Hello, First of let me explain you that a given medical problem can be due to various causes and the main objective of the treating doctor is to identify the exact cause/causes and deal accordingly. For example, fever can be due to viral fever, malaria, typhoid fever, tuberculosis, cancer and even AIDS can cause fever. Cognitive decline can be due to various causes too. It can be due to old head injury, brain infection etc. There are other causes of cognitive decline too which generally occur in old age, but can occur in young age also. These are Alzheimer’s disease, Fronto-temporal dementia etc. Let us see your problem. You have cognitive decline and you had history of head injury. Note that head injury can result in cognitive decline and it depends upon the severity of injury and the area of brain damaged like regional vs diffuse injury. That means the outcome of cognitive decline after head injury depends upon the severity of brain damage. Another important point which you need to note that your cognitive decline may not have any association with head injury. I understand the neuropsychological test that you have undergone. Note that these tests will tell us the area of brain damage and it will not reflect the cause. I strongly advise you to meet a local neurologist or cognitive expert who will assess you and will correlate your head injury with the current functional status. Further he will tell you if you have other problem which can account for the cognitive decline. The medicines which are taking may not help much if the problem is related to head injury. Hence you need neurological evaluation at the earliest Hope this clarifies