Table 4 Psychometric scales

Based on the literature review [24,25,26] we selected three psychometric scales to test pre-post variations in participants’ emotions and behavior.

The Decisional Conflict Scale [27] is frequently uses in ACP trials in order to assess decisional conflict about medical decisions before and after the intervention. The scale was translated in French [28] and comprises 16 items that participants have to rate on a 5-point Likert scale (0 = strongly agree to 4 = strongly disagree).

The Decisional Autonomy Scale [29] is a French-speaking scale developed in Québec that contains 28 questions that covers various aspects of independence in daily life. Respondents indicate how often (from “never” to “always”) they act according to a statement. Examples of statements are: “I am satisfied with the actions I take”, “I act according to my character”, “I choose activities that will help me keep my intellectual form”, “I prefer to do it myself- even all the things that are possible for me”.

The Zarit Burden Scale [30] measures relative’s perceived burden of care. It consists of 22 items rated on a 5-point Likert scale that ranges from 0 (never) to 4 (nearly always) with the sum of scores ranging between 0 and 88, higher scores indicating greater burden.

The Hospital Anxiety and Depression Scale (HADS, 27) was introduced in the protocol since the IRB expressed the concern that ACP might increase distress among participants. HADS is a standardized tool that exists in French and is used frequently to assess anxiety and depression among in- and out-patients. The is composed of statements relevant to either generalized anxiety or depression, the latter being largely (but not entirely) composed of reflections of the state of anhedonia. Each item had been answered on a four-point likert scale (0–3), so the possible scores ranged from 0 to 21 for anxiety and 0 to 21 for depression, 0 meaning being not very anxious or depressed and 21 meaning being very anxious or depressed.