Kimberly Edginton Bigelow

Development of a Protocol for Improving the Clinical Utility of Posturography as a Fall-Risk Screening Tool

BACKGROUND The usefulness of posturography in the clinical screening of older adults for fall risk has been limited by a lack of standardization in testing methodology and data reporting. This study determines which testing condition and postural sway measures best differentiate recurrent fallers and nonrecurrent fallers. METHODS One hundred and fifty older adults were categorized based on their fall status in the past year. Participants performed four quiet-standing tasks, eyes open and eyes closed in both comfortable and narrow stance, for 60 seconds while standing on a force-measuring platform. Traditional and fractal measures were calculated from the center of pressure data. Logistic regression was performed to determine the model for each condition that best discriminated between recurrent fallers and nonrecurrent fallers. RESULTS The eyes closed comfortable stance condition, with its associated model, best differentiated recurrent fallers and nonrecurrent fallers. Medial-lateral sway velocity, anterior-posterior short-term α-scaling exponent, medial-lateral short-term α-scaling exponent, mean frequency, body mass index, and age were included in this model. Sensitivity of the model was 75%, and specificity was 94%. CONCLUSIONS This resulting model demonstrates potential to differentiate recurrent fallers and nonrecurrent fallers in an eyes closed comfortable stance condition. The inclusion of traditional sway parameters, fractal measures, and personal characteristics in this model demonstrates the importance of considering multiple descriptions of postural stability together rather than using only a single measure to establish fall risk.

Measures of Balance Performance Are Affected by a Rested Versus Fatigued Testing Condition in People With Multiple Sclerosis

To investigate the effects of a rested and fatigued testing condition on measures of balance in people with multiple sclerosis (MS).

Using Posturography to Examine the Immediate Effects of Vestibular Therapy for Children with Autism Spectrum Disorders: A Feasibility Study

ABSTRACT Aims: The primary objective of this study was to determine the feasibility of using posturography to monitor acute changes in postural control induced by a Sensory Integration (SI) therapy intervention. A secondary objective was to identify which posturography outcome parameters, tests conditions and data analysis methods might be most useful in identifying post-intervention changes. Methods: Five children with Autism Spectrum Disorder (ASD) and five children with typical development (TD) participated in a 10 min vestibular swing activity and had their postural stability evaluated pre- and post-intervention under four different sensory testing conditions. Sway ranges, mean sway velocity, sway root mean square (RMS), and sample entropy were calculated from center of pressure (COP) data. Results: All five children with ASD demonstrated decreased mean sway velocity in the eyes open/flat plate condition post-intervention with an average decrease of 5.87 ± 2.69 mm/s. Four of the five children with ASD demonstrated an increase in RMS and a decrease in anterior/posterior sample entropy post-intervention in the eyes closed, foam pad condition and eyes open, flat plate condition respectively. Conclusion: Posturography may be useful for assessing acute physiologic responses to an SI therapy intervention and warrants further investigation.

Subtle Differences During Posturography Testing Can Influence Postural Sway Results: The Effects of Talking, Time Before Data Acquisition, and Visual Fixation.

The goal of this study was to examine the effects of 3 factors and their interactions on posturography: a period of time to become accustomed to the force platform before the initiation of data collection, presence of a visual fixation point, and participant talking during testing. The postural stability of 30 young adults and 30 older adults was evaluated to determine whether any observed effects were confounded with age. Analysis of variance techniques were used to test all possible combinations of the 3 factors. We hypothesized that all 3 factors would significantly affect postural stability. For both participant groups, the results suggest that a period of time to become accustomed to the force platform before the initiation of data collection and a visual fixation point significantly affect postural control measures, while brief participant talking does not. Despite this, no significant interactions existed suggesting that the effects of these factors, which may occur in clinical testing, do not depend on each other. Our results suggest that inconsistencies in posturography testing methods have the potential to significantly affect the results of posturography, underscoring the importance of developing a standardized testing methodology.

Identification of key outcome measures when using the instrumented timed up and go and/or posturography for fall screening

The Timed Up and Go (TUG) has been commonly used for fall risk assessment. The instrumented Timed Up and Go (iTUG) adds wearable sensors to capture sub-movements and may be more sensitive. Posturography assessments have also been used for determining fall risk. This study used stepwise logistic regression models to identify key outcome measures for the iTUG and posturography protocols. The effectiveness of the models containing these measures in differentiating fallers from non-fallers were then compared for each: iTUG total time duration only, iTUG, posturography, and combined iTUG and posturography assessments. One hundred and fifty older adults participated in this study. The iTUG measures were calculated utilizing APDM Inc.s Mobility Lab software. Traditional and non-linear posturography measures were calculated from center of pressure during quiet-standing. The key outcome measures incorporated in the iTUG assessment model (sit-to-stand lean angle and height) resulted in a model sensitivity of 48.1% and max re-scaled R2 value of 0.19. This was a higher sensitivity, indicating better differentiation, compared to the model only including total time duration (outcome of the traditional TUG), which had a sensitivity of 18.2%. When the key outcome measures of the iTUG and the posturography assessments were combined into a single model, the sensitivity was approximately the same as the iTUG model alone. Overall the findings of this study support that the iTUG demonstrates greater sensitivity than the total time duration, but that carrying out both iTUG and posturography does not greatly improve sensitivity when used as a fall risk screening tool.

Immediate Influence of Carbon Composite Ankle-Foot Orthoses on Balance and Gait in Individuals with Peripheral Neuropathy: A Pilot Study

ABSTRACT Currently, limited data exist supporting the use of ankle-foot orthoses (AFOs) on improving balance and gait in individuals with peripheral neuropathy (PN), and no studies have evaluated the effects of carbon composite AFOs in this population. The primary purpose of this study was to determine the immediate effects of carbon composite AFOs on postural control, dynamic balance, and gait in individuals with PN. Twelve subjects with neuropathy completed a single session of testing in this observational study. The subjects performed a battery of tests including quiet standing and limits of stability (LOS) force plate posturography, the Mini Balance Evaluation Systems Test (Mini-BESTest), gait speed, as well as the Timed Up and Go (TUG), both with and without carbon composite AFOs. The subjects exhibited significantly less sway in the anterior-posterior (p = 0.012) and medial-lateral (p = 0.047) sway directions with eyes closed while wearing the AFOs but experienced a reduction in anterior-posterior LOS (p = 0.000). There were no group differences for the Mini-BESTest, gait speed, and TUG; however, individual subjects experienced both positive and negative changes that exceeded minimally important change (MIC) values for the Mini-BESTest and gait speed. The results suggest that carbon composite AFOs have an immediate effect on balance in individuals with PN. In general, improvements in static postural control were observed when the AFOs were worn, but the effects on dynamic measures of balance and gait were more variable. Because of these trade-offs and variability, clinicians should evaluate how AFOs influence individual patients with the use of standardized measures that include a variety of dynamic balance and gait measures.