Table 2.

Performance on attention tasks of 15 participants with HFA and 15 healthy control subjects

Variable	HFA (n = 15)	Controls (n = 15)	t	df	p	d
	Mean (SD)	Mean (SD)
A. Alertness
Tonic alertness
Mean RTs	349.07 (102.08)	312.13 (101.48)	0.994	28	0.329	0.36
Variability of RTs in msec	94.47 (59.38)	51.20 (40.70)	2.328	28	0.027	0.85
Number of omission errors	0.20 (0.41)	0.07 (0.26)	1.058	23.46	0.301	0.38
Phasic alertness
Mean RTs	314.00 (101.93)	281.47 (83.96)	0.954	28	0.348	0.35
Variability of RTs in msec	72.53 (69.42)	39.13 (19.12)	1.797	28	0.083	0.65
Number of omission errors	0.07 (0.26)	0.07 (0.26)	< 0.001	28	1.00	0.00
B. Selective attention
Mean RTs	571.53 (97.47)	568.60 (124.99)	0.49	28	0.962	0.02
Variability of RTs in msec	139.60 (44.01)	99.27 (30.86)	2.906	28	0.007	1.06
Number of omission errors	2.53 (4.63)	0.27 (0.59)	1.882	14.461	0.080	0.68
C. Divided attention
Auditory task
Mean RTs	788.20 (303.19)	652.87 (83.25)	1.667	16.099	0.115	0.61
Variability of RTs in msec	290.53 (190.61)	141.07 (56.96)	2.910	16.480	0.010	1.06
Number of omission errors	1.87 (1.24)	0.53 (0.52)	3.829	18.672	0.001	1.41
Visual task
Mean RTs	982.20 (169.66)	902.00 (124.75)	1.475	28	0.151	0.54
Variability of RTs in msec	391.67 (146.91)	243.93 (111.95)	3.098	28	0.004	1.13
Number of omission errors	3.87 (2.72)	1.53 (1.35)	2.972	20.543	0.007	1.09
Total number of errors	31.93 (43.12)	3.27 (4.20)	2.563	14.266	0.022	0.93
D. Sustained attention
Mean RTs	678.93 (218.81)	666.40 (133.64)	0.189	28	0.851	0.07
Variability of RTs in msec	216.93 (106.65)	167.87 (79.05)	1.431	28	0.163	0.52
Number of omission errors	20.67 (13.13)	3.80 (4.19)	4.739	16.829	< 0.001	1.73
Number of commission errors	52.13 (41.64)	5.40 (6.03)	4.302	14.587	0.001	1.57

d.f degrees of freedom, SD standard deviation, RT reaction times

Significant p values are indicated in bold