Inclusion Criteria:  Male or female ≥ 6 years of age at Visit 1. Clinically planned for craniotomy, including for malignant tumors, whether awake or under general anesthesia. Able to provide written informed consent (and assent when applicable) - by subject or subject's legal representative - and agrees to comply with the requirements of the study.  Exclusion Criteria:  Language problems that would prevent from properly understanding instructions. Requirement of an interpreter. Patients who are excluded from consideration for the clinical operation are therefore excluded from the research study. Special populations: pregnant women, prisoners.