Table 2. Baseline characteristics of the experimental (ABA + HBOT) and control (ABA only) groups.

VB-MAPP: Verbal Behavior Milestones Assessment and Placement Program; ABLLS: Assessment of Basic Language and Learning Skills-Revised; ABA: Applied Behavior Analysis; HBOT: Hyperbaric Oxygen Therapy

Variable	Statistic	Experimental (ABA + HBOT) (n = 32)	Control (ABA only) (n = 33)	Total (n = 65)	p-value
Treatment months for HBOT	n	32	0	32	N/A
	Mean	5.53		5.53
	SD	1.08		1.08
	Median	6		6
	Minimum	2		2
	Maximum	6		6
Months from baseline verbal test to post baseline verbal test	n	32	33	65	0.215
	Mean	5.53	5.8	5.7
	SD	1.08	0.73	0.8
	Median	6	6	6
	Minimum	2	4	2
	Maximum	6	8	8
Months from baseline verbal test to first HBOT treatment	n	32	0	32	N/A
	Mean	1		1
	SD	1.22		1.22
	Median	0		0
	Minimum	0		0
	Maximum	4		4
Months from last HBOT treatment to post baseline verbal test	n	32	0	32	N/A
	Mean	2.81		2.81
	SD	1.4		1.4
	Median	3		3
	Minimum	0		0
	Maximum	5		5
Age, years	n	32	33	65	0.084
	Mean	5.1	6.55	5.7
	SD	2.93	3.58	3.08
	Median	4	5	5
	Minimum	2	2	2
	Maximum	17	16	17
Age, (VB-MAPP) years	n	23	12	35	0.744
	Mean	3.96	4.08	4
	SD	1.07	1.08	3.08
	Median	4	5	5
	Minimum	2	2	2
	Maximum	17	16	17
Age, (ABLLS) years	n	9	21	30	0.921
	Mean	8.1	7.96	7.7
	SD	4.01	3.76	3.46
	Median	8	7	7
	Minimum	3	4	3
	Maximum	17	16	17
Race/ethnicity, n (%)	African American Indian	1 (3.1%)	0 (0.0%)	1 (1.5%)	0.67
	Asian	0 (0.0%)	1 (3.0%)	1 (1.5%)
	Hispanic	1 (3.1%)	0 (0.0%)	1 (1.5%)
	Middle Eastern	4 (12.5%)	3 (9.1%)	7 (10.8%)
	White	3 (9.4%)	2 (6.1%)	5 (7.7%)
	American Indian	18 (56.3%)	23 (69.7%)	41 (63.1%)
	Unspecified	0 (0.00%)	1 (3.0%)	1 (1.5%)
		5 (15.6%)	4 (12.1%)	9 (13.8)
Autism severity level, n (%)	1	1 (3.1%)	3 (9.1%)	4 (6.2%)	0.495
	2	9 (28.1%)	11 (33.3%)	20 (30.8%)
	3	22 (68.8%)	19 (57.6%)	41 (63.1%)
Gender (%)	Male	31 (96.9%)	27 (81.8%)	89.20%	0.103
	Female	1 (3.1%)	6 (8.2%)	10.80%