Bilateral Improvements in Lower Extremity Function After Unilateral Balance Training in Individuals With Chronic Ankle Instability

Context:

Bilateral improvements in postural control have been reported among individuals with acute lateral ankle sprains and individuals with chronic ankle instability (CAI) when only the unstable ankle is rehabilitated. We do not know if training the stable ankle will improve function on the unstable side.

Objective:

To explore the effects of a unilateral balance-training program on bilateral lower extremity balance and function in individuals with CAI when only the stable limb is trained.

Design:

Cohort study.

Setting:

University clinical research laboratory.

Patients or Other Participants:

A total of 34 volunteers (8 men, 26 women; age = 24.32 ± 4.95 years, height = 167.01 ± 9.45 cm, mass = 77.54 ± 23.76 kg) with CAI were assigned to the rehabilitation (n = 17) or control (n = 17) group. Of those, 27 (13 rehabilitation group, 14 control group) completed the study.

Intervention(s):

Balance training twice weekly for 4 weeks.

Main Outcome Measure(s):

Foot and Ankle Disability Index (FADI), FADI Sport (FADI-S), Star Excursion Balance Test, and Balance Error Scoring System.

Results:

The rehabilitation and control groups differed in changes in FADI-S and Star Excursion Balance Test scores over time. Only the rehabilitation group improved in the FADI-S and in the posteromedial and anterior reaches of the Star Excursion Balance Test. Both groups demonstrated improvements in posterolateral reach; however, the rehabilitation group demonstrated greater improvement than the control group. When the groups were combined, participants reported improvements in FADI and FADI-S scores for the unstable ankle but not the stable ankle.

Conclusions:

Our data suggest training the stable ankle may result in improvements in balance and lower extremity function in the unstable ankle. This further supports the existence of a centrally mediated mechanism in the development of postural-control deficits after injury, as well as improved postural control after rehabilitation.Key Words: overflow, crossover training, rehabilitation

Key Points

• The rehabilitation group performed better over time on the Foot and Ankle Disability Index Sport and the Star Excursion Balance Test (SEBT) in the anterior, posteromedial, and posterolateral directions, but this was not dependent on ankle.
• Training the stable ankle may provide therapeutic benefit to the unstable ankle.
• Performance on the Balance Error Scoring System did not reflect a therapeutic benefit of the neuromuscular-control training program, but the result should be interpreted with caution.
• Clinicians should consider incorporating rehabilitation of the stable ankle in the overall plan for patients who may not be ready to initiate aspects of rehabilitation on the unstable ankle.

Lateral ankle sprain (LAS) is one of the most common injuries that athletes and recreationally active individuals sustain. Researchers have estimated that approximately 23 000 ankle sprains occur each day in the United States, equating to 1 sprain per 10 000 people.¹ As many as 33% to 42% of these injuries result in chronic ankle instability (CAI).^2,3 In the literature, CAI has been defined as the tendency of the ankle to “give way” during normal activity and can occur in the absence of mechanical instability.^4–6 One explanation for this tendency is that damage to the peripheral mechanoreceptors that provide proprioceptive input results in altered efferent modulation. Together, the changes in afferent input and efferent output are recognized as altered neuromuscular control (NMC). When specifically considering the role of NMC in facilitating joint stability, NMC has been defined as “the unconscious activation of dynamic restraints occurring in preparation for and in response to joint motion and loading.”⁷ Ultimately, altered NMC is thought to result in functional ankle instability.^3,4,8 Even after the injury has healed, mechanoreceptors may not function properly, resulting in NMC deficits that can lead to CAI.^3,8In addition to damage at the level of the receptors, changes in central nervous system processing and integration also may contribute to CAI.^9,10 Evidence has suggested that when an injury occurs, this central mechanism for NMC is disrupted.^9–12 Reports of bilateral postural-control deficits after acute LAS have provided further evidence that central pathways are affected by injury.^9,10,13 In addition, researchers^10,14–16 have found bilateral improvements in NMC and postural stability after rehabilitation of acute LAS and CAI. This suggests that NMC is not controlled solely by peripheral mechanoreceptors and that deficits after LAS may be partly due to adaptations in the central pathways. Whereas investigators^10,14–16 have shown a carryover effect after training the involved lower extremity, no one has examined whether training the stable ankle results in improvements to the unstable ankle.Given these reports of bilateral deficits after unilateral injury and improvements in NMC and postural stability in the stable ankle after training only the unstable ankle, it is conceivable that training the stable ankle in individuals with CAI would result in improvements of the unstable ankle. This is meaningful because clinicians may be able to begin neuromuscular retraining earlier and the athlete may be able to return to sport participation better prepared without increasing the time missed. After an acute LAS, many athletes return to sport participation within 15 days¹⁷ despite postural-control deficits being measured up to 21 days after injury⁹ and many reporting pain and functional deficits 6 months later.¹⁷ Researchers¹⁸ also have recommended that NMC training should not begin immediately because of pain and weight-bearing restrictions. Therefore, the amount of time spent restoring NMC before return to sport participation is minimal, likely resulting in athletes returning with residual dysfunction and increased risk for reinjury. By beginning NMC retraining sooner, it is plausible that athletes may return to sport participation with less dysfunction and more prepared for the functional demands of sport. Therefore, the purpose of our study was to explore the effects of a 4-week, unilateral balance-training program on bilateral lower extremity balance and function in individuals with CAI. Our hypothesis was that bilateral improvements would occur after training of the stable ankle.     

Skin and Adhesive Issues With Continuous Glucose Monitors: A Sticky Situation

Background:The purpose of this article is to describe challenges associated with successful use of continuous glucose monitoring (CGM) by young children with type 1 diabetes (T1D) and to detail the techniques and products used to improve the duration of sensor wear.Methods:The DirecNet Study Group conducted 2 studies in 169 children with T1D between the ages of 1 and 9 years who were instructed to wear a CGM device daily. Problems related to skin irritation and sensor adhesiveness in these young children presented challenges to daily use of the CGM. Study coordinators instituted a variety of techniques using commercially available products to attempt to overcome these problems.Results:Three primary factors that contributed to reduced CGM use were identified: the limited body surface area in smaller children, ambient temperature and humidity, as well as the type and duration of physical activity. Using supplemental products to minimize the impact of these factors resulted in improved adherence and reduced skin irritation.Conclusion:Achieving satisfactory adhesion of the CGM sensor and transmitter may involve finding the right supplemental product or combination of products through trial and error. Optimizing adhesion and minimizing skin irritation can significantly improve duration of use and tolerability of CGM devices by young children.     

Emotion dysregulation as a maintenance factor of borderline personality disorder features

We examined within-individual changes in emotion dysregulation over the course of one year as a maintenance factor of borderline personality disorder (BPD) features. We evaluated the extent to which (1) BPD symptom severity at baseline predicted within-individual changes in emotion dysregulation and (2) within-individual changes in emotion dysregulation predicted four BPD features at 12-month follow-up: affective instability, identity disturbances, negative relationships, and impulsivity. The specificity of emotion dysregulation as a maintaining mechanism of BPD features was examined by controlling for a competing intervening variable, interpersonal conflict. BPD symptoms at baseline predicted overall level and increasing emotion dysregulation. Additionally, increasing emotion dysregulation predicted all four BPD features at 12-month follow-up after controlling for BPD symptoms at baseline. Further, overall level of emotion dysregulation mediated the association between BPD symptom severity at baseline and both affective instability and identity disturbance at 12-month follow-up, consistent with the notion of emotion dysregulation as a maintenance factor. Future research on the malleability of emotion dysregulation in laboratory paradigms and its effects on short-term changes in BPD features is needed to inform interventions.