Abstract
Objectives: According to ICD-10 or DSM-IV criteria Post-Concussion Syndrome (PCS) requires a prior mild traumatic brain injury (mTBI). However, PCS symptoms are non-specific and can also affect non- mTBI populations. Symptoms further overlap with other diagnoses, such as depression. Consequently, the degree to which PCS is specific to or caused by mTBI is still debated. With the present study we aim to investigate the nature of PCS in greater detail by looking whether PCS is specific to mTBI, and the extent to which these symptoms and related factors (depression, anxiety,daytime sleepiness and cognitive failures) exist in the non-mTBI population. Method: An online survey was sent to University staff and students. Included in this survey were the Rivermead Post Concussion Questionnaire (RPQ), Cognitive Failures Questionnaire (CFQ), Hospital Anxiety and Depression Scale (HADS), Epworth Sleepiness Scale (ESS), along with demographic questions and those related to the mTBI sustained. PCS was diagnosed as 3 or more symptoms within DSM-IV criteria. Results: The survey created a database of 375 entries, 127 for mTBI and 248 controls (no history of mTBI). Within these groups the proportion of individuals experiencing PCS symptoms was not statistically different (39% for mTBI, 32% for control; Chi squared p¼0.2), and there was no group difference for the RPQ, HADS or ESS. However, respondents with a history of mTBI showed significantly higher CFQ scores (p<0.001) than controls. In contrast, when split by PCS diagnosis, those with PCS revealed significantly greater scores for all questionnaires p<0.001). When split into subgroups (mTBI+PCS, mTBI-PCS, Control+PCS, Control-PCS), a similar pattern was observed. The two groups with PCS both had greater scores for the RPQ, CFQ and HADS than both groups without PCS (p<0.005). There was only one difference when comparing the two groups with mTBI to those without (CFQ: mTBI+PCS greater than Control+PCS (p<0.05)). The ESS score for ControlþPCS was greater when compared to both groups without PCS (mTBI-PCS (p<0.01); Control-PCS (p<0.005)). Conclusions: The study suggests that PCS is equally common in a self-selected sample of persons with and without brain injury. Data on depression, anxiety, cognitive failures and daytime sleepiness scores show no increase in those with mTBI, but are significantly higher in those with PCS. Analysis of the four subgroups revealed no interaction between mTBI and PCS. This suggests that PCS is associated with but not specific to mTBI, as it is observed in the general population in similar proportions. It is worth considering how the presence of PCS in the control group may affect the data when designing prospective experiments. In addition to depression, anxiety and cognitive failures, this study suggests that those with PCS experience greater daytime sleepiness, a possible direction for future research.