David C. Ahern

Lowering the Floor on Trail Making Test Part B: Psychometric Evidence for a New Scoring Metric

The Trail Making Test Part B (TMT-B) is widely used in clinical and research settings as a measure of executive function. Standard administration allows a maximal time score (i.e., floor score) of 300 s. This practice potentially masks performance variability among cognitively impaired individuals who cannot complete the task. For example, performances that are nearly complete receive the same 300-s score as a performance of only a few moves. Such performance differences may have utility in research and clinical settings. To address this, we propose a new TMT-B efficiency metric designed to capture clinically relevant performance variability below the standard administration floor. Our metric takes into account time, correct moves, and errors of commission and omission. We demonstrate that the metric has concurrent validity, permits statistical analysis of performances that fall below the test floor, and captures clinically relevant performance variability missed by alternative methods.

Neuropsychological assessment without upper limb involvement: a systematic review of oral versions of the Trail Making Test and Symbol-Digit Modalities Test

ABSTRACT The Trail Making Test (TMT) and written version of the Symbol Digit Modalities Test (SDMT) assess attention, processing speed, and executive functions but their utility is limited in populations with upper limb dysfunction. Oral versions of the TMT and SDMT exist, but a systematic review of their psychometric properties and clinical utility has not been conducted, which was the goal of this study. Searches were conducted in PubMed and PsycINFO, test manuals, and the reference lists of included articles. Four measures were identified: the SDMT-oral, oral TMT-A, oral TMT-B, and the Mental Alternation Test (MAT). Two investigators independently reviewed abstracts to identify peer-reviewed articles that reported on these measures in adult populations. From each article, one investigator extracted information on reliability, validity, responsiveness, minimum detectable change, normative data, and demographic influences. A second investigator verified the accuracy of the data in a random selection of 10% of papers. The quality of the evidence for each psychometric property was rated on a 4-point scale (unknown, poor, adequate, excellent). Results showed excellent evidence for the SDMT-oral, adequate evidence for the oral TMT-B and MAT, and adequate to poor evidence for the oral TMT-A. These findings inform the clinical assessment of attention, processing speed, and executive functions in individuals with upper limb disability.

Trail-Making Test Part B: Evaluation of the Efficiency Score for Assessing Floor-Level Change in Veterans

Objective The Trail Making Test - Part B (TMT-B) is a commonly used executive control measure with a known floor effect, limiting the ability to distinguish impairment among individuals unable to complete this task in the standard time limit. Our group previously proposed the TMT-B Efficiency Score (TMT-Be), which captures performance variability among examinees who fail to complete the task. The present study assesses the TMT-Be in a longitudinal clinical sample. Method Data were collected via record review of veterans who underwent two clinical neuropsychological evaluations. We identified 30 veterans (mean age Visit 1:69 ± 8.7 years) who were unable to complete TMT-B during at least one evaluation (mean days between visits = 615). Two scoring systems were utilized to examine performance variability: TMT-Be and TMT-B Prorated Score (TMT-Bpr). Results TMT-Be distribution was less skewed, but more platykuric, compared to TMT-Bpr. TMT-Be and TMT-Bpr were highly correlated. Both metrics correlated with psychomotor speed and another executive task, but not confrontation naming, providing both convergent and discriminant evidence of validity. TMT-Be, but not TMT-Bpr, detected significant decline in performance longitudinally. Age and education were significant predictors of the TMT-Be, but not TMT-Bpr, difference scores. Conclusions Both metrics captured performance variability in a clinical sample and provided sufficient variance for examining floor-level performance on the TMT-B. TMT-Be appeared to be less prone to creating outliers and more likely to detect change. The results support the utility of the TMT-Be metric in research and clinical settings.

A Response to Commentary on Faust, Bridges, and Ahern's (2009) “Methods for the Identification of Sexually Abused Children”

Our series of three chapters (Faust, Bridges, & Ahern, 2009a, 2009b; Bridges, Faust, & Ahern, 2009) on the methodology of identifying sexually abused children elicited a number of comments, both supportive and critical. The criticisms appear related to three primary issues or apparent misconceptions of our work, perhaps due in part to incomplete exposition or ambiguity in presented material: our use of hypotheticals, our argument against “double-dipping,” and our use of Bayesian analyses. We address each of these criticisms here in the hope of clarifying any misunderstandings and contributing in a constructive way to progress in this critical arena.