CGH	Cervicogenic Headache
eVNS	external Vagus Nerve Stimulation
AA	Atlantoaxial
ANS	Autonomic Nervous System
SNS	Sympathetic Nervous System
VNS	Vagus Nerve Stimulation
AbV	Auricular branch vagus
NPRS	Numeric Pain Rating Scale
VAS	Visual Analogue Scale
NDI	Neck Disability Index
HDI	Headache Disability Index
AROM	Active Range Of motion
FRT	Flexion Rotation Test
HEP	Home Exercise Program
DNF	Deep Neck Flexors
MCID	Minimal Clinically Important Difference