Feeling the Body in Fibromyalgia: A Narrative Review of Interoception and Proprioception within a Phenomenological Perspective

BACKGROUND: Fibromyalgia (FM) is a chronic syndrome characterized by widespread pain, fatigue, and cognitive-emotional disturbances. Increasing evidence suggests that FM also involves alterations in bodily self-awareness. In particular, disturbances in interoception and proprioception-key processes underlying the perception and integration of bodily signals-may contribute to the altered bodily experience frequently reported by patients. This review aims to synthesize empirical findings on interoceptive and proprioceptive functioning in FM and to interpret them within a phenomenological framework of embodiment. METHODS: A narrative review was conducted using the PubMed database. Studies investigating interoception and/or proprioception in adults formally diagnosed with FM were considered. Interoception included measures of interoceptive accuracy, sensibility, and emotional responses to internal bodily signals, whereas proprioception included joint position sense, movement perception, and postural control. A total of 186 records were identified and screened. After applying inclusion criteria, 19 cross-sectional studies were included in the review. RESULTS: The reviewed studies reported consistent alterations in bodily awareness in FM. Interoceptive functioning was often characterized by reduced accuracy in detecting internal bodily signals, together with increased emotional reactivity and dysregulation associated with bodily sensations. Proprioceptive impairments were also frequently observed, particularly in joint position sense, movement perception, and balance or postural control tasks. Some studies described a paradoxical pattern of heightened attentional focus on bodily sensations alongside impaired integration of these signals into a coherent bodily experience. CONCLUSION: These findings suggest a disturbance in the integration of bodily signals underlying the experience of embodiment in FM. From a phenomenological perspective, this disturbance may reflect a disruption in coenaesthesia, the pre-reflective sense of bodily self. FM can thus be conceptualized as a disorder of embodiment, consistent with the optical-coenaesthetic disproportion model describing a breakdown between the body as felt from within and the body as perceived from outside.