Clinical predictors and neural correlates for compromised swallowing safety in Huntington disease

Dysphagia is one of the most common and important complications in Huntington disease (HD), frequently leading to aspiration pneumonia and mortality. Objective estimates of prevalence using instrumental diagnostics and data on neural correlates of dysphagia in HD are scarce or lacking entirely. Similarly, its correlation with other clinical markers is still not fully known. We aimed at defining clinical risk factors and neural correlates for compromised swallowing safety in HD more precisely.

Thirty-four HD subjects (16 female, Shoulson & Fahn Stage I-IV, two premanifest) underwent a full clinical-neurological examination including the cranial nerves, the Unified Huntington's Disease Rating Scale total motor score, and the Mini-Mental State Examination. Fiberoptic endoscopic evaluation of swallowing (FEES) was performed by a trained speech and language therapist. Twenty-six subjects additionally underwent a high-resolution anatomical magnetic resonance imaging (MRI) scan (T1, 3-T Siemens Prisma). Moreover, we correlated clinical and atrophy (MRI) measures with swallowing safety levels as judged by the validated Penetration-Aspiration Scale.

FEES showed penetration or aspiration in 70.6%. Using partial correlation, no significant correlations were found between swallowing safety and any of the clinical markers after correcting for disease duration and CAG repeat length. Voxel-based morphometry demonstrated atrophy associated with compromised swallowing safety in a network of parietothalamocerebellar areas related to sensorimotor communication, notably excluding striatum.

Our results characterise dysphagia in HD as a disorder of communication between sensory and motor networks involved in swallowing. This finding and high rates of silent aspiration argue in favor of instrumental swallowing evaluation early in the disease.