Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, Kings College London, London, SE5 8AF, UK.
Division of Psychiatry, University College London, London, W1T 7NF, UK.
J Neurodev Disord. 2019 Aug 30;11(1):20. doi: 10.1186/s11689-019-9279-8.
Measures of general cognitive and adaptive ability in adults with Down syndrome (DS) used by previous studies vary substantially. This review summarises the different ability measures used previously, focusing on tests of intelligence quotient (IQ) and adaptive behaviour (AB), and where possible examines floor effects and differences between DS subpopulations. We aimed to use information regarding existing measures to provide recommendations for individual researchers and the DS research community.
Nineteen studies reporting IQ test data met inclusion for this review, with 17 different IQ tests used. Twelve of these IQ tests were used in only one study while five were used in two different studies. Eleven studies reporting AB test data met inclusion for this review, with seven different AB tests used. The only AB scales to be used by more than one study were the Vineland Adaptive Behaviour Scale (VABS; used by three studies) and the Vineland Adaptive Behavior Scale 2nd Edition (VABS-II; used by two studies). A variety of additional factors were identified which make comparison of test scores between studies problematic, including different score types provided between studies (e.g. raw scores compared to age-equivalent scores) and different participant inclusion criteria (e.g. whether individuals with cognitive decline were excluded). Floor effects were common for IQ tests (particularly for standardised test scores). Data exists to suggest that floor effects may be minimised by the use of raw test scores rather than standardised test scores. Raw scores may, therefore, be particularly useful in longitudinal studies to track change in cognitive ability over time.
Studies assessing general ability in adults with DS are likely to benefit from the use of both IQ and AB scales. The DS research community may benefit from the development of reporting standards for IQ and AB data, and from the sharing of raw study data enabling further in-depth investigation of issues highlighted by this review.
以往研究中用于唐氏综合征（DS）成人的一般认知和适应能力的测量方法差异很大。本综述总结了之前使用的不同能力测量方法，重点介绍智商（IQ）和适应行为（AB）测试，并且在可能的情况下，检查地板效应和 DS 亚组之间的差异。我们旨在使用有关现有测量方法的信息，为个别研究人员和 DS 研究界提供建议。
有 19 项报告 IQ 测试数据的研究符合本综述的纳入标准，共使用了 17 种不同的 IQ 测试。其中 12 种 IQ 测试仅在一项研究中使用，而 5 种则在两项不同的研究中使用。有 11 项报告 AB 测试数据的研究符合本综述的纳入标准，共使用了 7 种不同的 AB 测试。仅有的两种被多项研究使用的 AB 量表是：Vineland 适应行为量表（VABS；被三项研究使用）和 Vineland 适应行为量表第二版（VABS-II；被两项研究使用）。还确定了许多其他因素，这些因素使得在研究之间比较测试分数变得很复杂，包括不同的研究之间提供的不同分数类型（例如原始分数与年龄等效分数的比较）和不同的参与者纳入标准（例如是否排除认知能力下降的个体）。IQ 测试普遍存在地板效应（特别是对于标准化测试分数）。数据表明，使用原始测试分数而不是标准化测试分数可以最小化地板效应。因此，原始分数在纵向研究中可能特别有用，可以追踪随着时间的推移认知能力的变化。
评估 DS 成人一般能力的研究可能会受益于 IQ 和 AB 量表的使用。DS 研究界可能会受益于 IQ 和 AB 数据报告标准的制定，以及原始研究数据的共享，从而可以更深入地研究本综述中突出的问题。
