Table.

Average peak velocities for symptomatic and asymptomatic patients by neck position and flow direction^a

Position/Flow Direction	Symptomatic			Asymptomatic			P Value
	No.	Mean (±SD)	Range	No.	Mean (±SD)	Range
Neutral
Systolic	23	6.0 (2.53)	(2.4–11.7)	22	6.6 (3.07)	(1.9–13.4)	.570
Diastolic	23	4.4 (2.24)	(1.5–10.9)	22	4.4 (1.61)	(0.9–7.7)	.525
Flexion
Systolic	21	5.9 (3.27)	(2.1–12.0)	16	5.7 (3.17)	(2.4–15.3)	.963
Diastolic	21	4.2 (2.35)	(1.9–9.2)	16	3.9 (2.19)	(0.7–10.3)	.842
Extension
Systolic	23	7.1 (3.93)	(2.0–8.9)	17	5.5 (2.33)	(2.3–10.1)	.256
Diastolic	23	4.9 (2.52)	(1.6–9.5)	17	4.1 (1.24)	(2.0–5.9)	.511

^aUnits for the means and range values are centimeters per second.