title: Base rate of post-concussion symptoms among normal people and its neuropsychological correlates.
abstract: 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.
  
  
  METHODS
  A cross-sectional study.
  
  
  METHODS
  A total of 85 participants without head injury, other identifiable neurological diseases or psychiatric diseases were recruited.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Psychiatry, University of Hong Kong, China. ckrchan@graduate.hku.hk
authors.forename: R C
authors.initials: RC
authors.lastname: Chan
mesh_terms: D000328:Adult; D001924:Brain Concussion / Q000175:diagnosis* / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values