Distinct patterns of word retrieval in right and left frontal lobe patients: a multidimensional perspective

Several studies have shown that patients with frontal lobe damage (FL) generate fewer words than control participants in verbal fluency tasks. In the current study, we were interested in assessing the quality of such verbal fluency data. Multidimensional exploratory techniques, namely, hierarchical clustering (HC) and correspondence analysis (CoA), were performed on verbal fluency data collected from 13 FL patients and 11 age-matched controls. HC of individual word-profiles distinguished between patients with left frontal lobe (LFL) and right frontal lobe (RFL) lesions. CoA revealed that LFL patients generated unusual word-profiles, as evidenced by their peripheral location on a CoA map, while RFL patients produced highly typical word-profiles. We would like to suggest that preserved functioning of the left frontal lobe might have constrained the responses of the RFL group resulting in typical word combinations, whereas preserved right frontal lobe functioning might have mediated greater diversification in the responses of the LFL group. The present study shows that HC and CoA can be applied to neuropsychological data to reveal complex relationships between cognitive performance and cerebral lesion sites.