Mental effort and recovery from task-induced fatigue in people with traumatic brain injury

Figures & data

Table 1. Demographics, subjective symptomatology, and neuropsychological functioning in traumatic brain injury and healthy control groups.

	Traumatic brain injury (N = 20)		Healthy controls (N = 19)		p Value
	Mean ± SD	N (%) or range	Mean ± SD	N (%) or range
Age	50.5 ± 12.8	24–75	51.6 ± 11.4	27–74	ns
Gender (male)		11 (55%)		10 (52.6%)	ns
Years of education	15.1 ± 2.1	12–18.5	16.0 ± 2.9	8–18.5	ns
Employed at the moment of the study		9 (45%)		16 (84.2%)	<0.05
PSQI	7.0 ± 3.5	1–15	3.9 ± 2.3	1–10	<0.01
Clinically significant (>5)		13 (65%)		4 (21.1%)
FSS	4.7 ± 1.4	2.3–7	2.7 ± 0.9	1.3–4.7	<0.001
Clinically significant (≥4)		14 (70%)		2 (10.5%)
HADS – total score	11.8 ± 8.3	1–33	5.6 ± 3.4	1–13	<0.01
HADS – depression	5.7 ± 4.4	1–20	1.9 ± 2.0	0–7	<0.01
Clinically significant (≥8)		6 (30%)		0 (0%)
HADS – anxiety	6.2 ± 4.5	0–16	3.7 ± 2.2	1–9	<0.05
Clinically significant (≥8)		7 (35%)		2 (10.5%)
COWAT	41.68 ± 9.95	24–60	48.63 ± 11.82	27–70	0.054
SDMT	50.25 ± 10.70	30–70	63.42 ± 9.44	45–80	<0.001
STROOP	50.16 ± 8.75	23–63	61.85 ± 9.90	46–82	<0.001
Digit Span forward	46.13 ± 9.29	27–67	53.13 ± 9.65	37–74	0.027
Digit Span backward	46.28 ± 11.82	30–77	52.55 ± 10.40	34–70	ns
Mean cognitive score	47.07 ± 5.73	35–60	56.69 ± 7.34	43–74	<0.001

SD: standard deviation; PSQI: Pittsburgh Sleep Quality Index; FSS: Fatigue Severity Scale; HADS: Hospital Anxiety and Depression Scale; COWAT: Controlled Word Association Test; SDMT: Symbol Digit Modalities Test. ns: non-significant.

Cognitive tasks scores are T-scores adjusted for age and education of the participant.

Figure 1. Relationship between effort and fatigue following the task for TBI participants (black circles) and controls (white triangles), including the 95% confidence intervals. VASpost: Visual Analog Scale fatigue immediately after the task; RSME: Rating Scale Mental Effort.

Scatterplot with regression lines displaying a similar slope between effort and fatigue following the task for the traumatic brain injury (TBI) group and the control group. With more variation in scores in the TBI group.

Table 2. Effort score and fatigue scores at the different time points for the traumatic brain injury and healthy control groups.

	Traumatic brain injury (N = 20)		Healthy controls (N = 19)		Effect size	p Value
	Mean ± SD	Range	Mean ± SD	Range	Cohen’s D
RSME	97.0 ± 29.5	55–150	70.9 ± 15.2	39–90	1.10	t(28.7)=3.5, p < 0.01
Task-induced fatigue (VASpost–VASpre)	12.5 ± 18.9	–38 to 56	9.7 ± 20.8	–41 to 39	0.14	t(37)=0.4, p=ns
VASpre	47.2 ± 25.4	7–87	20.7 ± 20.1	0–70	1.15	t(37)=3.6, p < 0.01
VASpost	59.6 ± 26.2	12–100	30.4 ± 20.5	0–73	1.23	t(37)=3.9, p < 0.001
VAS-5 min after task	50.5 ± 29.8	7–97	16.1 ± 14.5	0–51	1.46	t(28.0)=4.6, p < 0.001
VAS-10 min after task	48.1 ± 28.5	2–92	10.5 ± 13.7	0–55	1.65	t(27.9)=5.3, p < 0.001
VAS-15 min after task	45.9 ± 27.0	0–86	5.3 ± 6.9	0–26	2.01	t(21.7)=6.48, p < 0.001
VAS-20 min after task	45.4 ± 26.4	1–85	6.6 ± 8.3	0–26	1.94	t(23.1)=6.23, p < 0.001
VAS-30 min after task	41.9 ± 26.2	0–81	4.4 ± 5.3	0–18	1.94	t(20.7)=6.28, p < 0.001

SD: standard deviation; RSME: Rating Scale Mental Effort; VAS: Visual Analog Scale fatigue; VASpre: VAS before the task; VASpost: VAS directly after the task.

Table 3. Correlations between effort and fatigue scores for the traumatic brain injury and healthy control group.

	Traumatic brain injury (N = 20)		Healthy controls (N = 19)
	Effort (RSME)		Effort (RSME)
	r	p Value	r	p Value
Task-induced fatigue (VASpost–VASpre)	–0.05	ns	0.20	ns
VASpre	0.80	<0.001	0.26	ns
VASpost	0.74	<0.001	0.46	0.051
VAS-5 min after task	0.80	<0.001	0.34	ns
VAS-10 min after task	0.81	<0.001	0.23	ns
VAS-15 min after task	0.80	<0.001	–0.24	ns
VAS-20 min after task	0.77	<0.001	–0.06	ns
VAS-30 min after task	0.78	<0.001	–0.07	ns

RSME: Rating Scale Mental Effort; VAS: Visual Analog Scale fatigue; VASpre: VAS before the task; VASpost: VAS directly after the task.

Table 4. Results of hierarchical multiple linear regression analysis of the relationship between effort and fatigue, including the effect of group (traumatic brain injury and healthy controls) and the interaction between effort and group.

	R^2	Adjusted R^2	F	p Value	Variables	Standardized β [95% CI]	f^2	p Value
Fatigue following the task
Model 1	0.59	0.56	25.42	<0.001	RSME	0.60 [0.03–1.20]	0.06	<0.05
					Group	0.23 [–2.12 to 27.49]	0.04	ns
					RSME × group	0.03 [–0.61 to 0.69]	0.0002	ns
Fatigue following the task, controlled for fatigue before the task
Model 1	0.65	0.62	21.31	<0.001	VASpre	0.38 [0.07–0.73]	0.07	<0.05
					RSME	0.46 [–0.08 to 1.04]	0.03	ns
					Group	0.14 [–7.08 to 22.00]	0.01	ns
					RSME × group	−0.08 [–0.72 to 0.53]	0.001	ns

95% CI: 95% confidence interval; VASpost: Visual Analog Scale fatigue directly after the task; VASpre: Visual Analog Scale fatigue before the task; RSME: Rating Scale Mental Effort.

Figure 2. Levels of fatigue before and following the task, showing the task-induced increase and decline in fatigue during the 30-min rest-period for participants with TBI (circles, solid line) and controls (triangles, dashed line) with 95% confidence intervals (grey area). VAS-f: Visual Analog Scale fatigue; PreTask: before the task; PostTask: immediately after the task.

Line graph displaying a similar slope of decline in fatigue scores over the 30-minute rest period in traumatic brain injury (TBI) and control group. With higher fatigue scores in the TBI group compared to the control group at each time point.

Data availability statement

Data can be obtained via the Dutch Dataverse Network upon request: https://doi.org/10.34894/FA2XYR.