Assessing the Validity of the Dynamic Gait Index in a Balance Disorders Clinic: An Application of Rasch Analysis
Assessing the Validity of the Dynamic Gait Index in a Balance Disorders Clinic: An Application of Rasch Analysis
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DOI：
10.2522/ptj.20120163
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发表时间：
2013-06-01
期刊：
影响因子：
3.2
通讯作者：
Bolton, Kayla M.
中科院分区：
文献类型：
--
作者：
Dye, Deanna C.;Eakman, Aaron M.;Bolton, Kayla M.
背景动态步态指数（DGI）已成为平衡和前庭障碍患者功能性步态能力的有效指标。最近基于Rasch的分析表明，可能存在对DGI内的多维性和天花板效应的担忧。本研究的目的是评估患者样本中的DGI。以确定患者特征（例如头晕或跌倒史）是否影响DGI. Design的测量特性。本研究采用回顾性研究设计。对117例患者的病历样本进行了审查，根据原发性损害仅头晕或不平衡对患者进行分组，并根据福尔斯病史进行分类。采用单参数Rasch-Andrich评定量表模型，包括量表分析、项目难度层次、量表单维度性和项目功能差异性。DGI表现出有效的评级量表设计，并被认为是动态步态的一维测量。DGI表现出适度的天花板效应，主要是功能水平较高的患者表现出头晕症状。三个项目（“垂直头部摆动”，“在水平面上的步态”，和“跨越障碍物”）证明DIF的基础上的类别的患者特征，虽然对测量的影响是可以忽略的。功能分类是基于损伤，而不是来自回顾性病历审查的基础医学诊断，而有限的样本量可能低估了统计学上显著的DIF。这项研究的结果提供了额外的证据，支持DGI作为步态能力的衡量标准的有效性。目前的研究结果也与先前的研究一致，该研究表明平衡或前庭障碍患者的DGI具有天花板效应。DIF的影响被认为是可以忽略不计的，但在本样本中的DIP的存在有助于解释DGI项目难度层次从以前的研究中的一些差异。需要继续进行研究，以确定人口差异如何影响DGI的表现，并开发和测试能够测量更广泛的步态能力的评估。
Background. The Dynamic Gait Index (DGI) has emerged as a valid indicator of functional gait abilities for people with balance and vestibular disorders. Recent Rasch-based analyses have indicated possible concerns for multidimensionality and a ceiling effect within the DGI.Objective. The aim of this study was to evaluate the DGI in a sample of patients. from a dizziness and balance clinic to determine whether patient features such as dizziness or fall history influence the measurement characteristics of the DGI.Design. This study used a retrospective design.Methods. A sample of 117 patients' charts was reviewed, and patients were grouped according to a primary impairment of dizziness only or imbalance and were categorized based on a history of falls. A one-parameter Rasch-Andrich rating scale model was used with thorough analyses, including rating scale analysis, item-difficulty hierarchy, scale unidimensionality, and differential item functioning (DIF).Results. The DGI demonstrated an effective rating scale design and was found to be a unidimensional measurement of dynamic gait. The DGI displayed a modest ceiling effect, primarily with patients with higher functional levels displaying symptoms of dizziness. Three items ("vertical head nods," "gait on level surface," and "stepping over obstacles") demonstrated DIF based on categories of patient characteristics, although the effects on measurement were negligible.Limitations. Functional categories were based on impairments and not underlying medical diagnoses derived from a retrospective chart review, whereas the limited sample size may have underestimated statistically significant DIF.Conclusions. Results from this study offer additional evidence supporting the validity of the DGI as a measure of gait ability. The present findings also are in agreement with prior research that has shown a ceiling effect for the DGI in people with balance or vestibular disorders. Effects of DIF were found to be negligible, yet the presence of DIP within the present sample helped to explain some differences in DGI item-difficulty hierarchies from prior studies. Continued research is needed to determine how population differences may affect performance on the DGI and to develop and test assessments capable of measuring a broader range of gait abilities.