A 48-year-old lady suffered head trauma due to a car accident. Immediately after, the patient lost consciousness; thereafter, she experienced post-traumatic amnesia (PTA) for 10 mins.

On assessment, her Glasgow Coma Scale was 15. A diffusion tensor imaging (DTI) scan showed abnormalities – 6.9 (Fatigue Severity Scale) and 18 (Epworth Sleepiness Scale), 11 months after the accident.

The upper ascending reticular activating system (ARAS) did not show abnormalities on DTI. However, narrowing of the left dorsal lower ARAS and tearing of the left ventral lower ARAS between the pontine reticular formation (RF) and the hypothalamus were noted.

The patient was recommended for the reconstruction of the lower ARAS via probabilistic tractography. 

After this procedure, the patient was assessed after 4 months. Diffusion tensor tractography revealed that the fractional anisotropy and tract volume of the lower right ARAS reduced. After 40 months, these parameters reached close to the values of healthy subjects (within 2 SD difference). These results suggested recovery of the lower ARAS.

Sources:

Doi: 10.1097/MD.0000000000002628

DOI: 10.1097/PHM.0000000000000274