Airway somatosensory deficits and dysphagia in Parkinson's disease

Abstract

Background: Individuals with Parkinson's disease (PD) often experience substantial impairment of swallow control, and are typically unaware of the presence or severity of their impairments suggesting that these individuals may also experience airway sensory deficits. However, the degree to which impaired swallow function in PD may relate to airway sensory deficits has yet to be formally tested.

Objective: The purpose of this study was to examine whether airway sensory function is associated with swallow impairment in PD.

Methods: Eighteen PD participants and 18 healthy controls participated in this study and underwent endoscopic assessment of airway somatosensory function, endoscopic assessment of swallow function, and clinical ratings of swallow and disease severity.

Results: PD participants exhibited abnormal airway somatosensory function and greater swallow impairment compared with healthy controls. Swallow and sensory deficits in PD were correlated with disease severity. Moreover, PD participants reported similar self-rated swallow function as healthy controls, and swallow deficits were correlated with sensory function suggesting an association between impaired sensory function and poor self-awareness of swallow deficits in PD.

Conclusions: These results suggest that control of swallow is influenced by airway somatosensory function, that swallow-related deficits in PD are related to abnormal somatosensation, and that swallow and airway sensory function may degrade as a function of disease severity. Therefore, the basal ganglia and related neural networks may play an important role to integrate airway sensory input for swallow-related motor control. Furthermore, the airway deficits observed in PD suggest a disintegration of swallow-related sensory and motor control.

Keywords: Swallow; aspiration; larynx; non-motor; penetration; protection; residue.

Fig. 1

(a) Laryngeal somatosensory function for control and PD participants. The small black filled circles represent the group means and the open circles represent individual values for each participant in mm Hg (1 mm Hg = 133.32 Pa). (b through d) Self-reported swallow severity (Sydney Swallow Questionnaire) for control and PD participants. The small black filled circles represent the group means and the open circles represent individual values for each participant in mm. (b) Total swallow severity - arrow identifies upper range of normal, (c) Item 11 (cough or choke when swallowing liquids), (d) Item 14 (need to swallow more than once). Asterisk indicates statistical significance.

Fig. 2

Endoscopic assessment of swallow function for control and PD participants. For the stacked bar graphs, individual rectangle height represents mean value for each food item. (a) Penetration/Aspiration (1 = none, 8 = silent aspiration). (b) Residue (0 = none, 1 = coating, 2 = pooling). Asterisk indicates statistical significance.