The TRUE-GRIT study will assess the feasibility of a study protocol investigating the efficacy of a combination therapy consisting of cognitive strategy training (CST) and repetitive transcranial magnetic stimulation (rTMS) to reduce cognitive impairment in adult glioma patients. This study is part of the GRIP-project, a project aimed at investigating interventions for improving quality of life in brain tumor patients.

Inclusion Criteria:

• ≥ 18 years of age
• Histological diagnosis of diffuse glioma (WHO grade 2,3, or 4)
• Subjective cognitive impairment, defined as CFQ-score ≥ 44
• Being able to give informed consent and undergo treatment and measurements based on researchers insight
• Stable disease, i.e. no oncological treatment for ≤ 2 months prior to inclusion; no radiological progression on the most recent MRI, not older than 6 months, and no clinical progression at inclusion
• Stable dosage (for at least 8 weeks) of anti-epileptic medication

Exclusion Criteria:

• Current pregnancy or have given birth less than three months ago
• Current other treatment for cognitive complaints
• Karnofsky performance score <70
• A tumor located in the parietal cortex
• TMS exclusion: implanted medical devices (e.g. pacemaker, deep brain stimulator, cochlear implants, medical infusion device, etc.); metal in the body; sleep deprivation
• MRI exclusion: extreme claustrophobia or metallic objects in or on the body