Journal of Neurosurgical Sciences 2021 Nov 11

DOI: 10.23736/S0390-5616.21.05508-9

Copyright © 2021 EDIZIONI MINERVA MEDICA

language: English

Normal-appearing naming-related functional activation in incidentally discovered lowgrade gliomas: a single institution study

Elisa CARGNELUTTI ¹, Tamara IUS ², Miran SKRAP ², Barbara TOMASINO ¹ ✉

¹ Dipartimento/Unità Operativa Pasian, Scientific Institute, IRCCS E. Medea, Prato, Italy; ² SOC Neurochirurgia, Azienda Sanitaria Universitaria Friuli Centrale ASU FC, Udine, Italy

BACKGROUND: Incidentally discovered low-grade gliomas (iLGGs) represent a rare neurological condition, which is associated with a good clinical status and usually preserved - or borderline - cognitive functions; only recently, knowledge has increased on their development and clinical features. Better understanding these aspects is fundamental to set up the most appropriate clinical protocol.
METHODS: We used fMRI to conduct an exploratory investigation of the effects of iLGG growth on the brain and the potential occurrence of early rearrangement in the functional network associated with object naming. We compared this group of 13 patients with an iLGG in the left hemisphere (maximum lesion overlap in the left inferior frontal gyrus and median tumor volume 12 cm3) and with preserved naming skills with that of a healthy control group.
RESULTS: No significant differences were observed in the functional activations between the two groups, but a cluster in the controls vs. patients contrast mainly located in the right lateral visual cortex. As this region is unspecific for object naming and no significant changes emerged in the affected hemisphere nor in naming-specific homologues of the contralesional hemisphere, we concluded that iLGG growth did not affect the functional network and plasticity-related reorganization did not occur yet. We attributed this finding to iLGG features, such as small tumor size at the diagnosis and lack or minimal infiltration.
CONCLUSIONS: These findings are preliminary and we recommend future investigation to replicate them and test generalizability to other functional networks. Understanding the potential functional effects of iLGG growth is fundamental for the choice of the most appropriate treatment.

KEY WORDS: Incidentally discovered low-grade gliomas (iLGGs); fMRI; Naming; Language