Table 1. Review of studies comparing outcomes between Uncomplicated and Complicated MTBI subjects.
| First Author | Year | Country | Adult (A) or Pediatric (P) | Comp MTBI (N) | Uncomp MTBI (N) | Imaging method | MRI magnet strength, timing after injury | Timing of clinical testing | Recruitment location | Neuroimaging Findings Related to Outcome | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Functional | Cognitive Testing | Symptoms | ||||||||||
| Williams [10] | 1990 | USA | A | 77 | 78 | CT | NA | NP after clearing of PTA, GOS at 6 months | Neurosurgical service | Complicated less likely to show good recovery on GOS | Complicated worse on tests of processing speed and recognition memory, no difference on verbal fluency or verbal memory | NA |
| Hanlon [18] | 1999 | USA | A | 22 | 78 | CT, MRI | Not reported | NP mean 177 days post injury, vocational at 1 year. | Outpatient | No difference in vocational outcome | No difference | NA |
| Iverson [19] | 1999 | USA | A | 112 | 369 | CT | NA | NP—most within 1 week of injury | Trauma Service | NA | Complicated worse on COWAT. No other tests were reported. | NA |
| Hofman [20] | 2001 | Netherlands | A | 12 | 9 | MRI | 1.5T, 2–5 days | NP and Sx evaluation < 1 week, 2 months, and 6 months. | ER | NA | Complicated worse on 1/6 measures—Reaction time at 6 months | No difference |
| Borgaro [21] | 2003 | USA | A | 14 | 14 | CT, MRI | Magnet strength not reported, < 40 days | NP <40 days | Inpatient Rehabilitation | NA | Complicated worse on 1/7 subsets of the BNIS—speech/language testing | NA |
| Hughes [22] | 2004 | UK | A | 26 | 54 | MRI | 1.0T, 1–3 days | NP < 3 days, vocational status and Sx evaluation at 6 months | ER | No difference on return to work status | Complicated worse on a composite measure of attention, no difference on memory or executive functioning | No difference |
| Lange [23] | 2005 | USA | A | 117 | 328 | CT | NA | NP < 23 days, most < 7 days | Trauma Service | NA | Complicated worse on TMT-A and TMT-B. Other tests were not reported. | NA |
| Iverson [24] | 2006 | USA | A | 50 | 50 | CT | NA | NP < 2 weeks | Trauma Service | NA | Complicated worse on a minority of measures (5/13) including TMT-B, COWAT, Logical Memory Saving Score, Visual Reproduction I and II (d<0.51 for all scores) | NA |
| Kurca [25] | 2006 | Slovakia | A | 7 | 23 | MRI | 1.5T, <4 days | NP and Sx evaluation < 4 days | Unclear | NA | Complicated worse on a minority of measures (2/11)—more errors on the CAT and a learning interference test where a list of words is recalled after learning a subsequent list | No difference |
| Sadowski-Cron [26] | 2006 | Switzerland | A | 21 | 184 | CT | NA | NP < 2 hours, Sx evaluation 1 year | ER | NA | No difference | Complicated reported more symptoms |
| Lee [9] | 2008 | USA | A | 19 | 9 | CT, MRI | 3T, <14 days | NP and GOS-E within 2 weeks, 1 month, and 1 year | ER | No difference on GOS-E | No difference | NA |
| Levin [27] | 2008 | Canada/USA | P | 32 | 48 | CT | NA | NP at 2 weeks, 3 months, 6 months, and 12 months | Pediatric ER | NA | Complicated worse on 5/7 domains—general working memory, episodic memory, visuomotor speed, reading, and processing speed | NA |
| Stulemeijer[28] | 2008 | Netherlands | A | 40 | 133 | CT | NA | 6 months | ER | No difference RTW | NA | No difference |
| Lange [29] | 2009 | USA | A | 20 | 20 | CT | NA | NP Average 3.5 days | Trauma Service | NA | Complicated worse on 3/13 measures including Visual Reproduction I and II, and Hopkins Delay (d<.76) | NA |
| Muller [30] | 2009 | Norway | A | 15 | 45 | CT, MRI | <2 days | NP before discharge and at 6 months | Neurosurgery service | NA | Complicated worse at both time points on “mean impairment index”—a composite measure derived from a comprehensive NP battery | NA |
| de Guise [31] | 2010 | Canada | A | 45 | 131 | CT | NA | NP at 3 weeks, Sx evaluation at 2 weeks | Outpatient | No difference GOS-E, no difference return to work or discharge referrals pattern | No difference | Uncomplicated reported more symptoms |
| Iverson [3] | 2012 | Finland | A | 13 | 34 | CT, MRI | 3T MRI, 3–4 weeks | NP at 3–4 weeks | ER | Complicated more time to return to work | No difference | No difference |
| Lange [32] | 2012 | USA | A | 17 | 24 | CT, MRI | Magnet strength not reported, timing in first few weeks | NP within 6 months of injury | Combat evacuated | NA | Uncomplicated group worse on 1/11 measures tested—CVLT-II long delayed recall (d = 0.86) | Uncomplicated worse on a minority of PAI subscales—anxiety (d = .74) and aggression (d<0.72). |
| Babcock[33] | 2013 | USA | P | 14 | 206 | CT | NA | Symptoms at 3 months | ER | NA | NA | No difference |
| Beauchamp [34] | 2013 | Australia | P | 13 | 58 | CT, MRI | 3T MRI, 2–8 weeks | NP, outcome measures at 6 months | ER | Global adaptive functioning—no difference | No difference | NA |
| Dagher [35] | 2013 | Canada | A | 1,483 | 644 | CT | NA | Outcome measures at discharge | Inpatient | Complicated longer length of stay, worse on GOS-E and FIM | NA | NA |
| McMahon [36] | 2013 | USA | A | 165 | 210 | CT, MRI | NA | Sx and outcome evaluation at 3,6, and 12 months | ER | Complicated worse on GOS-E at 3 months, no difference at 6 or 12 months | NA | Uncomplicated reported more symptoms |
| Lannsjo[37] | 2013 | Sweden | A | 52 | 1210 | CT | NA | 3 months | ER | No difference on GOSE | NA | No difference |
| Kumar[38] | 2014 | USA | A | 71 | 57 | CT | NA | 3 months | ED | NA | NA | No difference |
| Yuh [8] | 2013 | USA | A | 64 | 71 | CT, MRI | 3T, average 12 days | GOS-E at 3 months | ER | Group with any CT abnormality showed no difference on GOS-E. Note: Subgroup of patients with Diffuse axonal injury, contusions, or subarachnoid hemorrhage worse on GOS-E at 3 months) | NA | NA |
| Yuh[39] | 2014 | USA | A | 32 | 44 | CT, MRI | 3T | 3 and 6 months | ED | No difference GOS-E Note: Subgroup with MRI contusions associated with worse outcome at 3 months only (see text). | No difference on CVLT-II, WAIS-IV-PSI, TMT-A, TMT-B | No difference |
Abbreviations: Comp = Complicated; Uncomp = Uncomplicated; NP = Neuropsychological testing; PTA = Post-Traumatic Amnesia; Sx = symptoms, ER = emergency room, GOS = Glasgow Outcome Scale; GOS-E = Glasgow Outcome Scale Extended, FIM = Functional Independence Measure; RT = Reaction Time; COWAT = Controlled Oral Word Association Test; TMT = Trail Making Test; BNIS = Neuropsychological Instrument BNI Screen for Higher Cerebral Functions; CVLT-II = California Verbal Learning test II; CAT = Concentration and Attention Test; SF-36 = Short-Form health survey; HI-FI = Head Injury Family Interview Checklist; WAIS IV-PSI = Weschler Adult Intelligence Scale IV edition processing speed index, RPQ = Rivermead Post-Concussion Symptom Questionnaire