Fig. 2.

Dendrograms depict relationships between structural changes in brain volumes following one month of intervention with the Continuous Positive Airway Pressure or Best Supportive Care treatment. Dendrograms were constructed using the results of Hierarchical Cluster Analysis (HCA) of the differential ∆ structural changes, using Average Linkage with squared Euclidean distance as a measure of distance (x-axis values). HCA resulted in the formation of clusters that were iteratively joined in a descending order of similarity. Resulting dendrograms show different patterns of neuroanatomical changes in patients with OSA following the interventions with BSC alone (N = 27) from those resulting post CPAP with BSC (N = 28) treatment. The HCA findings also suggest that the thalamic alterations (arrows) in the CPAP group are closely linked to wider core neurocircuitry adaptations (pink boxes).