Evidence regarding cognitive impairment following concussion/mild traumatic brain injury (mTBI) has been conflicting. Criticism has focused on what is being measured, how it is being measured, and who is being measured (Pertab et al, 2009; Iverson, 2010). However, literature suggests that clinicians and researchers should examine how individuals complete a task rather than what they achieve (Geary et al, 2011). Studies examining the drawing process used to complete the Rey-Osterrieth Complex Figure Task (RCF) have been inconclusive and methodologically weak. The current study addressed several criticisms and limitations by examining whether observing RCF drawing process, including a novel strategy construct, could support a diagnosis of persisting post-concussive symptoms.

Sixteen individuals with a history of concussion/mTBI and sixteen matched controls (age, sex, IQ) were included in multiple regression analyses to examine whether RCF drawing constructs predict post-concussive symptoms (mean age 43.59 years; 22 female). At least 3 months had passed since the concussive/mTBI event. Post-concussive symptoms were assessed with the Rivermead Post-Concussive Symptoms Questionnaire (RPCSQ) and the Mental Fatigue Scale (MFS). Separate regression analyses were conducted for each scale. Predictor variables were statistically selected from a catalogue of 4 RCF drawing process constructs - Wholeness, Order, Continuation and Strategy; 15 traditional measures of cognitive function; and 3 psychological state measures. 17 variables were included in the model for the RPCSQ, including Order and Strategy. 18 variables were included for the MFS, including Order, Continuation and Strategy.

Order scores were found to be one of the strongest predictors of RPCSQ scores (B = -2.06; ß= 0.20), and MFS scores (B = -1.54, ß = 0.26). Individuals drawing fewer core elements at the start of the drawing process were found to report more post-concussive symptoms. Participants who observed a stronger temporal-spatial strategy heuristic, as measured by the Strategy construct, reported more symptoms, particularly mental fatigue (RPCSQ: B = 0.49, ß = 0.09; MFS: B = 0.58, ß = 0.19). Continuation was also found to be predictive of MFS scores (B = -0.24, ß = -0.14), such that the fewer continuation points that were observed, the greater the MFS score.

Two constructs of RCF drawing process - Order and Strategy - were found to predict persisting post-concussive symptoms generally, and mental fatigue specifically. Continuation was also found to predict mental fatigue. Such findings provide a cognitive explanation for patient reports of mental fatigue following concussion - recognised as the most common and persistent symptom. Strict adherence to a temporal-spatial strategy may indicate cognitive inflexibility - a theory supported by the inclusion and influence of other cognitive tasks in the regression models that rely on cognitive flexibility. Individuals exert more effort to shift between perceptual planes and to override global bias, thereby expending cognitive resources more quickly and to a greater extent. These findings provide a credible explanation for the lack of evidence of cognitive impairments in previous research, where neuropsychological tasks focus on attainment rather than process. These findings highlight the clinical importance of assessing cognitive dysregulation, specific cognitive processes and cognitive deficits post-concussion/mTBI.