Table 2.

Fragile X Syndrome and Typically Developing Groups’ Descriptive Heart Activity Data Across Phases

Phase	Group	Vagal tone			Interbeat interval
		Observed M	Marginal M	SE	Observed M	Marginal M	SE
Reactivity	TD	4.53	4.43	0.20	473.71	469.24	8.72
	All FXS	3.83	3.87	0.18	442.95	447.92	7.88
	FXS + ASD	4.23	3.92	0.29	463.94	449.43	12.72
	FXS − ASD	3.57	3.83	0.24	429.69	446.88	10.49
Toy Play	TD	4.67	4.55	0.21	517.08	512.73	7.16
	All FXS	3.82	3.92	0.20	459.35	462.96	6.47
	FXS + ASD	4.04	3.65	0.31	475.98	461.78	10.44
	FXS − ASD	3.67	4.10	0.26	448.26	463.76	8.61
Change	TD	−0.14	−0.13	0.20	−43.37	−43.51	6.57
	All FXS	−0.03	−0.05	0.19	−15.16	−15.04	5.99
	FXS + ASD	.019	0.27	0.30	−12.04	−12.35	9.66
	FXS − ASD	−0.18	−0.27	0.24	−17.24	−16.89	7.97

Note. TD = typically developing; FXS = fragile X syndrome; ASD = autism spectrum disorders. For the typically developing and all fragile X syndrome groups, marginal means are reported from the multivariate analysis of covariance of typically developing versus the whole fragile syndrome sample.