Inclusion Criteria:  Newly diagnosed glioblastoma Karnofsky Index ≥ 70 Eastern Cooperative Oncology Group (ECOG) ≤ 2 ≥ 18 years Completed surgical therapy Completed radiation and chemotherapy Thrombocytes > 50.000/µl Hb > 8 mg/dl Ability to give consent Mother tongue German/very good German skills  Exclusion Criteria:  Diagnosed dementia (Mini-Mental-State-Test < 24/30 points) Pain (strong, permanent, restricting movement) Impairment of consciousness Fever Acute infection Pregnancy and lactation Insufficiently adjusted epilepsy (despite anticonvulsive therapy > 3 focal seizures per day or > 1 generalized seizure in the previous 3 days)