Recovery of an injured cingulum via an aberrant neural tract in a patient with traumatic brain injury

BACKGROUND We report on a patient who appeared to show recovery of an injured anterior cingulum via an aberrant neural tract between an injured cingulum and the basalis nucleus of Meynert following traumatic brain injury (TBI), which was demonstrated on diffusion tensor tractography (DTT). METHODS A 47-year-old male who had suffered a pedestrian traffic accident underwent conservative management for diffuse traumatic axonal injury. When starting rehabilitation at 6 weeks after onset, evaluation using the Mini-Mental State Examination (MMSE) could not be performed due to the severity of his cognitive dysfunction. The patient showed improvement of cognitive dysfunction on MMSE with 10 at 2 months, 13 at 6 months, and 26 at 10 months after onset. RESULTS On 6-week DTT, discontinuation superior to the genu of the corpus callosum was observed in both cingulums. However, on 6-month DTT, the discontinued anterior part of the right cingulum was elongated anteriorly, not through the cingulum, but through the anterolateral subcortical white matter of the cingulum, while on 10-month DTT, this elongated neural tract of the right cingulum was connected to the right basalis nucleus of Meynert in the basal forebrain. CONCLUSION Recovery of an injured anterior cingulum via an aberrant neural tract between an injured cingulum and Ch 4 was demonstrated in a patient with TBI. Our result appears to suggest a mechanism for recovery of an injured cingulum following brain injury.