Secondary electrophysiological outcome
As a surrogate marker for changes of brain states on a subclinical electrophysiological level, quantitative high density electroencephalography data (HD-qEEG) were recorded at a sampling rate of 250 Hz with a 256-channel geodesic sensor net with Net Amps 400 amplifier and Net Station 4.5. Software (Electrical Geodesic Inc., Eugene, OR, USA). During recording, electrodes were referenced to the vertex and impedance was kept below 50 µV. HD-qEEG was recorded at T0 with the patient in supine position and verticalization < 30°, and at the end of the intervention period (T4) after the last verticalization session. HD-qEEG was recorded for 10 min at both timepoints.To discover possible changes in the EEG signal, power spectrum and connectivity analyses were performed on EEG data of timepoints T0 and T4. The Mohawk pipeline was used to calculate the connectivity and power measures [