Impact of Parkinson’s disease on the efficiency of masticatory cycles: Electromyographic analysis

BACKGROUND: This study evaluated the efficiency of masticatory cycles by means of the linear envelope of the electromyographic signal of the masseter and temporalis muscles in individuals with Parkinson's disease. MATERIAL AND METHODS: Twenty-four individuals were assigned into two groups: with Parkinson's disease, average ± SD 66.1 ± 3.3 years (n = 12) and without the disease, average ± SD: 65.8 ± 3.0 years (n = 12). The MyoSystem-I P84 electromyograph was used to analyze the activity of masticatory cycles through the linear envelope integral in habitual mastication of peanuts and raisins and non-habitual mastication of Parafilm M®. RESULTS: There was statistically significant difference (P ≤ 0.05) between individuals with Parkinson's disease and without the disease in non-habitual mastication of Parafilm M®, in the right temporal muscle (P = 0.01); habitual mastication of peanuts, in the right temporal muscle (P = 0.02), left temporal muscle (P = 0.03), and right masseter muscle (P = 0.01); and habitual mastication of raisins in the right temporal muscle (P = 0.001), left temporal muscle (P= 0.001), right masseter muscle (P= 0.001) and left masseter muscle (P= 0.03). CONCLUSIONS: These results suggest that Parkinson's disease interferes in the electromyographic activity of the masticatory cycles by reducing muscular efficiency.