对依赖视觉的日常生活任务（DLTV）进行拉施分析。

Denny Frances, Marshall Adele H, Stevenson Michael R, Hart Patricia M, Chakravarthy Usha

Centre for Vision Sciences, School of Mathematics and Physics, Queen's University of Belfast, Belfast Northern Ireland, United Kingdom.

Invest Ophthalmol Vis Sci. 2007 May;48(5):1976-82. doi: 10.1167/iovs.06-0135.

PURPOSE

To examine internal consistency, refine the response scale, and obtain a linear scoring system for the visual function instrument, the Daily Living Tasks Dependent on Vision (DLTV).

METHODS

Data were available from 186 participants with a clinical diagnosis of AMD who completed the 22-item DLTV (DLTV-22) according to four-point ordinal response scale. An independent group of 386 participants with AMD were administered a reduced version of the DLTV with 11 items (DLTV-11), according to a five-point response scale. Rasch analysis was performed on both datasets and used to generate item statistics for measure order, response odds ratios per item and per person, and infit and outfit mean square statistics. The Rasch output from the DLTV-22 was examined to identify redundant items and for factorial validity and person item measure separation reliabilities.

RESULTS

The average rating for the DLTV-22 changed monotonically with the magnitude of the latent person trait. The expected versus observed average measures were extremely close, with step calibrations evenly separated for the four-point ordinal scale. In the case of the DLTV-11, step calibrations were not as evenly separated, suggesting that the five-point scale should be reduced to either a four- or three-point scale. Five items in the DLTV-22 were removed, and all 17 remaining items had good infit and outfit mean squares. PCA with residuals from Rasch analysis identified two domains containing 7 and 10 items each. The domains had high person separation reliabilities (0.86 and 0.77 for domains 1 and 2, respectively) and item measure reliabilities (0.99 and 0.98 for domains 1 and 2, respectively).

CONCLUSIONS

With the improved internal consistency, establishment of the accuracy and precision of the rating scale for the DLTV and the establishment of a valid domain structure we believe that it constitutes a useful instrument for assessing visual function in older adults with age-related macular degeneration.

目的

检验视觉功能仪器“依赖视力的日常生活任务量表（DLTV）”的内部一致性，完善反应量表，并获得线性评分系统。

方法

数据来自186名临床诊断为年龄相关性黄斑变性（AMD）的参与者，他们根据四点顺序反应量表完成了包含22个条目的DLTV（DLTV - 22）。另一组由386名AMD参与者组成的独立样本，根据五点反应量表接受了包含11个条目的DLTV简化版（DLTV - 11）。对两个数据集都进行了拉施分析，并用于生成项目统计数据，包括测量顺序、每个项目和每个人的反应优势比，以及内拟合和外拟合均方统计量。检查DLTV - 22的拉施分析输出结果，以识别冗余项目、检验因子效度以及人员项目测量分离信度。

结果

DLTV - 22的平均评分随潜在个体特质的大小单调变化。预期平均测量值与观察到的平均测量值极为接近，四点顺序量表的步长校准均匀分布。对于DLTV - 11，步长校准分布不均匀，表明五点量表应缩减为四点或三点量表。DLTV - 22中删除了5个项目，其余17个项目的内拟合和外拟合均方良好。基于拉施分析残差的主成分分析确定了两个领域，每个领域分别包含7个和10个项目。这两个领域具有较高的人员分离信度（领域1和领域2分别为0.86和0.77）和项目测量信度（领域1和领域2分别为0.99和0.98）。