For the treatment arm, the participants will complete the intervention protocol following the first in-person study visit 7 months post-injury. The intervention involves 16 weeks of online, in-home spatial navigation training. During the 16 weeks, the participant will complete exercises for 1 hour/day, 5 days a week.

The control arm participants will receive their typical standard of care; they will not complete the intervention but will complete all of the in-person visits at the same post-injury time-points as the treatment group.

Participants complete training tasks that test their spatial navigational abilities, cognitive map formation, and pattern separation. These training tasks involve map drawing, vector mapping, proximity judgments, and navigating with blocked routes.

Participants complete online spatial navigation training 5 days per week for 16 weeks. Improvement in spatial learning ability will be assessed based on the accuracy of answers to questions regarding the reproduction of spatial elements, the direction and proximity of certain landmarks, and describing the most efficient route from point A to point B. Improvement will be assessed at the end of each week and at the end of the intervention. The raw scores range from 0-15, with higher scores indicating better spatial learning ability.

Participants complete online spatial navigation training 5 days per week for 16 weeks. Improvement in cognitive map formation will be assessed based on the number of trails required by the participant to learn landmark placements and based on the accuracy of the participant's navigation to a specific destination. The raw scores range from 1-21 and 0-10, respectively. A decrease in the number of trials required by the participant and an increase in navigation accuracy both correspond to an improvement in cognitive map formation.

Measurement of pattern separation abilities are assessed in a task requiring the participant to differentiate memories in order to prevent interference from overlapping details. The following three variables are taken into account: i) percent correct ii) the discriminating value and iii) bias metric. Percent correct and bias metric are given as a percentage values (e.g., 80.63%) and the discriminating variable is given as a raw rate (e.g., 0.67). An improvement in pattern separation abilities are determined by an increase in percent correct and discrimination values from pre- to post-intervention. An increase in bias metric from pre- to post-intervention reflects an increased tendency for pattern separation.

The investigators will be analysing biomarkers in serum and plasma samples in relation to traumatic brain injuries. This will allow the investigators to generate hypotheses concerning the relationship between blood biomarkers and neuronal injury. Serum neurofilament light chains (NF-L), total tau, amyloid β-40 and amyloid β-42 will be assayed using Quanterix reagents on the Simoa HD-1 platform.