Aim: To determine the prevalence of drooling, swallowing, and feeding problems in persons with cerebral palsy (CP) across the lifespan.Method: A systematic review was conducted using five different databases (AMED, CINAHL, Embase, MEDLINE, and PubMed). The selection process was completed by two independent researchers and the methodological quality of included studies was assessed using the STROBE and AXIS guidelines. Meta‐analyses were conducted to determine pooled prevalence estimates of drooling, swallowing, and feeding problems with stratified group analyses by type of assessment and Gross Motor Function Classification System level.Results: A total of 42 studies were included. Substantial variations in selected outcome measures and variables were observed, and data on adults were limited. Pooled prevalence estimates determined by meta‐analyses were as high as 44.0% (95% confidence interval [CI] 35.6–52.7) for drooling, 50.4% (95% CI 36.0–64.8) for swallowing problems, and 53.5% (95% CI 40.7–65.9) for feeding problems. Group analyses for type of assessments were non‐significant; however, more severely impaired functioning in CP was associated with concomitant problems of increased drooling, swallowing, and feeding.Interpretation: Drooling, swallowing, and feeding problems are very common in people with CP. Consequently, they experience increased risks of malnutrition and dehydration, aspiration pneumonia, and poor quality of life.What this paper adds: Drooling, swallowing, and feeding problems are very common in persons with cerebral palsy (CP). The prevalence of drooling, swallowing, and feeding problems is 44.0%, 50.4%, and 53.5% respectively. There are limited data on the prevalence of drooling, swallowing, and feeding problems in adults. Higher Gross Motor Function Classification System levels are associated with higher prevalence of drooling, swallowing, and feeding problems. There is increased risk for malnutrition, dehydration, aspiration pneumonia, and poor quality of life in CP.

This review presents a current synopsis of newer research in cortical control of swallowing and its relationship to advancing knowledge in the field of human swallowing neurophysiology. The intent is to highlight recent findings and to stimulate potential research questions not yet investigated. Advances in human brain imaging have led to a wealth of newer insights into the cortical and subcortical control of human swallowing. This includes a better understanding of the hemispheric contributions to swallowing control and the mechanisms that underlie recovery or compensation after neurological injury. Through advances in imaging and neuroimaging techniques, our knowledge of the neuroanatomy and physiology of swallowing has increased dramatically over the last decade. Integration and interconnection of the diverse swallowing cortical network and how sensory input influences swallowing cortical activation has started to provide a better understanding of the physiological mechanisms that underpin this exquisite yet fundamental sensorimotor function. Experimental paradigms for swallowing neural reorganization have begun to provide evidence for their translation into clinical practice for dysphagia rehabilitation.

Swallowing problems following stroke may result in increased risk of aspiration pneumonia, malnutrition, and dehydration. Our hypothesis was that three neurostimulation techniques would produce beneficial effects on chronic dysphagia following stroke through a common brain mechanism that would predict behavioral response. In 18 dysphagic stroke patients (mean age: 66 ± 3 years, 3 female, time-post-stroke: 63 ± 15 weeks [±SD]), pharyngeal electromyographic responses were recorded after single-pulse transcranial magnetic stimulation (TMS) over the pharyngeal motor cortex, to measure corticobulbar excitability before, immediately, and 30 min, after real and sham applications of neurostimulation. Patients were randomized to a single session of either: pharyngeal electrical stimulation (PES), paired associative stimulation (PAS) or repetitive TMS (rTMS). Penetration-aspiration scores and bolus transfer timings were assessed before and after both real and sham interventions using videofluoroscopy. Corticobulbar excitability of pharyngeal motor cortex was beneficially modulated by PES, PAS and to a lesser extent by rTMS, with functionally relevant changes in the unaffected hemisphere. Following combining the results of real neurostimulation, an overall increase in corticobulbar excitability in the unaffected hemisphere (P = .005, F1,17 = 10.6, ANOVA) with an associated 15% reduction in aspiration (P = .005, z = -2.79) was observed compared to sham. In this mechanistic study, an increase in corticobulbar excitability the unaffected projection was correlated with the improvement in swallowing safety (P = .001, rho = -.732), but modality-specific differences were observed. Paradigms providing peripheral input favored change in neurophysiological and behavioral outcome measures in chronic dysphagia patients. Further larger cohort studies of neurostimulation in chronic dysphagic stroke are imperative.

Background & Aims Patients with stroke experience swallowing problems (dysphagia); increased risk of aspiration pneumonia, malnutrition, and dehydration; and have increased mortality. We investigated the behavioral and neurophysiological effects of a new neurostimulation technique (paired associative stimulation [PAS]), applied to the pharyngeal motor cortex, on swallowing function in healthy individuals and patients with dysphagia from stroke. Methods We examined the optimal parameters of PAS to promote plasticity by combining peripheral pharyngeal (electrical) with cortical stimulation. A virtual lesion was used as an experimental model of stroke, created with 1-Hz repetitive transcranial magnetic stimulation over the pharyngeal cortex in 12 healthy individuals. We tested whether hemispheric targeting of PAS altered swallowing performance before applying the technique to 6 patients with severe, chronic dysphagia from stroke (mean of 38.8 ± 24.4 weeks poststroke). Results Ten minutes of PAS to the unlesioned pharyngeal cortex reversed (bilaterally) the cortical suppression induced by virtual lesion (lesioned: F_1,9 = 21.347, P = .001; contralesional: F_1,9 = 9.648, P = .013; repeated-measures analysis of variance) compared with sham PAS. It promoted changes in behavior responses measured with a swallowing reaction time task (F_1,7 = 21.02, P = .003; repeated-measures analysis of variance). In patients with chronic dysphagia, real PAS induced short-term bilateral changes in the brain; the unaffected pharyngeal cortex had increased excitability (P = .001; 95% confidence interval, 0.21–0.05; post hoc paired t test) with reduced penetration-aspiration scores and changes in swallowing biomechanics determined by videofluoroscopy. Conclusions The beneficial neurophysiological and behavioral properties of PAS, when applied to unlesioned brain, provide the foundation for further investigation into the use of neurostimulation as a rehabilitative approach for patients with dysphagia from stroke.