FIGURE 1. Diagram overview of study design. Maximally, 4 SPECT scans were acquired: 2 at initial VNS onset and 2 during chronic follow-up. Effect of acute stimulation was investigated in initial situation (A) and in chronic situation (B). Chronic changes were evaluated between baseline, prestimulus SPECT scan and chronic situation (C). This pre-VNS study was also compared with studies of age- and sex-matched healthy individuals (D). Below timeline, t, stimulus intensity, I, is schematically shown for different conditions.