Personalizing exoskeleton assistance while walking in the real world.

Personalized exoskeleton assistance provides users with the largest improvements in walking speed1 and energy economy2-4 but requires lengthy tests under unnatural laboratory conditions. Here we show that exoskeleton optimization can be performed rapidly and under real-world conditions. We designed a portable ankle exoskeleton based on insights from tests with a versatile laboratory testbed. We developed a data-driven method for optimizing exoskeleton assistance outdoors using wearable sensors and found that it was equally effective as laboratory methods, but identified optimal parameters four times faster. We performed real-world optimization using data collected during many short bouts of walking at varying speeds. Assistance optimized during one hour of naturalistic walking in a public setting increased self-selected speed by 9 ± 4% and reduced the energy used to travel a given distance by 17 ± 5% compared with normal shoes. This assistance reduced metabolic energy consumption by 23 ± 8% when participants walked on a treadmill at a standard speed of 1.5 m s-1. Human movements encode information that can be used to personalize assistive devices and enhance performance.

A dynamic foot model for predictive simulations of human gait reveals causal relations between foot structure and whole-body mechanics.

The unique structure of the human foot is seen as a crucial adaptation for bipedalism. The foot's arched shape enables stiffening the foot to withstand high loads when pushing off, without compromising foot flexibility. Experimental studies demonstrated that manipulating foot stiffness has considerable effects on gait. In clinical practice, altered foot structure is associated with pathological gait. Yet, experimentally manipulating individual foot properties (e.g. arch height or tendon and ligament stiffness) is hard and therefore our understanding of how foot structure influences gait mechanics is still limited. Predictive simulations are a powerful tool to explore causal relationships between musculoskeletal properties and whole-body gait. However, musculoskeletal models used in three-dimensional predictive simulations assume a rigid foot arch, limiting their use for studying how foot structure influences three-dimensional gait mechanics. Here, we developed a four-segment foot model with a longitudinal arch for use in predictive simulations. We identified three properties of the ankle-foot complex that are important to capture ankle and knee kinematics, soleus activation, and ankle power of healthy adults: (1) compliant Achilles tendon, (2) stiff heel pad, (3) the ability to stiffen the foot. The latter requires sufficient arch height and contributions of plantar fascia, and intrinsic and extrinsic foot muscles. A reduced ability to stiffen the foot results in walking patterns with reduced push-off power. Simulations based on our model also captured the effects of walking with anaesthetised intrinsic foot muscles or an insole limiting arch compression. The ability to reproduce these different experiments indicates that our foot model captures the main mechanical properties of the foot. The presented four-segment foot model is a potentially powerful tool to study the relationship between foot properties and gait mechanics and energetics in health and disease.

Cerebral hemodynamics underlying ankle force sense modulated by high-definition transcranial direct current stimulation.

This study aimed to investigate the effects of high-definition transcranial direct current stimulation on ankle force sense and underlying cerebral hemodynamics. Sixteen healthy adults (8 males and 8 females) were recruited in the study. Each participant received either real or sham high-definition transcranial direct current stimulation interventions in a randomly assigned order on 2 visits. An isokinetic dynamometer was used to assess the force sense of the dominant ankle; while the functional near-infrared spectroscopy was employed to monitor the hemodynamics of the sensorimotor cortex. Two-way analyses of variance with repeated measures and Pearson correlation analyses were performed. The results showed that the absolute error and root mean square error of ankle force sense dropped more after real stimulation than after sham stimulation (dropped by 23.4% vs. 14.9% for absolute error, and 20.0% vs. 10.2% for root mean square error). The supplementary motor area activation significantly increased after real high-definition transcranial direct current stimulation. The decrease in interhemispheric functional connectivity within the Brodmann's areas 6 was significantly correlated with ankle force sense improvement after real high-definition transcranial direct current stimulation. In conclusion, high-definition transcranial direct current stimulation can be used as a potential intervention for improving ankle force sense. Changes in cerebral hemodynamics could be one of the explanations for the energetic effect of high-definition transcranial direct current stimulation.

Voluntary co-contraction of ankle muscles alters motor unit discharge characteristics and reduces estimates of persistent inward currents.

Motoneuronal persistent inward currents (PICs) are facilitated by neuromodulatory inputs but are highly sensitive to local inhibitory circuits. Estimates of PICs are reduced by group Ia reciprocal inhibition, and increased with the diffuse actions of neuromodulators released during remote muscle contraction. However, it remains unknown how motoneurons function in the presence of simultaneous excitatory and inhibitory commands. To probe this topic, we investigated motor unit discharge patterns and estimated PICs during voluntary co-contraction of ankle muscles, which simultaneously demands the contraction of agonist-antagonist pairs. Twenty participants performed triangular ramps of both co-contraction (simultaneous dorsiflexion and plantar flexion) and isometric dorsiflexion to a peak of 30% of their maximum muscle activity from a maximal voluntary contraction. Motor unit spike trains were decomposed from high-density surface EMG activity recorded from tibialis anterior using blind source separation algorithms. Voluntary co-contraction altered motor unit discharge rate characteristics. Discharge rate at recruitment and peak discharge rate were modestly reduced (∼6% change; P < 0.001; d = 0.22) and increased (∼2% change; P = 0.001, d = -0.19), respectively, in the entire dataset but no changes were observed when motor units were tracked across conditions. The largest effects during co-contraction were that estimates of PICs (ΔF) were reduced by ∼20% (4.47 vs. 5.57 pulses per second during isometric dorsiflexion; P < 0.001, d = 0.641). These findings suggest that, during voluntary co-contraction, the inhibitory input from the antagonist muscle overcomes the additional excitatory and neuromodulatory drive that may occur due to the co-contraction of the antagonist muscle, which constrains PIC behaviour. KEY POINTS: Voluntary co-contraction is a unique motor behaviour that concurrently provides excitatory and inhibitory synaptic input to motoneurons. Co-contraction of agonist-antagonist pairs alters agonist motor unit discharge characteristics, consistent with reductions in persistent inward current magnitude.

Ontogenic transformation of the ankle from the initial mediolateral arrangement of the calcaneus and talus: A histological study of human embryos and early fetuses.

The human calcaneus is robust and provides a prominent heel for effective bipedal locomotion, although the adjacent talus has no muscle attachments. However, there is incomplete information about the morphological changes in these prominent bones during embryo development. We examined serial histological sections of 23 human embryos and early-term fetuses (approximately 5-10 weeks' gestational age [GA]). At a GA of 5 weeks, the precartilage talus was parallel to and on the medial side of the calcaneus, which had a prolate spheroid shape and consisted of three masses. At a GA of 6 weeks, the cartilaginous talus extended along the proximodistal axis, and the tuber calcanei became long and bulky, with a small sustentaculum talus at the "distal" side. At a GA of 6 to 8 weeks, the sustentaculum had a medial extension below the talus so that the talus "rode over" the calcaneus. In contrast, the talus had a more complex shape, depending on the growth of adjacent bones. At a GA of 9 to 10 weeks, the talus was above the calcaneus, but the medial part still faced the plantar subcutaneous tissue because of the relatively small sustentaculum. Therefore, the final morphology appeared after an additional several weeks. Muscle activity seemed to facilitate growth of the tuber calcanei, but growth of the other parts of calcaneus, including the sustentaculum, seemed to depend on active proliferation at the different sites of cartilage. Multiple tendons and ligaments seemed to fix the talus so that it remained close to the calcaneus.

Muscle fiber strain rates in the lower leg during ankle dorsi-/plantarflexion exercise.

Static quantitative magnetic resonance imaging (MRI) provides readouts of structural changes in diseased muscle, but current approaches lack the ability to fully explain the loss of contractile function. Muscle contractile function can be assessed using various techniques including phase-contrast MRI (PC-MRI), where strain rates are quantified. However, current two-dimensional implementations are limited in capturing the complex motion of contracting muscle in the context of its three-dimensional (3D) fiber architecture. The MR acquisitions (chemical shift-encoded water-fat separation scan, spin echo-echoplanar imaging with diffusion weighting, and two time-resolved 3D PC-MRI) wereperformed at 3 T. PC-MRI acquisitions and performed with and without load at 7.5% of the maximum voluntary dorsiflexion contraction force. Acquisitions (3 T, chemical shift-encoded water-fat separation scan, spin echo-echo planar imaging with diffusion weighting, and two time-resolved 3D PC-MRI) were performed with and without load at 7.5% of the maximum voluntary dorsiflexion contraction force. Strain rates and diffusion tensors were calculated and combined to obtain strain rates along and perpendicular to the muscle fibers in seven lower leg muscles during the dynamic dorsi-/plantarflexion movement cycle. To evaluate strain rates along the proximodistal muscle axis, muscles were divided into five equal segments. t-tests were used to test if cyclic strain rate patterns (amplitude > 0) were present along and perpendicular to the muscle fibers. The effects of proximal-distal location and load were evaluated using repeated measures ANOVAs. Cyclic temporal strain rate patterns along and perpendicular to the fiber were found in all muscles involved in dorsi-/plantarflexion movement (p < 0.0017). Strain rates along and perpendicular to the fiber were heterogeneously distributed over the length of most muscles (p < 0.003). Additional loading reduced strain rates of the extensor digitorum longus and gastrocnemius lateralis muscle (p < 0.001). In conclusion, the lower leg muscles involved in cyclic dorsi-/plantarflexion exercise showed cyclic fiber strain rate patterns with amplitudes that varied between muscles and between the proximodistal segments within the majority of muscles.

Clinical and biomechanical effectiveness of foot-ankle exercise programs and weight-bearing activity in people with diabetes and neuropathy: A systematic review and meta-analysis.

BACKGROUND: Most interventions to prevent foot ulcers in people with diabetes do not seek to reverse the foot abnormalities that led to the ulcer. Foot-ankle exercise programs target these clinical and biomechanical factors, such as protective sensation and mechanical stress. Multiple RCTs exist investigating the effectiveness of such programs, but these have never been summarised in a systematic review and meta-analysis. METHODS: We searched the available scientific literature in PubMed, EMBASE, CINAHL, Cochrane databases and trial registries for original research studies on foot-ankle exercise programs for people with diabetes at risk of foot ulceration. Both controlled and non-controlled studies were eligible for selection. Two independent reviewers assessed the risk of bias of controlled studies and extracted data. Meta-analysis (using Mantel-Haenszel's statistical method and random effect models) was performed when >2 RCTs were available that met our criteria. Evidence statements, including the certainty of evidence, were formulated according to GRADE. RESULTS: We included a total of 29 studies, of which 16 were RCTs. A foot-ankle exercise programme of 8-12 weeks duration for people at risk of foot ulceration results in: (a) no increase or decrease risk of foot ulceration or pre-ulcerative lesion (Risk Ratio (RR): 0.56 (95% CI: 0.20-1.57)); (b) no increase or decrease risk of adverse events (RR: 1.04 (95% CI: 0.65-1.67)); (c) not increase or decrease barefoot peak plantar pressure during walking (Mean Difference (MD): -6.28 kPa (95% CI: -69.90-57.34)); (d) no increase or decrease health-related quality of life (no meta-analysis possible). Likely results in increases in ankle joint and first metatarsalphalangeal joint range of motion (MD: 1.49° (95% CI: -0.28-3.26)) may result in improvements in neuropathy signs and symptoms (MD: -1.42 (95% CI: -2.95-0.12)), may result in a small increase in daily steps in some people (MD: 131 steps (95% CI: -492-754)), and may not increase or decrease foot and ankle muscle strength and function (no meta-analysis was possible). CONCLUSIONS: In people at risk of foot ulceration, a foot-ankle exercise programme of 8-12 weeks duration may not prevent or cause diabetes-related foot ulceration. However, such a programme likely improves the ankle joint and first metatarsalphalangeal joint range of motion and neuropathy signs and symptoms. Further research is needed to strengthen the evidence base, and should also focus on the effects of specific components of foot-ankle exercise programs.

Knee movements cause changes in the firing behaviour of muscle spindles located within the mono-articular ankle extensor soleus in the rat.

We recently showed that within an intact muscle compartment, changing the length of one muscle affects the firing behaviour of muscle spindles located within a neighbouring muscle. The conditions tested, however, involved muscle lengths and relative positions that were beyond physiological ranges. The aim of the present study was to investigate the effects of simulated knee movements on the firing behaviour of muscle spindles located within rat soleus (SO) muscle. Firing from single muscle spindle afferents in SO was measured intra-axonally for different lengths (static) and during lengthening (dynamic) of the lateral gastrocnemius and plantaris muscles. Also, the location of the spindle within the muscle was assessed. Changing the length of synergistic ankle plantar flexors (simulating different static knee positions, between 45 and 130°) affected the force threshold, but not the length threshold, of SO muscle spindles. The effects on type II afferents were substantially (four times) higher than those on type IA afferents. Triangular stretch-shortening of synergistic muscles (simulating dynamic knee joint rotations of 15°) caused sudden changes in the firing rate of SO type IA and II afferents. Lengthening decreased and shortening increased the firing rate, independent of spindle location. This supports our prediction that the major point of application of forces exerted by connections between adjacent muscles is at the distal end of SO. We conclude that muscle spindles provide the CNS with information about the condition of adjacent joints that the muscle does not span.

A single sequence of intermittent hypoxia does not alter stretch reflex excitability in able-bodied individuals.

Spasticity attributable to exaggerated stretch reflex pathways, particularly affecting the ankle plantar flexors, often impairs overground walking in persons with incomplete spinal cord injury. Compelling evidence from rodent models underscores how exposure to acute intermittent hypoxia (AIH) can provide a unique medium to induce spinal plasticity in key inhibitory pathways mediating stretch reflex excitability and potentially affect spasticity. In this study, we quantify the effects of a single exposure to AIH on the stretch reflex in able-bodied individuals. We hypothesized that a single sequence of AIH will increase the stretch reflex excitability of the soleus muscle during ramp-and-hold angular perturbations applied to the ankle joint while participants perform passive and volitionally matched contractions. Our results revealed that a single AIH exposure did not significantly change the stretch reflex excitability during both passive and active matching conditions. Furthermore, we found that able-bodied individuals increased their stretch reflex response from passive to active matching conditions after both sham and AIH exposures. Together, these findings suggest that a single AIH exposure might not engage inhibitory pathways sufficiently to alter stretch reflex responses in able-bodied persons. However, the generalizability of our present findings requires further examination during repetitive exposures to AIH along with potential reflex modulation during functional movements, such as overground walking.

Intrinsic ankle stiffness is associated with paradoxical calf muscle movement but not postural sway or age.

Due to Achilles tendon compliance, passive ankle stiffness is insufficient to stabilise the body when standing. This results in 'paradoxical' muscle movement, whereby calf muscles tend to shorten during forward body sway. Natural variation in stiffness may affect this movement. This may have consequences for postural control, with compliant ankles placing greater reliance upon active neural control rather than stretch reflexes. Previous research also suggests ageing reduces ankle stiffness, possibly contributing to reduced postural stability. Here we determine the relationship between ankle stiffness and calf muscle movement during standing, and whether this is associated with postural stability or age. Passive ankle stiffness was measured during quiet stance in 40 healthy volunteers ranging from 18 to 88 years of age. Medial gastrocnemius muscle length was also recorded using ultrasound. We found a significant inverse relationship between ankle stiffness and paradoxical muscle movement, that is, more compliant ankles were associated with greater muscle shortening during forward sway (r ≥ 0.33). This was seen during both quiet stance as well as voluntary sway. However, we found no significant effects of age upon stiffness, paradoxical motion or postural sway. Furthermore, neither paradoxical muscle motion nor ankle stiffness was associated with postural sway. These results show that natural variation in ankle stiffness alters the extent of paradoxical calf muscle movement during stance. However, the absence of a clear relationship to postural sway suggests that neural control mechanisms are more than capable of compensating for a lack of inherent joint stiffness.

Arthroscopic ankle surgery in people with haemophilia.

INTRODUCTION: People with haemophilia (PWH) not administered primary haematological prophylaxis since childhood, that is, those treated haematologically on demand or not treated at all, often experience the degeneration of the ankles, leading to pain and functional impairment. AIM: To analyse the outcomes and complications of arthroscopic ankle surgery performed on PWH. METHODS: For this narrative review of the literature, a search was conducted in PubMed on 2, December 2023, using the keywords "haemophilia", "ankle" and "arthroscopy". Of the 29 articles identified, 15 specifically related to ankle arthroscopy in PWH were selected (inclusion criterion). The remaining articles did not meet this requirement (exclusion criterion) and were therefore eliminated. RESULTS: Arthroscopic procedures (arthroscopic synovectomy, debridement and arthrodesis of the ankle) are increasingly used in the surgical treatment of haemophilic ankle arthropathy. Although arthroscopic ankle surgery offers good outcomes in patients with haemophilia, the procedure is not free of complications, which range from 7.9% for arthroscopic ankle debridement to 13.1% in arthroscopic ankle synovectomy and 17.8% in arthroscopic ankle arthrodesis, respectively. The non-union rate of arthroscopic ankle arthrodesis is 7.1% (2/28). CONCLUSION: Although arthroscopic interventions in the haemophilic ankle (synovectomy, debridement, arthrodesis) offer good functional outcomes, they are associated with a non-negligible rate of complications. Arthroscopic ankle surgery in PWH is major surgery and should be treated as such.

Combined Dexamethasone and Dexmedetomidine as Adjuncts to Popliteal and Saphenous Nerve Blocks in Patients Undergoing Surgery of the Foot or Ankle: A Randomized, Blinded, Placebo-controlled Clinical Trial.

BACKGROUND: Both dexamethasone and dexmedetomidine increase the duration of analgesia of peripheral nerve blocks. The authors hypothesized that combined intravenous dexamethasone and intravenous dexmedetomidine would result in a greater duration of analgesia when compared with intravenous dexamethasone alone and placebo. METHODS: The authors randomly allocated participants undergoing surgery of the foot or ankle under general anesthesia and with a combined popliteal (sciatic) and saphenous nerve block to a combination of 12 mg dexamethasone and 1 µg/kg dexmedetomidine, 12 mg dexamethasone, or placebo (saline). The primary outcome was the duration of analgesia measured as the time from block performance until the first sensation of pain in the surgical area as reported by the participant. The authors predefined a 33% difference in the duration of analgesia as clinically relevant. RESULTS: A total of 120 participants from two centers were randomized and 119 analyzed for the primary outcome. The median [interquartile range] duration of analgesia was 1,572 min [1,259 to 1,715] with combined dexamethasone and dexmedetomidine, 1,400 min [1,133 to 1,750] with dexamethasone alone, and 870 min [748 to 1,138] with placebo. Compared with placebo, the duration was greater with combined dexamethasone and dexmedetomidine (difference, 564 min; 98.33% CI, 301 to 794; P < 0.001) and with dexamethasone (difference, 489 min; 98.33% CI, 265 to 706; P < 0.001). The prolongations exceeded the authors' predefined clinically relevant difference. The duration was similar when combined dexamethasone and dexmedetomidine was compared with dexamethasone alone (difference, 61 min; 98.33% CI, -222 to 331; P = 0.614). CONCLUSIONS: Dexamethasone with or without dexmedetomidine increased the duration of analgesia in patients undergoing surgery of the foot or ankle with a popliteal (sciatic) and saphenous nerve block. Combined dexamethasone and dexmedetomidine did not increase the duration of analgesia when compared with dexamethasone.

Simulating the effect of ankle plantarflexion and inversion-eversion exoskeleton torques on center of mass kinematics during walking.

Walking balance is central to independent mobility, and falls due to loss of balance are a leading cause of death for people 65 years of age and older. Bipedal gait is typically unstable, but healthy humans use corrective torques to counteract perturbations and stabilize gait. Exoskeleton assistance could benefit people with neuromuscular deficits by providing stabilizing torques at lower-limb joints to replace lost muscle strength and sensorimotor control. However, it is unclear how applied exoskeleton torques translate to changes in walking kinematics. This study used musculoskeletal simulation to investigate how exoskeleton torques applied to the ankle and subtalar joints alter center of mass kinematics during walking. We first created muscle-driven walking simulations using OpenSim Moco by tracking experimental kinematics and ground reaction forces recorded from five healthy adults. We then used forward integration to simulate the effect of exoskeleton torques applied to the ankle and subtalar joints while keeping muscle excitations fixed based on our previous tracking simulation results. Exoskeleton torque lasted for 15% of the gait cycle and was applied between foot-flat and toe-off during the stance phase, and changes in center of mass kinematics were recorded when the torque application ended. We found that changes in center of mass kinematics were dependent on both the type and timing of exoskeleton torques. Plantarflexion torques produced upward and backward changes in velocity of the center of mass in mid-stance and upward and smaller forward velocity changes near toe-off. Eversion and inversion torques primarily produced lateral and medial changes in velocity in mid-stance, respectively. Intrinsic muscle properties reduced kinematic changes from exoskeleton torques. Our results provide mappings between ankle plantarflexion and inversion-eversion torques and changes in center of mass kinematics which can inform designers building exoskeletons aimed at stabilizing balance during walking. Our simulations and software are freely available and allow researchers to explore the effects of applied torques on balance and gait.

Variability of corticospinal and spinal reflex excitability for the ankle dorsiflexor tibialis anterior across repeated measurements in people with and without incomplete spinal cord injury.

To adequately evaluate the corticospinal and spinal plasticity in health and disease, it is essential to understand whether and to what extent the corticospinal and spinal responses fluctuate systematically across multiple measurements. Thus, in this study, we examined the session-to-session variability of corticospinal excitability for the ankle dorsiflexor tibialis anterior (TA) in people with and without incomplete spinal cord injury (SCI). In neurologically normal participants, the following measures were obtained across 4 days at the same time of day (N = 13) or 4 sessions over a 12-h period (N = 9, at 8:00, 12:00, 16:00, and 20:00): maximum voluntary contraction (MVC), maximum M-wave and H-reflex (Mmax and Hmax), motor evoked potential (MEP) amplitude, and silent period (SP) after MEP. In participants with chronic incomplete SCI (N = 17), the same measures were obtained across 4 days. We found no clear diurnal variation in the spinal and corticospinal excitability of the TA in individuals with no known neurological conditions, and no systematic changes in any experimental measures of spinal and corticospinal excitability across four measurement days in individuals with or without SCI. Overall, mean deviations across four sessions remained in a range of 5-13% for all measures in participants with or without SCI. The study shows the limited extent of non-systematic session-to-session variability in the TA corticospinal excitability in individuals with and without chronic incomplete SCI, supporting the utility of corticospinal and spinal excitability measures in mechanistic investigation of neuromodulation interventions. The information provided through this study may serve as the reference in evaluating corticospinal plasticity across multiple experimental sessions.

Control of motor output during steady submaximal contractions is modulated by contraction history.

The purpose of the study was to investigate the influence of contraction history on force steadiness and the associated EMG activity during submaximal isometric contractions performed with the dorsiflexor muscles. The key feature of the protocol was a triangular ramp contraction performed in the middle of a steady contraction at a lower target force. The target force during the ramp contraction was 20% MVC greater than that during the steady contraction. Thirty-seven healthy individuals (21 men and 16 women) performed the submaximal tasks with the ankle dorsiflexors. Electromyography (EMG) signals were recorded from tibialis anterior with a pair of surface electrodes. The coefficient of variation for force was significantly greater during the second steady contraction compared with the first one at each of the seven target forces (p < 0.015; d = 0.38-0.92). Although the average applied force during the steady contractions before and after the triangular contraction was the same (p = 0.563), the mean EMG amplitude for the steady contractions performed after the triangular contraction was significantly greater at each of the seven target forces (p < 0.0001; d = 0.44-0.68). Also, there were significant differences in mean EMG frequency between the steady contractions performed before and after the triangular contraction (p < 0.01; d = 0.13-0.82), except at 10 and 20% MVC force. The greater force fluctuations during a steady submaximal contraction after an intervening triangular contraction indicate a change in the discharge characteristics of the involved motor units.

The effects of severe periodontitis on arterial stiffness using cardio-ankle vascular index in patients with type 2 diabetes.

BACKGROUND AND OBJECTIVE: Arterial stiffness, which is a measure of the elasticity of the arteries, is also a risk factor for the development of cardiovascular diseases and its measurement is important for evaluating the atherosclerosis process. The purpose of this cross-sectional study to investigate whether severe periodontitis in short-term type 2 diabetes may be associated with increased cardio-ankle vascular index (CAVI) values specified for subclinical atherosclerosis risk. METHODS: A total of 136 subjects, including 69 subjects with short-term type 2 diabetes (35 with severe periodontitis and 34 with periodontally healthy) and 67 systemically healthy subjects (32 with severe periodontitis and 35 with periodontally healthy) were enrolled to this study. Assessment of all participants included in this study in terms of arterial stiffness was determined by CAVI. Serum fasting plasma glucose (FPG), glycated haemoglobin (HbA1c), triglyceride (TRG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol (TC) and C-reactive protein (CRP) levels were calculated using standard methods. Full mouth periodontal measurements were recorded. Multiple linear regression analysis was performed to evaluate the relationship between periodontal parameters and mean CAVI values of the groups. RESULTS: Mean CAVI levels were significantly higher in diabetic and periodontitis group compared to the other study groups (p < .05). In diabetes and periodontitis group, CAVI was showed positive correlations with CRP (r = .337, p = .048) and HbA1c (r = .442, p = .008). Also, positive significant correlations were found with probing depth (PD) and clinical attachment level (CAL) in the periodontitis groups. Multiple regression analysis revealed that CAL independently predicted CAVI levels in periodontitis groups (ß = .433, p = .019 in diabetes and periodontitis groups and ß = .57, p = .001 in systemically healthy and periodontitis group respectively). CONCLUSION: This is the first study investigating the association between severe periodontitis and CAVI in patients with short-term diabetes. Our findings suggest that severe periodontitis may be an intermediate factor in the pathway between type 2 diabetes and cardiovascular disease by increasing the arterial stiffness.

CAVI (Cardio-Ankle Vascular Index) as an independent predictor of hypertensive response to exercise.

OBJECTIVES: Hypertensive response to exercise (HRE) is related to the development of future hypertension, cardiovascular morbidity, and mortality, independent of resting blood pressure. We hypothesized that arterial stiffness as measured by cardio-ankle vascular index (CAVI) could be an independent predictor of HRE. MATERIALS AND METHODS: Retrospective chart review of patients participated in the preventive health program at the Bangkok Heart Hospital who underwent both CAVI and treadmill stress testing on the same day between June and December 2018 were performed. Variables for the prediction of HRE were analyzed using univariate analysis, and significant variables were entered into multiple logistic regression. An ROC curve was created to test the sensitivity and specificity of CAVI as a predictor of HRE. RESULTS: A total of 285 participants (55.1% female) were enrolled in this study. There were 58 patients (20.4%) who met the HRE definition (SBP > 210 mmHg in males, SBP > 190 mmHg in females, or DBP > 110 mmHg in both males and females), with a mean age of 46.4 12.8 years. In univariate analysis, age, systolic blood pressure at rest, diastolic blood pressure at rest, pulse pressure at rest, diabetes mellitus, hypertension, dyslipidemia, history of beta-blocker, and CAVI results were statistically significant. Multiple logistic regression revealed that CAVI and systolic blood pressure were statistically significant predictors of HRE with OR of 5.8, 95%CI: 2.9-11.7, P < 0.001 and OR 1.07, 95%CI: 1.03-1.10, P = 0.001 respectively. ROC curve analysis of the CAVI revealed an AUC of 0.827 (95%CI: 0.76-0.89, p < 0.001), and the sensitivity and specificity of cut-point CAVI > 8 were 53% and 92%, respectively. CONCLUSION: This study demonstrated that CAVI is an independent predictor of hypertensive response to exercise. Additionally, the findings suggest that CAVI > 8 can be a valuable tool in identifying individuals at risk for hypertensive responses during exercise.

Anodal transcranial direct current stimulation enhances ankle force control and modulates the beta-band activity of the sensorimotor cortex.

This study aimed to investigate the cortical responses to the ankle force control and the mechanism underlying changes in ankle force control task induced by transcranial direct current stimulation (tDCS). Sixteen young adults were recruited, and they completed the electroencephalogram (EEG) assessment and high-definition tDCS (HD-tDCS) sessions. Root mean square (RMS) error was used to evaluate ankle force control task performance. Spectral power analysis was conducted to extract the average power spectral density (PSD) in the alpha (8-13 Hz) and beta (13-30 Hz) bands for resting state and tasking (i.e. task-PSD). The ankle force control task induced significant decreases in alpha and beta PSDs in the central, left, and right primary sensorimotor cortex (SM1) and beta PSD in the central frontal as compared with the resting state. HD-tDCS significantly decreased the RMS and beta task-PSD in the central frontal and SM1. A significant association between the percent change of RMS and the percent change of beta task-PSD in the central SM1 after HD-tDCS was observed. In conclusion, ankle force control task activated a distributed cortical network mainly including the SM1. HD-tDCS applied over SM1 could enhance ankle force control and modulate the beta-band activity of the sensorimotor cortex.

Correlation of Posterior Tibial Tendon Ultrasound with Calcaneal Inclination Angle in Indonesian Professional Athletes with Medial Ankle Pain.

Background: Adult-acquired flatfoot deformity (AAFD) is characterized by partial or complete flattening of the longitudinal medial arch, which develops after maturity. AAFD secondary to posterior tibialis tendon dysfunction (PTTD) is one of professional athletes' most common foot and ankle pathologies. Different modalities and procedures can be used to establish the diagnosis of AAFD and PTTD. However, imaging measurements such as the calcaneal inclination index and ultrasonography (US) of the posterior tibialis tendon (PTT) in professional athletes with medial ankle and focal pain along the PTT have yet to be widely studied. This study investigates the correlation of PTT ultrasound for evaluating PTTD with calcaneal inclination angle (CIA) for evaluating AAFD in professional athletes with medial ankle and focal pain along the PTT. Through this study, clinicians and radiologists may benefit from considering AAFD in athletes with PTTD. Methods: 112 Indonesian professional athletes with medial ankle or foot pain and focal pain along the direction of the PTT underwent foot radiography using the CIA and ankle ultrasound to observe PTT abnormalities. Results: A negative correlation between fluid thickness surrounding the PTT and the CIA (p<0.001; 95% CI - 0.945, - 0.885), as well as a negative correlation between PTT thickness and CIA (p<0.001, 95% CI - 0.926, - 0.845), with a correlation coefficient (r) of - 0.921 and - 0.892, respectively. No significant correlation was found between PTT tear and CIA (p = 0.728; 95% CI -0.223, - 0.159; r - 0.033). Conclusion: This study showed a negative correlation between PTTD and AAFD via ultrasound and CIA in professional athletes with medial ankle and focal pain along the PTT. A better understanding of PTTD and AAFD imaging will lead to more effective management and prompt treatment.

The Pediatric Ankle: Normal Variations and Maturation-Dependent Pathology.

The pediatric ankle can present a broad range of normal variation and pathology unique to certain stages of development. Understanding the expected age ranges of ossification and fusion about the ankle is essential to provide accurate diagnoses regarding skeletal integrity. This conclusion has been well characterized radiographically and is supported by cadaveric research.The range of appearances on magnetic resonance imaging has also been well described. Knowledge about the structure of the periosteum and perichondrium aids in image interpretation as well as explaining typical injury patterns. The expected appearance of the physis and regional bone marrow signal is also of utmost importance.Ultrasonography is a valuable tool in pediatric musculoskeletal imaging but is limited when there is concern for intra-articular pathology. Computed tomography tends to be reserved for preoperative evaluation. We describe normal variation and maturation-dependent pathology of the pediatric ankle with an emphasis on imaging considerations.