Atrophy of hypothalamic subunits in Alzheimer’s disease

Abstract Background Non‐cognitive deficits (e.g., sleep‐cycle and neuroendocrine alterations) are commonly observed in Alzheimer’s disease (AD) and are suggestive of hypothalamic (HPT) dysfunctions (Ishii and Iadecola., 2015). However, studies on the HPT involvement in the early stages of the disease are limited. Here, we compared the volumes of HPT and its subunits in cognitively unimpaired (CU), mild cognitive impairment (MCI), and AD. Method Twenty‐nine cognitively unimpaired (CU), 21 MCI, and 21 AD participants were enrolled and underwent 3T MRI and neuropsychological exams. 3D T1‐weighted images were processed using the standard FreeSurfer v7.2 pipeline, and the newly released tool for the automated segmentation of HPT and its subunits (Billot et al., 2020). After normalization to the total intracranial volume, whole and subunits HTP volumes were compared among groups using the Kruskall‐Wallis test with Dunn‐Bonferroni correction. Result MCI and AD showed lower left ( p <.001) and right ( p = .013) whole HPT volume than CU. Furthermore, lower volumes were detected in both the hemisphere for the anterior ( p <.011) and posterior ( p <.001) subunits in AD, and for right anterior posterior ( p = .025) and for the superior tubular ( p = .045) subunits in MCI, as compared with CU. No HPT differences were observed between AD and MCI patients. Conclusion Posterior HPT subunit atrophy was detectable since MCI stage and increased according to the disease progression. These results suggest a possible involvement of hypothalamus in early AD phases.