The aim of this study is to investigate whether a high definition tDCS-accompanied intensive cognitive training of working memory leads to performance improvement in women with post-chemotherapy cognitive impairment after breast cancer treatment.

Patients who have undergone chemotherapy, may develop post-chemotherapy cognitive impairment (PCCI), which may occur in several cognitive domains and persist for many years. These declines in cognitive functions can lead to psychological distress and affect overall patients' quality of life. The goal of the present study is to assess behavioral effects of a multi-session cognitive training combined with high-definition transcranial direct current stimulation (tDCS) in women with PCCI. First studies have shown positive effects of cognitive training on trained and untrained functions and the subjective perception of stress, however the effects are small and transfer effects are inconsistent. A promising approach to elongate and increase the effects of cognitive training is to combine the training with tDCS. Therefore, in this study women with PCCI will participate in a three-week cognitive training with concurrent online high-definition tDCS application. Cognitive performance (primary), as well as Quality of Life scores and Sleep data will be examined before, during and after the intervention. In order to draw conclusions about the effect of tDCS in addition to cognitive training, a control group, receiving sham stimulation during training, will be assessed. A Follow-up session to assess long-term effects is planned four weeks after the post assessment. The results of the study will offer valuable insights into efficacy of combined tDCS and cognitive training intervention in women with PCCI in order to establish its potential to induce improvements in cognitive functions, and to beneficially affect patient-reported outcome measures.

Inclusion Criteria:

1. Chemotherapy to treat breast cancer (≥ 6 months post-treatment).
2. Self-reported concerns regarding cognitive functioning.
3. Age: 18-65 years.
4. right-handedness

Exclusion Criteria:

1. History of dementia before treatment of cancer.
2. Other neurodegenerative neurological disorders; epilepsy or history of seizures.
3. Severe and untreated medical conditions that preclude participation in the training, as determined by responsible physician.
4. History of moderate to severe substance use disorder according to DSM-5
5. Moderate to severe acute psychiatric disorders according to DSM-5
6. Contraindication to tDCS application (Antal et al., 2017)