Progressive compromise of nouns and action verbs in posterior cortical atrophy

BRENDA STEEB; CORDERO, INDIRA GARCÍA; MARJOLEIN HUIZING; LUCAS COLLAZO; GERALDINE BOROVINSKY; FERRARI JESICA; MACARENA CUITIÑO; IBAÑEZ AGUSTIN; SEDEÑO LUCAS; GARCIA ADOLFO

Frontiers in Psychology

FRONTIERS

Año: 2018

1664-042X

Processing of nouns and action verbs can be differentially compromised following lesions to posterior and anterior/motor brainregions, respectively. However, little is known about how these deficits progress in the course of neurodegeneration. To addressthis issue, we assessed productive lexical skills in a patient with posterior cortical atrophy at two different stages of hispathology. On both occasions, he underwent a structural brain imaging protocol and completed semantic fluency tasks requiringretrieval of animals (nouns) and actions (verbs). Imaging results were compared with those of controls via voxel-basedmorphometry, whereas fluency performance was compared to age-matched norms through Crawford?s t-tests. In the firstassessment, the patient exhibited atrophy of more posterior regions supporting multimodal semantics (medial temporal andlingual gyri), together with a selective deficit in noun fluency. Then, by the second assessment, the patient?s atrophy hadprogressed mainly towards fronto-motor regions (rolandic operculum, inferior and superior frontal gyri) and subcortical motorhubs (cerebellum, thalamus), and his fluency impairments had extended to action verbs. These results offer unprecedentedevidence of the specificity of the pathways related to noun and action-verb impairments in the course of neurodegeneration,highlighting the latter?s critical dependence on damage to regions supporting motor functions, as opposed to multimodal semanticprocesses.