Table 2.

Behavioural performance: Cognitive background measures in adulthood and fMRI task performance

		VP/VLBW (N = 73)						Controls (N = 73)						P‐value
Wechsler intelligence scales		M ± SD						M ± SD
Full scale IQ		96 ± 12.6						102 ± 12.4						<0.01
Verbal IQ		100.6 ± 13.9						105.7 ± 15.3						<0.05
Performance IQ		91.4 ± 13.3						97.9 ± 10.3						0.001
Letter number sequencing		9.9 ± 3.1						10.8 ± 3						<0.1
Digit‐symbol substitution		10 ± 3.6						10.2 ± 2.8						ns
Digit span forward		10.5 ± 1.9						10.3 ± 1.9						ns
N‐back performance
Median reaction time (in msec): M (SD)	0‐back	498 ± 74						474 ± 76						<0.1
	1‐back	553 ± 106						508 ± 87						<0.01
	2‐back	614 ± 130						581 ± 121						ns
Standard deviation of reaction times (in msec): M (SD)	0‐back	93 ± 72						75 ± 43						<0.1
	1‐back	130 ± 82						113 ± 65						ns
	2‐back	192 ± 101						176 ± 88						ns
Percentage hit rate: N (subjects)		50%	60%	70%	80%	90%	100%	50%	60%	70%	80%	90%	100%
	0‐back	0	0	1	0	1	71	0	0	0	0	1	72	ns
	1‐back	1	0	0	1	6	65	0	0	0	0	6	67	ns
	2‐back	0	0	3	5	38	27	0	0	1	5	30	37	ns
Number of false alarms: N (subjects)		N = 0		N = 1		N = 2		N = 0		N = 1		N = 2
	0‐back	71		2		0		68		5		0		ns
	1‐back	73		0		0		71		2		0		ns
	2‐back	65		7		1		69		4		0		ns

Abbreviations: N – Number, M – Mean, SD – Standard deviation.