The impact of lesion aetiology on our understanding of visuoconstruction: a comparison between stroke and tumor patients

Abstract

Objectives: Visuoconstruction is a crucial function in neuropsychology, that relies on multiple mechanisms. Generally, visuoperception and executive functioning are seen as the main underlying components of this function. However, the extent to which these mechanisms contribute to visuoconstruction is poorly understood. Research studying visuoconstruction has mainly focused on stroke patients, whereas tumor patients might form valid study subjects as well and might provide convergent evidence for the findings on visuoconstruction. Therefore, the aim of this study is to assess whether stroke and tumor patients, subdivided into Low Grade Glioma (LGG) and High Grade Glioma (HGG) patients, can be used together in studying visuoconstructional abilities and assessing whether our current understanding of visuoconstruction is dependent on lesion aetiology. Methods: 57 first-ever ischemic stroke patients and 91 tumor patients who were scheduled for awake brain surgery, subdivided into 35 LGG and 56 HGG, were assessed on the Rey-Osterrieth Complex Figure (ROCF) test, the Judgement of Line Orientation (JLO) test, the Digit Span test WAIS-III or WAIS-IV and Letter Fluency as part of standard clinical care in the University Medical Centre (UMC) Utrecht. Performance was adjusted for age, sex and education when necessary. First, the amount of impaired patients (<5th percentile) per task was evaluated per group. In addition, the mean performance was compared between the groups to assess patients’ abilities in more detail. Furthermore, hemispheric dominance for visuoconstruction was investigated. Finally, stepwise multiple regression analyses were performed in all groups to reveal what role the two central components, visuoperception and executive functioning, play in visuoconstruction. Results: Results showed that 1) stroke, LGG and HGG only differed on the JLO in the amount of impaired patients, with the most impaired patients in the stroke group, 2) stroke, LGG and HGG differed on all tasks when performance was assessed; the stroke performed worse than LGG on all tasks and worse than HGG only on the ROCF and JLO; the LGG and HGG patients differed from each other only on executive tasks, with the LGG patients performing worse than HGG patients, 3) right hemispheric dominance was found in stroke patients, whereas no hemispheric dominance was found in the tumor patients, 4) in the stroke patients, the JLO and Digit Span contributed significantly to performance on the ROCF; in the LGG patients, the JLO contributed significantly to ROCF performance, and in the HGG patients, Letter Fluency was found to be a significant predictor. Conclusions: The differences between the findings within the stroke and tumor populations in visuoconstructional abilities and underlying mechanisms demonstrate the importance of including more than one aetiology in studying visuoconstruction. The current study suggests tumor patients can provide convergent evidence for the findings on visuoconstruction based on stroke populations. Generalisation from the one aetiology to the other, however, should be made with caution.