Study of the Link Between Freezing of Gait and Oropharyngeal Freezing in Parkinson's Patients

Parkinson's Disease: Study of the Link Between Gait Freezing and Oropharyngeal Freezing Parkinson's disease is the second most common neurodegenerative disorder worldwide. Parkinsonian dysphagia is a frequently encountered disorder in this condition, affecting all phases of swallowing: oral, pharyngeal, and esophageal. This dysphagia can occur at any stage of the disease. While most swallowing difficulties develop in the advanced stages of Parkinson's disease, they can also appear early on and are often underdiagnosed. The prevalence of swallowing disorders in Parkinson's disease is estimated to range from 40% to 80%, with this variability explained by the significant differences in the precision of swallowing evaluations conducted and the fact that dysphagia is still too frequently underdiagnosed. Yet, dysphagia is the leading cause of mortality in Parkinson's patients.

Dysphagia can negatively affect patients' quality of life. It leads to difficulties during oral intake (food, liquids, and medications), weight loss, dehydration, malnutrition, and limitations in social activities. Depression is frequently associated with reduced quality of life in Parkinson's patients with swallowing disorders. Moreover, aspiration pneumonia due to mis-swallowing is one of the primary reasons for hospitalization in Parkinson's patients, potentially leading to severe complications and, at times, death.

Oropharyngeal freezing, also called oral festination, is an involuntary, repetitive anteroposterior movement of the tongue against the soft palate performed before transferring the food bolus to the pharynx. This movement is also observed during multiple swallows. This phenomenon is more frequent in dysphagic Parkinson's patients, yet its impact on swallowing dynamics remains poorly understood. Oropharyngeal freezing has been observed in approximately 40% to 75% of Parkinson's patients during videofluoroscopic swallow studies, also known as swallowing pharyngography. Oropharyngeal freezing inhibits the initiation of swallowing, keeping the airway open and leading to tracheal aspiration of residues. Some fragments then slide into the valleculae and pyriform sinuses. Thus, oropharyngeal freezing exacerbates pharyngeal phase incoordination, increasing the risk of aspiration pneumonia. Therefore, addressing this swallowing disorder is essential.

Oropharyngeal freezing is intrinsically rhythmic. While limited studies have been conducted on the topic, they agree that gait freezing (difficulty initiating walking, stopping in response to obstacles, or circumventing them) and oropharyngeal freezing share common pathophysiological mechanisms. Gait freezing is not limited to deficits in the locomotor network but is part of a broader deficit affecting spatiotemporal coordination in various tasks, similar to oropharyngeal freezing.

It is, therefore, crucial to detect this oral phase swallowing disorder as early as possible, enabling tailored early intervention that helps patients maintain their swallowing abilities for as long as possible and prevents complications mentioned earlier. Since gait freezing is diagnosed much earlier and more systematically, it would be interesting to investigate whether there is a correlation between the presence of gait freezing and oropharyngeal freezing in these patients. This could guide patients with gait freezing toward early speech-language assessments to evaluate the presence of oropharyngeal freezing.

The objectives of the study are examine the prevalence of oropharyngeal freezing in Parkinson's patients. Based on the results obtained from the NFOG-Q (New Freezing of Gait Questionnaire), two groups will be formed: The first group will consist of patients exhibiting gait freezing. The second group will consist of patients without gait freezing. The secondary objectives of the study are examine the common characteristics between these two types of freezing (gait and oropharyngeal). To assess the sensitivity and reliability of the NFOG-Q in detecting oropharyngeal freezing.To determine the prevalence of oropharyngeal freezing based on the score obtained on the UPDRS (Unified Parkinson's Disease Rating Scale). To analyze the link between patients' rhythmic abilities and the presence or absence of one or both types of freezing.