Lifespan data on postural balance in multiple standing positions

Effects of the BalanCI on Working Memory and Balance in Children and Young Adults With Cochleovestibular Dysfunction

OBJECTIVES

This study aimed to: (1) determine the interaction between cognitive load and balance in children and young adults with bilateral cochleovestibular dysfunction who use bilateral cochlear implants (CIs) and (2) determine the effect of an auditory balance prosthesis (the BalanCI) on this interaction. Many (20 to 70%) children with sensorineural hearing loss experience some degree of vestibular loss, leading to poorer balance. Poor balance could have effects on cognitive resource allocation which might be alleviated by the BalanCI as it translates head-referenced cues into electrical pulses delivered through the CI. It is hypothesized that children and young adults with cochleovestibular dysfunction will demonstrate greater dual-task costs than typically-developing children during dual balance-cognition tasks, and that BalanCI use will improve performance on these tasks.

DESIGN

Study participants were 15 typically-developing children (control group: mean age ± SD = 13.6 ± 2.75 years, 6 females) and 10 children and young adults who use bilateral CIs and have vestibular dysfunction (CI-V group: mean age ± SD=20.6 ± 5.36 years, 7 females). Participants completed two working memory tasks (backward auditory verbal digit span task and backward visuospatial dot matrix task) during three balance conditions: seated, standing in tandem stance with the BalanCI off, and standing in tandem stance with the BalanCI on. Working memory performance was quantified as total number of correct trials achieved. Postural stability was quantified as translational and rotational path length of motion capture markers worn on the head, upper body, pelvis, and feet, normalized by trial time.

RESULTS

Relative to the control group, children and young adults in the CI-V group exhibited poorer overall working memory across all balance conditions ( p = 0.03), poorer translational postural stability (larger translational path length) during both verbal and visuospatial working memory tasks ( p < 0.001), and poorer rotational stability (larger rotational path length) during the verbal working memory task ( p = 0.026). The CI-V group also exhibited poorer translational ( p = 0.004) and rotational ( p < 0.001) postural stability during the backward verbal digit span task than backward visuospatial dot matrix task; BalanCI use reduced this stability difference between verbal and visuospatial working memory tasks for translational stability overall ( p > 0.9), as well as for rotational stability during the maximum working memory span (highest load) participants achieved in each task ( p = 0.91).

CONCLUSIONS

Balance and working memory were impaired in the CI-V group compared with the control group. The BalanCI offered subtle improvements in stability in the CI-V group during a backward verbal working memory task, without producing a negative effect on working memory outcomes. This study supports the feasibility of the BalanCI as a balance prosthesis for individuals with cochleovestibular impairments.

Evaluating the use of a balance prosthesis during balance perturbations in children and young adults with cochleovestibular dysfunction

Study objectives were to: (1) quantify stability in children and young adults using cochlear implants with concurrent cochleovestibular dysfunction (CI-V) during balance perturbations and (2) to assess effects of an auditory head-referencing device (BalanCI) on their stability. The BalanCI provides auditory feedback via cochlear implants to cue posture and potentially avoid falling in children with CI-V. It was hypothesized that children and young adults with CI-V respond with larger movements to floor perturbations than typically-developing peers (controls) and that BalanCI use decreases these movements. Motion in response to treadmill perturbations was captured by markers on the head, torso, and feet in eight CI-V and 15 control participants. Stability (area under the curve of motion displacement) and peak displacement latencies were measured. The CI-V group demonstrated less stability and slower responses than the control group during medium and large backwards perturbations (p's < 0.01). In the CI-V group, BalanCI use improved stability during large backwards perturbations (p < 0.001), but worsened stability during large sideways perturbations (p's < 0.001). Children and young adults with CI-V move more to remain upright during perturbations than typically-developing peers. The BalanCI has potential to aid physical/vestibular therapy in children with CIs who have poor balance.

Characteristics of balance performance in the Chinese elderly by age and gender

BACKGROUND

Population aging has been an emerging public and health concern globally. Balance performance can be applied as an indicator of functional status and a predictor of health outcomes in the elderly. However, reference data of balance performance in the elderly generated from large scale studies have been very limited. In research and geriatric assessment settings, the age and gender specific data on balance performance are indispensable prerequisites for identifying subpopulation with and at risk of impairments and subsequently implementing targeted interventions in clinics and public health to improve their balance performance.

METHODS

A total of 1984 elderly subjects aged 60 to 97 years from community settings in urban China were investigated. The balance performances together with 3 individual domains and 16 items were evaluated using the X16 balance testing scale.

RESULTS

In the elderly, with age increases each item, individual domain, and overall balance performance scores decreased gradually. Meanwhile, individual variations of individual domains and overall balance performance were all increased over age. Relative to levels of 60- years, postural stability and overall balance performance decreased significantly since 65 years old, static balance and dynamic balance capacities started to decrease significantly since 70 years old. There was no significant difference in each balance domain and overall balance performance between men and women. Across age groups, portions of individuals able to perform task 4, 8 and 11 successfully were the lowest amongst their corresponding domains static balance, postural stability, and dynamic balance, respectively. Similar patterns were observed in both men and women. Balance performances were categorized into poor, fair, and good groups with scores of 0 to 10, 11 to 17, and 18 to 20, respectively. With increases of age, proportions with poor and fair balance capacities elevated stably.

CONCLUSIONS

In the elderly, with advances in age, abilities of overall balance performance, individual domains of static balance, postural stability, and dynamic balance, and successful performances on specific tasks declined gradually and stably. The deterioration started to be obvious since 65-75 years. Men and women had similar patterns.