Table 3.

Results on verbal 2-back task for ADHD and control children in noise and in silence. Number of correct responses and response times are displayed.

Task /Group	N	No noise (SD)	Noise (SD)	Noise vs. no noise t-statistics
2-back task, number correct
ADHD off med	20	22.2 (3.9)	23.0 (3.3)	ns.
ADHD on med	20	21.8 (4.6)	22.9 (3.8)	ns.
Control	20	23.1 (6.8)	22.8	ns.
2-back task, response time in sec.
ADHD off med	20	40.4 (7.6)	40.1 (8.3)	ns.
ADHD on med	20	40.1 (11.6)	42.8 (8.6)	ns.
Control	20	35.3 (8.8)	32.8 (11.2)	ns.

ADHD children were medicated on one test occasion, in counterbalanced order.