When I was 45 I developed some cognitive issues, was tested and my information processing speed was in the 8th percentile!!! I can’t imagine how this would impact a kid. It took everything I had to speak up for myself and keep my self-confidence. Lucky the neuropsychologist impressed upon me that I was “very very bright” but even then it was really hard. Especially for family members who were used to me being fast.
Source: Slow Processing Speed: How It Affects Kids in School and in Daily Life