Following a traumatic brain injury (TBI), the majority of patients report difficulties with prospective memory (PM). However, there is not always a significant relationship between subjective and objective PM measures. Several variables may influence the degree of severity of perceived difficulties, including the severity of the injury and psychoemotional status. The aim of this study was to determine whether the severity of the TBI and anxiety and depressive symptoms were related to objective and subjective difficulties of PM.

50 patients (mean age = 31,3 years old) with a TBI (20 mild and 30 moderate/severe) in the post-acute phase of recovery and 15 matched healthy control participants (mean age = 32,3 years old) were recruited. They completed inventories assessing the presence of anxiety (BAI) and depressive (BDI) symptoms and performed the Ecological test of prospective memory (TEMP), an objective measure of PM. The Comprehensive Assessment of PM (CAPM), a subjective measure of PM, was also filled out by participants and their relatives.

In patients with moderate/severe TBI, significant correlations were found between the CAPM and the BDI (r =.601, p<.001) and the BAI (r =.507, p=.004). A negative correlation was also observed between the relatives’ CAPM scores and the performance of the patients on the TEMP (r= -.374, p=.042). In patients with mild TBI, there was only a strong significant correlation between the CAPM and the BAI scores (r =.574, p=.008). However, no other correlation was significant between this group of patients and their relatives. Additionally, results on the TEMP were not significantly correlated with the CAMP completed by healthy control participants or their relatives. A linear regression conducted in the group of participants with TBI showed that BAI and BDI scores are the only significant predictors of the results on the CAPM (31% of the variance), while TBI severity is the only significant predictor of the results on the TEMP (37% of the variance).

The perception of PM difficulties in patients with a TBI does not seem to be related to their objective performance. Anxiety and depressive symptoms appear to influence their perception more than their objective performance. As suggested by their relatives, a decrease in self-awareness could explain the lack of relationship between subjective PM difficulties of patients with moderate/severe TBI and their objective performance. On the other hand, TBI severity is more strongly related to objective performance on PM tests. These results highlight the importance of using different measures to accurately assess PM and the various factors influencing this construct.