Oral motor function is associated with pharyngeal residue in isolated parietal lobe stroke after cognitive adjustment

Abstract Swallowing impairment after parietal lobe stroke remains poorly characterized, and oral hesitation has traditionally been attributed to cognitive dysfunction. We examined the relationship between oral motor function, oral hesitation, and pharyngeal residue in patients with isolated parietal lobe stroke, after adjustment for global cognition, and tested whether these associations differed between hemispheres. In this retrospective study, 204 patients with isolated parietal lobe stroke underwent videofluoroscopic swallowing studies and Clinical Dysphagia Scale (CDS) scoring, with cognition assessed by the Mini-Mental State Examination (MMSE). Partial Spearman correlations adjusting for MMSE were calculated between oral motor components and swallowing outcomes (pharyngeal residue and oral hesitation), with Benjamini–Hochberg false discovery rate (FDR) correction. Hemispheric differences were evaluated using a formal side × predictor interaction test. Chewing and mastication were associated with vallecular residue (ρ = 0.265), pyriform residue (ρ = 0.214), and oral hesitation (liquid ρ = 0.172; semisolid ρ = 0.220), all remaining significant after FDR correction. MMSE was not correlated with oral hesitation, and hesitation prevalence did not differ between cognitively impaired and normal groups. Oral hesitation during semisolid—but not liquid—swallowing was associated with vallecular residue (ρ = 0.157, p = 0.028). The formal side × predictor interaction was non-significant for all outcomes, providing no evidence of hemispheric lateralization. In isolated parietal lobe stroke, impaired chewing is associated with pharyngeal residue and oral hesitation after adjustment for global cognition, consistently across both hemispheres. These findings support multi-consistency swallowing assessment that extends beyond cognitive screening.