Limitations of the Trail Making Test Part-B in Assessing Frontal Executive Dysfunction

Abstract

Part B of the Trail Making Test (TMT-B) is one of the most widely used neuropsychological tests of "executive" function. A commonly held assumption is that the TMT-B can be used to detect frontal executive dysfunction. However, so far, research evidence has been limited and somewhat inconclusive. In this retrospective study, performance on the TMT-B of 55 patients with known focal frontal lesions, 27 patients with focal non-frontal lesions and 70 healthy controls was compared. Completion time and the number of errors made were examined. Patients with frontal and non-frontal lesions performed significantly worse than healthy controls for both completion time and the number of errors. However, there was no significant difference for both completion time and the number of errors when patients with frontal and non-frontal lesions were compared. Performance was also not significantly different between patients with focal lesions within different regions of the frontal lobe (orbital, left lateral, right lateral, medial). Our findings suggest that the TMT-B is a robust test for detection of brain dysfunction. However, its capacity for detecting frontal executive dysfunction appears rather limited. Clinicians should be cautious when drawing conclusions from performance on the TMT-B alone. (JINS, 2015, 21, 169-174)

Relationship of Cognitive Function to Motor Symptoms and Mood Disorders in Patients With Isolated Dystonia

“…14 However, it should be stated that poor performance on the Trail-Making Test has been found to be an unspecific marker of brain dysfunction (Chan et al, 2015;Demakis, 2004). It also remains unclear whether any strong conclusions can be drawn on the basis of impaired Stroop performance in two patients only.…”

Get a grip: individual variations in grip strength are a marker of brain health

“…When patterns of association with the levels of performance exhibited on other neuropsychological tests are analysed, it has been surmised that the TMT-A draws mainly upon visuoperceptual abilities, that the TMT-B is primarily an expression of working memory and task-switching ability, and that B-A difference scores are a "relatively pure indicator of executive control abilities" (Sánchez-Cubillo et al, 2009). The TMT is also used extensively in clinical contexts with a view to detecting frontal executive dysfunction (Chan et al, 2015). It is notable therefore that when variants of the TMT (with the same visual and motor demands) specifically adapted for neuroimaging are employed, the contrast between the TMT-A and TMT-B reveals differences in BOLD response in the dorsal part of M1 (Jacobson et al, 2011; see also Zakzanis et al, 2005), consistent with previous observations that activity in this brain region varies in a nearly linear fashion with working memory load (Tsukiura et al, 2001;Zarahn et al, 2005).…”

The Prefrontal Cortex and Neurological Impairments of Active Thought

“…If, the critical areas for one test do not overlap with those of another, we will take this as evidence that the two tests do not rely on the same set of subsystems. We will discuss later how two tests that appear to involve inhibition -the Stroop and the Hayling Making, which later research shows not to be specific for frontal lesions (Chan et al, 2015), to be more susceptible to differences in aetiology than the other three tests. We therefore conclude that it is acceptable practice to mix aetiologies to overcome the great variability in the population under study.…”