Visual Puzzles, Figure Weights, and Cancellation: Some Preliminary Hypotheses on the Functional and Neural Substrates of These Three New WAIS-IV Subtests

Abstract

In this study, five consecutive patients with focal strokes and/or cortical excisions were examined with the Wechsler Adult Intelligence Scale and Wechsler Memory Scale-Fourth Editions along with a comprehensive battery of other neuropsychological tasks. All five of the lesions were large and typically involved frontal, temporal, and/or parietal lobes and were lateralized to one hemisphere. The clinical case method was used to determine the cognitive neuropsychological correlates of mental rotation (Visual Puzzles), Piagetian balance beam (Figure Weights), and visual search (Cancellation) tasks. The pattern of results on Visual Puzzles and Figure Weights suggested that both subtests involve predominately right frontoparietal networks involved in visual working memory. It appeared that Visual Puzzles could also critically rely on the integrity of the left temporoparietal junction. The left temporoparietal junction could be involved in temporal ordering and integration of local elements into a nonverbal gestalt. In contrast, the Figure Weights task appears to critically involve the right temporoparietal junction involved in numerical magnitude estimation. Cancellation was sensitive to left frontotemporal lesions and not right posterior parietal lesions typical of other visual search tasks. In addition, the Cancellation subtest was sensitive to verbal search strategies and perhaps object-based attention demands, thereby constituting a unique task in comparison with previous visual search tasks.

Figure 1

Participant no. 1 with a left temporoparietal lesion. The CT image in (a) depicts an axial scan through the maximum width of the lesion in the left angular gyrus. The dark area within the confines of the left hemisphere shows surgical evacuation of infarcted tissue within the left temporoparietal cortex. The CT image in (b) depicts the maximal width of the lesion in the left inferior temporal lobe. According to neuroradiological convention left side of the image is the right hemisphere and the right side of the image is the left hemisphere.

Figure 2

Participant no. 2 with a left frontal lobe lesion. The CT image in (a) depicts the extensive left inferior frontal lobe lesion occurring as a result of an anterior communicating artery aneurysm. The CT image in (b) depicts the same lesion extending contiguously to include the infarcted tissue in the left anterior superior frontal lobe.

Figure 3

Participant no. 3 with a right frontotemporal lesion. The CT image in (a) depicts a large lesion within the right anterior inferior medial temporal lobe with incursion of the lesion to include both straight gyri of the orbitofrontal lobes. The CT image in (b) depicts bilateral lesions in the cortex underlying the anterior-inferior cingulate gyri. Although the lesions are bilateral, (and this poses some degree of difficulty in making firm conclusions), the lesions are significantly larger and of greater extent in the right hemisphere.

Figure 4

Participant no. 4 with a right thalamic lesion. The MRI image in (a) depicts a calcified third ventricular mass occluding the third ventricle which was subsequently resected. Lateral ventricular dilation is evident. The CT image in (b) depicts resolution of ventricular dilatation subsequent to tumour resection and reopening of the cerebrospinal fluid cisterns. However, (b) shows a right posterior thalamic ischemic infarct appearing two weeks after resection of the third ventricular tumour.

Figure 5

Participant no. 5 with a right temporoparietal lesion. The CT image in (a) depicts severe damage to the right inferior parietal lobe and right temporoparietal junction. The CT image in (b) shows the downward extension of the lesion into the right superior temporal gyrus. The dark areas in (a) and (b) panels illustrate evacuation of infarcted brain tissue by neurosurgery.

Figure 6

Topography of participant's brain infarcts conceptualized in terms of Milner and Goodale's theory of ventral and dorsal streams [47]. (a) depicts the left hemisphere view of the distribution of lesions in the cortex, whereas (b) illustrates the distribution of lesions in the right hemisphere. Note that participant no. 4 with a right posterior thalamic lesion is not depicted. Legend: PPC: posterior parietal cortex, V1: primary visual cortex, OFC: orbitofrontal cortex, ATL: anterior temporal lobe, and DLPFC: dorsolateral prefrontal cortex.