Excessive Drooling a Sign of Greater Dysfunction in Parkinson's Disease

Pauline Anderson

June 24, 2021

Excessive drooling by patients with advanced Parkinson's disease is an indicator of greater motor and nonmotor dysfunction, new research shows.

"Sialorrhea is not just a cosmetic problem," study investigator Francesca Morgante, MD, associate professor of neurology, St. George's University, London, United Kingdom, told Medscape Medical News.

"We need to understand the relationship between sialorrhea and these speech and swallowing disturbances and whether treatment for sialorrhea improves that," Morgante added.

The findings were presented at the virtual Congress of the European Academy of Neurology (EAN) 2021.

Underrecognized Symptom

Sialorrhea is an underrecognized nonmotor symptom that can affect up to 70% of patients with PD, co-investigator Ioana Cociasu, PhD, postdoctoral research fellow, Neurosciences Research Center, St. George's University, told meeting attendees. The impact on quality of life increases with disease severity, she said.

The current study included 101 consecutive patients attending an advanced PD disorders clinic. Researchers collected demographic data that included information on gender, age, age at PD onset, and disease duration.

They also gathered data on motor symptoms by assessing total levodopa equivalent daily dose (LEDD) and LEDD dopamine agonists. They also assessed results on the Unified Parkinson's Disease Rating Scale (UPDRS) part III and the Hoehn and Yahr scale for on- and off-medication states.

Nonmotor functioning was assessed using the Non-Motor Symptoms Scale (NMSS) and Scales for Outcomes in Parkinson's disease–autonomic dysfunction (SCOPA-AUT) questionnaire. Among patients with PD, autonomic dysfunction can precede motor impairment and can involve orthostatic and postprandial hypotension, among other symptoms, the investigators note.

Health status and quality of life were assessed using the Parkinson's disease questionnaire–39 items (PDQ-39). The Radboud Oral Motor Inventory for PD (ROMP) was used to measure orofacial symptoms. ROMP is a self-administered questionnaire that evaluates speech, swallowing disturbances, and drooling of saliva. The Montreal Cognitive Assessment test was also used.

Investigators compared participants with sialorrhea to those without sialorrhea, described as droolers and nondroolers. Droolers were defined as those scoring >1 on the UPDRS-II item 6. This signified slight but definite presence of saliva in the mouth and/or the possibility of nighttime drooling.

Greater Impairment

Among the participants, 65 (64.4%) were classified as droolers, and 36 (35.6%) as nondroolers.

Patients with both PD and sialorrhea were significantly more impaired in terms of motor functioning than those without sialorrhea. In these patients, the UPDRS-III was more severe in both the off- (P = .03) and on-states (P = .002), and they had less improvement with the levodopa challenge test (P = .007).

Droolers were also more severely affected by nonmotor problems. They had more severe speech dysfunction (P < .0001) and swallowing dysfunction (P < .05), and they had higher scores on the NMSS (P = .0008) and SCOPA-AUT (P = .003) and poorer quality-of-life scores on the PDQ-39 (P = .049).

To evaluate respiratory tract infections, the researchers used electronic health records. About 15.4% of the study population had had a documented respiratory infection since they were diagnosed with PD.

Upper and lower respiratory tract infections were more frequent among droolers than nondroolers (P = .05).

"Infections might arise from swallowing disturbances leading to aspiration and drooling," Morgante noted.

The drooling did not appear to affect cognition or sleep in these patients.

Treatment Options?

Following the study presentation, session co-chair Philippe G. Damier, MD, PhD, professor of neurology, University Hospital, Nantes, France, asked about the best treatment for sialorrhea for these patients.

In general, those with milder disease might try chewing gum to improve swallowing; patients with more severe cases may benefit from botulinum toxin injections, said Cociasu. The treatment choice, she added, "very much depends on the severity of the sialorrhea."

Botulinum toxin therapy involves injections into the salivary gland to reduce saliva production. It is typically administered about every 4 months.

The second session co-chair, Elena Moro, MD, PhD, director of the Movement Disorders Unit at Grenoble Alpes University, Grenoble, France, pointed out that chewing gum may be a swallowing hazard for patients with PD and severe dementia.

Asked by Moro whether patients with higher scores on balance and posture were more likely to have sialorrhea, Cociasu said she and her colleagues are currently looking into this.

Morgante told Medscape Medical News that the current study did not examine the effect of treatment on speech disorders associated with sialorrhea.

"We are running another study now to understand the effect of treatment of sialorrhea on these features," she said.

Morgante and Cociasu have reported no relevant financial relationships.

Congress of the European Academy of Neurology (EAN) 2021: Session: Movement Disorders 1. Presented June 20, 2021.

For more Medscape Neurology news, join us on Facebook and Twitter.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.