ASD in terms of aetiopathology and clinical presentation. Future research should elucidate the aetiological factors behind the association between ASD and GJH and evaluate how the comorbidity of GJH affects ASD outcomes.

Impaired Lower Limb Proprioception in Spinocerebellar Ataxia Type 3 and Its Affected Factors.

BackgroundSpinocerebellar ataxia type 3 (SCA3) is one of the most common hereditary neurodegenerative diseases. Postural control dysfunction is the main symptom of SCA3, and the proprioceptive system is a critical sensory component of postural control. Accordingly, proprioception quantification assessment is necessary in monitoring the progression of SCA3.ObjectiveWe aimed to quantitatively assess lower limb proprioception and investigate the relationship between proprioception and clinical characteristics in patients with SCA3.MethodsA total of 80 patients with SCA3 and 62 health controls were recruited, and their lower limb proprioception was measured using the Pro-kin system. Clinical characteristics of the SCA3 patients were collected. Multivariable linear regression was used to investigate potential affected factors for lower limb proprioception.ResultsWe found that the patients with SCA3 experience poorer lower limb proprioception characterized by significant impairment in the average trace error (ATE) and time to carry out the test time execution (TTE) compared to controls (P < 0.05). Moreover, there were significant differences in TTE between the right and left lower limbs (P < 0.05) of the patients. Regression analyses revealed that increasing age at onset (AAO) predicts poorer lower limb proprioception for both ATE (β = 2.006, P = 0.027) and TTE (β = 1.712, P = 0.043) and increasing disease duration predicts poorer lower limb proprioception for ATE (β = 0.874, P = 0.044). AAO (β = 0.328, P = 0.019) along with the expanded alleles (β = 0.565, P = 0.000) could affect the severity of ataxia. By contrast, ATE (β = 0.036, P = 0.800) and TTE (β = −0.025, P = 0.862) showed no significant predictors.ConclusionsLower limb proprioception in patients with SCA3 is significantly impaired when compared to healthy controls. Increasing AAO and disease duration are related to impaired lower limb proprioception.

Characterization of a PIEZO2 hypomorph

PIEZO2 is a mechanically activated ion channel expressed in the skin and peripheral sensory nerves. PIEZO2 loss-of-function causes greatly impaired touch perception and proprioception. Here, in two sibling patients, we identify an inherited PIEZO2 missense variant in compound heterozygosity with a clear loss-of-function variant. Interestingly, these patients present with generally milder symptoms than homozygous loss-of-function patients, including motor delay and poor coordination. Their motor function has improved steadily and by age 15 have no major motor limitations.

Effects of Rehabilitation Materials With Different Stability Properties on Muscle Activity: A Narrative Review

Significant muscle imbalance and proprioceptive sensory impairment are seen in patients who apply to physiotherapy and rehabilitation clinics. Bosu, balance tools of different hardness (stability trainer), balance board, treatment balls, and oscillation devices are used in physiotherapy clinics for the restoration of these disorders. However, it is not known exactly how these therapy devices change the activation in different muscles. The aim of this study is to examine the effect of therapy devices with different stability features on muscular activation. For this purpose, a search was performed using “Medline (PubMed), Embase, and Cochrane Library” databases in June 2021. Studies investigating the effect of rehabilitation material with different stability properties on muscular activation were included in the narrative review. 7 studies met inclusion criteria. The change in the stability and hardness level of the surface causes an increase in activation in certain muscle groups, while it does not cause a significant change in the activation of some muscle groups. For this reason, it is important to determine the target muscle group well and to use treatment devices suitable for this purpose when determining the treatment program of patients who apply to physiotherapy and rehabilitation clinics.

The relationship between cervical proprioception and balance in patients with fibromyalgia syndrome.

Proprioceptive abnormalities, balance, and postural disorders have been previously reported in fibromyalgia syndrome (FMS). Unlike previous research, the aim of this study was to compare the proprioception of the cervical region of patients with FMS with a healthy control group. The relationship between cervical proprioception impairment and loss of balance was also examined. A total of 96 female FMS patients and 96 female healthy control subjects were enrolled in this case-control study. The cervical joint position error test (CJPET) was administered to the patient and control groups for cervical proprioception evaluation. FMS patients were assessed with a visual analogue scale (VAS), fibromyalgia impact questionnaire (FIQ), and fatigue severity scale (FSS). Balance tests were applied to both groups. FMS patients had significantly impaired CJPET results in all directions (p < 0.001). There were significant positive correlations between FIQ scores and CJPET results (r = 0.542 and p < 0.001 for right rotation; r = 0.604 and p < 0.001 for left rotation; r = 0.550 and p < 0.001 for flexion; r = 0.612 and p < 0.001 for extension). Significant correlations were found between CJPET measurements and balance tests (for sit-to-stand test; r = 0.510 and p < 0.001 for right rotation; r = 0.431 and p < 0.001 for left rotation; r = 0.490 and p < 0.001 for flexion; r = 0.545 and p < 0.001 for extension), (for timed up and go test; r = 0.469 and p < 0.001 for right rotation; r = 0.378 and p < 0.001 for left rotation; r = 0.410 and p < 0.001 for flexion; r = 0.496 and p < 0.001 for extension) and (for one-legged balance test; r = -0.479 and p < 0.001 for right rotation; r = -0.365 and p < 0.001 for left rotation; r = -0.392 and p < 0.001 for flexion; r = -0.469 and p < 0.001 for extension). Cervical proprioception and balance were impaired in FMS patients. As the disease activity and fatigue level increased, so the deterioration in cervical proprioception became more evident. There were correlations that demonstrated an association between impaired cervical proprioception and poor balance tests. Therefore, proprioception and balance assessments should be integrated into the physical examination processes of FMS patients.

Comparsion of the Effect on Balance Training with Foam Balance Activity and Tilt Board Exercise to Improve Fall Risk among Physically Active Chronic Knee Osteoarthritis Patients in Selected Places of Bengaluru

Background and purpose: Knee osteoarthritis is one of the most prevalent musculoskeletal complaints worldwide.Individuals with knee OA display impairments in knee joint proprioception. Reduced balance function isassociated with an increased risk of falling. The aim of this study was to measure the balance between foam and tiltboard training among physically active chronic osteoarthritis patients and to compare the effectiveness of balancetraining using proprioceptive tools like foam and tilt table among physically active chronic osteoarthritis patients.Methods: This study included subjects between the ages of 40-70 years with chronic knee osteoarthritis and a bodymass index of 30 and above. Subjects were recruited based on inclusion and exclusion criteria. It was a comparativestudy with 40 subjects divided into two groups of 20 each. Demographic data and other variables were collectedand recorded and measures like VAS, WOMAC, Functional reach test and Berg balance scale were used.Results: The foam balance activity group as well as the wobble board exercise group showed effective improvementsclinically after the intervention. Comparison between groups did not show statistically significant improvement isany one over the other but clinically significant improvements were seen more in the wobble board exercise group.Conclusion: The study concludes that the wobble board exercise group subjects showed clinically betterimprovements in balance and functional abilities when compared to the foam balance activity group subjects.Comparison between both groups did not show statistically significant improvement.

Does cervical proprioception affect hand dexterity of physiotherapists with and without mechanical neck pain?

Purposes. This study was conducted to compare between cervical proprioception and hand dexterity in physiotherapists with and without mechanical neck pain, and to determine the relationship between cervical proprioception and hand dexterity in physiotherapists. Materials and methods. Sixty physiotherapists (30 with chronic mechanical neck pain (G1), mild to moderate neck pain lasted more than 6 months and 30 healthy control (GII)). Both sexes were enrolled with; age ranged from 25 to 35 years, normal body mass index (BMI) and at least one year of practice of manual work. All participants undergone evaluation of cervical joint position error (JPE) using cervical range of motion device (CROM) through head-to-neutral repositioning (NHR) and head-to-target repositioning (THR) tests in flexion direction in addition to evaluation of hand dexterity using Purdue pegboard test. Results. There was statistically significant difference in median values of JPE and hand dexterity between both groups. There was statistically significant indirect medium to strong correlation between JPE in flexion (NHR and THR) and hand dexterity (in dominant and assembly tests). Conclusions. Physiotherapists with neck pain have impairment in cervical proprioception which in turn negatively affects hand dexterity. Hand dexterity is important functional property for physiotherapist to apply different manual techniques. So, impairment of hand dexterity may interfere with the efficiency of manual application.

Increased upper-limb sensory attenuation with age.

The pressure of our own finger on the arm feels differently than the same pressure exerted by an external agent: the latter involves just touch, whereas the former involves a combination of touch and predictive output from the internal model of the body. This internal model predicts the movement of our own finger, and hence the intensity of the sensation of the finger press is decreased. A decrease in intensity of the self-produced stimulus is called sensory attenuation. It has been reported that, because of decreased proprioception with age and an increased reliance on the prediction of the internal model, sensory attenuation is increased in older adults. In this study, we used a force matching paradigm to test whether sensory attenuation is also present over the arm and whether aging increases sensory attenuation. We demonstrated that, although both young and older adults overestimate a self-produced force, older adults overestimate it even more, showing an increased sensory attenuation. In addition, we also found that both younger and older adults self-produce higher forces when activating the homologous muscles of the upper limb. Although this is traditionally viewed as evidence for an increased reliance on internal model function in older adults because of decreased proprioception, proprioception appeared unimpaired in our older participants. This begs the question of whether an age-related decrease in proprioception is really responsible for the increased sensory attenuation observed in older people.NEW & NOTEWORTHY Forces generated externally (by the environment on the participant) and internally (by the participant on her/his body) are not perceived with the same intensity. Internally generated forces are perceived less intensely than externally generated ones. This difference in force sensation has been shown to be higher in elderly participants when the forces were applied on the fingers because of their impaired proprioception. Here we replicated this finding for the arm but suggest that it is unlikely to be linked to impaired proprioception.

Contribution of Sensory Function to Preclinical Indicators of Physical and Cognitive Functioning With Aging

There are well established associations between sensory loss and physical and cognitive deficits with aging, but gaps remain in our understanding of the associations between sensory function and early preclinical indicators of physical and cognitive decline. This symposium will present data from the Baltimore Longitudinal Study of Aging (BLSA) on a series of studies investigating the links among sensory function, motor function, and physical and cognitive outcomes in older adults. In the first study, Dr. Gross will present an operational definition of early cognitive impairment (ECI) based on a combination of two cognitive measures – the Card Rotations test and the California Verbal Learning Test Immediate Recall – to predict progression to MCI/AD. In the second study, Dr. Cai will evaluate the relationship between multisensory impairment (in vision, hearing, olfaction, proprioception and vestibular function) and the algorithmic definition of ECI. In the third study, Dr. Armstrong will evaluate the association between multisensory impairment and another biomarker of ECI or preclinical AD, specifically PET-PiB deposition. In the fourth study, Dr. Schrack, will present the joint contribution of multisensory (hearing and vision) impairment and motor function (gait speed) on risk of incident MCI/AD in longitudinal analyses. Finally, Dr. Martinez Amezcua will present the longitudinal association between hearing and vestibular function and decline in higher level physical function and endurance performance. Taken together, these studies present compelling data about the contribution of sensory function to preclinical indicators of physical and cognitive functioning with aging.

Balance and proprioception impairment, assessment tools, and rehabilitation training in patients with total hip arthroplasty: a systematic review

BackgroundOsteoarthritis and subsequent total hip arthroplasty (THA) lead to damages to hip joint mechanoceptors, which in turns lead to impairments in proprioception. One of the abilities mainly affected by an altered joint proprioception is balance. The aim of this work was to investigate the balance and proprioception impairments, current assessment tools, and rehabilitation training after THA.MethodsA systematic literature revision was conducted on PubMed, Web of Science and Cochrane databases. Articles reporting balance and proprioception impairments, current assessment tools, or rehabilitation interventions were included. Methodological quality was assessed using the Downs and Black checklist. A total of 41 articles were included, 33 discussing balance and proprioception assessment, and 8 dealing with training. Data related to type of surgical approach, type and timing of assessment protocols, assessment instrumentation, and type, volume and duration of the rehabilitation training were extracted from each study.ResultsThirty-one studies were of high quality, 2 of moderate quality and 8 of low-quality. Literature review showed an improvement in balance following THA in comparison with the pre-operative performance, although balance abnormalities persist up to 5 years after surgery, with THA patients showing an increased risk for falls. Balance training is effective in all the rehabilitation phases if specifically structured for balance enhancement and consistent in training volume. It remains unclear which assessments are more appropriate for the different rehabilitation phases, and if differences exist between the different surgical procedures used for THA. Only two studies assessed proprioception.ConclusionBalance and proprioception show impairments up to 5 years after THA, increasing the risk of falls. However, patients with THA may benefit of an adequate balance training. Further research is needed to investigate the gaps in balance and proprioception assessment and training following THA surgery.

Proprioception-based movement goals support imitation and are disrupted in apraxia

The ability to imitate observed actions serves as an efficient method for learning novel movements and is specifically impaired (without concomitant gross motor impairments) in the neurological disorder of limb apraxia, a disorder common after left hemisphere stroke. Research with apraxic patients has advanced our understanding of how people imitate. However, the role of proprioception in imitation has been rarely assessed directly. Prior work has proposed that proprioceptively sensed body position is transformed into a visual format, supporting the attainment of a desired imitation goal represented visually (i.e., how the movement should look when performed). In contrast, we hypothesized a more direct role for proprioception: we suggest that movement goals are also represented proprioceptively (i.e., how a desired movement should feel when performed), and the ability to represent or access such proprioceptive goals is deficient in apraxia. Using a novel imitation task in which a robot cued meaningless trajectories proprioceptively or visually, we probed the role of each sensory modality. We found that patients with left hemisphere stroke were disproportionately worse than controls at imitating when cued proprioceptively versus visually. This proprioceptive versus visual disparity was associated with apraxia severity as assessed by a traditional imitation task, but could not be explained by general proprioceptive impairment or speed-accuracy trade-offs. These data suggest that successful imitation depends in part on the ability to represent movement goals in terms of how those movements should feel, and that deficits in this ability contribute to imitation impairments in patients with apraxia.

Cross-legged sitting posture effect on lumbar proprioception in young adults: a cross-sectional study

BackgroundThe cross-legged sitting posture (CLS) is assumed by young adults’ results in a bent and unbalanced posture. The study purpose was to assess the effect of sitting in a cross-legged position (knee on knee) on lumbar proprioception. Thirty-six participants of both genders aged from 18 to 25 were selected and divided equally into group A who adapt to a cross-legged sitting posture and group B who adapt to erect sitting (not prefer cross-legged sitting). The Biodex System 3 pro isokinetic dynamometer was utilized to assess the lumbar proprioception by testing the lumbar region repositioning accuracy.ResultsThe lumbar repositioning error of group A increased statistically significantly as compared to group B (p < 0.05).ConclusionsCross-legged sitting posture negatively affects lumbar proprioception compared with participants who adapt to erect sitting, and this effect should be considered in the avoidance of sitting in a cross-legged position and in prevention and intervention programs of lumbar proprioception impairment.

The Cortical Response Evoked by Robotic Wrist Perturbations Reflects Level of Proprioceptive Impairment After Stroke

Background: Proprioception is important for regaining motor function in the paretic upper extremity after stroke. However, clinical assessments of proprioception are subjective and require verbal responses from the patient to applied proprioceptive stimuli. Cortical responses evoked by robotic wrist perturbations and measured by electroencephalography (EEG) may be an objective method to support current clinical assessments of proprioception.Objective: To establish whether evoked cortical responses reflect proprioceptive deficits as assessed by clinical scales and whether they predict upper extremity motor function at 26 weeks after stroke.Methods: Thirty-one patients with stroke were included. In week 1, 3, 5, 12, and 26 after stroke, the upper extremity sections of the Erasmus modified Nottingham Sensory Assessment (EmNSA-UE) and the Fugl-Meyer Motor Assessment (FM-UE) and the EEG responses (64 channels) to robotic wrist perturbations were measured. The extent to which proprioceptive input was conveyed to the affected hemisphere was estimated by the signal-to-noise ratio (SNR) of the evoked response. The relationships between SNR and EmNSA-UE as well as SNR and time after stroke were investigated using linear regression. Receiver-operating-characteristic curves were used to compare the predictive values of SNR and EmNSA-UE for predicting whether patients regained some selective motor control (FM-UE > 22) or whether they could only move their paretic upper extremity within basic limb synergies (FM-UE ≤ 22) at 26 weeks after stroke.Results: Patients (N = 7) with impaired proprioception (EmNSA-UE proprioception score < 8) had significantly smaller SNR than patients with unimpaired proprioception (N = 24) [EmNSA-UE proprioception score = 8, t(29) = 2.36, p = 0.03]. No significant effect of time after stroke on SNR was observed. Furthermore, there was no significant difference in the predictive value between EmNSA-UE and SNR for predicting motor function at 26 weeks after stroke.Conclusion: The SNR of the evoked cortical response does not significantly change as a function of time after stroke and differs between patients with clinically assessed impaired and unimpaired proprioception, suggesting that SNR reflects persistent damage to proprioceptive pathways. A similar predictive value with respect to EmNSA-UE suggests that SNR may be used as an objective predictor next to clinical sensory assessments for predicting motor function at 26 weeks after stroke.

Inter-segmental coordination amplitude and variability differences during gait in patients with Ehlers-Danlos syndrome and healthy adults

BackgroundThere is limited research examining gait and inter-segmental coordination in patients with Ehlers-Danlos syndrome. The objective was to compare lower extremity inter-segmental coordination amplitude and variability during gait between patients with Ehlers-Danlos syndrome and healthy adults. MethodsThis cross-sectional study included participants with Ehlers-Danlos syndrome (n = 13) and healthy adults (n = 14). Gait data were acquired using a motion capture system and force plates. Participants ambulated at self-selected speeds for five trials. Inter-segmental coordination was quantified using continuous relative phase, which examined the dynamic interaction between the thigh-shank and shank-foot paired segments (i.e. phase space relation). A 2-way mixed analysis of variance examined the effects of groups (Ehlers-Danlos and healthy) and gait phases (stance and swing phase) on inter-segmental coordination amplitude and between-trial variability. Effect sizes were calculated using Cohen's d. FindingsThe Ehlers-Danlos group had greater inter-segmental coordination variability compared to the healthy group for foot-shank and shank-thigh segment pairs in the sagittal plane over stance and swing phases (P = 0.04; small to large effect sizes). The Ehlers-Danlos group also had greater variability in the frontal plane at the foot-shank segment pair during stance phase (P = 0.03; large effect). There were no differences in inter-segmental coordination amplitude between groups (P = 0.06 to 0.85). InterpretationPatients with Ehlers-Danlos syndrome have more variability between gait trials in lower limb motor coordination than healthy adults. This may be related to the impaired proprioception, reduced strength, pain, or slower gait speed seen in this population.

Validity and reliability of video analysis to evaluate ankle proprioceptive reintegration during postural control

BackgroundThe ability to dynamically reintegrate proprioceptive signals after they have been perturbated is impaired in certain pathologies. Evaluation of proprioceptive reintegration is useful for clinical practice but currently requires expensive laboratory tools. We developed a simple method, accessible to clinicians.Research question: Is two-dimensional (2D) video analysis of earlobe displacement a valid and reliable tool for the evaluation of ankle proprioceptive reintegration following muscle vibration? MethodsThirty-eight healthy individuals underwent vibration of the triceps surae while standing on a force plate (FP). Anterior (sagittal plane) earlobe displacement (‘overshoot’) was recorded at vibration cessation using 2D video analysis and rated by 3 blind examiners. Correlation analysis was performed between earlobe and center of pressure displacement (dCoP, recorded with the FP) to determine validity. Intra and interrater reliability were determined by calculation of the intraclass correlation coefficient (ICC), change in the mean (CiM), standard error of measurement (SEM) and the minimal detectable change (MDC). Results and significanceStrong positive correlations (r = 0.82–0.94, p < .001) were found between video and FP data. Intra- and interrater reliability were excellent (ICC from 0.99 to 1.00 and from 0.90 to 0.97 respectively). For intrarater analysis, the CiM was 0.01 cm, SEM were 0.27 cm (95% CI: 0.23–0.33) and 3.43% (95% CI: 2.92–4.20) and the MDC was 0.74 cm. For interrater reliability, the CiM ranged from − 0.81–0.55 cm, the SEM from 0.61 to 1.12 cm and the MDC from 1.69 to 3.10 cm. 2D video analysis of anterior (sagittal) earlobe displacement is therefore a valid and reliable method to assess postural recovery following muscle vibration. This simple method could be used by clinicians to evaluate the ability of the central nervous system to reintegrate proprioceptive signals from the ankle. Further studies are needed to assess its validity in individuals with proprioceptive impairment.

Connecting brain and body: Transdiagnostic relevance of connective tissue variants to neuropsychiatric symptom expression.

The mind is embodied; thoughts and feelings interact with states of physiological arousal and physical integrity of the body. In this context, there is mounting evidence for an association between psychiatric presentations and the expression variant connective tissue, commonly recognised as joint hypermobility. Joint hypermobility is common, frequently under-recognised, significantly impacts quality of life, and can exist in isolation or as the hallmark of hypermobility spectrum disorders (encompassing joint hypermobility syndrome and hypermobile Ehlers-Danlos syndrome). In this narrative review, we appraise the current evidence linking psychiatric disorders across the lifespan, beginning with the relatively well-established connection with anxiety, to hypermobility. We next consider emerging associations with affective illnesses, eating disorders, alongside less well researched links with personality disorders, substance misuse and psychosis. We then review related findings relevant to neurodevelopmental disorders and stress-sensitive medical conditions. With growing understanding of mind-body interactions, we discuss potential aetiopathogenetic contributions of dysautonomia, aberrant interoceptive processing, immune dysregulation and proprioceptive impairments in the context of psychosocial stressors and genetic predisposition. We examine clinical implications of these evolving findings, calling for increased awareness amongst healthcare professionals of the transdiagnostic nature of hypermobility and related disorders. A role for early screening and detection of hypermobility in those presenting with mental health and somatic symptoms is further highlighted, with a view to facilitate preventative approaches alongside longer-term holistic management strategies. Finally, suggestions are offered for directions of future scientific exploration which may be key to further delineating fundamental mind-body-brain interactions.

Investigating the neuroanatomy underlying proprioception using a stroke model

Neuroanatomical investigations have associated cortical areas, beyond Primary Somatosensory Cortex (S1), with impaired proprioception. Cortical regions have included temporoparietal (TP) regions (supramarginal gyrus, superior temporal gyrus, Heschl's gyrus) and insula. Previous approaches have struggled to account for concurrent damage across multiple brain regions. Here, we used a targeted lesion analysis approach to examine the impact of specific combinations of cortical and sub-cortical lesions and quantified the prevalence of proprioceptive impairments when different regions are damaged or spared.Seventy-seven individuals with stroke (49 male; 28 female) were identified meeting prespecified lesion criteria based on MRI/CT imaging: 1) TP lesions without S1, 2) TP lesions with S1, 3) isolated S1 lesions, 4) isolated insula lesions, and 5) lesions not impacting these regions (other regions group). Initially, participants meeting these criteria (1–4) were grouped together into right or left lesion groups and compared to each other, and the other regions group (5), on a robotic Arm Position Matching (APM) task and a Kinesthesia (KIN) task. We then examined the behaviour of individuals that met each specific criteria (groups 1–5).Proprioceptive impairments were more prevalent following right hemisphere lesions than left hemisphere lesions. The extent of damage to TP regions correlated with performance on both robotic tasks. Even without concurrent S1 lesions, TP and insular lesions were associated with impairments on the APM and KIN tasks. Finally, lesions not impacting these regions were much less likely to result in impairments.This study highlights the critical importance of TP and insular regions for accurate proprioception. Significance statementThis work advances our understanding of the neuroanatomy of human proprioception. We validate the importance of regions, beyond the dorsal column medial lemniscal pathway and S1, for proprioception. Further, we provide additional evidence of the importance of the right hemisphere for human proprioception. Improved knowledge on the neuroanatomy of proprioception is crucial for advancing therapeutic approaches which target individuals with proprioceptive impairments following neurological injury or with neurological disorders.