Clinical correlates of retrograde amnesia in mild traumatic brain injury

Abstract

Primary objective: The purpose of this study was to examine the clinical significance of retrograde amnesia (RA) in patients with acute mild traumatic brain injuries (MTBI).

Methods and procedures: An emergency department sample of patients (n = 75), aged 18–60 years, with no pre-morbid medical or psychiatric conditions, who met the WHO criteria for MTBI were enrolled in this prospective, descriptive, follow-up study. This study examined the presence and duration of RA in relation to socio-demographics, MTBI severity markers including neuroimaging (CT, MRI) and clinical outcomes (Rivermead post-concussion symptoms questionnaire, post-concussion syndrome (PCS) diagnosis and return to work (RTW) status) at 2 weeks, 1 month and 6 months post-injury.

Main outcomes and results: GCS scores and duration of post-traumatic amnesia (PTA) were related to RA. Those with GCS scores of 14 vs. 15 were more likely to have RA (χ²(1) = 13.70, p < 0.0001) and a longer duration (Mann-Whitney U = 56.0, p < 0.0001, d = 1.15) of RA. The duration of RA and PTA correlated positively (Spearman ρ(75) = 0.42, p < 0.0001) and those with RA had longer durations of PTA (Mann-Whitney U = 228.5, p = 0.001, d = 1.21). During the follow-up, the presence and duration of RA were not significantly associated with PCS diagnosis or time to RTW.

Conclusions: In this study, the presence and duration of RA was not associated with outcome.

• Concussion
• head injury
• post-concussion syndrome
• retrograde amnesia
• return to work
• traumatic brain injury

Acknowledgements

The authors thank research assistants Anne Simi and Marika Suopanki-Ervasti for their contribution in data collection. This study was done as part of the first author’s PhD thesis research program. A portion of this study was presented at the 9^th World Congress on Brain Injury in Edinburgh, Scotland, in March 2012. This study has been supported by the Medical Research Fund of Tampere University Hospital.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Grant Iverson, PhD, has been reimbursed by the government, professional scientific bodies and commercial organizations for discussing or presenting research relating to mild TBI and sport-related concussion at meetings, scientific conferences and symposiums. He has a clinical practice in forensic neuropsychology involving individuals who have sustained mild TBIs (including athletes). He has received honorariums for serving on research panels that provide scientific peer review of programs. He is a co-investigator, collaborator or consultant on grants relating to mild TBI funded by several organizations. The other authors report no competing or conflicts of interest. GLI notes that this work was supported in part by the INTRuST Posttraumatic Stress Disorder and Traumatic Brain Injury Clinical Consortium funded by the Department of Defense Psychological Health/Traumatic Brain Injury Research Program (X81XWH-07-CC-CSDoD).