Disorganized behavior on Link's cube test is sensitive to right hemispheric frontal lobe damage in stroke patients

Abstract

One of Luria's favorite neuropsychological tasks for challenging frontal lobe functions was Link's cube test (LCT). The LCT is a cube construction task in which the subject must assemble 27 small cubes into one large cube in such a manner that only the painted surfaces of the small cubes are visible. We computed two new LCT composite scores, the constructive plan composite score, reflecting the capability to envisage a cubical-shaped volume, and the behavioral (dis-) organization composite score, reflecting the goal-directedness of cube construction. Voxel-based lesion-behavior mapping (VLBM) was used to test the relationship between performance on the LCT and brain injury in a sample of stroke patients with right hemisphere damage (N = 32), concentrated in the frontal lobe. We observed a relationship between the measure of behavioral (dis-) organization on the LCT and right frontal lesions. Further work in a larger sample, including left frontal lobe damage and with more power to detect effects of right posterior brain injury, is necessary to determine whether this observation is specific for right frontal lesions.

Keywords: Link's cube test; executive function; frontal lobe; problem solving; right hemisphere damage; spatial behavior.

Figure 1

The stimulus materials of the LCT (Metzler, 2000). Left panel: 27 small wooden cubes (3 by 3 by 3 cm each) are scattered on the table in front of the subject. Eight of them have three white surfaces and three wooden surfaces. Twelve cubes have two white and four wooden surfaces, six cubes have one white and five wooden surfaces. One cube is all wooden. Right panel: The subject is instructed to construct a single large cube—by using all small cubes—whose outer surface is entirely white. Reproduced from Kopp et al. (2008) with permission of the copyright owner.

Figure 2

Overlay lesion plot of all 32 patients and the results of the retrospective power analyses for each of the three LCT composite scores. The number of overlapping lesions (A) is illustrated by color, from violet (N = 3) to red (N = 10). Maximum overlap occurred in the right frontal lobe. The results of the power analyses (B) are shown in red [top row: LCT global composite, middle row: LCT constructive plan composite, bottom row: LCT behavioral (dis) organization composite]. These power maps demonstrate that in all areas where the lesions of at least three patients overlapped, we had sufficient power to potentially detect a significant difference between the behavioral scores of patients with a lesion and the behavioral scores of patients without a lesion. Numbers indicate MNI z-coordinates.

Figure 3

Anatomical results obtained from the voxel-based lesion-behavior mapping on the LCT global composite score (A), the LCT constructive plan composite score (B), and the LCT (dis-) organization composite score (C). The anatomical results without control for multiple comparisons (z_crit = 1.65) are depicted in blue. The significant result obtained for the LCT behavioral (dis-) organization composite score is shown in red (see magnified cut-out for a better view). Numbers indicate MNI z-coordinates.