Research Reports - The risk of dementia and chronic cognitive impairment after mild traumatic brain injury
Arch Phys Med Rehabil. 2014 Mar;95
Godbolt AK(1), Cancelliere C(2), Hincapié CA(3), Marras C(4), Boyle E(5), Kristman VL(6), Coronado VG(7), Cassidy JD(8)
OBJECTIVE: To synthesize the best available evidence regarding the risk of
dementia and chronic cognitive impairment (CCI) after mild traumatic brain injury
DATA SOURCES: MEDLINE and other databases were searched (2001-2012) using a
previously published search strategy and predefined criteria. Peer-reviewed
reports in 6 languages were considered.
STUDY SELECTION: Systematic reviews, meta-analyses, randomized controlled trials,
cohort studies, and case-control studies, with a minimum of 30 MTBI cases in
subjects of any age, assessing the risk of dementia or CCI after MTBI were
DATA EXTRACTION: Eligible studies were critically appraised using a modification
of the Scottish Intercollegiate Guidelines Network criteria. Two reviewers
independently reviewed each study and extracted data from accepted articles (ie,
with a low risk of bias) into evidence tables.
DATA SYNTHESIS: Evidence from accepted studies was synthesized qualitatively
according to modified Scottish Intercollegiate Guidelines Network criteria, and
prognostic information was prioritized as exploratory or confirmatory according
to design. Of 77,914 records screened, 299 articles were eligible and reviewed.
Methodological quality was acceptable for 101 (34%) articles, of which 1 article
considered dementia and 7 articles considered CCI. The study examining the risk
of dementia after MTBI did not find an association. One randomized controlled
trial found that being informed about possible cognitive dysfunction after MTBI
was associated with worse cognitive performance on standard tests. Children with
MTBI and intracranial pathology ("complicated" MTBI) performed worse than did
children without intracranial pathology. Children showed higher rates of
cognitive symptoms a year after MTBI than did a control group.
CONCLUSIONS: There is a lack of evidence of an increased risk of dementia after
MTBI. In children, objective evidence of CCI exists only for complicated MTBI.
More definitive studies are needed to inform clinical decisions, assessment of
prognosis, and public health policy.