How does the TOL^DX differ from other tower systems, including that developed by Shallice (1982)?

     The TOL^DX incorporates 6- to 7-move problems; permits only one trial per test item; provides standardized instructions for administration, scoring, and interpretation; and presents extensive norm data for ages 7-through 60+ years (n » 975). 

How does the TOL^DX differ from the TOH?

     The TOL^DX structure employs three pegs of descending height, and beads or rings of similar size and different colors, whereas the TOH structure is comprised of three pegs of equal height and rings or disks of descending size.  Both the TOH and TOL^DX prohibit the examinee from removing more than one ring/bead at a time from the pegs in solving test items.  While the instructions for performing the TOH prohibit the placement of a larger ring on top of a smaller ring, the instructions for the TOL^DX do not permit the placement of more beads on a peg than it is designed to hold. Finally, there is increasing evidence that the TOL^DX and TOH measure different psychological constructs.     

Do females and males differ in their TOL^DX performance?

     In analyzing the TOL^DX normative data, there was minimal evidence of a difference in TOL^DX performance as a function of gender.

What clinical groups have been compared to normal children/adults with the TOL^DX?

     Our initial efforts focused on developing normative data for the TOL^DX with healthy children and adults.  We have now turned our attention to different clinical groups.  For example, we have draw normative data for children   (n = 200+) with attention-deficit/hyperactivity disorder (ADHD).  Additionally, Dr. Carrie Kennedy studied a group of mentally retarded adults (n = 64) who were assessed with a battery of neuropsychological measures, including the TOL^DX, to determine their competency in rendering sexual consent.  This latter data is included in the TOL^DX Manual.  

Which TOL^DX scores have been found most clinically useful?

     Although all seven scores provide valuable information concerning executive planning and problem solving, the three that have been found to be most clinically useful are Total Move Score, Rule Violations, and Execution Time.

Who should use the TOL^DX?

     Any professional who is interested in assessing executive planning and problem solving can potentially use the TOL^DX.  However, it is important that the user have an understanding of brain-behavior relationships (particularly the complexities of the developmental trajectory of executive functions) and possess the necessary clinical skills to carry out a competent assessment.

Should the appraisal of an individual’s executive functions be based solely on the TOL^DX?

     No, an adequate assessment of executive functions requires a comprehensive evaluation involving multiple measures of executive and non-executive functions.  The TOL^DX provides but one sample of executive functioning, specifically planning and problem-solving, that can be integrated with other data to draw pertinent conclusions. 

How much time is allotted for each TOL^DX test item, and when is a time violation scored?

     The time limit for each TOL^DX test item is 2-minutes.  If the examinee fails to solve a given test item within 1-minute, a time violation is scored, but the individual’s performance is not interrupted until the 2-minute limit is reached.  If the examinee has not solved a test item at the expiration of the 2-minute time limit, a score of 20 is assigned regardless of the number of moves that have been executed.  For example, if a child/adult, at 2-minutes, has made 16 unsuccessful moves on test item 10 (a 7-move problem), (s)he is asked to suspend performance, and the item move score is calculated as follows: 20 - 7 = 13.  The perceptive reader will note that a time violation is also scored at 1-minute for this item.

What is the rationale for assigning a time violation at 1-minute?

     In our preliminary research with the TOL^DX we found that the majority of children/adults solved the individual test items within 1-minute. Thus, solving TOL^DX items in a minimum number of moves within 1-minute suggested relatively effective planning and problem solving.  The extra 1-minute (time limit per test item is 2-minutes) was added to enable the clinician to differentiate between the slow-accurate and slow-inaccurate planner and problem-solver.     

Do children and adults find the TOL^DX to be “user friendly?”

     Without a doubt!  Most children and adults report that they find the measure enjoyable.  Its game-like appearance is appealing to both children and adults.  The hands-on nature of the measure, coupled with its limited demands for verbal or academic skills, is attractive to many individuals, particularly those with impaired or limited language skills.