Base rate of post-concussion symptoms among normal people and its neuropsychological correlates.

OBJECTIVE: To explore the base rate of symptoms similar to those of post-concussion symptoms (PCS) among a group of participants without head injury. The effect of subjective complaints upon cognitive functioning was also examined.
DESIGN: A cross-sectional study. PARTICIPANTS: A total of 85 participants without head injury, other identifiable neurological diseases or psychiatric diseases were recruited. OUTCOME MEASURES: These included Rivermead Post-concussion Symptoms Checklist, Cognitive Failures Questionnaire, Colour Trails Test, Stroop Word-Colour Test, Paced Auditory Serial Addition Test, Symbol Digits Modality Test, Word Fluency Test, Design Fluency Test, Digits Forward and Backward Span Test, and Modified Six Elements Test.
RESULTS: A relatively high proportion of the participants reported symptoms similar to those of patients with PCS. These included longer time to think (65.9%), forgetfulness (58.9%), poor concentration (58.9%), fatigue easily (53.5%), and sleep disturbances (50.6%). Gender effect was not significant for either the individual item or the total score of the Rivermead Post-concussion Symptoms Checklist. Moreover, there was no difference found between low symptom reporters and high symptom reporters in terms of attention, working memory, mental fluency, and strategy allocation.
CONCLUSION: The base rates of symptoms were consistent with previous studies among the nonclinical groups. However, persons reporting a high score of concussion-like symptoms did not perform less well than those reporting a low score of symptoms in attention, working memory, mental fluency and strategy allocation.