Color Trails Test (CTT)

Purpose

The Color Trails Test (CTT) is a language-free version of the Trail Making Test (TMT) that was developed to allow for broader cross-cultural assessment of sustained attention and divided attention“The allocation of attentional resources across more than one task” (Ponsford, 2008, p. 514)
in adults.

In-Depth Review

Purpose of the measure

The Color Trails Test (CTT) (Maj, D’Elia, Satz, Janssen, Zaudig, Uchiyama et al., 1993; D’Elia, Satz, Uchiyama & White, 1996) is a language-free version of the Trail Making Test (TMT) that was developed to allow for broader cross-cultural application to measure sustained attention and divided attention"The allocation of attentional resources across more than one task" (Ponsford, 2008, p. 514)
in adults.

Available versions

There are 4 versions of the CTT (forms A, B, C, and D) but only the first version (form A) has normative data and is the only version that should be used in a clinical setting. Versions B-D are experimental and should be used in research only (Mitrushina, Boone, Razzani, & D’Elia, 2005).

Features of the measure

Items:

The CTT is comprised of two tasks:

• CTT1: Must be administered first and requires the respondent to connect circles in an ascending numbered sequence (1-25).
• CTT2: Must follow the CTT1 and requires the respondent to connect numbers in an ascending sequence while alternating between pink and yellow colors. Numbers are presented twice, once in pink and once in yellow, so the client must ignore the distracter item (e.g. start at pink 1, avoid pink 2 to select yellow 2, avoid yellow 3 to select pink 3, etc.).

Untimed practice trials are completed for both the CCT1 and CCT2 to ensure that the client understands the task.

Scoring and score interpretation:

Time taken to complete each part of the CTT is recorded in seconds and is compared to normative data. Qualitative aspects of the performance that may be indicative of brain dysfunction (e.g. near misses, prompts required, sequencing"The coordination and proper ordering of the steps that comprise the task, requiring a proper allotment of attention to each step" (Lezak, 1989; as cited in (Baum, Morrison, Hahn & Edwards, 2007))
errors for colour and number) are also recorded.

Time:

The CTT manual reports that it takes 3-8 minutes to complete the CTT. A task is discontinued if the client takes longer than ?240 seconds to complete it.

Equipment:

• Table and chair
• Test
• Pencil
• Stopwatch

Training requirements:

This is a level “C” qualification meaning that it requires an experienced professional to administer the test.

Alternative Forms of the Colour Trails Test

• Trail Making Test (TMT)
• Comprehensive Trail Making Test (Reynolds, 2002)
• Delis-Kaplan Executive Function Scale (D-KEFS): includes subtests modeled after the TMT
• Oral TMT: an alternative for patients with motor deficits or visual impairments (Ricker & Axelrod, 1994).
• Repeat testing TMT: alternate forms have been developed for repeat testing purposes (Franzen et al., 1996; Lewis & Rennick, 1979)

Client suitability

Can be used with:

• Individuals with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.
• Clients 18-89 years old
• Individuals who are colourblind
• The CTT requires relatively intact motor abilities (i.e. ability to hold and manoeuvre a pen or pencil, ability to move the upper extremity). The Oral TMT may be more appropriate if the examiner considers that the participant’s motor ability may impact his/her performance.
• Clients must be able to understand Arabic numbers and numerical sequence.

Should not be used with:

• Clients with motor or coordination impairments (e.g. apraxia). If motor ability may impact performance, consider using the Oral TMT.
• Should be used with caution in older adults with low education. Age and education have been reported to influence response times in both parts of the CCT, such that older individuals with low education levels have demonstrated significantly slower response times (D’Elia et al, 1996; Messinis, Malegiannaki, Christodoulou, Panagiotopoulos, & Papathanasopoulos, 2011).

In what languages is the measure available?

This is a language-free measure however cultural norms have been published for the following populations:

• Adult Greek population with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. (Messinis et al., 2011)
• Turkish population with schizophrenia (Güleç, Kavakçı, Güleç, & Küçükalioğlu, 2006)
• Healthy Turkish population (Dugbartey, Townes & Mahurin, 2000)
• Healthy Spanish population (LaRue, Romero, Oritz, Chi Liang, & Lindeman, 1999)
• Healthy Brazilian sample (Sant’Ana Rabelo, Pacanaro, Rossetti, Almeida de Sa Leme, de Castro, Guntert, et al., 2010)
• Healthy sample from China (Hsieh & Riley, 1997)
• Healthy sample from Hong Kong (Lee & Chan, 2000).

Summary

What does the tool measure?	Language-free measure of sustained and divided attention“The allocation of attentional resources across more than one task” (Ponsford, 2008, p. 514) .
What types of clients can the tool be used for?	The CTT can be used with, but is not limited to, patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
Is this a screeningTesting for disease in people without symptoms. or assessment tool?	Assessment tool
Time to administer	The TMT takes approximately 3 to 8 minutes to administer.
Versions	Trail Making Test (TMT) Comprehensive TMT Oral TMT Repeat testing TMT (developed for repeat testing purposes) Symbol TMT Delis-Kaplan Executive Function Scale (D-KEFS)
Other Languages	Language-free measure but norms established for Greek, Turkish, Chinese, Brazilian, and Spanish populations
Measurement Properties
ReliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of “true” variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to “noise” in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .	Internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency.: No studies have examined internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency. of the CTT in patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.. Test-retest: No studies have examined test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society). of the CTT in a strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population but the authors of the measure report excellent test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society). for CTT2 and adequate test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society). for CTT1 in a healthy sample. Inter-rater: No studies have examined inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept. of the CTT in patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
ValidityThe degree to which an assessment measures what it is supposed to measure.	Content: No studies have examined content validityRefers to the extent to which a measure represents all aspects of a given social concept. Example: A depression scale may lack content validity if it only assesses the affective dimension of depression but fails to take into account the behavioral dimension. of the CTT in patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.. Criterion: Concurrent: One study reported excellent correlations between the CTT1 and CTT2 and the TMT-A and TMT-B respectively. Predictive: Two studies reported that the CTT1 predicted on-road driving test failure in samples of clients that included strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.. Construct: Convergent: One study reported adequate to excellent correlations between the CTT and the Useful Field of View (UFOV) subtests. Known groups: One study reported significant differences in time to complete the CCT between the patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. and healthy adults.
Floor/Ceiling Effects	No studies have examined floor/ceiling effects of the CTT in patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
Does the tool detect change in patients?	The responsivenessThe ability of an instrument to detect clinically important change over time. of the CTT has not formally been studied, however it has been used to detect changes in a clinical trial of 2 participants with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
Acceptability	The CTT is simple and easy to administer and is language-free.
Feasibility	The CTT is relatively inexpensive and highly portable. The CTT must be purchased and should be administered by an experienced professional.
How to obtain the tool?	The CTT can be purchased from: Psychological Assessment Resources (http://www4.parinc.com/Products/Product.aspx?ProductID=CTT)

* Initially developed for a traumatic-brain injured population, the psychometric properties of the tool with this population are described in the administration guide of the tool.

Psychometric Properties

Overview

We conducted a literature search to identify all relevant publications on the psychometric properties of the CTT in individuals with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. We identified 4 studies.

Floor/Ceiling Effects

No studies have reported on floor/ceiling effects of the CTT when used with an adult strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Reliability

Internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency.:
No studies have reported on internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency. of the CTT when used with an adult strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

Test-retest:
D’Elia et al. (1996) examined the test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society).
of the CTT in 27 healthy individuals. The CTT was administered twice, two weeks apart. Excellent test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society).
was reported for the CTT2 (r=0.79), and adequate test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society).
was reported for the CTT1 (r=0.64).

Inter-rater:
No studies have reported on inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
of the CTT when used with an adult strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Validity

Content:

No studies have reported on content validityRefers to the extent to which a measure represents all aspects of a given social concept. Example: A depression scale may lack content validity if it only assesses the affective dimension of depression but fails to take into account the behavioral dimension.
of the CTT when used with an adult strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. population.

Criterion:

Concurrent:
Elkin-Frankston, Lebowitz, Kapust, Hollis, & O’Connor (2007) examined the concurrent validityTo validate a new measure, the results of the measure are compared to the results of the gold standard obtained at approximately the same point in time (concurrently), so they both reflect the same construct. This approach is useful in situations when a new or untested tool is potentially more efficient, easier to administer, more practical, or safer than another more established method and is being proposed as an alternative instrument. See also “gold standard.”
of the CTT with the TMT in 29 individuals with various medical conditions including strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. (n=8). Completion times on the CTT and TMT were highly correlated (CTT1 vs. TMT-A: r=0.91; CTT2 vs. TMT-B: r=0.72) suggesting excellent concurrent validityTo validate a new measure, the results of the measure are compared to the results of the gold standard obtained at approximately the same point in time (concurrently), so they both reflect the same construct. This approach is useful in situations when a new or untested tool is potentially more efficient, easier to administer, more practical, or safer than another more established method and is being proposed as an alternative instrument. See also “gold standard.”
with the original TMT.

Predictive:
Elkin-Frankston et al. (2007) examined the ability of the CTT to predict on-road driving test failure in 29 individuals with various medical conditions including strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. (n=8). Patients who failed an on-road driver evaluation performed the CTT1 significantly slower than those who passed (Cohens d=0.66, p<0.05). This relationship was also found for the CTT2 but it did not reach statistical significance.

Hartman-Maeir et al. (2008) examined predictive validityA form of criterion validity that examines a measure's ability to predict some subsequent event. Example: can the Berg Balance Scale predict falls over the following 6 weeks? The criterion standard in this example would be whether the patient fell over the next 6 weeks.
of the CTT in a sample of 30 individuals with acquired brain injury including strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. (n=17) wishing to obtain a drivers licence. There was a significant difference in time taken to complete CTT1 between those who passed and failed the on-road test (Cohen’s d = 0.67, p=0.02). Performance time <60 seconds on the CTT1 was found to predict passing the on-road evaluation, whereas >60 seconds was predictive of failing.

Construct:

Convergent/Discriminant:
Hartman-Maeir, Erez, Ratzon, Mattatia and Weiss (2008) examined convergent validityA type of validity that is determined by hypothesizing and examining the overlap between two or more tests that presumably measure the same construct. In other words, convergent validity is used to evaluate the degree to which two or more measures that theoretically should be related to each other are, in fact, observed to be related to each other.
of the CTT in a sample of 30 individuals with acquired brain injury (including strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain., n=17) wishing to obtain a drivers licence, using Spearman correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
coefficients. The CTT1 and CTT2 showed adequate to excellent correlations with Useful Field of View (UFOV) subtests of processing speed (CTT1 r=0.407; CTT2 not significant), divided attention“The allocation of attentional resources across more than one task” (Ponsford, 2008, p. 514)
(r=0.457, 0.486 respectively) and selective attention (r=0.602, 0.629 respectively). Results support validityThe degree to which an assessment measures what it is supposed to measure.
of the CTT as a pre-driving assessment tool.

Known groups:
Messinis, Malegiannaki, Christodoulu, Panagiotopoulos, and Papathanasopoulos (2011) examined known groups validityKnown groups validity is a form of construct validation in which the validity is determined by the degree to which an instrument can demonstate different scores for groups know to vary on the variables being measured.
of the CTT with 25 clients who had recently experience a strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. and 26 healthy participants matched for age, educational level and gender (Greek population). Clients in the strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. group required significantly more time to complete the CTT1 and CCT2 than the healthy controls (p < 0.001).

Responsiveness

Liu, Chan, Lee, and Hui-Chan (2004) used the CTT to evaluate the effectiveness of mental imagery in clients with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain. (n=2). In this study, the CTT detected change in both clients with reduced time to complete the CTT1 and CTT2 post-intervention.

Sensitivity/ Specificity

No studies have reported on sensitivitySensitivity refers to the probability that a diagnostic technique will detect a particular disease or condition when it does indeed exist in a patient (National Multiple Sclerosis Society). See also “Specificity.”
/specificity of the CTT when used with an adult strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. population.

References

• Barncord, S. W. & Wanlass, R. L. (2001). The Symbol Trail Making Test: test development and utility as a measure of cognitive impairment. Applied Neuropsychology, 8, 99-103
• D’Elia, L. F., Satz, P., Uchiyama, C.L., & White, T. (1996). Color Trails Test. Odessa, FL: PAR.
• Dugbartey, A. T., Townes, B. D., & Mahurin, R. K. (2000). Equivalence of the Color Trail Making Test in nonnative English-speakers. Archives of Clinical Neuropsychology, 15, 425-31.
• Elkin-Frankston, S., Lebowitz, B. K., Kapust, L. R., Hollis, A.M., & O’Connor, M.G. (2007). The use of the Colour Trails Test in the assessment of driver competence: preliminary reports of a culture-fair instrument. Archives of Clinical Neuropsychology, 22(5), 631-5.
• Franzen, M., Paul, D., & Iverson, G. L. (1996). Reliability of alternate forms of the trail making test. The Clinical Neurologist, 10(2), 125-9.
• Güleç, H., Kavakçı, O., Güleç, M. Y., & Küçükalioğlu, C. I. (2006). The reliability and validity of the Turkish Color Trails Test in evaluating frontal assessment among Turkish patients with schizophrenia. Düşünen Adam, 19(4), 180-5.
• Hartman-Maeir, A., Erez, A. B., Ratzon, N., Mattatia, T., & Weiss, P. (2008). The validity of the Color Trails Test in the pre-driver assessment of individuals with acquired brain injury. Brain Injury, 22, 994-1008.
• Hsieh, S. & Riley, N. (1997, November). Neuropsychological performance in the People’s Republic of China: Age and educational norms for four attentional tasks Presented at the National Academy of Neuropsychology, Las Vegas, Nevada. In Mitrushina, M. Boone, K., & D’Elia L. Handbook of Normative Data for Neuropsychological Assessment. (pp.70-73). New York, NY: Oxford University Press.
• LaRue, A., Romero, L., Ortiz, I., Liang, H.C., & Lindeman, R. D. (1999). Neuropsychological performance of Hispanic and non-Hospanic older adults: an epidemiologic survey. Clinical Neuropsychologist, 13, 474-86.
• Lee, T. M. & Chan, C. C. (2000). Are Trail Making and Color Trails Tests of equivalent constructs? Journal of Clinical and Experimental Neuropsychology, 22, 529-34.
• Lewis, R. F. & Rennick, P. M. (1979). Manual for the repeatable Cognitive-Perceptual-Motor Battery. Grosse Point Park, MI: Axon Publishing Company.
• Liu, K. P., Chan, C. C., Lee, T. M., & Hui-Chan, C.W. (2004). Mental imagery for relearning of people after brain injury. Brain Injury, 18(11), 1163-72.
• Maj, M., D’Elia, L. D., Satz, P., Janssen, R., Zaudig, M., Uchiyama, C., Starace, F., Galderisi, S., & Chervinsky, A. (1993). Evaluation of two new neuropsychological tests designed to minimize cultural bias in the assessment of HIV-1 Seropositive persons: a WHO study. Archives of Clinical Neuropsyhology, 8, 123-35.
• Messinis, L., Malegiannaki, A. C., Christodoulou, T., Panagiotopoulos, V., & Papathanasopoulos, P. (2011). Color Trails Test: normative data and criterion validity for the greek adult population. Archives of Clinical Neuropsychology, 26(4), 322-30.
• Mitrushina, M., Boone, K. B., Razzani J., & D’Elia, L. F. (2005). Handbook of normative data for neuropsychological assessment. (2nd ed.). New York: Oxford University Press.
• Reynolds, C. (2002). Comprehensive Trail Making Test. Austin, TX: Pro-Ed.
• Ricker, J.H. & Axelrod, B. N. (1994). Analysis of an oral paradigm for the Trail Making Test. Assessment, 1, 47-51.
• Sant’Ana Rabelo, I., Pacanaro, S.V., de Oliveira Rosetti, M., de Sa Leme, I.F., de Castro, N.R., Guntert, C. M., Correa Miotto, E., & Souza de Lucia, M. C. (2010). Color Trails Test: a Brazilian normative sample. Psychology and Neuroscience, 3, 93-9.

See the measure

How to obtain the CTT

The CTT can be purchased from Psychological Assessment Resources (http://www4.parinc.com/Products/Product.aspx?ProductID=CTT)