The impact of everyday acoustic environments on chronic pain mechanisms in fibromyalgia: a randomized, triple-blind, placebo-controlled 4 × 4 crossover trial

ABSTRACT: Given the limited efficacy of current therapeutic approaches, shifting the focus beyond individual-level factors toward environmental influences may offer potential complementary, nonpharmacological strategies for preventive and therapeutic purposes. The neuromodulatory effects of auditory stimuli have been shown to influence pain processing through central mechanisms. Given the heightened sensory sensitivity that characterizes fibromyalgia syndrome, everyday acoustic environments may represent a relevant yet understudied environmental determinant of chronic pain. To address this gap, this study investigated whether everyday acoustic environments modulate clinical outcomes and experimental indices of pain processing in fibromyalgia. A randomized, triple-blind, placebo-controlled 4 × 4 Williams crossover design was employed. Eighty-eight patients with fibromyalgia syndrome underwent 4 different 20-minute listening sessions: natural acoustic environments, urban acoustic environments, broadband sounds (active comparator), and silence (attention-placebo control). The primary outcome was pain intensity, while secondary outcomes comprised patient global impression of change and quantitative sensory testing measures, including mechanical pain sensitivity, temporal summation of pain, and pressure pain detection thresholds and intensity ratings. Prespecified covariates included pain catastrophizing, somatosensory amplification, and connectedness to nature. Linear mixed-effects models showed significant between-condition differences. After controlling for baseline values, exposure to urban acoustic environments worsened outcomes, with large effects for patient global impression of change and medium effects for pain intensity and static quantitative sensory testing measures compared with both control conditions. Pain intensity was predicted by pain catastrophizing. These findings suggest that auditory environments may function as clinically relevant environmental factors in chronic pain, bridging environmental neuroscience and chronic pain research, with potential implications for public health policy.