Last year, I told my neuro about my memory and word recall problems. He had me to a neuropsych test. The psychologist told me that b/c I don't have lesions in my brain, the cause for my cognitive problems is b/c I have stress.
Did he scan for lesions in your grey matter as well? Most MS scans are done looking in the white matter. As well, lesions can come and go on their own so to say that because he didn't find any lesions with one scan, your cognitive problems are stress relate is kind of a brush off.
I'd strongly suggest you get a second opinion on this.