Impaired corticospinal tract in chronic ankle instability: a diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) study at 7.0 tesla

Exploring low- and high-order functional connectivity in chronic ankle instability through resting-state fMRI

BACKGROUND

The functional connectivity (FC) has emerged as a valuable tool for comprehending the cerebral operational mechanism. Understanding the FC changes in patients with chronic ankle instability (CAI) helps reveal the underlying central nervous system mechanisms of the disease and provides clues for developing personalized treatment plans.

OBJECTIVES

To explore differences between low- and high-order FC in patients with CAI and healthy controls, as well as the correlation among the feature connections and clinical data.

METHODS

In our study, we recruited 40 patients with CAI and 42 healthy individuals who had not experienced ankle injuries. All participants underwent clinical assessments of ankle joints, collected the number of ankle sprains within the past 6 months, and performed resting-state functional magnetic resonance imaging (rs-fMRI) scans. Pearson correlation and matrix variate normal distribution (MVND) were used to construct low-order and high-order FC networks, respectively. Feature selections between groups were performed by two-sample t-tests, and a multi-kernel support vector machine (MK-SVM) was subsequently applied to combine the multiple connection patterns for the classification. Using leave-one-out cross-validation (LOOCV) to assess classification performance and identify the consensus connections contributing most to classification.

RESULTS

FC was reduced in certain brain regions of CAI patients. More consensus connections were recognized in low-order FC network than in high-order FC network. The highest classification accuracy of 91.30% was achieved by combining three connection patterns. The most discriminating functional connections were primarily centered on the default mode network and spanned the visual network, sensorimotor network, ventral attention network, and central executive network. In addition, FC strength in the left cingulate and paracingulate gyrus (DCG.L) and right superior temporal gyrus (STG.R) was negatively correlated with the number of ankle sprains in the past 6 months in all FC networks (p < 0.05).

CONCLUSIONS

Abnormalities in connectivity in patients with CAI were observed in both low- and high-order FC networks. The adaptive changes in the brain related to CAI may extend beyond the sensorimotor networks, primarily involving higher-level default mode networks associated with attention. Moreover, the FC strength between DCG.L and STG.R may predict the risk of ankle re-sprains and help clinicians develop personalized treatment plans.

Gray Matter Volumes Mediate the Relationship Between Disease Duration and Balance Control Performance in Chronic Ankle Instability

The relationship between structural changes in the cerebral gray matter and diminished balance control performance in patients with chronic ankle instability (CAI) has remained unclear. This paper aimed to assess the difference in gray matter volume (GMV) between participants with CAI and healthy controls (HC) and to characterize the role of GMV in the relationship between disease duration and balance performance in CAI. 42 participants with CAI and 33 HC completed the structural brain MRI scans, one-legged standing test, and Y-balance test. Regional GMV was measured by applying voxel-based morphometry methods. The result showed that, compared with HC, participants with CAI exhibited lower GMV in multiple brain regions (familywise error [FWE] corrected p < 0.021). Within CAI only, but not in HC, lower GMV in the thalamus (β = -0.53, p = 0.003) and hippocampus (β = -0.57, p = 0.001) was associated with faster sway velocity of the center of pressure (CoP) in eyes closed condition (i.e., worse balance control performance). The GMV in the thalamus (percentage mediated [PM] = 32.02%; indirect effect β = 0.119, 95% CI = 0.003 to 0.282) and hippocampus (PM = 33.71%; indirect effect β = 0.122, 95% CI = 0.005 to 0.278) significantly mediated the association between the disease duration and balance performance. These findings suggest that the structural characteristics of the supraspinal elements is critical to the maintenance of balance control performance in individuals suffering from CAI, which deserve careful consideration in the management and rehabilitation programs in this population.

Causal Relationships of Ligamentous Injuries in the Knee on Corticospinal Tract Structure: A Mendelian Randomization Analysis

BACKGROUND

The association between ligamentous knee injuries and corticospinal tract (CST) structure has attracted attention; however, any causal relationship remains uncertain. We performed Mendelian randomization (MR) analysis to identify the causal effects of ligamentous knee injuries on the CST.

HYPOTHESIS

Ligamentous knee injuries impair CST microstructure (ie, by reducing fractional anisotropy [FA] and increasing mean diffusivity [MD]).

STUDY DESIGN

MR analysis.

LEVEL OF EVIDENCE

Level 2.

METHODS

MR uses genetic variants as instrumental variables to infer causal relationships between exposures and outcomes. Summary data for ligamentous injuries in knee and CST structure were obtained from genome-wide association study datasets. Significant and independent (5 × 10-6; r2 < 0.001; 10,000 kb) single-nucleotide polymorphisms were extracted for MR analysis. Three methods for MR analysis were used (hypothesis-driven 1-tailed inverse variance weighted, MR-Egger, and weighted median), and sensitivity analyses were conducted to test reliability and stability.

RESULTS

Results from 3 MR methods consistently demonstrated that ligamentous knee injuries increased MD of the right CST (β, 0.063; 90% CI, 0.003-0.123; P = 0.04), and weak statistical significance suggested increased MD of the left CST (β, 0.060; 90% CI, -0.002 to -0.121; P = 0.05). However, no significant causal relationships were observed in CST FA, and no significant pleiotropy or heterogeneity was observed. Sensitivity analysis utilizing 2-tailed tests had no significant associations between ligamentous knee injuries and changes in CST structure.

CONCLUSION

There is statistically weak genetic evidence that corticospinal pathway abnormalities may evolve after ligamentous knee injuries, which manifests as abnormally organized neurites.

CLINICAL RELEVANCE

Ligamentous knee injuries require attention not only to damage to the structure of the knee joint itself but also to the process of maladaptive neuroplasticity that leads to structural and functional changes of the CST; novel interventions that target the corticospinal pathway may provide subsequent treatment of ligamentous knee injuries.

Randomized controlled trial study of intelligent rehabilitation training system for functional ankle instability

To investigate the intervention effect of an intelligent rehabilitation training system on patients with functional ankle instability (FAI) and to advance the research to optimise the effect of FAI rehabilitation training. Thirty-four FAI patients who participated in this trial in Guilin City from April 2023 to June 2023 were recruited as research subjects, and all subjects were randomly divided into the control group (n = 17) and the observation group (n = 17). Both groups received the conventional rehabilitation training intervention for 6 weeks, and the observation group received the additional training using the intelligent rehabilitation training system training invented by our team. Visual analogue scale (VAS), ankle active mobility, ankle muscle strength and Y-balance test (YBT) were assessed before and after treatment. Two-way repeated measures ANOVA shows that the interaction effect between time and group of VAS scores was significant (F = 35.644, P < 0.05). The interaction effect between time and group of plantar flexion mobility was significant (F = 23.948, P < 0.05), the interaction effect between time and group of dorsiflexion mobility was significant (F = 6.570, P < 0.05), the interaction effect between time and group of inversion mobility was significant (F = 8.360, P < 0.05), the interaction effect between time and group of eversion mobility was significant (F = 10.113, P < 0.05). The interaction effect between time and group of inversion muscle strength was significant (F = 18.107, P < 0.05). The interaction effect between time and group of YBT scores was significant (F = 33.324, P < 0.05). The Intelligent Rehabilitation Training System can effectively reduce pain in FAI patients, improve joint range of motion, increase inversion strength, and improve dynamic balance of the affected limb.

In Vivo Characterization of Cerebellar Peduncles in Chronic Ankle Instability: A Single and Multishell Diffusion-Weighted Imaging Study

BACKGROUND

Ankle sprain causes proprioceptor injuries and prolonged joint deafferentation, which might lead to maladaptive neuroplasticity in patients with chronic ankle instability (CAI), especially in the cerebellum. Previous studies have indicated the impairment of superior cerebellar peduncle (SCP), but the inferior cerebellar peduncle (ICP) and middle cerebellar peduncle (MCP) have not been fully analyzed.

HYPOTHESIS

The cerebellar peduncles of participants with CAI would have altered fractional anisotropy (FA) and orientation dispersion index (ODI) in comparison with healthy controls without ankle injury history. In addition, FA and ODI would be correlated with the duration or severity of the sensorimotor deficits in CAI.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A group of 27 participants with CAI and 26 healthy controls underwent diffusion-weighted imaging scanning, with the cerebellar peduncles as the regions of interest. The measures obtained by single-shell diffusion tensor imaging and the multishell neurite orientation dispersion and density imaging were used. Correlation analyses were performed to examine the potential relationship between the FA/ODI and both the normalized Y-balance scores and the durations of ankle instability.

RESULTS

The ipsilateral ICP of the injured ankle in participants with CAI showed significantly lower FA (Cohen d 95% CI, -1.33 to -0.21; P = 0.04) and marginally significant higher ODI (Cohen d 95% CI, 0.10 to 1.20, P = 0.08) when compared with the same measures in the control group, with the ODI being positively correlated with the duration of ankle instability (r = 0.42, P = 0.03).

CONCLUSION

The ICP in participants with CAI exhibited impaired integrity and a trend of abnormally organized neurites in comparison with a healthy control group.

CLINICAL RELEVANCE

The impairments of ICP might be an ongoing part of the pathological process of CAI, having the potential to become a target for the diagnostic evaluation of this clinical entity.

Effects of whole-body vibration on sensorimotor deficits and brain plasticity among people with chronic ankle instability: a study protocol for a single-blind randomized controlled trial

BACKGROUND

Chronic ankle instability (CAI) is a form of musculoskeletal disease that can occur after a lateral ankle sprain, and it is characterized by pain, recurrent ankle sprains, a feeling of "giving way" at the ankle joint, and sensorimotor deficits. There has been increasing evidence to suggest that plastic changes in the brain after the initial injury play an important role in CAI. As one modality to treat CAI, whole-body vibration (WBV) has been found to be beneficial for treating the sensorimotor deficits accompanying CAI, but whether these benefits are associated with brain plasticity remains unknown. Therefore, the current study aims to investigate the effect of WBV on sensorimotor deficits and determine its correlation with plastic changes in the brain.

METHODS

The present study is a single-blind randomized controlled trial. A total of 80 participants with CAI recruited from the university and local communities will be divided into 4 groups: whole-body vibration and balance training (WBVBT), balance training (BT), whole-body vibration (WBV), and control group. Participants will be given the WBV intervention (25-38 Hz, 1.3-2 mm, 3-time per week, 6-week) supervised by a professional therapist. Primary outcome measures are sensorimotor function including strength, balance, proprioception and functional performance. Brain plasticity will be evaluated by corticomotor excitability, inhibition, and representation of muscles, as measured by transcranial magnetic stimulation. Activation of brain areas will be assessed through functional near-infrared spectroscopy. Secondary outcome measures are self-reported functional outcomes involving the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure. All tests will be conducted before and after the WBV intervention, and at 2-week follow-up. Per‑protocol and intention-to-treat analysis will be applied if any participants withdraw.

DISCUSSION

This is the first trial to investigate the role of brain plasticity in sensorimotor changes brought by WBV for individuals with CAI. As plastic changes in the brain have been an increasingly important aspect in CAI, the results of the current study can provide insight into the treatment of CAI from the perspective of brain plasticity.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2300068972); registered on 02 March 2023.

Brain Neuroplasticity Related to Lateral Ankle Ligamentous Injuries: A Systematic Review

BACKGROUND

Lateral ankle sprains are the most common ankle injuries in sports and have the highest recurrence rates. Almost half of the patients experiencing lateral ankle sprains develop chronic ankle instability. Patients with chronic ankle instability experience persistent ankle dysfunctions and detrimental long-term sequelae. Changes at the brain level are put forward to explain these undesirable consequences and high recurrence rates partially. However, an overview of possible brain adaptations related to lateral ankle sprains and chronic ankle instability is currently lacking.

OBJECTIVE

The primary purpose of this systematic review is to provide a comprehensive overview of the literature on structural and functional brain adaptations related to lateral ankle sprains and in patients with chronic ankle instability.

METHODS

PubMed, Web of Science, Scopus, Embase, EBSCO-SPORTDiscus and Cochrane Central Register of Controlled Trials were systematically searched until 14 December, 2022. Meta-analyses, systematic reviews and narrative reviews were excluded. Included studies investigated functional or structural brain adaptations in patients who experienced a lateral ankle sprain or with chronic ankle instability and who were at least 18 years of age. Lateral ankle sprains and chronic ankle instability were defined following the recommendation of the International Ankle Consortium. Three authors independently extracted the data. They extracted the authors' name, publication year, study design, inclusion criteria, participant characteristics, the sample size of the intervention and control groups, methods of neuroplasticity testing, as well as all means and standard deviations of primary and secondary neuroplasticity outcomes from each study. Data reported on copers were considered as part of the control group. The quality assessment tool for observational and cross-sectional studies was used for the risk of bias assessment. This study is registered on PROSPERO, number CRD42021281956.

RESULTS

Twenty articles were included, of which only one investigated individuals who experienced a lateral ankle sprain. In all studies combined, 356 patients with chronic ankle instability, 10 who experienced a lateral ankle sprain and 46 copers were included. White matter microstructure changes in the cerebellum have been related to lateral ankle sprains. Fifteen studies reported functional brain adaptations in patients with chronic ankle instability, and five articles found structural brain outcomes. Alterations in the sensorimotor network (precentral gyrus and supplementary motor area, postcentral gyrus and middle frontal gyrus) and dorsal anterior cingulate cortex were mainly found in patients with chronic ankle instability.

DISCUSSION

The included studies demonstrated structural and functional brain adaptations related to lateral ankle sprains and chronic ankle instability compared to healthy individuals or copers. These adaptations correlate with clinical outcomes (e.g. patients' self-reported function and different clinical assessments) and might contribute to the persisting dysfunctions, increased re-injury risk and long-term sequelae seen in these patients. Thus, rehabilitation programmes should integrate sensorimotor and motor control strategies to cope with neuroplasticity related to ligamentous ankle injuries.

Regional brain atrophy in patients with chronic ankle instability: A voxel-based morphometry study

The objective of this study was to investigate whether brain volume changes occur in patients with chronic ankle instability (CAI) using voxel-based morphometry and assessing correlations with clinical tests. Structural magnetic resonance imaging data were prospectively acquired in 24 patients with CAI and 34 healthy controls. CAI symptoms and pain intensity were assessed using the Foot and Ankle Ability Measure (FAAM), Cumberland Ankle Instability Tool (CAIT), American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and visual analog scale (VAS). The gray matter volume (GMV) of each voxel was compared between the two groups while controlling for age, sex, weight, and education level. Correlation analysis was performed to identify associations between abnormal GMV regions and the FAAM score, AOFAS score, VAS score, disease duration, and body mass index. Patients with CAI exhibited reduced GMV in the right precentral and postcentral areas, right parahippocampal area, left thalamus, left parahippocampal area, and left postcentral area compared to that of healthy controls. Furthermore, the right parahippocampal (r = 0.642, p = 0.001), left parahippocampal (r = 0.486, p = 0.016), and left postcentral areas (r = 0.521, p = 0.009) were positively correlated with disease duration. The left thalamus was positively correlated with the CAIT score and FAAM activities of daily living score (r = 0.463, p = 0.023 and r = 0.561, p = 0.004, respectively). A significant positive correlation was found between the local GMV of the right and left parahippocampal areas (r = 0.487, p = 0.016 and r = 0.763, p < 0.001, respectively) and the AOFAS score. Neural plasticity may occur in the precentral and postcentral areas, parahippocampal area, and thalamus in patients with CAI. The patterns of structural reorganization in patients with CAI may provide useful information on the neuropathological mechanisms of CAI.