Table 4.

Scores of Externalizing Behaviors from the MBA in RTT

	Externalizing Behaviors
	MBA Individual Items (Range 0–4)
Diagnosis Group	Irritability	Self-mutilation	Aggressive behavior	Biting self & others
Classic (n=736)	0.46 ± 0.9	0.26 ± 0.7	0.21 ± 0.6	0.24 ± 0.6
Atypical Mild (n=66)	0.53 ± 0.9	0.36 ± 0.8	0.52 ± 1.0**↑	0.30 ± 0.8
Atypical Severe (n=59)	0.63 ± 1.0	0.34 ± 0.8	0.10 ± 0.4	0.31 ± 0.7
Non-RTT (n=48)	0.25 ± 0.7	0.38 ± 1.0	0.08 ± 0.3	0.02 ± 0.1

Note. All values are reported as mean ± SD. Scores are directly related to severity. All score comparisons are in reference to classic RTT cohort using the non-parametric Independent Samples Kruskal-Wallis Test. Bolded values are significantly ↑ higher than classic RTT;

^**p-value<.001.

Significance values have been adjusted by the Bonferroni correction for multiple comparisons. MBA = Motor Behavioral Assessment. RTT= Rett syndrome.