Objective To determine correlations of alternation motor rate (AMR), sequential motor rate (SMR), and maximum phonation time (MPT) with the severity of dysphagia in subacute stroke patients.Methods This was a retrospective chart review study. Data of 171 subacute stroke patients were analyzed. Patient’s AMR, SMR, and MPT data were collected from their language evaluations. Video fluoroscopic swallowing study (VFSS) was done. Data of dysphagia scales including penetration-aspiration scale (PAS), American Speech-Language-Hearing Association National Outcomes Measurement System (ASHA-NOMS) scale, clinical dysphagia scale (CDS), and videofluoroscopic dysphagia scale (VDS) were obtained. AMR, SMR, and MPT were compared between a non-aspirator group and an aspirator group. Correlations of AMR, SMR, and MPT with dysphagia scales were analyzed.Results AMR ("ka"), SMR, and modified Rankin Scale were significant associated factors between non-aspirator group and aspirator group, while AMR ("pa"), AMR ("ta"), and MPT were not. AMR, SMR, and MPT showed significant correlations with PAS score, ASHA-NOMS scale, CDS, VDS oral, and VDS pharyngeal scores. The cut-off value for distinguishing non-aspirator group and aspiration group was 18.5 for AMR ("ka") (sensitivity of 74.4%, specificity of 70.8%) and 7.5 for SMR (sensitivity of 89.9%, specificity of 61.0%). AMR and SMR were significantly lower in before-swallow aspiration group.Conclusion Articulatory diadochokinetic tasks that can be easily performed at the bedside would be particularly helpful in determining the oral feeding possibility of subacute stroke patients who cannot undergo VFSS, which is the gold standard for dysphagia assessment.

Background and Objectives: Comparisons of swallowing physiology between coronavirus disease 2019 (COVID-19) pneumonia and clinically diagnosed aspiration pneumonia (AP) have largely relied on ordinal scales, leaving etiology-specific biomechanical profiles unclear. We quantitatively compared videofluoroscopic swallowing study (VFSS) measures of pharyngeal residue and clearance mechanics to identify differential dysphagia phenotypes. Materials and Methods: This single-center retrospective cohort study included 50 adult inpatients with pneumonia (COVID-19, n = 25; AP, n = 25) who underwent VFSS for suspected dysphagia. COVID-19 pneumonia was laboratory-confirmed, and AP was clinically diagnosed after negative tests for severe acute respiratory syndrome coronavirus 2. Blinded ImageJ analysis examined the first standardized semisolid yogurt swallow (International Dysphagia Diet Standardisation Initiative level 4). Primary outcomes were Normalized Residue Ratio Scale values for the valleculae (NRRSv) and piriform sinuses (NRRSp); secondary outcomes were upper esophageal sphincter (UES) opening width and epiglottic rotation angle. Penetration–Aspiration Scale (PAS) score, hyoid displacement, and pharyngeal transit time were exploratory. Results: Baseline characteristics were comparable. COVID-19 pneumonia showed higher NRRSv (0.20 [0.12–0.56] vs. 0.13 [0.00–0.20]; p = 0.01). NRRSp was numerically higher but not statistically significant (0.12 [0.00–0.43] vs. 0.00 [0.00–0.17]; p = 0.07). COVID-19 pneumonia also showed smaller UES opening width (5.08 ± 2.48 vs. 6.50 ± 2.01 mm; p = 0.03) and reduced epiglottic rotation angle (66.0 [29.0–80.8] vs. 93.4 [74.2–100.4] degrees; p = 0.04). No statistically significant between-group difference was detected in PAS-defined airway invasion severity on the standardized semisolid task. Conclusions: These findings suggest an efficiency-predominant dysphagia phenotype in COVID-19 pneumonia, characterized by greater vallecular residue and restrictive clearance-related mechanics on a standardized semisolid task. The results indicate that PAS-defined safety metrics alone may underestimate residue-related dysphagia burden in this population.