2.4. Procedure
The independent variable considered was that of listening to self-chosen music as a complementary intervention. Prior to the intervention, all caregivers (both in the control group and the intervention group) received conventional health care under the same conditions, including basic therapeutic education for palliative care, which is part of the regular health care service provided by nurses at the respective health centres.The caregivers in the intervention group also received a music-based complementary intervention, listening to pre-recorded music on an mp3 device or mobile phone. To ensure that the intervention enhanced the participants’ well-being, the music selection was chosen by each individual, who provided a list of musical items they liked. This benefit was later confirmed in a personal interview with a nurse, who prepared a playlist accordingly. The personal interview mentioned was the one in which sociodemographic characteristics were also registered. The intervention consisted of a 30 min music session, received daily for seven consecutive days. The caregiver was instructed not to perform any other activity during the session.The participants in the control group received a recorded repetition of the basic therapeutic training education given (also delivered via an mp3 device or mobile phone), thus masking their membership in the control group both to other participants and to the evaluators. This activity was also performed in 30 min sessions received daily for seven consecutive days, and the caregivers were also instructed not to perform any other activity during the session.Both groups were advised to listen to the recordings in the morning, when they could be alone. No healthcare professional was present during the listening. The types of music chosen by the intervention group and details of the basic therapeutic education messages given to the control group are described in The CSI data were obtained before and after the intervention for both groups.