Neurocognitive changes after awake surgery in glioma patients: a retrospective cohort study

Deficits in neurocognitive functioning (NCF) frequently occur in glioma patients. Both treatment and the tumor itself contribute to these deficits. In order to minimize the harmful effects of surgery, an increasing number of patients undergo awake craniotomy. To investigate whether we can indeed preserve cognitive functioning after state-of-the art awake surgery and to identify factors determining postoperative NCF, we performed a retrospective cohort study.

In diffuse glioma (WHO grade 2-4) patients undergoing awake craniotomy, we studied neurocognitive functioning both pre-operatively and 3-6 months postoperatively. Evaluation covered five neurocognitive domains. We performed analysis of data on group and individual level and evaluated the value of patient-, tumor- and treatment-related factors for predicting change in NCF, using linear and logistic regression analysis.

We included 168 consecutive patients. Mean NCF-scores of psychomotor speed and visuospatial functioning significantly deteriorated after surgery. The percentage of serious neurocognitive impairments (- 2 standard deviations) increased significantly for psychomotor speed only. Tumor involvement in the left thalamus predicted a postoperative decline in NCF for the domains overall-NCF, executive functioning and psychomotor speed. An IDH-wildtype status predicted decline for overall-NCF and executive functioning.

In all cognitive domains, except for psychomotor speed, cognitive functioning can be preserved after awake surgery. The domain of psychomotor speed seems to be most vulnerable to the effects of surgery and early postoperative therapies. Cognitive performance after glioma surgery is associated with a combination of structural and biomolecular effects from the tumor, including IDH-status and left thalamic involvement.