Reduced Amygdala Volume Is Associated with Deficits in Inhibitory Control: A Voxel- and Surface-Based Morphometric Analysis of Comorbid PTSD/Mild TBI

Table 1

Demographic and self-report information for the PTSD/TBI and control group. Numbers represent % (𝑁) or median (range) in self-report measures. Fisher's exact or Wilcoxon rank sum test were used for all 𝑃 values.

Characteristic	Control (𝑛=16)	TBI/PTSD (𝑛=21)	𝑃 value
Gender			0.57
Male	87.5% (14)	95.2% (20)
Female	12.5% (2)	4.8% (1)
Age	28.0 (24–45)	29.0 (23–43)	0.62
Race			0.37
Caucasian	75.0% (12)	90.5% (19)
Other	25.0% (4)	9.5% (2)
Years of education	15.5 (12–18)	14.5 (11–22)	0.14
Alcohol use			0.005
No history	81.3% (13)	38.1% (8)
Past history of abuse	12.5% (2)	9.5% (2)
Past history of dependence	6.3% (1)	52.4% (11)
Substance use			0.60
No history	87.5% (14)	71.4% (15)
Past history of abuse	6.3% (1)	9.5% (2)
Past history of dependence	6.3% (1)	19.1% (4)
Most severe TBI from deployment of related TBI
Alteration of consciousness		38.1% (8)
Loss of conscious < 5 minutes		52.4% (11)
Loss of conscious 5 minutes to 30 minutes		9.5% (2)
Number of symptoms from most recent injury		5 (0–9)
Barratt Impulsivity Scale
Attention	8.5 (5–15)	14 (9–19)	0.0002
Cognitive instability	5 (3–10)	6 (3–12)	0.16
Motor	14 (11–22)	15 (12–25)	0.11
Perseverance	7.5 (4–11)	9 (6–14)	0.01
Self-control	9 (6–16)	14 (6–22)	0.001
Cognitive complexity	10 (6–17)	12 (6–20)	0.09
Trauma Symptom Inventory
Intrusive Experiences (IE)	45 (42–61)	75 (58–87)	<0.0001
Defensive Avoidance (DA)	44 (41–63)	67 (49–79)	<0.0001
Dissociation (DIS)	47 (41–55)	64 (47–98)	<0.0001
Shipley 2 Institute of Living Scale
Vocabulary score	112 (99–121)	108 (86–121)	0.18
Abstraction score	108 (84–122)	93 (59–122)	0.004
Composite A score	112.5 (90–125)	99 (79–118)	0.006