Processi di selezione del verbo e del nome in pazienti con malattia di Parkinson con differente prevalenza di lato

[Autom. eng. transl.] Patients with Parkinson's disease (PD) show a deficit in word production as a possible expression of an executive dysfunction in word selection processes. However, in a condition where the noun has to be selected from a greater number of alternatives than the verb, the production of the noun becomes slower and less accurate. The left frontal inferior gyrus (GFIs) appears crucial in selection processes. In the present study we explore whether ability in noun and verb selection processes is related to cortical thickness of GFIs in patients with PD. Nine patients with right PD-left hemispheric damage (MPD-ES), 7 patients with left PD-right hemispheric damage (MPS-ED), and 16 healthy controls performed morphological tasks differing in the number of alternatives among which the answer must be selected : deriving nouns from verbs (NV), [“observation” from “observe”] and generating verbs from nouns (NV) [“fail” from “failure”]. Accuracy and reaction times (TR) were recorded. The 32 subjects also received a structural MRI examination. The cortical thickness of the GFI was determined using FreeSurfer. In VN production MPD-ES patients show lower accuracy than MPS-ED patients (58% vs. 74%). Furthermore, accuracy and TR correlated with GFI cortical thickness only in MPD-ES and only with GFIs, not only for noun but also for verb production. The results suggest that the selection deficit emerges as a function of the difficulty of the task in the presence of a dysfunction of the GFIs, coherently with the hypothesis that the production of words requires to resolve a competition between multiple alternatives. However, not only the demand for executive resources but also the linguistic nature of the stimuli is relevant in selection processes. Executive resources and language interact in GFIs in word selection processes and confirm the role of GFIs in language production.