Rehabilitation Research and Practice matter hyperintensities, were not considered as abnormal. Patients were excluded if signiﬁcant non-trauma-related ab- normalities were identiﬁed. Most were excluded due to small vessel ischemic disease, but there were also patients with multiple sclerosis, unusually large ventricles, and a history of neurosurgery. This sample included patients (N = 13; 27.7%) who had an intracranial abnormality on day-of-injury CT or follow- up MRI (i.e., a complicated MTBI). None of the patients required inpatient rehabilitation. None of the patients were involved in litigation. All patients provided written informed consent according to the Declaration of Helsinki. The study protocol was approved by the Ethical Committee of the Tampere University Hospital. All patients completed self- report measures and neurocognitive testing at 3-4 weeks after injury (M = 25.8, SD = 2.9, Range 21–34 days). 2.2. Measures. Postconcussion symptoms were assessed using the Rivermead Post-Concussion Questionnaire (RPSQ) [15]. The RPSQ is a 16-item self-report questionn- aire that measures the severity of common postoncussion symptoms on a 5-point Likert scale. The patients rated the presence of the symptoms over the past 24 hours on a scale from 0 to 4 (0 = not experienced at all after the injury, 1 = experienced but no more of a problem compared with before the injury, 2 = a mild problem, 3 = a moderate problem, and 4 = a severe problem). A total score was calculated by adding all items with a score greater than 1 (not present anymore). Possible depressive symptoms were assessed using the Beck Depression Inventory-Second Edition (BDI-II) [16], a 21-item self-report questionnaire. Subjects were asked to rate each item on a four-point scale ranging from zero to three. In this study, we used the total score which is the sum of all 21 items, giving a range from zero to 63. It should be noted that many symptoms on this questionnaire overlap with postconcussion symptom measured by the RPSQ. Self-reported fatigue was examined using the Barrow Neurological Institute Fatigue Scale (BNI-FS), an 11-item self-report questionnaire designed to assess fatigue during the early stages of recovery after brain injury [17]. Subjects were asked to rate the extent to which each of the 10 primary items has been a problem for them since the injury on a 7- point scale. Response options are as follows: 0-1 = rarely a problem; 2-3 = occasional problem, but not frequent; 4-5 = frequent problem; 6-7 = a problem most of the time. The ﬁnal item (item 11) asks subjects to provide an overall rating of their level of fatigue on a scale from 0 (no problem) to 10 (severe problem). In this study the total BNI-FS score is used which is the sum of all 10 scores (min = 0, max = 70). General verbal intelligence was assessed with the Wech- sler Adult Intelligence Scale-Third Edition (WAIS III) infor- mation subtest [18]. Learning and memory was assessed with the Rey Auditory Verbal Learning Test (RAVLT) total score (total number of words recalled in trials 1 through 5) and delayed recall (number of words recalled after 30 mi- nutes delay) [19]. Attention and executive functioning were assessed with Stroop Color Word Test (color-word inter- ference score, Golden version) [19], Trail Making Test (TMT) A and B (time needed to ﬁnish the task) [20], and two verbal 3 ﬂuency tasks: animal naming (category ﬂuency, total number of words in one minute) and single-letter-based word genera- tion (phonemic ﬂuency, total number of words produced across the 3 trials) [21]. Raw scores for the neurocognitive tests were analyzed unless otherwise stated. 3. Results There were no signiﬁcant diﬀerences between MTBI groups for age, education, gender, GCS score, mechanism of injury, days tested after injury, or duration of LOC, PTA, or retro- grade amnesia (see Table 2). There was a large statistically signiﬁcant diﬀerence in time to return to work between groups. The patients with uncomplicated MTBIs had a median of 6.0 days (mean = 12.9, SD = 18.8, IQR = .75– 14.75, range = 0–77) off work compared to a median of 36 days (mean = 58.0, SD = 83.8, IQR = 13.5–53, range = 3–315) for the complicated MTBI group. There were no signiﬁcant diﬀerences between MTBI groups for self-reported depression (BDI-II) or postconcus- sion symptoms (RPSQ) (all P > .05). There were, however, medium eﬀect sizes for the BDI-II total score (Cohen’s d = .52) and RPSQ total score (d = .43) between groups. These eﬀects sizes suggest that the complicated MTBI group reported fewer depression symptoms and postconcussion symptoms compared to the uncomplicated MTBI group. There was not a statistically signiﬁcant diﬀerence in the percentages of patients in the uncomplicated (44.1%) versus complicated (38.5%) MTBI groups who met ICD-10 criteria for postconcussional syndrome based on the report- ing of symptoms on the RPSQ as “mild” or greater (i.e., score of 2 or higher on individual items). In contrast, 17.6% of the patients in the uncomplicated MTBI group met ICD- 10 criteria for postconcussional syndrome based on the re- porting of symptoms on the RPSQ as “moderate” or greater (i.e., score of 3 or higher on individual items); no patients in the complicated MTBI group met this criterion for the syndrome. As seen in Table 3, there were no signiﬁcant diﬀerences between MTBI groups on the neuropsychological tests (all P > .05). Although not signiﬁcantly diﬀerent, medium eﬀect sizes were found for the RAVLT total score (d = .39), RAVLT delayed recall score (d = .47), Animal Naming test (d = .43), and Stroop Color-Word (d = .47). Paradoxically, the complicated MTBI group performed better on verbal learning and memory (RAVLT) and executive functioning (Stroop), but worse on a test of verbal ﬂuency (Animal Nam- ing). The prevalence of low scores across the battery of cog- nitive tests was determined for each group (i.e., eight scores (not including the Rey Copy) derived from the six tests were considered simultaneously). A low score on the neurocog- nitive tests was deﬁned as falling below the 10th percentile compared to published normative data. There was not a signiﬁcant diﬀerence in the percentage of patients with un- complicated (26.5%) versus complicated (23.1%) MTBIs who had two or more low scores, when eight test scores were considered simultaneously.