Concussion and Dementia

Why don’t doctors look at studies; I have have been diagnosed with dementia and had multiple bad concussion and my doctors state they are not related. I even had my head split open where a finger was able to fit in the opening and the doctors state this would not relate to dementia. I keep seeing studies where concussion do raise the risk of early on-site of dementia. I was 57 when I was told I had dementia; I am now 63 and it is still getting worse.