Community versus orthopaedic controls in traumatic brain injury research: how comparable are they?

Community (CC) or orthopaedic/injury (OC) control groups are typically used to evaluate the consequences of traumatic brain injuries (TBIs). Whereas CCs match for demographic variables and are readily available, OCs may additionally control for other pre- and post-injury variables but are more costly to recruit. Together, they enable an evaluation of brain- vs general-injury effects. However, the comparability of these two groups and the increase in control over confounding variables when OCs are used has rarely been examined.

The current study compared samples of CCs (n = 71) and OCs (n = 69), aged between 18-80, on a range of demographic (age, gender, education, socio-economic status), background (medical history, handedness), psychosocial (alcohol use, fatigue, pain, depression, social support, community integration, 'post-concussion' symptoms) and cognitive (motor and processing speed, memory, intellectual ability) variables.

The two groups were comparable on all variables, except alcohol use, with the OC group having higher levels of alcohol consumption. However, alcohol use did not correlate with any other variable, including commonly used measures of outcome following TBI.

The current findings suggest that an orthopaedic injury control group does not have any clear advantages over a carefully recruited community control group.