Table 3. Percentage of Participants Impaired or Not Impaired on the Driving Simulator Who Exhibited Clues on FSTs at First FST Evaluation.

SFST clue	Participants with cluesa		Unadjusted analysisb		Adjusted analysisc
	Not impaired on simulator (n = 112)	Impaired on simulator (n = 68)	Odds ratio (95% CI)	P value	95% CI	P value
Walk and Turn Test
Instructions	23 (20.5)	24 (35.8)d	2.16 (1.10-4.25)	.03	1.01-4.62	.05
Balancee	33 (29.5)	38 (55.9)	3.03 (1.62-5.68)	.001	1.25-7.37	.005
Starts too soon	9 (8.0)	4 (6.0)d	0.73 (0.21-2.46)	.61	0.21-2.46	.61
Stops when walking	45 (40.2)	30 (44.8)d	1.21 (0.65-2.23)	.55	0.65-2.26	.61
Steps off line	22 (19.6)	22 (32.8)c	2.00 (1.00-3.99)	.05	0.94-4.23	.07
Wrong number of stepse	17 (15.2)	20 (29.9)d	2.38 (1.14-4.96)	.02	1.01-5.60	.05
Misses heel to toee	24 (21.4)	27 (40.3)d	2.47 (1.27-4.81)	.008	1.05-5.86	.03
Raises arm to balance	51 (45.5)	40 (59.7)d	1.77 (0.96-3.27)	.07	0.93-3.38	.09
Improper turn	47 (42.0)	40 (59.7)d	2.05 (1.11-3.79)	.02	1.01-4.16	.05
Total clues, median (IQR)e	2.0 (1.0-3.0)	3.0 (2.0-5.0)	1.50 (1.23-1.83)	<.001	1.18-1.90	<.001
≥2 WAT clues	71 (63.4)	52 (77.6)d	2.00 (1.00-4.00)	.05	NA	NA
One Leg Stand Test
Puts foot downe	22 (20.0)d	31 (45.6)	3.35 (1.72-6.54)	<.001	1.56-7.19	.001
Uses arms to balance	37 (33.3)f	38 (56.7)d	2.62 (1.40-4.89)	.002	1.35-5.08	.003
Swayse	73 (65.2)	62 (91.2)	5.52 (2.19-13.9)	<.001	1.82-16.7	.001
Hops	4 (3.6)g	8 (12.1)h	3.66 (1.06-12.7)	.04	1.06-12.7	.04
Total clues, median (IQR)	1.0 (0.0-2.0)	2.0 (1.0-3.0)	2.17 (1.57-3.02)	<.001	1.41-3.35	<.001
≥2 OLS clues	45 (40.9)g	45 (68.2)h	3.09 (1.63-5.88)	<.001	NA	NA
≥2 WAT clues and ≥2 OLS clues	35 (31.8)g	36 (55.4)i	2.66 (1.41-5.01)	.002	NA	NA
Finger to Nose Test
Instructions	26 (23.2)	26 (38.2)	2.05 (1.06-3.95)	.03	0.93-4.53	.09
Incorrect sequence	19 (17.0)	11 (16.2)	0.94 (0.42-2.13)	.89	0.42-2.13	.89
Uses pad rather than finger	62 (55.4)	42 (61.8)	1.30 (0.70-2.41)	.40	0.67-2.52	.56
Leaves finger on nose	14 (12.5)	9 (13.2)	1.07 (0.44-2.62)	.89	0.43-2.62	.89
Eyelid tremor	86 (76.8)	48 (70.6)	0.73 (0.37-1.43)	.36	0.34-1.53	.56
Body tremore	17 (15.2)	23 (33.8)	2.86 (1.39-5.87)	.004	1.06-7.68	.03
Sways	54 (48.2)	43 (64.2)d	1.92 (1.03-3.58)	.04	0.93-3.99	.09
Total clues, median (IQR)	3.0 (2.0-3.0)	3.0 (2.0-4.0)	1.32 (1.05-1.66)	.02	1.03-1.70	.03
Lack of Convergence
Instructions	7 (6.2)	5 (7.4)	1.19 (0.36-3.91)	.77	0.36-3.91	.77
Eyes do not converge	66 (58.9)	46 (67.6)	1.46 (0.77-2.74)	.24	0.71-3.00	.49
Pupillary diameter, median (IQR), mmj	5.5 (4.5-6.0)	5.5 (4.5-6.5)	1.11 (0.85-1.45)	.45	NA	NA
Total clues, median (IQR)	1.0 (0.0-1.0)	1.0 (0.0-1.0)	1.45 (0.80-2.60)	.22	0.78-2.68	.28
Modified Romberg Balance Test
Instructions	30 (27.0)g	24 (35.3)	1.47 (0.77-2.82)	.24	0.66-3.26	.74
Internal clock, median (IQR), sk	33 (33.0-39.0)	32 (28.8-23.2)	0.98 (0.96-1.01)	.20	NA	NA
Internal clock (not acceptable)	51 (45.9)g	31 (45.6)	0.99 (0.54-1.81)	.96	0.54-1.81	.96
Eyelid tremors	91 (81.2)	52 (76.5)	0.75 (0.36-1.56)	.44	0.33-1.69	.74
Body tremors	29 (25.9)	19 (27.9)	1.11 (0.56-2.19)	.76	0.55-2.26	.95
Sways	75 (67.6)g	49 (73.1)d	1.31 (0.67-2.56)	.43	0.62-2.75	.74
Total clues, median (IQR)	2.0 (2.0-3.0)	2.0 (2.0-3.0)	1.13 (0.85-1.51)	.39	0.85-1.51	.39
Total clues for all tests, median (IQR)d,e	9.0 (7.0-11.2)	12.0 (9.0-14.0)	1.23 (1.11-1.36)	<.001	1.11-1.36	<.001

Abbreviations: FST, field sobriety test; NA, not applicable; OLS, One Leg Stand; SFST, standardized field sobriety test; THC, Δ⁹-tetrahydrocannabinol; WAT, Walk and Turn.

^a Data are presented as the number (percentage) of participants unless otherwise indicated.

^b Based on logistic regression assessing the associations with impairment.

^c Adjusted values were calculated using the false discovery rate method.

^d n = 67.

^e Estimates within treatments showed an association in the THC group only.

^f n = 111.

^g n = 110.

^h n = 66.

ⁱ n = 65.

^j Numeric variable (not included in calculation of total clues).

^k Numeric variable for estimate of when 30 seconds had passed (not included in calculation of total clues).