NP	Neck pain.
CNP	Chronic neck pain
NSCNP	Non-specific neck pain
TENS	Transcutaneous electrical nerve stimulation
SPIRIT	Standard protocol items: recommendations for interventional trials
NDI	Neck disability index
CEA	Cost-effectiveness analysis
CUA	Cost-utility analysis
QALY	Quality adjusted life years
ICER	Incremental cost-effectiveness ratio
CHEERS	Consolidated health economic evaluation reporting standards