Clinical features associated with drooling in Parkinson's disease

Dysphagia Pattern in Early to Moderate Parkinson's Disease Caused by Abnormal Pharyngeal Kinematic Function

Airway invasion is common in patients with Parkinson's disease (PD) and can cause serious complications. However, a PD-related dysphagic pattern has not been clearly elucidated. In this study, 53 patients with early to moderate PD were enrolled to undergo a videofluoroscopic study of swallowing evaluation (VFSS) and a battery of neuropsychological assessments. A set of VFSS variables (three visuoperceptual, nine temporal, and six spatial) were measured. The main effects of bolus viscosity and volume on airway invasion were calculated. Statistical analyses were performed to determine key kinematic factors of airway invasion for swallowing each bolus type. Airway invasion frequency was significantly higher for liquid boluses (liquid vs. pudding P < 0.001; liquid vs. honey P = 0.006). Laryngeal vestibule closure reaction time (LVCrt) was the key kinematic factor of airway invasion for 3 ml liquid swallow (P = 0.040), anterior displacement of hyoid bone was the key kinematic factor for both 5 ml and 10 ml liquid swallows (P = 0.010, 0.034, respectively). Male sex and advanced Hoehn and Yahr stage were significantly related to reduced anterior displacement of hyoid bone. These results reveal the dysphagic pattern related to PD, demonstrating that prolonged LVCrt and reduced anterior displacement of hyoid bone are two crucial kinematic factors contributing to airway invasion during the liquid swallow. In addition, hyoid bone dysfunction was correlated with disease severity and male sex. Our findings warrant further investigation of the pathophysiological mechanism of dysphagia in PD and would guide clinical intervention.

Drooling disrupts the brain functional connectivity network in Parkinson's disease

AIMS

This study aimed to investigate the causal interaction between significant sensorimotor network (SMN) regions and other brain regions in Parkinson's disease patients with drooling (droolers).

METHODS

Twenty-one droolers, 22 PD patients without drooling (non-droolers), and 22 matched healthy controls underwent 3T-MRI resting-state scans. We performed independent component analysis and Granger causality analysis to determine whether significant SMN regions help predict other brain areas. Pearson's correlation was computed between imaging characteristics and clinical characteristics. ROC curves were plotted to assess the diagnostic performance of effective connectivity (EC).

RESULTS

Compared with non-droolers and healthy controls, droolers showed abnormal EC of the right caudate nucleus (CAU.R) and right postcentral gyrus to extensive brain regions. In droolers, increased EC from the CAU.R to the right middle temporal gyrus was positively correlated with MDS-UPDRS, MDS-UPDRS II, NMSS, and HAMD scores; increased EC from the right inferior parietal lobe to CAU.R was positively correlated with MDS-UPDRS score. ROC curve analysis showed that these abnormal ECs are of great significance in diagnosing drooling in PD.

CONCLUSION

This study identified that PD patients with drooling have abnormal EC in the cortico-limbic-striatal-cerebellar and cortio-cortical networks, which could be potential biomarkers for drooling in PD.

Comparison of factors associated with drooling between intractable neuromuscular disease and cerebral palsy

Drooling represents a common and noteworthy symptom in patients with intractable neuromuscular disease (IND) and cerebral palsy (CP) and can lead to poor quality of life (QOL) and higher incidence of death due to aspiration of saliva. Identifying the factors affecting drooling is crucial to improving QOL and improving the poor prognosis of patients with IND and CP. This study sought to assess the prevalence of drooling and to elucidate the associated factors, drugs, and differences between patients with IND and CP. We included hospitalized patients with IND and CP. Among the 269 patients, 69 of 162 patients with IND (42.6%) and 75 of 107 patients with CP (70.1%) exhibited drooling. Drooling in IND was significantly higher in patients with tube feeding and those who had a previous stroke than in patients with potential oral intake and those having no history of stroke. In individuals with CP, drooling was significantly negatively associated with age. Taltirelin in patients with IND had a significant positive association with drooling, and antipsychotics and centrally acting muscle relaxants in those with CP had a significant negative association with drooling. Our results suggest that the factors associated with frequent drooling differ between IND and CP cases, and patients who should be screened for drooling are those with decreased swallowing function, those with IND who have had a previous stroke, and young patients with CP. Moreover, clinicians should consider the impact of drugs on drooling in IND and CP cases.

Application Site of Transdermal Scopolamine Influences Efficacy and Drug Concentration in Salivary Glands in Rats

Transdermal scopolamine applied to the postauricular area is used to treat drooling. We investigated the duration of action of scopolamine ointment and the effect of the application site on drug efficacy and concentration in the salivary glands of rats. Scopolamine ointment was applied to the skin over the salivary glands (SSG) and back (SB). Saliva volume was measured after intraperitoneal administration of pilocarpine. Blood and salivary glands were collected after scopolamine ointment application, and scopolamine concentrations in the plasma and salivary glands were measured. Saliva volume after application in the SSG group was significantly lower at all time points than in the non-treated group, and the change in saliva volume in the SSG group was greater than that in the SB group at all time points. This suggests that applying scopolamine ointment to the SSG strongly suppresses salivary secretion. Scopolamine concentration in the salivary glands of the SSG group was significantly higher at 9 h. The change in the efficacy of scopolamine ointment depending on the application site was due to the difference in transfer to the salivary glands. Transdermal administration of scopolamine to the skin over the salivary glands may have high efficiency in treating drooling.

Pathophysiology and Symptomatology of Drooling in Parkinson’s Disease

Drooling can present in patients with Parkinson’s disease (PD), and it is manifested as an excessive pooling of saliva inside the oral cavity. Currently, the exact pathophysiological mechanism of drooling in PD is not yet fully explicated. Thus, it becomes crucial to understand if some clinical characteristics may emphasize drooling or if they are just concomitant. In PD, excessive drooling has been associated with a higher burden of non-motor symptoms, such as cognitive impairment, sleep problems, autonomic dysfunction, constipation and orthostatic hypotension, and of worse severity of motor fluctuations and bradykinesia. PD patients with excessive drooling also showed a reduction of striatal DAT availability at DaTSCAN imaging. Excessive drooling in patients with Parkinson’s cannot be attributed to a single factor but to a mixture of factors, including but not limited to impaired nigrostriatal pathways.

Drooling rating scales in Parkinson's disease: A systematic review

BACKGROUND

Drooling is a clinically relevant non-motor symptom of people with Parkinson's disease (PwP). Several drooling rating scales are available. Nevertheless, the compelling scientific evidence supporting their validity is limited. This study aims to evaluate clinical rating scales for drooling, assessing their characteristics, clinimetric properties, and clinical utility classification.

METHODS

A systematic review was undertaken. Two reviewers performed independent literature searches using the CENTRAL®, CINAHL®, Embase®, MEDLINE®, SciElo®, and SPEECH BITE® databases. We used consensus-based standards for the selection of health measurement instruments (COSMIN) and the International Parkinson's disease and the Movement Disorders (MDS) criteria to evaluate the included rating scales.

RESULTS

The following six rating scales were identified: Drooling Impact Scale (DIS), Sialorrhea Scoring Scale (SSS), Drooling Severity and Frequency Scale (DSFS), Drooling Rating Scale (DRS), Sialorrhea Clinical Scale for Parkinson Disease (SCS-PD), and the Radboud Oral Motor inventory for Parkinson's disease - Saliva (ROMP-saliva). The scales had heterogeneous characteristics: (i) not all were created/adapted for PwP; (ii) different dimensions associated with drooling are assessed; (iii) cross-cultural adaptations are limited to some languages. The clinimetric properties showed: (i) target population size limitations; (ii) incomplete reliability analysis; (iii) lack of robust validity; (iv) sensitivity to change not fully explored. Following the MDS criteria, only one tool was classified as "recommended", the ROMP-saliva.

CONCLUSIONS

This review provides information for an adequate selection of a drooling rating scale for clinical and/or research purposes. To date, ROMP-saliva is the only scale with substantial evidence of its clinimetric properties adequacy and data in PwP.