Fig. 2

Symptom-based clusters using self-organizing maps. All clusters of patients are displayed in the direction of left to right and bottom to top. Each hexagon represents a cluster, and the number within a hexagon shows the number of patients in the cluster. The x-axis and y-axis indicate the number of clusters, starting from 0. In particular, coordinate (0,0) corresponds to Cluster 1, coordinate (1,0) corresponds to Cluster 2, etc. The 13 clusters including at least 10 patients are shown in purple. a Symptom-based clusters in Dutch ME/CFS population. b Connection between symptom-based clusters. The blue hexagons represent the clusters. The colors in the regions containing the red lines indicate the distances between clusters: darker colors represent larger distances (less similarity between the two clusters), lighter colors represent smaller distances (more similarity between the two clusters). c Symptom-based clusters in US population