Lesion-Specific Clinical Implications of Oral Hesitation After Stroke: A Comparative Study of Frontal Versus Parietal...

Background and Objectives: Whether post-stroke oral hesitation carries different clinical implications by lesion location is unclear. We compared oral hesitation and its relationship with chewing, cognition, and aspiration risk between frontal and parietal lobe stroke. Materials and Methods: We retrospectively analyzed 242 patients (35 frontal, 207 parietal) from 946 consecutive stroke admissions (2016-2020) with isolated lesions and videofluoroscopic swallowing study within one month. Oral hesitation, chewing, Clinical Dysphagia Scale (CDS), and Mini-Mental State Examination (MMSE) were recorded. Penetration-Aspiration Scale (PAS) scores were categorized as Normal (1), Penetration (2-5), or Aspiration (6-8). Multivariable logistic regression adjusting for age, sex, stroke type, and lesion side was performed. Firth's penalized estimation was used for models with quasi-separation. Results: Groups were demographically comparable in age (68.1 ± 15.0 vs. 71.7 ± 12.2 years; p = 0.206) and female sex (48.6% vs. 42.0%; p = 0.590). Oral hesitation was significantly more prevalent in the frontal group (liquid: 80.0% vs. 23.2%, p < 0.001; semisolid: 68.6% vs. 26.6%, p < 0.001). Frontal patients scored worse on six of seven CDS subcomponents (p < 0.01), yet chewing was uncorrelated with oral hesitation or residue (p > 0.3), unchanged after MMSE adjustment. In parietal patients, chewing correlated with all outcomes (ρ = 0.19-0.30, p < 0.01). In parietal stroke, oral hesitation was linked with liquid aspiration (64.3% vs. 35.7%; OR = 3.25, p = 0.001) and semisolid airway invasion (OR = 2.70, p = 0.005); these associations remained significant after multivariable adjustment and FDR correction. No such association was detected in the frontal group, although this finding is limited by the smaller sample size. Conclusions: Oral hesitation may carry different clinical implications by lesion site. In parietal stroke, it was associated with chewing impairment and higher aspiration risk, suggesting a possible sensorimotor contribution. Frontal group findings were underpowered and should be considered exploratory. Lesion-specific interpretation warrants larger-cohort confirmation.