Transcutaneous cervical vagal nerve stimulation reduces sympathetic responses to stress in posttraumatic stress disorder: A double-blind, randomized, sham controlled trial

Term	Abbreviation
DBP	Cuff-based diastolic blood pressure
SBP	Cuff-based systolic blood pressure
MAP	Average pressure in patient's arteries during one cardiac cycle ((SBP+2*DBP)/3)
PP	Difference between SBP and DBP
HR	Instantaneous heart rate calculated by locating the R-peaks of ECG signal
HF HRV	The power in the high-frequency range (0.15–0.4 Hz), obtained from the non-constant R-R intervals from ECG R-peaks.
LF HRV	The power in the low-frequency range (0.04–0.15 Hz), obtained from the non-constant R-R intervals from ECG R-peaks.
LF/HF HRV	The ratio of the two power bands, LF and HF HRV
SD1	Poincare-based short-term HRV: Standard deviation of points perpendicular to the axis of line-of-identity of the scatter plot (R–R_n versus R–R_n+1)
SD2	Poincare-based short- and long-term HRV: Standard deviation of points along the axis of line-of-identity of the scatter plot (R–R_n versus R–R_n+1)
SD1/SD2	The unpredictability of R-R intervals based on Poincaré-based HRV
f_NSSCR	Frequency of non-specific skin conductance responses
SCL	The slow tonic component of EDA signal
SCR	The faster phasic component of EDA signal
L_SCR	Latency from the start of the interval to the first peak appearance in SCR signal
PAT	Time delay from the electrical depolarization of the heart to the arrival of the pressure wave
PPG Amplitude	Beat-by-beat amplitude of the peripheral blood volume pulse
PTT	The time it takes a pulse wave to travel between two arterial sites
PEP	Latency between the start of electrical depolarization of the ventricles to the opening of the aortic valve.
RR	Instantaneous rate of respiration peak appearance
RP	Prominence of each respiration peak. i.e., how much the peak stands out due to its intrinsic height and its location relative to other peaks
RW	The width of each respiration cycle

Table 2.