have spent most of my professional career providing
psychological services to children and adolescents.
During the early 1990’s, I found myself frustrated
over the relatively meager advances, both empirically and
theoretically, to the neuropsychological understanding of
I was particularly dissatisfied with the practice of
conceptualizing childhood disorders, such as
attention-deficit/hyperactivity disorder (ADHD), as a
“set” or “list” of specific behavioral symptoms with
minimal attention to developmental factors.
exceptional research and theorization of Joaquin Fuster in The Prefrontal Cortex (1989) helped crystallize for me the role of
the prefrontal cortex in the generation, organization, and
evaluation of complex human behavior, both healthy and
Unfortunately, at this point our understanding of the
relationship of prefrontal functioning to childhood behavior
was limited, in part, due to the traditional
neuropsychological view of the frontal lobes as “silent”
structures until late adolescence/early adulthood.
Subsequent research has challenged this view by
revealing the emergence of frontal/executive functions early
in childhood that follow a protracted trajectory to maturity
Moreover, advances in neuroimaging have identified, and
continue to identify, anatomical and functional differences in
the brains of children with ADHD and other childhood disorders
relative to healthy children.
planning provided a potential heuristic for integrating and
understanding the diverse behaviors of childhood disorders,
Accordingly, I set out to find a measure sensitive to
executive planning for children.
My search led to Shallice’s Tower of London (1982).
Unfortunately, the measure had been developed for adult
patients with frontal lobe damage.
Adaptions of the Tower of London and normative data for
children were not available at this time.
As a consequence, I decided to modify and standardize
the Tower of London.
My association with Dr. Zillmer of Drexel University
revealed the need to include adults, in addition to children
and adolescents, in the standardization sample.
Multi-Health Systems agreed to assist in providing
normative data, and subsequently recruited a significant
number of children, adolescents, and adults for assessment.
The Tower of London-Drexel University (TOLDX)
reflects the culmination of these events.
consists of a Technical Manual, two tower structures (each
with a set of beads) and Record Forms (Child and Adult).
The measure presents 10 problems of ascending
difficulty that require from 3 to 7 moves to solve.
The examinee is asked to match a presented bead
configuration while adhering to two specific rules.
takes approximately 15 minutes to administer and is well
tolerated by examinees due to its brevity, novelty, and
Seven scoring variables, representing different,
although overlapping aspects of executive planning and problem
solving, are provided.
Normative data is available for children and adults
ranging in age from 7 to 60+ years.
Principles for interpreting the scoring variables, both
qualitatively and quantitatively, are outlined for children
Preliminary studies of the psychometric characteristics
of the TOLDX
are supportive of its reliability and validity.
can be obtained from Multi-Health Systems, Inc.