Patient subtyping in juvenile fibromyalgia: the role of multisensory hypersensitivity and neurophysiological correlates.

Objective: The aim of this study was to investigate whether we could identify groups of adolescents with juvenile fibromyalgia (JFM) based on their subjective perception of non-painful multisensory stimuli in daily life and to study brain function differences between these groups.

Method: 43 female adolescents with JFM (16.56 ± 1.01 years) and 34 healthy controls (16.21 ± 0.89 years) completed validated measures of multisensory hypersensitivity and an fMRI multisensory task. We conducted average linkage cluster analyses, including measures of multisensory sensitivity, and tested between-group differences in core disease-related features, affect-related measures, and task-evoked brain activation in a priori defined regions of interest.

Results: We identified two clusters of participants. The first cluster included 22 patients with higher multisensory sensitivities, and the second one consisted of 21 patients and 34 healthy controls with lower multisensory sensitivities. A second cluster analysis, including only adolescents with JFM, confirmed the same patient division. The two patient subgroups were similar in affective symptoms and coping efficacy but differed in core symptoms of JFM. Adolescents with JFM who experienced higher sensory sensitivities showed increased brain activation in the left primary motor cortex and the left amygdala.

Conclusions: We found two clusters of adolescents with JFM with regard to their non-painful multisensory sensitivities. Greater multisensory hypersensitivity was associated with greater severity of core disease symptoms without compromising affective/cognitive regulation. It was also associated with increased activity of the primary motor cortex and amygdala in response to multisensory stimulation. The study highlights the potential of patient subtyping to understand contributing psychobiological mechanisms.