The Preferred Live Music (PLM) aims to elicit participants' responses from live music and the ensuing musical and non-musical interactions with the music therapist (MT). In the PLM intervention, preferred songs performed live on guitar or electronic keyboard will be played by a credentialed MT. When appropriate participants may also play percussion instruments offered to them. Elements of improvisation will be incorporated to allow for active engagement by the participants, and to provide opportunities for musical and non-musical attunement to emerge.

The Preferred Recorded Music (PRM) intervention aims to detect responses directly attributable to the music. Participants listen to pre-recorded preferred originally-published versions of music accessed by Spotify music-streaming service and played through loud-speakers. The MT will only start the music, and otherwise not be present during the interventions to ensure the minimal direct interaction with the participants.

Preferred Recorded Music (PRM) involves a credentialed music therapist in planning and administering, which qualifies it as music therapy, which is defined as a professional use of music and its elements to improve physical, social, communicative, emotional, intellectual, and spiritual health, optimize quality of life and wellbeing(Aigen, 2013; Bruscia, 2014). PRM intervention will be delivered for 30 minutes, once per day at the same time of the day, for three consecutive days. The intervention will consist of the previously assessed preferred songs/musical pieces. During the PRM intervention the MT will start/stop the music and otherwise not engage with the participants during the listening session.

How many participants were recruited and randomized per month on average from those eligible, calculated by dividing the total number of the participants recruited by the total number of months that the trial recruited for.

Retention is defined as trial completion on study intervention, and will be calculated by dividing the number of participants completing the study by the total number of participants recruited. Attrition rates will be estimated by the percentage of participants that withdrew from the study, and calculated by dividing the number of the participants who withdrew by the total number recruited.

Adherence to the study protocol is defined as compliance with the described study protocol, and protocol deviations as any change or divergence from the study protocol for each participant. Adherence rate will be estimated by calculating the percentage of the music sessions (interventions) actually completed from those described in the protocol (by dividing the number of completed sessions by the number of planned sessions), and deviation rates will be measured by counting the deviations per participant during their participation in the study.

The level of treatment fidelity will be determined using NIH Behavioral Change Consortium questionnaire which assesses 5 mutually exclusive categories: study design, training, delivery, receipt, and enactment. The tool lists 25 fidelity attributes that should be rated dichotomously as:" Present", "Absent but should be present", or "Not applicable".

Delirium severity as assessed by Observational Scale of Level of Arousal (OSLA), Richmond Agitation Sedation Scale (RASS).

Pre-post interventions changes in attention, orientation and short-term memory, assessed by backwards tests and digit span tests, recall tasks and orientation questions from Memorial Delirium Assessment Scale-MDAS)