DISCUSSION
neurophysiological abnormalities, Pain, arousability, CRPS, pain, sleep restlessness, Chronic pain
SECONDARY, CORTEX
S2‐targeted rTMS influenced sleep in CRPS patients, seen as a reduction of restlessness as measured by the Oura ring. Furthermore, multivariate testing using machine learning‐based classification showed that four out of the seven tested models led to classification accuracies exceeding 95% confidence levels. Thus, monitoring changes across multiple Oura variables allowed separating the rTMS and sham groups from each other.Chronic pain with impaired quality of sleep is a well‐known problem, and they interact in a bidirectional manner (Bjurstrom & Irwin, Data about sleep among CRPS patients is scarce, consisting mostly of subjective sleep measurements. Galer et al. (The effect of rTMS on sleep is complex and depends on the rTMS target area and the chosen stimulation protocol, among others. For example, in PI, rTMS targeted to the dorsolateral prefrontal cortex might inhibit the over‐excited state associated with PI, and this could lead to improved sleep (Nardone et al., S2‐targeted rTMS was significantly more effective than sham in decreasing restlessness during sleep. Univariate analysis did not reveal other significant changes in the Oura‐measured parameters, but our machine learning‐assisted multivariate analysis revealed that including multiple parameters in the classification improved results. The model utilizing parameters “restless” and “onset_latency” yielded classification accuracy with the lowest In this study sample, the analgesic effect of S2‐targeted rTMS did not differ from sham. Pain reduction, surprisingly, associated with an increase in sleep restlessness, but other sleep‐related parameters did not correlate with the pain reduction. Thus, the beneficial effect of S2‐targeted rTMS on sleep does not seem to be secondary to the possible analgesic effect of the intervention. A recent fMRI‐EEG study suggested that insula, among other brain areas, is part of a network that affects arousability during sleep (Kokkinos et al., A number of studies have revealed neurophysiological abnormalities at the cortical level in CRPS (Zangrandi et al., 