Introduction

Sialorrhoea is a common debilitating symptom in amyotrophic lateral sclerosis (ALS). It occurs when there is excessive saliva in the mouth beyond the lip margin.1 In ALS, sialorrhoea is not related to the increased production of saliva but to the impaired swallowing resulting from dysfunction of bulbar muscles.2

Swallowing requires an efficient coordination of several muscles in the mouth, pharynx, larynx and oesophagus, involved in oral, pharyngeal and oesophageal phases of the swallowing process.3 The first phase is under voluntary control, while the remaining steps are automatic.4 Spontaneous swallowing is necessary for drool control.3 Salivary secretion is regulated via a reflex arch, with the information processed in the salivary nuclei in the medulla oblongata. The afferent pathway consists of chemoreceptors in taste buds, mechanoreceptors in the periodontal ligament and afferents in the V, VII, IX and X cranial nerves. Parasympathetic efferencies enter the VII (submandibular, sublingular and minor glands) and IX cranial nerves (parotid gland).5 In bulbar patients, dysphagia, weak mouth occlusion, head drop, impaired tongue–palate coordination and swallowing reflex impairment increase the risk of sialorrhoea.6 Pharyngo-oesophageal dysfunction can lead to aspiration and the unpleasant feeling of thick saliva in the pharyngeal walls.

Excessive saliva in the mouth can cause halitosis and perioral skin erosion, which have professional and social implications.3 ,7 Increased risk of dehydration and reduced compliance with facial masks on non-invasive ventilation are relevant problems.3 ,8 Anticholinergic drugs, botulinum …