Objectives: The Tower of London (TOL) test has probably become the most often used task to assess planning ability in clinical and experimental settings. Since its implementation, efforts were made to provide a task version with adequate psychometric properties, but extensive normative data are not publicly available until now. The computerized TOL-Freiburg Version (TOL-F) was developed based on theory-grounded task analyses, and its psychometric adequacy has been repeatedly demonstrated in several studies but often with small and selective samples. Method: In the present study, we now report reliability estimates and normative data for the TOL-F stratified for age, sex, and education from a large population-representative sample collected in the Gutenberg Health Study in Mainz, Germany (n=7703; 40–80 years). Results: The present data confirm previously reported adequate indices of reliability (>.70) of the TOL-F. We also provide normative data for the TOL-F stratified for age (5-year intervals), sex, and education (low vs. high education). Conclusions: Together, its adequate reliability and the representative age-, sex-, and education-fair normative data render the computerized TOL-F a suitable diagnostic instrument to assess planning ability. (JINS, 2019, 25, 520–529)

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.

Executive Function is a multidimensional construct that includes a wide range of cognitive abilities that allow solving goal-directed behaviors efficiently. Its development begins in early childhood and continues through adolescence. A key aspect of Executive Function is planning, defined as the capacity to generate and organize the necessary step sequence to carry out a goal-directed behavior. The aim of this study was to assess the development of planning in children. The Tower of London task was used in 270 children aged 6, 8, 11, and 13 years. The results showed that the time required to generate and organize the plan to solve a goal-directed problem increases as the difficulty of the problem increases, and that older children need less time to solve problems with a certain level of difficulty than younger children F(15, 1330) = 8.787; MSE = 1.441; p < .01; η2 =.090. These results are in line with the findings that planning develops through childhood and even during the first years of adolescence.

Previous studies show that MS patients take longer than healthy controls to plan their solutions to Tower of London (TOL) problems but yield conflicting results regarding the quality of their solutions. The present study evaluated performance under untimed or timed conditions to assess the possibility that differences in planning ability only occur when restrictions in solution times are imposed. MS patients (n = 39) and healthy controls (n = 43) completed a computerized version of the TOL under one of two conditions. In the untimed condition, participants were allowed as much time as needed on each problem. In the timed condition, limits were imposed on solution times and time remaining was displayed with each problem. Patients exhibited longer planning times than controls, and the disparity between groups increased with problem difficulty. Planning performance depended upon condition. In the untimed condition, patients and controls performed equally well. When solution times were restricted, however, patients solved fewer problems than controls. MS patients’ planning ability is intact when permitted sufficient time to formulate the required plan. Deficiencies in planning are only evident when time is restricted, and, therefore, are more accurately considered a relative consequence of disease-related problems in information processing speed. (JINS, 2013, 19, 1–8)

Amnestic mild cognitive impairment (aMCI) represents a group of individuals who are highly likely to develop Alzheimer's disease (AD). Although aMCI is typically conceptualized as involving predominantly deficits in episodic memory, recent studies have demonstrated that deficits in executive functioning may also be present, and thorough categorization of cognitive functioning in MCI may improve early diagnosis and treatment of AD. We first provide an extensive review of neuropsychology studies that examined executive functioning in MCI. We then present data on executive functioning across multiple sub-domains (divided attention, working memory, inhibitory control, verbal fluency, and planning) in 40 aMCI patients (single or multiple domain) and 32 normal elderly controls (NECs). MCI patients performed significantly worse than NECs in all 5 sub-domains, and there was impairment (>1.0 SD below the mean of NECs) in all sub-domains. Impairment on each test was frequent, with 100% of MCI patients exhibiting a deficit in at least one sub-domain of executive functioning. Inhibitory control was the most frequently and severely impaired. These results indicate that executive dysfunction in multiple sub-domains is common in aMCI and highlights the importance of a comprehensive neuropsychological evaluation for fully characterizing the nature and extent of cognitive deficits in MCI. (JINS, 2012, 18, 541–555)

This study aimed to assess planning ability in adults with traumatic brain injury (TBI) using a 4-disk version of the Tower of London (TOL). Thirty three individuals with TBI were compared with equivalent numbers of matched controls. Overall, the TOL4 was shown to be sensitive to the effects of brain injury, with the TBI group performing significantly more poorly on this version of the planning test than the matched controls. More specifically, group differences were found to be related to the complexity of the planning problems, particularly among a TBI subgroup with localised prefrontal damage. Results of the study provide support for the adverse effects of TBI on planning ability, and the important role of the prefrontal cortex in planning.