After each vignette is presented, the written stimu-
lus is removed, and patients are asked to answer a
series of questions that test distinct consent abilities.
These consent abilities are derived from psychiatric lit-
erature and case law and reflect four well-established
standards (S) for decisional capacity: evidencing a
choicefor or against treatment (S1),appreciatingthe
personal consequences of a treatment choice (S3),rea-
soning about treatment, or making a treatment choice
based on rational reasons (S4), and understandingthe
treatment situation and choices (S5). The CCTI also
assesses the capacity to make a reasonable choice
(S2). This is an experimental standard that has not
received legal or clinical acceptance due to arbitrari-
ness in determining what constitutes a “reasonable”
treatment choice.
Administration time for the CCTI is about 20 to 25
minutes for both vignettes.CCTI Scoring System
The CCTI has a detailed and well-operationalized
scoring system that yields information regarding both
capacity performance and capacity status. Capacity
performance is the quantitative score that a patient
receives for each standard. Scores across vignettes are
summed to create a composite score for each stan-
dard. There is no CCTI total score.
Capacity status refers to the categorical outcome
(capable, marginally capable, or incapable of consent-
ing to treatment) obtained on a particular standard.
Depending on the standard, capacity status on the
CCTI is operationalized using either predetermined
cut scores or psychometric cutoff scores derived from
the performance of cognitively intact older adults.
CCTI capacity outcomes must be used cautiously
insofar as they are derived from cut scores and do not
represent legal or clinical competency findings.Reliability and Validity of the CCTI
The CCTI has reliability and validity as a measure of
consent capacity. Three separate raters trained in
administration and scoring of the CCTI achieved high
interrater reliability for interval scales (>.83, p <
.0001; S3–S5) and categorical scales (96% agree-
ment; S1 and S2). The CCTI demonstrates face and
content validity. The medical content of each vignette
was reviewed and approved by a neurologist special-
izing in aging and dementia. The CCTI has been
found to discriminate well between cognitively intactolder adults and persons with both mild and moderate
AD. The CCTI also discriminates well between older
controls and patients with Parkinson’s disease and
dementia. With respect to construct validity, factor
analysis of the CCTI in an AD sample revealed a two-
factor model of verbal reasoning and verbal memory,
which was subsequently confirmed using neuropsy-
chological factor analysis. In addition, the CCTI has
demonstrated utility as a psychometric criterion for
investigating the neurocognitive changes associated
with loss of TCC.Clinical and Research Utility
The CCTI provides a standardized and norm-referenced
basis for evaluating TCC in individual patients and
across different patient populations. For this reason, it
has very good research application. In addition, by
objectively evaluating different consent abilities, it pro-
vides clinicians with flexibility in a particular case to
consider different standards of capacity in relation to
the risks and benefits of a particular treatment situation.LLiimmiittaattiioonnss
The CCTI has three key limitations. First, because
it uses standardized, hypothetical clinical vignettes
(brain tumor, heart disease), the CCTI does not
directly assess specific issues of TCC presenting clin-
ically (e.g., in the treatment of bone cancer). Instead,
it provides objective, norm-referenced information
about a patient’s treatment consent abilities that the
clinician can consider as part of his or her overall
assessment of TCC. Thus, the CCTI gives up clinical
specificity for standardization. A second limitation of
the CCTI is its use of hypothetical medical vignettes.
Patients dealing with real, personal medical problems
arguably may display treatment consent abilities that
differ somewhat from those demonstrated when
responding to hypothetical medical situations. Finally,
the CCTI and its performance and outcome scores are
intended to support but not replace clinical judgment.
Determination of consent capacity is ultimately a
judgment made by a clinician.Daniel C. Marson and Katina R. HebertSee also Capacity to Consent to Treatment; Competency,
Foundational and Decisional; Competency Assessment
Instrument (CAI); Consent to Clinical Research; End-of
Life Issues; Hopkins Competency Assessment Test
(HCAT); MacArthur Competence Assessment Tool forCapacity to Consent to Treatment Instrument (CCTI)——— 55C-Cutler (Encyc)-45463.qxd 11/18/2007 12:41 PM Page 55