Psychological distress and gender predict cognitive complaint after adult civilian mild traumatic brain injury in pre-morbidly healthy adults

Figures & data

Figure 1. Flow chart of participant recruitment for mild traumatic brain injury (mTBI) and trauma control (TC) patients between December 2016 and January 2020.

Flow chart showing the number of participants in each group who were approached on the hospital ward, recruited, and included in the study, as well as the exclusion reasons at each stage.

Table 1. Demographic information and injury characteristics.

	mTBI (n = 68)	TC (n = 40)	Test statistic^a	p
Age, mean (SD), range	36.8 (14.8), 18–60	37.1 (12.8), 18–59	−0.095	.925
Gender, n (%)			0.323	.570
Male	53 (77.9%)	33 (82.5%)
Female	15 (22.5%)	7 (17.5%)
Years of education, mean (SD)	13.3 (2.4)	13.4 (2.7)	−0.023	.982
Predicted FSIQ, mean (SD)	105.9 (9.2)	106.0 (9.5)	−0.068	.946
Current work status			0.095	.954
Full-time	33 (48.5%)	20 (50%)
Part-time	11 (16.2%)	7 (17.5%)
Not working	24 (35.3%)	13 (32.5%)
Litigant, n (%)	8 (11.8%)	4 (10.0%)	0.079	1.000^b
Previous mTBI, n (%)				–
None	51 (75%)	–
1	12 (17.6%)	–
> 1	5 (7.4%)	–
Days since injury, mean (SD), range	60.4 (10.4), 37–84	56.7 (12.0), 39–88	1.643	.105
Mechanism of injury, n (%)				.680^b
Motor vehicle accident	10 (14.7%)	9 (22.5%)
Motorbike accident	10 (14.7%)	9 (22.5%)
Cycling accident	22 (32.4%)	9 (22.5%)
Fall	13 (19.1%)	6 (15.0%)
Sports	4 (5.9%)	3 (7.5%)
Other	9 (13.2%)	4 (10.0%)
Glasgow Coma Scale score, n (%)^c				–
13	5 (7.4%)	–
14	14 (20.6%)	–
15	48 (70.6%)	–
Loss of consciousness, n (%)^d				–
None	10 (14.7%)	–
< 1 min	27 (39.7%)	–
1–5 mins	20 (29.4%)	–
5–10 mins	5 (7.4%)	–
10–20 mins	1 (1.5%)	–
20–30 mins	4 (5.9%)	–
Post-traumatic amnesia, n (%)				–
< 1 min	18 (26.5%)	–
1–5 mins	19 (27.9%)	–
5–60 mins	12 (17.6%)	–
1–6 hrs	5 (7.4%)	–
6–18 hrs	8 (11.8%)	–
18–24 hrs	6 (8.8%)	–
Psychological distress, mean (SD)^e	27.5 (21.2)	22.0 (15.1)		.128
Pain, mean (SD)^f	1.4 (1.5)	1.3 (1.0)	0.384	.702
Fatigue, mean (SD)^g	50.6 (15.1)	49.8 (13.4)	0.317	.752

Note: FSIQ = full-scale IQ; mTBI = mild traumatic brain injury; TC = trauma control.

^a Test statistics are the t values for continuous variables (age, education, FSIQ, days since injury, psychological distress, pain, fatigue) and the Chi-squared values for categorical variables (gender, work status, litigation, mechanism of injury).

^b Based on Chi-squared test with simulated p-value (2000 replicates).

^c GCS score was unknown for one mTBI participant.

^d Loss of consciousness data was unavailable for one mTBI participant.

^e Psychological distress data was missing for one mTBI and two TC participants.

^f Pain data was missing for one mTBI and one TC participant.

^g Fatigue data was missing for one mTBI participant.

Table 2. Group comparisons on cognitive performance measures.

Cognitive domain	Measure	mTBI (n = 68)	TC (n = 40)	t	p	Cohen’s d [95% CI]
Processing speed	SDMT	67.81 (12.15)	66.65 (13.10)	0.456	.650	0.09 [−0.30, 0.48]
Attention	Digit span	28.91 (4.91)	29.50 (4.72)	−0.616	.539	−0.12 [−0.51, 0.27]
Memory	RAVLT^a	11.33 (2.61)	10.67 (2.74)	1.220	.226	0.25 [−0.15, 0.64]
Executive function	TMT-B	58.56 (17.32)	59.83 (23.80)	−0.294	.770	−0.06 [−0.45, 0.33]
	COWAT	36.94 (10.18)	39.78 (9.56)	−1.453	.150	−0.28 [−0.68, 0.11]

Note: CI = confidence interval; COWAT = Controlled Oral Word Association Test; mTBI = mild traumatic brain injury; RAVLT = Rey Auditory Verbal Learning Test; SDMT = Symbol Digit Modalities Test; TC = trauma control; TMT-B = Trail Making Test-Part B.

^a RAVLT data was missing for one mTBI participant and one TC participant.

Table 3. Group comparisons of cognitive and post-concussion symptom measures.

	mTBI (n = 68)	TC (n = 40)	Test statistic^a		Cohen’s d [95% CI]	Odds Ratio [95% CI]
	M (SD)	M (SD)		p
CCAMCHI Total	94.6 (7.9)	89.7 (6.7)	3.396	.001	0.65 [0.25, 1.05]
RPQ Total	12.2 (10.7)	9.6 (9.8)	1.275	.206	0.25 [−0.14, 0.64]
RPQ Cognitive	2.94 (3.02)	1.64 (2.36)	4.000	.046		2.24 [1.01, 4.97]
ABNAS Total	11.1 (11.6)	9.8 (7.9)	0.665	.507	0.12 [−0.27, 0.51]

Note: An odds ratio of 1 indicates no difference between groups. ABNAS = A-B Neuropsychological Assessment Schedule; CCAMCHI = Cognitive Complaint After Mild Closed Head Injury; CI = confidence interval; mTBI = mild traumatic brain injury; RPQ = Rivermead Post-Concussion Symptoms Questionnaire; TC = trauma control.

^a The test statistic provided is the t value for all measures except for RPQ Cognitive, for which the Chi-squared value is provided.

Table 4. Correlations between symptom variables within each group.

	mTBI (n = 68)
	RPQ total	RPQ cognitive	ABNAS
CCAMCHI	.62*** [.43, .75]	.66*** [.44, .79]	.76*** [.61, .86]
RPQ total		.84*** [.69, .90]	.78*** [.65, .86]
RPQ cognitive			.75*** [.59, .85]
	TC (n = 40)
	RPQ Total	RPQ Cognitive	ABNAS
CCAMCHI	.18 [−.18, .50]	.16 [−.23, .50]	.29 [−.10, .59]
RPQ total		.73*** [.50, .85]	.65*** [.40, .81]
RPQ cognitive			.68*** [.45, .80]

Note. Bootstrapped 95% confidence intervals (BCa method; 9999 replications) are provided in brackets. ABNAS = A-B Neuropsychological Assessment Schedule; CCAMCHI = Cognitive Complaint After Mild Closed Head Injury; mTBI = mild traumatic brain injury; RPQ = Rivermead Post-Concussion Symptoms Questionnaire; TC = trauma control.

***p < .001

Table 5. Predictors of cognitive and post-concussion symptoms within each group.

Dependent variable	Group	Independent variable	b	SE b	β	p	Semipartial r^2	Bootstrapped 95% CIs^a
CCAMCHI	mTBI	Psychological distress	0.201	0.037	.536	<.001	.24	0.143, 0.277
		Gender	4.789	1.860	.253	.012	.02	0.515, 9.424
	TC	Psychological distress	0.004	0.085	.008	.967	.00	−0.213, 0.204
		Gender	−0.559	3.250	−.032	.864	.00	−10.019, 8.028
RPQ Total	mTBI	Psychological distress	0.302	0.047	.596	<.001	.37	0.134, 0.419
		Gender	6.244	2.363	.244	.010	.02	0.617, 13.020
	TC	Psychological distress	0.399	0.095	.612	<.001	.18	0.176, 0.559
		Gender	1.028	3.635	.041	.779	.01	−7.741, 8.669

Note. Due to missing psychological distress data (one mTBI participant; two TC participants), sample sizes for regression analyses were n = 67 for the mTBI group and n = 40 for the TC group. Gender was coded as 1 for males and 2 for females. CCAMCHI = Cognitive Complaint After Mild Closed Head Injury; CI = confidence interval; mTBI = mild traumatic brain injury; RPQ = Rivermead Post-Concussion Symptoms Questionnaire; TC = trauma control.

^a Bootstrapped confidence intervals for the regression coefficients (BCa method; 2000 replicates). Note that when the confidence interval does not include zero (bolded values), this indicates significant results.