BMJ 1997;315:569-572 (6 September)

Papers

Duration of cognitive dysfunction after concussion, and cognitive dysfunction as a risk factor: a population study of young men

Thomas W Teasdale, associate professor,a Aase Engberg, senior resident b

a Psychological Laboratory, University of Copenhagen, Njalsgade 88, DK-2300 Copenhagen S, Denmark, b Department of Neurology, Odense University Hospital, 5000 Odense C, Denmark

Correspondence to: Dr Teasdale teasdale@axp.psl.ku.dk

Objectives: To establish how long cognitive dysfunction lasts after concussion, and the extent to which it may be a predisposing risk factor for concussion, by examining the prevalence of cognitive dysfunction among young men who have sustained concussion.
Design: Observational study.
Setting: Denmark.
Subjects: 1220 young men who had been admitted to hospital for concussion between the ages of 16 and 24 (identified in a national register of admissions) and who had also been cognitively tested by the Danish conscription draft board.
Main outcome measure: Score on the draft board's cognitive screening test, dichotomised as dysfunctional or non-dysfunctional (20.4% of the general population of Danish men appearing before the draft board had a dysfunctional score).
Results: 700 of the 1220 men had been tested after sustaining concussion; 520 had been tested before concussion. Four (50%) of the eight men who were tested less than seven days after the injury had a dysfunctional score. Among groups of the remaining 692 men who were tested at later time points after injury, the rates were only marginally raised (range 21.4% to 26.5%) above the population level. Among men tested before injury, the rate of dysfunctional scores was higher (30.4% (158/520)). Apart from suggesting cognitive dysfunction as a risk factor for concussion, this higher proportion seems to relate to the fact that they were typically injured as young adults, whereas those men who were tested after concussion had more often been injured as adolescents. The relative risk for concussion in the presence of cognitive dysfunction is estimated to be 1.57 (95% confidence interval 1.32 to 1.86).
Conclusions: Cognitive dysfunction is not only a short term consequence of concussion but also a predisposing risk factor for concussion, more so for young adults than for adolescents.

Key messages

  • This study supports earlier evidence of a direct influence of concussion on cognitive function of comparatively short duration (up to 1 week)

  • Cognitive dysfunction is also a risk factor for sustaining concussion

  • The risk factor is greater among young adults than among adolescents


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Relevant Article

Cognitive dysfunction after concussion
Mark W J Strachan, Brian M Frier, Ian J Deary, Thomas W Teasdale, and Aase Engberg
BMJ 1998 316: 865. [Extract] [Full Text]

This article has been cited by other articles:

  • Teasdale, T W, Engberg, A W (2003). Cognitive dysfunction in young men following head injury in childhood and adolescence: a population study. J. Neurol. Neurosurg. Psychiatry 74: 933-936 [Abstract] [Full text]  
  • Fann, J R, Leonetti, A, Jaffe, K, Katon, W J, Cummings, P, Thompson, R S (2002). Psychiatric illness and subsequent traumatic brain injury: a case control study. J. Neurol. Neurosurg. Psychiatry 72: 615-620 [Abstract] [Full text]  
  • Teasdale, T W, Engberg, A W (2001). Suicide after traumatic brain injury: a population study. J. Neurol. Neurosurg. Psychiatry 71: 436-440 [Abstract] [Full text]  
  • FLEMINGER, S. (1998). Neuropsychiatric sequelae one year after a minor head injury. J. Neurol. Neurosurg. Psychiatry 65: 809-809 [Full text]  
  • Strachan, M. W J, Frier, B. M, Deary, I. J, Teasdale, T. W, Engberg, A. (1998). Cognitive dysfunction after concussion. BMJ 316: 865-865 [Full text]  



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