Despite how important it is to assess executive functioning in persons with Intellectual Disability (ID), instruments adapted and validated for this population are scarce. This study's primary goal was to find evidence for the validity of the ID version of the Tower of London (TOLDXtm) test in persons with mild (IDMi) and moderate (IDMo) levels of ID with Down Syndrome (DS). A multicenter study was carried out. Subjects (n = 63, ≥ 39 years old) had DS with mild (n = 39) or moderate ID (n = 24) with no minor neurocognitive disorder or Alzheimer's disease. Assessment protocol: TOLDXtm for ID, Kaufman Brief Intelligence Test Second Edition (K-BIT II), Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities (CAMDEX-DS), Weigl's Color-Form Sorting Test (WCFST), Barcelona Test for Intellectual Disability (BT-ID), and the Behavior Rating Inventory of Executive Function (BRIEF-P). The internal consistency (IDMi and IDMo), factor structure of the different subscales, and relationship between TOLDXtm subscales and other cognitive measures (BT-ID, WCFST, and BRIEF-P) were analyzed. A normative data table with ID population quartiles is provided. TOLDXtm for ID showed a robust one factor structure and coherentassociations with other, related neuropsychological instruments. Significant differences between IDMi and IDMo on movement-related variables like Correct (Corr; p = .002) and Moves (Mov; p = .042) were observed, along with good internal consistency values, Corr (α = .75), Mov (α = .52). Regarding internal consistency, no between-groups differences were observed (all p-value > 0.05). The TOLDXtm for ID is thus an instrument, supported by good validity evidence, to evaluate problem-solving and planning in ID. It distinguishes between individuals with mild and moderate ID, and is highly associated with other measures of executive functioning.

The ability to generate memory strategies is a key factor in performance of episodic memory tests. There is evidence about the inefficient use of memory strategies in old adults. However, a question remains unresolved: Worse performance on memory test in the older people is due to an inability to mobilize cognitive strategies or to an episodic memory deficit? In this study we tried to answer it by using the Test of Memory Strategies (TMS), which parametrically reduces the need of executive functions on memory tests. The test consists of five experimental conditions (TMS1–5) where a progressive external organization of the material reduces the need to mobilize memory strategies. TMS was applied to a sample of 180 participants (n = 180) divided into three age groups (25–45; 46–65; 66–85). The results showed an increased performance in all groups groups (F(2, 177) = 14.79, p < .001) across conditions (F(3.88,674.04) = 292.48, p < .001), without group differences in those conditions with a maximum reduction of the need of executive functions (F(7.61,674.04) = 1.95, p = .053). However, middle age and older adults showed more difficulties in establishing cognitive strategies, in the initial conditions. These results lead to the conclusion that the typical pattern of low performance on episodic memory tasks in the older population may be due to the deterioration of executive functions and not mainly to a primary decline of memory process.