Base rates of post-concussional symptoms.

Several cognitive, physical and psychological symptoms have been reported as common sequelae of head injury. However, these data have been reported largely in absence of established base rates. This study employed self-report and relative report questionnaires to assess base rates of these symptoms in uninjured subjects. Chi square analysis was used to compare the rate of symptoms reported by head injured subjects, relatives of head injured subjects, uninjured subjects and relatives of uninjured subjects. In most cases, no significant difference was found between the symptoms reported by the head injured group and the uninjured group. These results demonstrate the importance of establishing base rates of symptoms in non-clinical populations prior to drawing conclusions about symptoms in clinical populations.