Dual task cost in adults with persistent concussion symptoms.

BACKGROUND: Persistent concussion symptoms (PCS) negatively affects common activities of daily living including deficits in both single and dual-task (DT) gait. DT gait deficits are present post-concussion; however, task prioritization and the effects of differing cognitive challenge remain unexplored in the PCS population. RESEARCH QUESTION: The purpose of this study was to investigate single and dual-task gait performance in individuals with persistent concussion symptoms and to identify task priorization strategies during DT trials. METHODS: Fifteen adults with PCS (age: 43.9+11.7 y.o.) and 23 healthy control participants (age: 42.1+10.3 y.o.) completed five trials of single task gait followed by fifteen trials of dual task gait along a 10-m walkway. The cognitive challenges consisted of five trials each of visual stroop, verbal fluency, and working memory cognitive challenges. Groups were compared on DT cost stepping characteristics with independent samples t-test or Mann-Whitney U tests. RESULTS: There were significant overall gait Dual Task Cost (DTC)difference between groups for gait speed (p = 0.009, d=0.92) and step length (p = 0.023, d=0.76). Specific to each DT challenge, PCS participants were slower during Verbal Fluency (0.98 + 0.15 m/s and 1.12 + 0.12 m/s, p = 0.008; d=1.03), Visual Stroop (1.06 + 0.19 m/s and 1.20 + 0.12 m/s, p = 0.012, d=0.88), and Working Memory (1.02 + 0.15 m/s and 1.16 + 0.14 m/s, p = 0.006, d=0.96). There were significant cognitive DTC differences between groups for WM accuracy (p = 0.008, d=0.96), but not for VS accuracy (p = 0.841, d=0.061) or VF total words (p = 0.112, d=0.56). SIGNIFICANCE: The PCS participants displayed a posture-second strategy whereby gait performance generally decreased in the absence of cognitive changes. However, during the Working Memory DT, PCS participants had a mutual interference response whereby both motor and cognitive performance decreased suggesting the cognitive task plays a key role in the DT gait performance of PCS patients.

Reliability and practical clinical application of an accelerometer-based dual-task gait balance control assessment.

BACKGROUND: Gait balance control assessment using whole body center of mass (COM) kinematic measures in concussed individuals reveals persistent balance deficits up to two months post-injury. A reliable and clinically practical gait balance control assessment leveraging similar kinematic measures is necessary to improve concussion assessment and management. RESEARCH QUESTION: Can peak accelerations collected during a dual-task (DT) gait assessment from a single low back placed accelerometer be measured reliably on different days, by different raters, in different environments, and be practically applied in a Division One (D1) athletics program? METHODS: A single accelerometer placed on the low back over the L5 vertebra was utilized with a DT gait analysis protocol. Twenty (10 F) healthy participants performed the assessment in a laboratory and non-laboratory environment, on two separate days, and with two different raters. Eight gait event specific peak accelerations along three orthogonal axes were collected. In addition, data were collected from a cohort of 14 D1 female soccer players during a single assessment to explore the practical clinical application. RESULTS: Cronbach's α values for the eight metrics ranged from 0.881 to 0.980 and ICC values from 0.868 to 0.987. Average assessment time for the 14 D1 female athletes was 8.50 ± 0.58 min, and significant differences between walking conditions were identified for Vert Accel 1 (p < .01), Vert Accel 2 (p = .01), and A-P Accel (p < .01). SIGNIFICANCE: High Cronbach's α and ICC values coupled with a short assessment time and sensitivity to differences in gait balance control indicate our testing apparatus and protocol are both reliable and clinically practical. Additionally, gait event specific peak accelerations from a single accelerometer can detect subtle changes in gait balance control and may facilitate improvements in sport-related concussion diagnosis and return to activity decision making.

Cost-Effectiveness of a Therapeutic Tai Ji Quan Fall Prevention Intervention for Older Adults at High Risk of Falling.

BACKGROUND: Data on the cost-effectiveness of proven fall prevention exercise interventions are limited. We aimed to establish the cost-effectiveness of Tai Ji Quan: Moving for Better Balance (TJQMBB) compared with a conventional exercise intervention for older adults at high risk of falling. METHODS: We conducted a trial-based cost-effectiveness analysis involving 670 older adults who had a history of falling or impaired mobility. Participants received one of three interventions-TJQMBB, multimodal exercise, or stretching exercise (control)-each of which was implemented twice weekly for 24 weeks. The primary cost-effectiveness measure was the incremental cost per additional fall prevented, comparing TJQMBB and multimodal exercise to Stretching and TJQMBB to multimodal exercise, with a secondary measure of incremental cost per additional quality-adjusted life-year (QALY) gained. The intervention was conducted between February 2015 and January 2018, and cost-effectiveness was estimated from a health care system perspective over a 6-month time horizon. RESULTS: The total cost to deliver the TJQMBB intervention was $202,949 (an average of $906 per participant); for multimodal exercise, it was $223,849 ($1,004 per participant); and for Stretching, it was $210,468 ($903 per participant). Incremental cost-effectiveness ratios showed that the multimodal exercise was cost-effective ($850 per additional fall prevented; $27,614 per additional QALY gained) relative to Stretching; however, TJQMBB was the most economically dominant strategy (ie, having lower cost and being clinically more efficacious) compared with multimodal and stretching exercises with regard to cost per additional fall prevented and per additional QALY gained. TJQMBB had a 100% probability of being cost-effective, relative to Stretching, at a threshold of $500 per each additional fall prevented and $10,000 per additional QALY gained. Sensitivity analyses showed the robustness of the results when extreme cases, medical costs only, and missing data were considered. CONCLUSIONS: Among community-dwelling older adults at high risk for falls, TJQMBB is a cost-effective means of reducing falls compared with conventional exercise approaches. TRIAL REGISTRATION: Clinicaltrials.gov (NCT02287740).

Consistency and cost of dual-task gait balance measure in healthy adolescents and young adults.

Matched control data are commonly used to examine recovery from concussion. Limited data exist, however, examining dual-task gait data consistency collected over time in healthy individuals. The study purposes were to: 1) assess the consistency of single-task and dual-task gait balance control measures, 2) determine the minimal detectable change (MDC) of gait balance control measures, and 3) examine the extent to which age and task complexity affect dual-task walking costs in healthy adolescents and young adults. Twenty-four adolescent (mean age=15.5±1.1years) and 21 young adult (mean age=21.2±4.5years) healthy participants completed 5 testing sessions across a two-month period, which involved analyses of gait balance control and temporal-distance variables during single-task and dual-task walking conditions in a motion analysis laboratory. Cronbach's α and MDCs were used to determine the consistency of the gait balance control variables and the smallest amount of change required to distinguish true performance from change due to the performance/measurement variability, respectively. Dual-task costs were evaluated to determine the effect of task complexity and age across time using 3-way ANOVAs. Good to excellent test-retest consistency was found for all single-task and dual-task walking (Cronbach's α range: 0.764-0.970), with a center-of-mass medial-lateral displacement MDC range of 0.835-0.948cm. Greater frontal plane dual-task costs were observed during more complex secondary tasks (p<0.001). The results revealed good-excellent consistency across testing sessions for all variables and indicated dual-task costs are affected by task complexity. Thus, healthy controls can be effective comparators when assessing injured subjects.

An assessment of gait and balance deficits after traumatic brain injury.

OBJECTIVE: To assess the sensations of instability that many patients report after traumatic brain injury (TBI). DESIGN: A controlled study. SETTING: A motion analysis and vestibular and balance laboratory. PARTICIPANTS: Twenty subjects, 10 with TBI and complaints of instability, and 10 without TBI. INTERVENTIONS: Balance and gait analysis. MAIN OUTCOME MEASURES: Dizziness Handicap Inventory (DHI), caloric irrigation, optokinetic testing, Dix-Hallpike Test, posturography, and center of mass (COM) movement. RESULTS: Subjects were well matched in terms of age, height, weight, and gender. DHI scores of those with and without TBI differed significantly (32.2+/-23.0 vs 0.2+/-0.63, P<.001). Caloric and optokinetic circularvection testing were abnormal only in subjects with TBI (8/10 and 4/10, respectively). Benign paroxysmal positioning vertigo was present in only 3 subjects with TBI, and this either resolved spontaneously (n=1) or was successfully treated (n=2). Composite posturography scores of those with and without TBI differed significantly (69.6+/-35.8 vs 79.5+/-40.5, P=.02). Gait parameters also differed significantly between the groups (P=.05), with the subjects with TBI having lower anterior and posterior and higher medial and lateral COM displacements and velocities. CONCLUSIONS: Patients' complaints of instability after TBI may have objective correlates and may be rectifiable. Balance and gait testing in these patients is warranted.