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

To evaluate masticatory function and oral sensorimotor ability (OSA) in elders with Parkinson's disease (PD) during the levodopa on and off-periods.

Participants were 11 partially and completely edentulous elders with PD. Masticatory function was evaluated by mandibular movements, maximum bite force (MBF), and masticatory performance (MP). Mandibular movements reflecting jaw range of motion (ROM) and jaw movements while chewing silicone test material (Optocal), were evaluated using a kinesiograph. MBF was assessed by strain sensors, and MP was determined using the median Optocal particle size (X₅₀ ) after 40 masticatory cycles. OSA was evaluated using oral stereognosis test scores and response time. Evaluations were carried out 30 min before levodopa intake (off-period) and within a 3-day interval 1 h after levodopa intake (on-period). Data were analyzed by Student's t-test, considering a significance level of 5%. During the levodopa off-period, elders showed decreased ROM during protrusion and lateral movements, while no difference was found in maximum opening and mandibular movements during chewing. MBF was lower and X₅₀ was higher during the off-period, indicating worse mastication. However, OSA did not differ between the evaluated times.

Elders with PD had impaired mastication during the levodopa off-period, although OSA was not altered.