Latham Keziah, Baranian Mohammad, Timmis Matthew A, Fisher Andy, Pardhan Shahina
*PhD, FCOptom †MSc ‡PhD §BA, CLVT ∥PhD, MCOptom Department of Vision & Hearing Sciences (KL), Vision & Eye Research Unit, Postgraduate Medical Institute (KL, MB, MAT, SP), Sports and Exercise Sciences Research Group (MB, MAT), Anglia Ruskin University, United Kingdom; and Focal Point UK, Bridgend, United Kingdom (AF).
Optom Vis Sci. 2017 Mar;94(3):317-328. doi: 10.1097/OPX.0000000000001046.
To determine the relative difficulty of activity of daily living tasks for people with retinitis pigmentosa (RP).
Participants with RP (n = 166) rated the difficulty of tasks (n = 43) underpinning the Dutch Activity Inventory goals of mobility indoors and outdoors, shopping, and using public transport. Demographic characteristics were also determined. Responses were Rasch analyzed to determine properties of the scale, derive unidimensional subscales, and consider differential item functioning (DIF).
After removal of one ill-fitting item, the remaining 42 tasks formed a scale with reasonable Rasch parameters but poor unidimensionality. The most difficult tasks were orienting in poor and bright light both indoors and outdoors, and avoiding peripheral obstacles outdoors. Eight subscales were derived with unidimensional properties, each of which could be considered as requiring similar skills. DIF identified that tasks from the "poor light and obstacles" subscale were more difficult for those younger than the median age, nonusers of mobility aids, and those not registered or registered sight impaired. Tasks from the "finding products" and "public transport" subscales were more difficult for those older than the median age, with longer duration of visual loss, users of mobility aids, and those registered severely sight impaired.
The most difficult tasks for people with RP of orienting in poor light and avoiding peripheral obstacles are relatively more difficult for those not registered as "severely sight impaired," but are less difficult for those who use mobility aids. Mobility aids (guide dog or cane), therefore, do benefit users in their perceived ability in these particular tasks. The derived unidimensional subscales reorganize the tasks from those grouped together by goal (researcher driven) to those perceived as requiring similar skills by people with RP (patient driven) and can be used as an evidence base for orientation and mobility training protocols.
确定视网膜色素变性（RP）患者日常生活活动任务的相对难度。
RP患者（n = 166）对支撑荷兰活动量表中室内外活动、购物及使用公共交通目标的任务（n = 43）的难度进行评分。同时确定人口统计学特征。对回答进行拉施分析，以确定量表的特性，得出单维度子量表，并考虑项目功能差异（DIF）。
剔除一个拟合不佳的项目后，其余42项任务形成了一个具有合理拉施参数但单维度性较差的量表。最困难的任务是在室内外弱光和强光下定向，以及在户外避开周边障碍物。得出了8个具有单维度特性的子量表，每个子量表可被视为需要类似技能。DIF表明，对于年龄低于中位数、不使用移动辅助工具、未登记或登记为视力受损的人来说，“弱光和障碍物”子量表中的任务更难。对于年龄高于中位数、视力丧失时间较长、使用移动辅助工具以及登记为严重视力受损的人来说，“寻找商品”和“公共交通”子量表中的任务更难。
对于RP患者来说，在弱光下定向和避开周边障碍物这些最困难的任务，对于未登记为“严重视力受损”的人相对更难，但对于使用移动辅助工具的人则难度较小。因此，移动辅助工具（导盲犬或拐杖）确实有利于使用者完成这些特定任务。得出的单维度子量表将任务从按目标分组（研究者驱动）重新组织为RP患者认为需要类似技能的任务（患者驱动），可作为定向和移动训练方案的证据基础。
