It could be true. Note that some folks are gluten-sensitive but not celiac, which may not have been studied.

Check this out regarding CD and gluten:
https://pubmed.ncbi.nlm.nih.gov/32088203/
Other diseases seem to affect white matter too:

Correlation between White Matter Hyperintensities Related Gray Matter Volume and Cognition in Cerebral Small Vessel Disease.
Wang Y, Yang Y, Wang T, Nie S, Yin H, Liu J.
J Stroke Cerebrovasc Dis. 2020 Dec;29(12):105275. doi: 10.1016/j.jstrokecerebrovasdis.2020.105275. Epub 2020 Sep 6.
PMID: 32992182
Relationship between neuropsychological impairment and grey and white matter changes in adult-onset myotonic dystrophy type 1.
Baldanzi S, Cecchi P, Fabbri S, Pesaresi I, Simoncini C, Angelini C, Bonuccelli U, Cosottini M, Siciliano G.
Neuroimage Clin. 2016 Jun 15;12:190-7. doi: 10.1016/j.nicl.2016.06.011. eCollection 2016.
PMID: 27437180 Free PMC article.
A Diffusion Tensor Imaging Study on White Matter Abnormalities in Patients with Type 2 Diabetes Using Tract-Based Spatial Statistics.
Xiong Y, Sui Y, Xu Z, Zhang Q, Karaman MM, Cai K, Anderson TM, Zhu W, Wang J, Zhou XJ.
AJNR Am J Neuroradiol. 2016 Aug;37(8):1462-9. doi: 10.3174/ajnr.A4740. Epub 2016 Mar 17.
PMID: 26988810

Thank you so much!!

Is there a way to be tested for gluten sensitivity' as opposed to allergy/celiac disease? I don't have gastrointestinal problems although I do have an endoscopy and colonoscopy planned soon, so I am wondering if that might show the sensitivity. Or is there a blood test for gluten sensitivity?