1. Department of Nutrition, Institute of Basic Medical Sciences University of Oslo Oslo Norway
2. The Norwegian Centre for Movement Disorders Stavanger University Hospital Stavanger Norway
3. The Norwegian Parkinson Association Oslo Norway
4. Department of Nursing and Health Promotion, Faculty of Health Sciences OsloMet—Oslo Metropolitan University Oslo Norway
5. Department of Oncology, European Palliative Care Research Centre (PRC) Oslo University Hospital Oslo Norway