Abnormal patterns of breathing during swallowing in neurological disorders

Swallowing momentarily inhibits breathing, and normally the great majority of apnoeas which accompany a swallow are followed by expiration (xE swallow s), This swallowing-breathing interaction is regarded as one of several mec hanisms by which the airway is protected from aspiration during swallowing. The purpose of this study was to investigate the interaction of breathing and swallowing in two groups of neurological patients. Twenty-two patients with defined neurological disorders involving various structures or pathway s (brain, spinal cord and peripheral nerves) were studied to determine whet her particular lesions resulted in breakdown of the normal breathing patter n (22 normal subjects were also assessed and their breathing-swallowing pat tern was compared with that of neurological patients). Subsequently, 32 pat ients with motor neurone disease (MND) were studied to identify factors ass ociated with an abnormal pattern (i.e. swallow apnoeas followed by inspirat ion) and to clarify whether an abnormal pattern is related to chest infecti ons, episodes of coughing and choking during meals, and prognosis. The swal low apnoea in patients with brain, spinal cord and peripheral neurological diseases was followed by inspiration more frequently than expected [20/22 ( 91%) patients compared with 2/22 (9%) of normal subjects, P < 0.001], but t his was not associated with a specific site of lesion(s), However, patients with corticobulbar involvement tended to have post-apnoea inspiration more often than those without. MND patients commonly displayed an abnormal patt ern during swallowing [14/32 (44%) patients] characterized by inspiration a fter swallow, prolonged swallow apnoea and multiple swallows per bolus, Ove r the period of follow-up (12-18 months) this pattern did not predict chest infections, coughing and choking episodes during meals or survival. It see ms likely that post-swallowing apnoea inspiration is a non-specific concomi tant of disordered swallowing and/or breathing rather than being an importa nt mechanism of aspiration per se or of symptom production.