2.2. Measurements

The Multidimensional dyspnea profile (MDP), the Brief dyspnea inventory (BDI), the Athens sleep scale (AIS) and the Hospital Anxiety and Depression Scale (HADS) were administered. The MDP is a tool developed to separately measure the immediate unpleasantness or discomfort of breathing, the presence and intensity of five sensory quality items, and the intensity of five emotional responses to breathlessness (for each item, the score is 0–10) [13,14]. The BDI is a valid and reliable measure for evaluating dyspnea, and to inform about the relative severity and interference of dyspnea in daily life activities (7 items, score 0–10) [15]. The AIS is a self-assessment psychometric instrument designed for quantifying sleep difficulty. It consists of eight items: the first five items pertain to sleep induction, awakenings during the night, final awakening, total sleep duration and sleep quality; while the last three refer to well-being, functioning capacity and sleepiness during the day [16]. Each item is scored from 0 to 3. The HADS is a self-assessment tool and consists of 14 items, with two separate subscales for anxiety and depression. The total score ranges from 0 to 42, with a higher score indicating severe depression and anxiety [17].