Neuropsychological Outcomes after Surgery for Olfactory Groove Meningiomas

SIMPLE SUMMARY: Olfactory groove meningiomas account for 9% of all meningiomas, present with unique molecular characteristics and are standardly treated by surgical removal. Due to their location (in direct contact with cortical structures exerting key-role functions in cognition), olfactory groove meningiomas might negatively impact cognitive abilities. However, little is known about the effects of both their presence and surgical removal on patients’ neuropsychological functions. In this retrospective study, we analyze the evolution of neuropsychological abilities in 17 patients benefitting from surgical removal of an olfactory groove meningioma. We observed that those patients already presented with preoperative deficits in pre-frontal cortex cognitive functions, more pronounced in the domain of cognitive flexibility, followed by attention. After an initial postoperative worsening, patients tended to improve in the majority of cognitive aspects, with attention and flexibility remaining impaired at one-year follow-up. ABSTRACT: Background: In recent years, several studies have reported abnormal pre- and postoperative neuropsychological functioning in patients with meningiomas located in the prefrontal cortex (notably the ventromedial region). In the case of olfactory groove meningiomas, the tumor is in direct contact with the inferior aspect of the prefrontal cortex, a cortical region with crucial roles in decision-making, cognition and memory functions, potentially negatively impacting neuropsychological functions. Materials and Methods: We retrospectively compared pre- and post-operative neuropsychological testing of 17 patients undergoing surgical removal of olfactory groove meningiomas in our institution between January 2013 and December 2018. Neuropsychological results were obtained from the patients’ medical history and normalized as z-scores of their respective cognitive functions. Results: Assessment of cognitive follow-up showed an important heterogeneity among patients. Pre-operative cognitive impairment was observed in most patients, particularly in cognitive flexibility (mean z-score: −1.35). Immediate post-operative cognitive status showed an overall impairment in all domains of cognition, significant for the domains of attention (p = 0.0273) and flexibility (p = 0.0234) and almost significant for the domain of language (p = 0.0547). The late follow-up at one year showed a trend towards general improvement, although attention and flexibility remained impaired. Discussion: Olfactory groove meningiomas impact pre-frontal cortex cognitive functions, particularly in the domain of cognitive flexibility. After an initial postoperative worsening, patients tended to improve in most aspects after one year, aside from cognitive flexibility and attention.