Severe disinhibition due to injuries of neural tracts related to emotion circuit in a patient with traumatic brain injury: A case report

RATIONALE: Approximately 30% of patients with traumatic brain injury (TBI) develop disinhibition, a condition that involves several brain structures, including the amygdala, orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC). Using diffusion tensor tractography (DTT), we report on a patient with severe disinhibition and injuries of the amygdala, OFC, and ACC following TBI. PATIENT CONCERNS: A 27-year-old male patient suffered an in-car accident. DIAGNOSES: Since the onset of the TBI, the patient showed severe disinhibition including violence, as follows: 1) he sometimes attacked therapists and nurses with no provocation, 2) while he was laying on a bed, he shouted and kicked the bed when asked questions, and 3) during therapy with a difficult task, he behaved violently to a therapist. The subscale of disinhibition in Neuropsychiatric Inventory scored three points for severity and for distress. INTERVENTIONS: N/A. Outcomes: On 10-month DTT, the connectivity of amygdala to the prefrontal cortex including the medial prefrontal cortex and OFC had decreased in both hemispheres. In the prefronto-thalamic tracts, the orbitofronto-thalamic tractshad narrowed (the right hemisphere), and were non-reconstructed (the left hemisphere). Discontinuations of both anterior cingulums were observed in both hemispheres. LESSONS: Using DTT, concurrent injuries of the amygdala, OFC, and ACC were demonstrated in a patient with severe disinhibition following TBI. Our result suggests the need to assess these neural structures in patients with disinhibition after brain injury.