Development of a Novel Prognostic Model to Predict 6-Month Swallowing Recovery After Ischemic Stroke

Abstract

Background and Purpose— The aim of this study was to explore clinical and radiological prognostic factors for long-term swallowing recovery in patients with poststroke dysphagia and to develop and validate a prognostic model using a machine learning algorithm. Methods— Consecutive patients (N=137) with acute ischemic stroke referred for swallowing examinations were retrospectively reviewed. Dysphagia was monitored in the 6 months poststroke period and then analyzed using the Kaplan-Meier method and Cox regression model for clinical and radiological factors. Bayesian network models were developed using potential prognostic factors to classify patients into those with good (no need for tube feeding or diet modification for 6 months) and poor (tube feeding or diet modification for 6 months) recovery of swallowing function. Results— Twenty-four (17.5%) patients showed persistent dysphagia for the first 6 months with a mean duration of 65.6 days. The time duration of poststroke dysphagia significantly differed by tube feeding status, clinical dysphagia scale, sex, severe white matter hyperintensities, and bilateral lesions at the corona radiata, basal ganglia, or internal capsule (CR/BG/IC). Among these factors, tube feeding status ( P <0.001), bilateral lesions at CR/BG/IC ( P =0.001), and clinical dysphagia scale ( P =0.042) were significant prognostic factors in a multivariate analysis using Cox regression models. The tree-augmented network classifier, based on 10 factors (sex, lesions at CR, BG/IC, and insula, laterality, anterolateral territory of the brain stem, bilateral lesions at CR/BG/IC, severe white matter hyperintensities, clinical dysphagia scale, and tube feeding status), performed better than other benchmarking classifiers developed in this study. Conclusions— Initial dysphagia severity and bilateral lesions at CR/BG/IC are revealed to be significant prognostic factors for 6-month swallowing recovery. The prediction of 6-month swallowing recovery was feasible based on clinical and radiological factors using the Bayesian network model. We emphasize the importance of bilateral subcortical lesions as prognostic factors that can be utilized to develop prediction models for long-term swallowing recovery.

Role of bilateral corticobulbar tracts in dysphagia after middle cerebral artery stroke

“…This result suggests that disruption of the integrity of the corticobulbar tract may contribute to the occurrence of post-stroke dysphagia. Several lesions, including those to the frontal operculum, insular cortex, corona radiata, internal capsule and basal ganglia, are associated with poststroke dysphagia [6,[9][10][11], and these cortical and subcortical structures are often damaged after MCA stroke. However, determining the extent of damage to the corticobulbar tract based on information on the lesion gleaned from conventional neuroimages is difficult.…”

“…Several studies using conventional structural images have revealed that a bi‐hemispheric stroke affects the occurrence or recovery of dysphagia. Bilateral lesions of the basal ganglia, corona radiata and internal capsule were poor prognostic indicators of dysphagia recovery [11]. Leukoaraiosis involving the unaffected corticobulbar tract was an independent predictor of dysphagia in patients with a unilateral corona radiata infarction [22].…”

“…Lesions of the frontal operculum, insular cortex, corona radiata, internal capsule and basal ganglia cause post-stroke dysphagia [6,[9][10][11] and are often associated with middle cerebral artery (MCA) stroke.…”

“…Lesions of the frontal operculum, insular cortex, corona radiata, internal capsule and basal ganglia cause post‐stroke dysphagia [6,9–11] and are often associated with middle cerebral artery (MCA) stroke. However, solely identifying lesion location related to dysphagia is insufficient in explaining the injury and recovery mechanisms of post‐stroke dysphagia.…”

Role of rs6265 BDNF polymorphisms and post‐stroke dysphagia recovery—A prospective cohort study

“…Also, stroke prevalence is high in the elderly. Old age has been implicated as a poor prognostic factor for poor swallowing recovery 22 . Therefore, one could hypothesize that the SNPs that have been already implicated in increasing the risk of dysphagia in the elderly would also negatively affect the post‐stroke outcome in swallowing.…”