The Effects of Sensory Enrichment After a Laboratory Stressor on Human Skin Barrier Recovery in a Randomized Trial

ABSTRACT Objective Environmental enrichment (EE) can reduce stress, alter immunity, and speed wound healing in animals. However, it is not known whether these effects translate to humans. This study aimed to investigate whether sensory EE could improve wound healing after a stressor in humans. Methods A total of 105 participants underwent a tape-stripping procedure and were then stressed using a laboratory stress paradigm. After this, they were randomized to interact for 30 minutes with one of two possible sensory EE interventions (music as auditory enrichment or a Paro robot as multisensory enrichment) or to a control condition. Skin barrier recovery was measured using transepidermal water loss at baseline, after the stressor, and after the intervention. Stress was measured using self-report, heart rate, blood pressure, and salivary stress-related biological measures. Enjoyment during the intervention was measured by self-report as a possible mediator. Results The Paro condition had significantly improved skin barrier recovery (mean [M] = 44%, standard error [SE] = 1.92) compared with the control condition (M = 37% SE = 2.01, F (2,88) = 3.25, p = .043), both with and without controlling for covariates. The music condition did not significantly differ from the other conditions (M = 42%, SE = 1.95, p values > .05). Both objective and subjective stress measures did not significantly differ between conditions. Mediational analysis showed that enjoyment levels during the intervention period significantly mediated the relationship between condition and skin barrier recovery ( z = 2.00, p = .046). Conclusions Paro, or other companion robots, may be an effective form of enrichment to improve skin barrier recovery in humans after a laboratory stressor, and this effect may be due to enjoyment. Further research with patient groups is required to investigate whether Paro can help heal clinical wounds. Trial Registration: ACTRN12618000953235, registered at https://anzctr.org.au.