Effects of central dopaminergic stimulation by apomorphine on swallowing disorders in Parkinson's disease

Swallowing disorders are common in Parkinson's disease but are of obscure and complex nature and pathophysiology. The effect of central dopaminergic stimulation on disordered swallowing is not well known. We studied the effects of apomorphine (in combination with domperidone) on buccolinguofacial motoricity and on various swallowing stages by using videofluoroscopy in eight patients with dysphagia. Swallowing abnormalities more frequently encountered were vallecular stasis (n = 7), fragmentation of the bolus (n = 7), and buccal stagnation of the bolus. Apomorphine improved vallecular stasis and fragmentation in about half the cases and improved buccal stagnation in all cases. Direct laryngeal penetration was found in three cases and improved in two of them. The total swallowing duration was improved by apomorphine in a subset of patients (n = 5). This improvement correlated with an improvement of the buccolinguofacial motoricity and was combined with an improvement of pharyngeal transit time. Thus central dopaminergic stimulation by apomorphine improved swallowing in a subgroup of patients, mainly in its early stages.