Table 1.

Participant and ERP characteristics by exposure group

	CTL			PNE
	Mean	SE	Range	Mean	SE	Range
Gestational age at birth (days)a	279.9	1.9	266–294	270.4	1.4	261–278
Postmenstrual age at EEGb	418.4	3.3	400–446	419.4	5.6	381–455
Age at EEG, months	4.61	0.5	4.0–5.5	4.96	0.8	3.9–6.2
Birth weight, gramsc	3610.5	118	2778–4423	3130.6	156	2155–4111
Male, n (%)	7 (.44)			7 (.47)
Nonwhite	4 (.25)			4 (.24)
3rd Trimester Maternal expired CO, ppmd	1.67	0.14	1.0–2.0	9.6	2.5	1.0–33.5
3rd Trimester Maternal COHb, %d	1.00	0.08	0.8–1.8	2.2	0.4	0.8–6.0
Cigarettes/day Trimester 1e	0			14.1	1.9	5–20
Cigarettes/day Trimester 2e	0			7.7	2.0	0–20
Cigarettes/day Trimester 3e	0			5.5	1.4	0–10
Maternal Cotinine 3rd Trimesterf,g	1.97	0.44	0.3–5.3	104.5	29.8	31–520
Maternal Postpartum expired CO, ppma	2.27	1.15	1.0–7.0	9.7	1.4	1.0–26.0
K-Complex Characteristics
% of acceptable ERP epochsg	28.1	2.3	9.5–41	25.3	2.3	15–42
Peak-to-peak amplitudeh, µVg	122.04	11.9	55.8–216.2	102.0	6.8	65.6–161.2
Delta power of N550, µV^2g	1574.3	343	231–5496	907.4	89.6	479–1789.5

Abbreviations: CTL, drug free control, n = 17; PNE, prenatal nicotine exposure n = 16; SE, standard error of the mean; CO, carbon monoxide; PPM, parts per million; Hb, hemoglobin

^a p < .001.

^bdays since conception;

^c p <.09,

^d p < .01, Gestational age at birth, birthweight, Maternal COHb, CO, and cotinine results of 2-sample t-test, df: 2, 31.

^eTime Line Follow Back Interview.

^f Maternal urinary cotinine (ng cotinine per mg creatinine).

^g[AQ: Please provide significance for “g.”]

^hPeak-to-peak difference between P200 and N550 components of elicited K-complex, adjusted for gestational age at EEG.