Masticatory function and oral sensorimotor ability in Parkinson's disease: Levodopa on versus off periods

Orofacial pain and dysfunction in patients with Parkinson's disease: A scoping review

BACKGROUND

Parkinson's disease (PD) is commonly known as a disorder that affects the smooth performance of body movements. In addition to the motor impairments, patients with PD often experience pain. Both motor impairments and pain can occur throughout the body, hence including the orofacial region. However, currently, there is a lack of knowledge on the orofacial manifestations. Since orofacial pain and dysfunction can, amongst others, reduce the quality of life of patients with PD, it is important to explore the prevalence of these symptoms in the PD population.

OBJECTIVE

To provide a broad overview of the relevant literature on orofacial pain and dysfunction in patients with PD. Furthermore, we aim to generate hypotheses for future research on this topic.

DATABASES AND DATA TREATMENT

A literature search (in PubMed, Embase.com, Web of Science [Core collection], and Cochrane Library) was performed on 20 January 2022, in collaboration with a medical librarian. In total, 7180 articles were found, of which 50 were finally included in this scoping review.

RESULTS

In the included studies, pain (e.g. orofacial pain (N = 2) and temporomandibular disorder pain (N = 2)), orofacial motor dysfunction (e.g. limited jaw movements (N = 10), reduced maximum muscle output (N = 3), chewing difficulties (N = 9), unspecified TMD (N = 3), sensory disturbances (N = 1)), and bruxism (N = 3) were observed more often in patients with PD than in healthy controls.

CONCLUSION

Patients with PD experience more pain in the orofacial area and more dysfunction of the masticatory system than their healthy peers.

SIGNIFICANCE

This scoping review can increase health care providers' awareness of the problems that can be encountered in the orofacial area of PD patients, especially pain syndromes also occur in the orofacial region and not only in the extremities. Besides, dysfunction of the orofacial area is elaborated in this scoping review, which helps to understand that this limits PD patients' quality of life. Further, the outcomes of this scoping review can assist in encouraging collaboration between medicine and dentistry. Finally, this scoping review suggests new research areas, based on the gaps identified in the current literature on this topic. Ultimately, this will improve individualized strategies for reducing orofacial pain and/or dysfunction in PD patients.

Orofacial myofunctional assessment and quality of life of individuals with Parkinson's disease

OBJECTIVES

To characterize orofacial myofunctional structures of elders with Parkinson's disease (PD) and examine the relationship with the stages of PD, pharmacotherapy, and quality of life.

METHODS

PD Group with 45 elders and a control group (CG) of 10 healthy elders of both sexes were included (60-86 years). Structured interviews, medical records, and clinical examination gathered information on health aspects such as the use of drugs, Hoehn & Yahr stages 1-4, and oral health status. The Mini-Mental State Examination, Parkinson's Disease Questionnaire, and Orofacial Myofunctional Evaluation with Scores for Elders were applied.

RESULTS

Better oral health status was found in participants diagnosed as Hoehn & Yahr stage 1 compared to the later stages. OMES-Elders scores for appearance/posture, mobility, breathing, and speech functions were different between groups, and decreased overall OMES-Elders was observed across the Hoehn & Yahr stages. A higher number of masticatory cycles was required for chewing and ingestion of the test food in the PD group compared to CG (p < .05). Significant differences were found in the mobility and daily living activities domains and an overall score of QoL between the Hoehn & Yahr stages 1 and 4, and worst orofacial functioning was accompanied by the worst self-perception of QoL in the communication domain (rho = -0.32; p = .034). The use of xerogenic drugs did not affect the OMES-Elders swallowing domain.

CONCLUSION

Worse dental condition and performance of orofacial functions was observed in the elders with PD as the disease progresses, and poorer orofacial performance negatively affects their perception of communication skills.

Neural Correlates of Oral Stereognosis—An fMRI Study

Oral stereognosis is the ability to recognize, discriminate and localize a bolus in the oral cavity. Clinical observation indicates deficits in oral stereognosis in patients with vascular or neurodegenerative diseases particularly affecting the parietal lobes. However, the precise neural representation of oral stereognosis remains unclear whereas the neural network of manual stereognosis has already been identified. We hypothesize that oral and manual stereognosis share common neuronal substrates whilst also showing somatotopic distribution. Functional magnetic resonance images (fMRI; Siemens Prisma 3 T) from 20 healthy right-handed participants (11 female; mean age 25.7 years) using a cross-modal task of oral and manual spatial object manipulation were acquired. Data were analyzed using FSL software using a block design and standard analytical and statistical procedures. A conjunction analysis targeted the common neuronal substrate for stereognosis. Activations associated with manual and oral stereognosis were found in partially overlapping fronto-parietal networks in a somatotopic fashion, where oral stereognosis is located caudally from manual stereognosis. A significant overlap was seen in the left anterior intraparietal sulcus. Additionally, cerebellar activations were shown particularly for the oral condition. Spatial arrangement of shaped boli in the oral cavity is associated with neuronal activity in fronto-parietal networks and the cerebellum. These findings have significant implications for clinical diagnostics and management of patients with lesions or atrophy in parietal lobule (e.g. Alzheimer’s disease, stroke). More studies are required to investigate the clinical effect of damage to these areas, such as loss of oral stereognosis or an impaired oral phase.