Aging Related Cognitive Decline

The goal of this clinical trial is to learn if combining brain stimulation with cognitive training can improve thinking skills in older adults who have had a traumatic brain injury (TBI). The main questions are: * Does transcranial direct current stimulation (tDCS) make cognitive training more effective for improving attention, memory, and decision-making? * Is this type of home-based program feasible and acceptable for older adults with TBI? Researchers will compare two groups: one group will receive active tDCS during cognitive training, and the other group will receive sham (placebo) tDCS during cognitive training. Participants will: * Complete computer-based cognitive training exercises (BrainHQ) to practice attention, memory, and decision-making. * Receive either active or sham tDCS during training sessions. * Complete assessments before and after the program to measure changes in thinking and daily functioning.