The Trail-Making Test (TMT) is a useful cognitive screen because it is accessible, easy to use, and modifiable. The TMT is given in two parts (A and B). Developed by the U.S. Army, the test is considered to be within the public domain and thus may be reproduced without permission. Part A requires the patient to draw lines connecting consecutively numbered circles on a worksheet. Part B tests cognitive flexibility skills and requires patients to shift sets by drawing lines connecting numbered to lettered circles—from 1, to A, to 2, to B, and so on. This format has been modified for use with non-English-speaking populations by using two colors—pink and yellow—rather than letters in the trails (6). In the color version of the test, part A is essentially the same as in the English-language version, but part B requires the patient to match numbers with colors in a progressive and alternating pattern—1 with yellow, 1 with pink, 2 with yellow, 2 with pink, and so on. Cross-cultural studies have shown that this color trails test is very effective in discriminating HIV-positive and -negative persons (6). However, the test's ability to differentiate between HIV-related dementia and other types of dementia has not been investigated.
The TMT and the visual reproduction subtest of the Wechsler Memory Scale (WMS) have been used to evaluate various groups of emergency psychiatric patients. The visual reproduction subtest of the WMS requires the patient to copy four designs after a brief presentation of ten seconds' duration and then approximately 30 minutes later. Use of the TMT and the WMS in combination was found to successfully discriminate among patients with schizophrenia, mood disorder, or adjustment disorder (4). The screen detected greater cognitive impairment among patients with schizophrenia and mood disorder than among patients with adjustment disorder and than among control patients. Moreover, performance on this screen was associated with likelihood of admission to the hospital. Patients who were admitted to the inpatient service demonstrated greater cognitive impairment on the cognitive screen than did patients who were treated and released from the psychiatric emergency service (4).