Virtual Nature Versus Guided Imagery for Anxiety and Well-Being in Hospitalized Older Adults

Heart rate variability during intervention sessions relative to resting and cognitive-load recordings (RMSSD)

Root mean square of successive differences (RMSSD, ln-transformed) recorded during intervention sessions and compared within each participant with their own resting recording (20-minute recording during the usual care period, five-minute window analysed) and cognitive-load recordings (T0 and T1). RMSSD is computed from a five-minute artifact-free window in all contexts; higher values indicate greater parasympathetic activity. Recordings with more than 5 percent corrected beats are excluded from the primary analysis. Recordings are made with an optical photoplethysmographic armband sensor; the first five participants were recorded with a chest-strap ECG sensor in all contexts. The between-arm comparison of session RMSSD is a secondary, exploratory analysis.

Primary Outcome 1 - HADS-A

Anxiety symptoms measured with the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A). Scores range from 0 to 21; lower scores indicate less anxiety. The primary comparison is the change during the intervention period (T1 to T2) relative to the change during the preceding usual care observation period (T0 to T1), with each participant serving as their own control (self-controlled, non-randomised contrast, both arms pooled). The randomised between-arm comparison of T2 scores adjusted for T1 scores is a secondary analysis. Analyses use linear mixed models.

Change in depressive symptoms (HADS-D)

Depressive symptoms measured with the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D). Scores range from 0 to 21; lower scores indicate fewer depressive symptoms.

Change in depressive symptoms (GDS-15)

Depressive symptoms measured with the 15-item Geriatric Depression Scale (GDS-15). Scores range from 0 to 15; higher scores indicate more depressive symptoms.

Change in global cognitive performance (MoCA)

Global cognitive performance measured with the Montreal Cognitive Assessment, Hungarian version. Scores range from 0 to 30 with education correction; higher scores indicate better cognitive performance. Three parallel versions (8.1, 8.2, 8.3) are administered in fixed order across the three assessment points to reduce practice effects.

Change in memory index (MoCA-MIS)

Memory Index Score derived from the delayed recall section of the Montreal Cognitive Assessment, weighting free recall, category-cued recall, and multiple-choice recall. Scores range from 0 to 15; higher scores indicate better memory performance.

Affective state before intervention sessions (Emotion Thermometers)

Affective state assessed with the Emotion Thermometers, comprising five visual analogue dimensions (distress, anxiety, depression, anger, and need for help). Each dimension is rated from 0 to 10; higher scores indicate greater distress. The instrument is administered at each assessment point (baseline, Week 2, Week 4) and immediately before each intervention session. It is not administered after the sessions, in order to minimise participant burden and to preserve the period immediately following the session, during which participants in the guided imagery arm give their verbal account. The measure characterises the affective state at the start of each assessment and session day and its trajectory across the four weeks of participation, rather than acute within-session change.

Immersive tendency (ITQ-10)

Dispositional tendency to become involved and absorbed in an experience, measured with the 10-item Hungarian version of the Immersive Tendencies Questionnaire. Higher scores indicate a greater tendency towards immersion. The questionnaire is administered once, before randomisation, in both arms, and is treated as a trait-level moderator variable rather than a mediator. Only the total score is used; the subscales are not analysed separately because two items of the attention focus subscale refer to current alertness and physical condition, which in hospitalised older adults primarily reflect current illness burden.

Virtual reality sickness symptoms (VRSQ)

Symptoms associated with virtual reality use, measured with the Virtual Reality Sickness Questionnaire, comprising nine items grouped into an oculomotor and a disorientation component; higher scores indicate more severe symptoms. The questionnaire is administered in the virtual reality arm only, after the first session. It is used to monitor tolerability rather than as an efficacy outcome. Tolerability in both arms is additionally monitored at every session through structured recording of adverse events by the facilitator.