Association of Dysphagia with Thalamic and Cerebellar Volumes in Alzheimer’s Disease: A Pilot MRI Study

Mihriban Güngör¹, Alper Özdemir², Cemile Özsürekçi³, Ekim Gümeler², Mustafa Levent¹, Elif Gecegelen¹, Selen Serel Arslan⁴, Numan Demir⁴, Mert Eşme¹, Cafer Balcı¹, Burcu Balam Doğu¹, Mustafa Cankurtaran¹, Meltem Gülhan Halil¹

¹Hacettepe University, Department of Internal Medicine, Division of Geriatric Medicine, Ankara, Turkey

²Hacettepe University, Department of Radiology, Ankara, Turkey

³Lokman Hekim University Hospital, Department of Internal Medicine, Division of Geriatric Medicine, Ankara, Turkey

⁴Hacettepe University, Faculty of Physical Therapy and Rehabilitation, Ankara, Turkey

 

Background:
Dysphagia is a critical geriatric syndrome in Alzheimer’s disease (AD) that significantly increases the risk of aspiration pneumonia and mortality. While cortical mechanisms have been investigated, the structural involvement of subcortical regions remains incompletely understood. This exploratory pilot study aimed to investigate the association between dysphagia and subcortical brain volumes in patients with AD.

Methods:
This retrospective cross-sectional pilot study included 21 patients with Alzheimer’s disease who underwent fluoroscopic swallowing assessment between 2016-2018. Dysphagia was defined by clinical symptoms and a Penetration-Aspiration Scale (PAS) score > 1. All patients had brain MRI scans including 3 dimensional T1weighted imaging. Analysis was performed with volbrain software (vol2brain pipeline), volumetric measurements of whole brain structures were obtained.  Subcortical brain volumes were compared between patients with and without dysphagia using analysis of covariance (ANCOVA) adjusted for age and sex.

Results:

Among 21 AD patients (mean age 78.14±6.16 years, 42.9% female), 33.3% (n=7) presented with dysphagia. The median interval between MRI and swallowing assessment was 3.3 months (interquartile range: 0.3–13.8 months). There were no significant differences in demographic characteristics between groups. Patients with dysphagia had significantly lower thalamic and cerebellar volumes compared with those without dysphagia (p=0.004 and p=0.025 respectively). After adjustment for age and sex, thalamic volume remained strongly associated with dysphagia (p<0.001), with a large effect size. In contrast, no significant differences were observed in volumes of the hippocampus (p=0.881), putamen (p=0.086), or caudate nucleus (p=0.101) between the groups.

 

Conclusion:
This exploratory retrospective pilot study demonstrates that dysphagia in AD is associated with reduced thalamic and cerebellar brain volumes. These findings suggest a potential role of thalamic and cerebellar structures in swallowing dysfunction in AD. Larger prospective studies are needed to confirm these preliminary findings.

Keywords: Alzheimer dementia, dysphagia, MRI imaging, PAS score, subcortical brain volumes

References:

1. Espinosa-Val MC, Martín-Martínez A, Graupera M, Arias O, Elvira A, Cabré M, Palomera E, Bolívar-Prados M, Clavé P, Ortega O. Prevalence, Risk Factors, and Complications of Oropharyngeal Dysphagia in Older Patients with Dementia. Nutrients. 2020 Mar 24;12(3):863. doi: 10.3390/nu12030863. PMID: 32213845; PMCID: PMC7146553.