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Sensory Reweighting System Differences on Vestibular Feedback with Increased Task Constraints

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Blog Post Author Biography: Yuki Sugimoto is an Assistant Professor in the Department of Physical Therapy & Human Movement Science at the Feinberg School of Medicine, Northwestern University, and has a clinical background as a certified athletic trainer. One of Dr. Sugimoto’s research interests is the sensory reweighting system and changes in reliance on visual and vestibular feedback in individuals with chronic ankle instability.

Citation: Sugimoto YA, McKeon PO, Rhea CK, et al. Sensory Reweighting System Differences on Vestibular Feedback With Increased Task Constraints in Individuals With and Without Chronic Ankle Instability. J Athl Train. 2024;59(7):713-723. doi:10.4085/1062-6050-0246.22

Take-to-the-clinic message: The results highlight the importance of considering vestibular feedback reliance during postural control assessment and rehabilitation in individuals with chronic ankle instability (CAI). Combining tests such as the horizontal head impulse test with single-limb postural assessments may reveal underlying sensory reweighting dysfunction, especially under varying environmental and task conditions. Clinicians should explore multisensory feedback approaches that challenge vestibular function to improve rehabilitation outcomes in individuals with CAI.

Background: Postural stability is critical for motor behavior in dynamic environments and relies on the ability to reweight sensory feedback from somatosensory, visual, and vestibular systems as environmental and task constraints change. Individuals with CAI may have sensory reweighting deficits, leading to an over-reliance on visual feedback and difficulties maintaining postural control, especially in complex tasks like single-limb stance. However, current evidence suggests that somatosensory feedback contributions to postural control in individuals with CAI cannot be ruled out based solely on balance scores in single-limb stance with and without eyes closed. In addition, the sensory reweighting system in individuals with CAI and whether they upweight visual feedback to maintain posture in bilateral and unilateral (uninjured, injured) stances compared to healthy individuals remains unknown.

Purpose: The primary purpose of the study was to examine the sensory reweighting system changes to control posture in a simple double-limb stance and a more complex uninjured- or injured-limb stance under increased environmental constraints, manipulating somatosensory and visual information, for individuals with and without CAI. The secondary purpose of the study was to determine the effect of environmental and task constraints on postural stability.

Methods: The study included 42 physically active individuals with and without unilateral CAI. Participants completed postural control assessments using the Sensory Organization Test (SOT) on a NeuroCom dynamic posturography platform, which measures the ability to integrate somatosensory, visual, and vestibular feedback across six conditions of varying complexity. Equilibrium balance scores were calculated based on center-of-gravity sway, and sensory reweighting ratios were determined to assess the weighting of different sensory systems.

Results: The study is the first investigation of how the sensory reweighting system adapts to control posture under increased task constraints and how postural control is influenced by both environmental and task constraints in individuals with and without CAI. Notably, the CAI group did not reduce their reliance on vestibular feedback when standing on the injured limb. However, the inability to downweight vestibular feedback may represent a compensatory reliance for individuals with CAI, as they maintained postural stability on the injured limb better than healthy controls. Both groups showed different patterns of sensory feedback use depending on the task. Somatosensory input was the most emphasized during double-limb stance, whereas visual feedback was prioritized during single-limb stance in both injured and uninjured limbs. Differences in postural control between groups were shaped by task and environmental demands, although individuals with CAI demonstrated postural control similar to that of healthy participants.

Rolling the field forward: This research demonstrates that while individuals with CAI do not downweight vestibular feedback to maintain posture on their injured limb, this reliance may serve as a compensatory mechanism, allowing them to maintain better postural stability than those without CAI. In addition, postural control in both groups was influenced by the specific sensory systems engaged and the constraints imposed by the task. Clinicians should consider using a multisensory feedback approach in their interventions, challenging vestibular input, with and without visual cues, during tasks with increased demands to improve postural control for individuals with CAI.

Question for the researchers: How might clinicians implement multisensory feedback approaches in rehabilitation programs to specifically address the compensatory reliance on vestibular feedback observed in individuals with CAI?

Participant-Level Improvements in Health-Related Quality of Life in Those With Chronic Ankle Instability

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Blog Post Author Biography: Dr. Cameron Powden is an Associate Professor in the Department of Athletic Training at the University of Indianapolis. Dr. Powden’s interests include the investigation of clinically relevant interventions for ankle sprains and chronic ankle instability.

Citation: Powden CJ, Koldenhoven RM, Simon JE, et al. Participant-Level Analysis of the Effects of Interventions on Patient-Reported Outcomes in Patients With Chronic Ankle Instability. Journal of Sport Rehabilitation. 2023;32(2):124-132. DOI: 10.1123/jsr.2022-0053

Take-to-the-clinic message: This investigation matches previous literature indicating that the available chronic ankle instability (CAI) interventions are capable of improving self-reported ankle function, global well-being, and injury-related fear at the group level for patients with CAI. This study uniquely assessed individual level responses of patients with CAI to multimodal interventions. Between 13.8% and 53.3% of patients demonstrated improvements, for individual patient-reported outcomes (PROs), that exceeded the minimal detectable change (MDC) of the measure. These findings signify that individually, we may hope to only have about half of our patients have meaningful improvements following intervention.

Background: CAI intervention studies have often focused on improving physical impairments of the ankle complex. Recently, increased emphasis has been placed on the sensory-perceptual impairments associated with CAI. This has resulted in CAI investigations examining the health-related quality of life (HRQoL) through PROs of those with CAI, and the influence of intervention on such PROs. While most studies have assessed self-reported ankle function and through the lens of group level response, there is a need to investigate the impact of interventions on other aspects of HRQoL (such as global well-being and injury-related fears) and the individual level response to treatment within those with CAI.

Purpose: To evaluate improvements in multiple domains of HRQoL, self-reported ankle function, global well-being, and injury-related fear, following multimodal interventions in patients with CAI by using group- and participant-level responder analyses.

Methods: A secondary analysis was completed on a compiled data set of original, participant-level data from seven previously published investigations. Each of the investigations investigated self-reported function in patients with CAI. A total of 136 physically active individuals with self-reported CAI were included in the analysis. These individuals underwent a wide range of multimodal interventions that ranged from 1 to 6 weeks in length, 1 to 12 supervised sessions, and may have included a home intervention component. PROs included were the Foot and Ankle Ability Measure (FAAM) ADL and Sport, Tampa Scale of Kinesiophobia-11 (TSK-11), Fear Avoidance Belief Questionnaire (FABQ) and the Disablement in the modified Physically Active Scale (mDPA) physical summary component (PSC) and the mental summary component (MSC). The research team examined preintervention to postintervention changes in each PRO, as well as effect sizes (ES) and individual-level response rates through changes exceeding published MDCs.

Results: There was significant improvement in ankle-specific function following intervention that was associated with strong ESs and responder rates of 39.0% to 53.3%. There was a significant reduction in injury-related fear following intervention that was associated with moderate to strong effects and responder rates of 13.8% to 51.4%. Finally, there was a significant improvement in global well-being that was associated with strong effects and responder rates of 31.3%. 

Rolling the field forward: This investigation is part of the expanding evidence regarding interventions for those with CAI. It builds on previous multimodal intervention studies by combining various intervention protocols to allow for robust group and individual level analysis. The findings indicate that patients with CAI exhibit holistic HRQoL improvements following varied interventions. This investigation continues the exploration into individual-level responses within the CAI population. Further research is needed to better understand the clinical impact of this new form of analysis. Lastly, to enhance the ability to examine CAI interventions, at the group and individual level, there is a need to identify common clinician-, laboratory-, and patient-oriented outcome measures to allow for robust and comparative analysis.

Question for the researchers: What interventions would be beneficial for CAI patients to enhance aspects of HRQoL? How do researchers and clinicians work to develop common outcome measures to explore? Can the individual level responder analysis be used in clinical practice to examine patient progress?

Impact of Electrical Stimulation with Balance Training in those with CAI

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Blog Post Author Biography: Alan Needle is a Professor at Appalachian State University in the Department of Public Health and Exercise Science and the Department of Rehabilitation Sciences. He has been a certified and licensed athletic trainer since 2007, and conducts research related to assessing and treating neurological impairments in individuals with ankle sprains and chronic ankle instability.

Citation: Gottlieb U, Hayek R, Hoffman JR, Springer S. Exercise combined with electrical stimulation for the treatment of chronic ankle instability – A randomized controlled trial. J Electromyogr Kines. 2024; 74: 102856. https://doi.org/10.1016/j.jelekin.2023.102856.

Take-to-the-clinic message: Combining neuromuscular electrical stimulation with balance exercises improved long-term ankle function in individuals with chronic ankle instability better than therapeutic exercise combined with transcutaneous electrical nerve stimulation. These effects were observed with 12 total treatment sessions over 4-6 weeks, with improvements seen at 6 and 12 months following the intervention.

Background: While therapeutic exercises are a common method for treating individuals with chronic ankle instability (CAI), continued high rates of re-injury and many required treatment sessions creates a need for manners to augment CAI rehabilitation. In individuals with ACL injury, forms of electrical stimulation, including transcutaneous electrical nerve stimulation (TENS) and neuromuscular electrical stimulation (NMES) are often implemented to address neurological changes following injury. TENS and NMES have shown limited efficacy in individuals with CAI; however, it is unclear how they would affect function when combined with therapeutic exercise.

Purpose: This study aimed to assess the short, medium, and long-term effects of balance training in conjunction with NMES or TENS on dynamic postural control and patient-reported outcome measures.

Methods: This study implemented a double-blind randomized controlled trial design conducted in 34 young adults with CAI, following International Ankle Consortium guidelines. Participants were randomized into groups receiving NMES or TENS over the peroneal (fibularis) muscles, while all individuals conducted ankle rehabilitation exercises emphasizing static and dynamic balance. Outcome measures included dynamic balance conducted through a Y-balance test and time-to-stabilization from a single-leg drop jump. Patient function was quantified through the Foot and Ankle Ability Measure (FAAM) activities of daily living (FAAM-ADL) and sport subscales (FAAM-Sport), as well as the Cumberland Ankle Instability Tool (CAIT) and Identification of Functional Ankle Instability (IdFAI) instrument. Participants were instructed on performing the balance exercises and operation of a portable electrical stimulation device, with exercises being conducted during active stimulation. Participants performed 12 total treatment sessions over a period of 4 to 6 weeks, with follow-up immediately, 6-months, and 12-months following the intervention.

Results: Of the 34 individuals who enrolled in the study, 10 out of 14 participants in the NMES group completed the study, while 14 out of 15 participants in the TENS group completed the study. Patient-reported outcome measures improved across both groups at the 12-month follow-up. The NMES group showed improvements beyond the TENS group at 6 and 12 months for the IdFAI and FAAM-Sport measures. Large, but non-significant effects were observed in dynamic balance measures following the intervention.

Rolling the field forward: The researchers in this study explored how augmenting rehabilitation with treatments designed to be neuromodulatory (i.e. improve muscle reflexive actions) may improve clinician- and patient-oriented measures of function. The results showed improved long-term improvements in perceived disease-oriented function in individuals that received exercise and NMES, compared to those receiving exercise and TENS, with these improvements being in disease-oriented outcomes (IdFAI) and those reflecting more challenging function (FAAM-Sport). Importantly, these outcomes were achieved with a program carried out at home.

Question for the researchers: Do the authors feel that balance exercises were the ideal therapeutic exercise to pair with the NMES and TENS interventions? Given the programming needed on the stimulators, what steps would be needed to make this treatment more accessible to the average practicing clinician?

Chronic Ankle Instability, Kinesiophobia, and Postural Control

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Blog Post Author Biography: Ji Yeon Choi is a PhD student in the Department of Biomechanics and Kinesiology at The University of Nebraska at Omaha and certified AT. She has extensive background working with ankle injury extending from her education, research, and clinical experience.

The effects of kinesiophobia on postural controls with chronic ankle instability

Seunguk Han, Minsub Oh, Hyunwook Lee, Jon Tyson Hopkins

Take-to-the-clinic message: CAI patients with kinesiophobia rely more on visual feedback for static balance and show reduced performance in dynamic balance compared to those without kinesiophobia and controls. Clinicians should address both psychological and physical factors in rehab programs.

Background: Following ankle injuries, patients with chronic ankle instability (CAI) may develop kinesiophobia, which is characterized as an injury-related fear that occurs during physical activity and movement.1 Although the influence of kinsiophobia in patients with CAI is unknown.2 

Purpose: The purpose of this study was to examine the impact of kinesiophobia on static and dynamic balance within a CAI population.

Methods: Seventy patients were recruited for this study, 25 with kinesiophobia (CAI-K), 25 without kinesiophobia (CAI-N), and 20 controls. Inclusion criteria for CAI are consistent with the guidelines of the International Ankle Consortium.3 Kinesiophobia was assessed using the Tampa Scale for Kinesiophobia (TSK-17), with a score of 37 or higher indicating the presence of kinesiophobia.4 Static balance was measured using force plate. All participants performed a single-leg balance test with eyes open (EO) and eyes closed (EC). Participants performed the Y-balance test (YBT) for dynamic balance with EO. Romberg ratios were calculated as EC/EO and used for statistical analysis.

Results: There were no significant differences on the static balance among three groups. However, the CAI-K group showed a greater Romberg ratio in the mediolateral direction during static balance compared to CAI-N and control groups. On dynamic balance, the CAI-K group demonstrated less reaching distance in the anterior direction compared to CAI-N and control groups during YBT.

Rolling the field forward: This study found that CAI patients with kinesiophobia demonstrated increased visual reliance during static postural control in the ML direction and reduced reaching distance in the anterior direction during YBT compared to CAI patients without kinesiophobia and control groups. This study provides an approach for preventing further lateral ankle sprain for the CAI population by integrating both psychological and physical elements into rehabilitation programs.

Question for the researchers: What interventions would be beneficial for CAI patients with kinesiophobia? Given that kinesiophobia can occur in individuals with various musculoskeletal injuries, are there specific interventions that would be particularly effective for addressing patients with ankle injuries?

References

  1. Larsson C, Ekvall Hansson E, Sundquist K, Jakobsson U. Kinesiophobia and its relation to pain characteristics and cognitive affective variables in older adults with chronic pain. BMC Geriatr. 2016;16:128. Published 2016 Jul 7. doi:10.1186/s12877-016-0302-6
  2. Devecchi V, Alalawi A, Liew B, Falla D. A network analysis reveals the interaction between fear and physical features in people with neck pain. Sci Rep. 2022;12(1):11304. Published 2022 Jul 4. doi:10.1038/s41598-022-14696-8
  3. Gribble PA, Delahunt E, Bleakley C, et al. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium. J Orthop Sports Phys Ther. 2013;43(8):585-591. doi:10.2519/jospt.2013.0303
  4. Luque-Suarez A, Martinez-Calderon J, Falla D. Role of kinesiophobia on pain, disability and quality of life in people suffering from chronic musculoskeletal pain: a systematic review. Br J Sports Med. 2019;53(9):554-559. doi:10.1136/bjsports-2017-098673