Apathy-a lack of motivation, interest and self-initiation-is a common symptom after moderate and severe traumatic brain injuries. Apathy is not easy to diagnose because it can be easily misinterpreted as depression or fatigue, both of which are also common after a brain injury.
Researchers have thought that apathy after a brain injury is the result of damage to white matter connections between certain areas of the brain. Some case studies have found that apathy may also be related to damage to the insula, an area found deep in the brain.
A recent study of veterans who experienced a penetrating brain injury used a comprehensive brain mapping analysis to further pinpoint the areas of the brain associated with apathy, in order to better understand and diagnose the disorder. They found that the left middle, superior and inferior frontal lobe; the supplementary motor area of the frontal lobe, the anterior cingulate cortex, and the insula were significantly associated with apathy.
Damage to white matter connections were also associated with apathy, as previously found, but the study determined that white matter connections specific to areas closest to the anterior cingulate cortex had the most significant association. There was no correlation between overall brain volume loss and apathy.
This study may help determine when post-traumatic symptoms are a result of apathy, or a different disorder, which will help clinicians provide the most appropriate treatments.
Knutson KM, Monte OD, Raymont V, et al. Neural correlates of apathy revealed by lesion mapping in participants with traumatic brain injuries. Human Brain Mapping. (March 2014).