Table 1.

Fixed Effects Estimates for Each of the Linear and Nonlinear Terms in the Multilevel Model of Pain Oscillations

	Model Category
Model Term	Full	Top 1/3	Bottom 1/3	Top 1/3	Bottom 1/3	Top 1/3	Bottom 1/3
	Model	NA	NA	PA	PA	Pain Control	Pain Control
Velocity (β1)	1.19 × 10−3	0.04	−0.07	−0.02	−0.02	2.28 × 10−3	7.38 × 10−3
Squared Frequency (β2)	−2.74***	−2.79***	−2.67	−2.76***	−2.788***	−2.74***	−2.75
Rayleigh (β3)	−1.20 × 10−4**	−1.50 × 10−4*	1.38 × 10−4	−1.20 × 10−4	−1.50 × 10−4	−2.50 × 10−4**	−1.00 × 10−4
van der Pol (β4)	6.50 × 10−5	3.20 × 10−5	−2.00 × 10−5	1.12 × 10−4	1.55 × 10−4	1.86 × 10−4**	3.30 × 10−5
Duffing (β5)	−3.00 × 10−5	−1.00 × 10−5	−7.00 × 10−5	−3.00 × 10−5	−5.00 × 10−5	−3.00 × 10−5	−1.00 × 10−5
π-mix Odd (β6)	−3.9 × 10−4***	−3.70 × 10−4**	−3.10 × 10−4	−3.00 × 10−4**	−5.30 × 10−4***	−5.70 × 10−4***	−3.50 × 10−4

^*Note. p < .05,

^**p < .01,

^***p < .001