Transcript Title in 48 point font Authors and Affiliations in 24

Use of the Modified 2X3 Test to
Assess Executive Functioning in Traumatic Brain Injury.
Margaret A. Struchen, Ph.D.1, 2 & Laura Rosas, M.A.2
1
Baylor College of Medicine/University of Texas-Houston PM&R Alliance, Houston, Texas
2 Brain Injury Research Center, The Institute for Rehabilitation and Research (TIRR)
Mean Task Accomplishment and Rule Violation Errors on Modified 2X3 Test.
Measures:
Introduction
Executive dysfunctions are regarded as common sequelae following
traumatic brain injury (TBI). Such impairments are hypothesized to pose
obstacles to social integration and employment. Executive functions
regulate how a person formulates, initiates, and executes planned activities.
Attentional flexibility, planning, and self-monitoring are key components
of executive functions that can impact success in daily living.
Investigation of the relationship between executive functioning and
functional outcome has been limited, however. Since the goals of
neuropsychological assessment today are often focused on the prediction
and enhancement of everyday functioning for persons with brain injury,
establishing the ecological validity of test instruments has become critical.
Assessment of executive functioning poses challenges since,
paradoxically, it requires a structured test to measure how others develop
and implement structure to accomplish goals. The Modified 2X3 Test is a
task that shows promise in the assessment of executive functions, since it
requires the individual to initiate, set goals, and impose structure in
completing a series of tasks. This modified version is an extension of the
procedure developed by Schwartz et al.1-2, based on Shallice and Burgess’
Six Elements Test.3 Subjects are required to perform 2 exemplars of 3 realworld tasks (e.g., packing a lunch) while adhering to a set of performance
constraints.
The purpose of the current study was to examine the utility of the
Modified 2X3 Test in the assessment of adults with TBI. It was
hypothesized that adults with TBI would produce lower accomplishment
scores and make a larger number of errors on the task than would age-,
gender-, and education-matched controls. It was also hypothesized that
poorer performance on the Modified 2X3 Test would be associated with
poorer functional outcome.
Methods
Participants:
Participants were 8 adults with moderate to severe TBI who
participated in a study examining the assessment of social
communication and executive functioning abilities and 8 age-, gender-,
and education-matched non-injured control subjects drawn from among
family members and friends of the injured individuals. Participants with
TBI were drawn from a sample of individuals participating in follow-up
evaluations as part of the NIDRR TBI Model Systems study, all of whom
had received inpatient rehabilitation and were at least 1-year post-injury.
Demographic and injury-related information are presented below.
Comparisons between adults with TBI and controls revealed no
significant differences between age and education, confirming that
matching was adequate.
Adults with TBI
Controls
M (SD)
M (SD)
Age (yrs.):
37.5 (12.8)
36.6 (12.6)
Education (yrs.):
12.8 (1.0)
12.5 (1.1)
Gender (males):
5 (63%)
5 (63%)
Emergency Room GCS*:
6.5 (3.9)
Time since Injury (yrs.):
6.9 (3.8)
*GCS = Glasgow Coma Scale score
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Modified 2X3 Test (2X3).1-3 As described in the introduction, the 2X3 involves the
completion of 2 exemplars of 3 real-world tasks (packing lunchboxes, wrapping
gifts as presents, and making toast with butter and jam). Participants are required
to plan, order, and initiate task performance in accordance with a set of rules. Each
overall task consists of several subtasks (e.g., for lunchbox, making a sandwich is
1 subtask) and participants receive a point for each subtask completed. The sum of
these points comprises a “Task Accomplishment” score. In this modified version
of the 2X3, 3 rules were imposed. Participants were not to complete the same 2
tasks in a row, must ring a bell after the completion of each task, and must
complete an entire task before beginning another. For the current study, key
measures utilized from the 2X3 were the Task Accomplishment score and the total
Rule Violation errors.
Community Integration Questionnaire (CIQ).4-5 The CIQ is a 15-item structured
interview assessing three domains of functional outcome from TBI: Productivity
(e.g., school attendance, employment); Home Integration (e.g., shopping, meal
preparation); and Social Integration (e.g., friendships, visits). The CIQ measures
actual performance of activities, as compared with measuring potential to perform
activities. The reliability and validity of the CIQ have been confirmed in the TBI
population.4 Subscales utilized for the current study reflect the more recent factor
analysis by Sander et al. (1999).5
Procedure:
All participants completed the 2X3 and the CIQ as part of a more extensive
assessment of social communication and executive functioning. Participants were
brought into the room and asked to sit at a table containing all of the requisite test
materials (a toaster, lunchboxes, various food items, gift wrapping materials, etc.)
The test administrator presented posters, each with visual cues that described the 6
tasks and the 3 rules. Rules and task requirements were explained and the posters
were later hidden from view. Participants were then asked to repeat all tasks and
rules in order to establish whether they understood and could remember the test
procedures. When testing began, no further instructions were given, although
general encouragement was provided. On completion of testing, participants were
asked to repeat the 6 tasks and the 3 rules to verify recall. All participants were
videotaped during task performance. Videotapes were then independently coded
by two raters.
Results
Comparison of Modified 2X3 Test Performance between Adults with TBI
and Matched Controls:
Results of paired t-test comparisons revealed no statistically significant
differences on task accomplishment scores between persons with TBI
(M = 23.0, sd = 5.5) and non-injured matched control participants (M = 24.6,
sd = 1.3). However, persons with TBI committed significantly more rule
violation errors (M=5.13, sd = 3.9) than did matched control participants
(M = 0.8, sd = 1.2) (t = 2.79, p < 0.03).
This project was partially supported by funding from the National Institute on Disability and Rehabilitation
Research , United States Department of Education (Grant #H133G010152).
20
15
TBI
C on trol s
10
* p < 0.03
5
0
Tas k Accomplis hment
Rule Violation Errors
Relationship between Modified 2X3 Test scores and Functional Outcome:
For individuals with TBI, performance on task accomplishment was highly
correlated with functional outcome, as measured by CIQ Total Scores
(r = 0.79, p < 0.01). The number of rule violation errors was also significantly
negatively correlated with CIQ Total Scores for participants with TBI
(r = -0.65, p < 0.05).
Although the small sample size limits the interpretation of additional
analyses, exploration of the relationship between task accomplishment scores
and CIQ subscale scores revealed that the relationship with the Home
Integration subscale ( r = 0.64, p < 0.05) and the Social Integration subscale
(r = 0.58, p < 0.07) approached statistical significance. The correlation
between the number of rule violation errors and CIQ subscale scores revealed
a moderate negative relationship between the number of rule violation errors
and scores on the Home Integration subscale (r = -0.71, p < 0.02).
Conclusions
•These preliminary data indicate that the Modified 2X3 Test may have
clinical utility in the evaluation of executive functioning for individuals with
TBI. Adults with TBI were able to accomplish the set of tasks required at the
same level as age-, education-, and gender-matched controls. Although
participants with TBI were able to complete essentially an equal number of
subtasks, differences in the quality of their performance were observed.
•Performances for those with TBI were characterized by an increased number
of rule violations. Such violations suggest that while individuals with TBI
may be able to complete assigned tasks, they may experience difficulties in
inhibition and/or maintaining cognitive set to follow task constraints.
•Preliminary evidence for the ecological validity of this instrument has been
demonstrated, in that performance on the 2X3 was significantly related to
functional outcome on the CIQ. In particular, the preliminary evidence of a
relationship between task performance on the 2X3 and Home Integration
subscales appears to have face validity.
•Further evaluation of the Modified 2X3 Test with a larger sample of adults
with TBI and matched controls will provide additional information on the
utility of this instrument and will allow for further evaluation of qualitative
aspects of task performance.
References
1. Schwartz MF, et al. (1998). Naturalistic action impairment in closed head injury. Neuropsychology,12, 13-28.
2. Buxbaum LJ, Schwartz MF, & Carew TG. (1997). The role of semantic memory in object use. Cognitive
Neuropsychology, 14, 219-254.
3. Shallice T & Burgess PW. (1991). Deficits in strategy application following frontal lobe damage in man. Brain, 114,
727-741.
4. Willer B, Ottenbacher KJ, & Coad ML. (1994). The Community Integration Questionnaire: a comparative examination.
American Journal of Physical Medicine and Rehabilitation, 73, 103-111.
5. Sander AM, et al.(1999). The Community Integration Questionnaire revisited: an assessment of
factor structure and validity. Archives of Physical Medicine and Rehabilitation, 80, 1303-1308.