Table 3.

Genetic modeling of framewise and absolute head displacement for all participants scanned (prior to motion exclusion, including excessive head motion); for participants with moderate head motion (excluding excessive head motion); and for participants with minimal head motion (after stringent quality control).

Max motion		MZ	DZ		A²	C²	E²
Excessive head motion
Framewise Displacement	r	.51**	.19	ACE	0,29	0,05	0,66
	na	129	108	95% CI	0.00-0.46	0.00-0.39	0.54-0.80
Absolute Displacement	r	.70**	.17	ACE	0,65	0,00	0,35
	na	129	108	95% CI	0.54-0.73	0.00-0.12	0.27-0.46
Moderate head motionb
Framewise Displacement	r	.29**	.28*	ACE	0,12	0,22	0,66
	na	96	72	95% CI	0.00-0.52	0.00-0.45	0.48-0.84
Absolute Displacement	r	.29**	.23	ACE	0,14	0,15	0,71
	na	92	67	95% CI	0.00-0.46	0.00-0.39	0.54-0.90
Minimal head motionc
Framewise Displacement	r	.26	.49*	ACE	0,00	0,33	0,67
	na	28	18	95% CI	0.00-0.47	0.00-0.54	0.46-0.94
Absolute Displacement	r	.32	.28	ACE	0,06	0,29	0,65
	na	24	20	95% CI	0.00-0.61	0.00-0.55	0.39-0.95

^*p < .05.

^**p < .001.

^aNumber of complete twin pairs.

^bMean FD < 1 mm; mean AD < 3 mm.

^cMean FD < 0.3 mm; mean AD < 1 mm.