Tongue and lip movement speed
The tongue and lip movements were evaluated using oral diadochokinesis (ODK). ODK was measured using the KENKO-KUN Handy, an oral function-measuring device (Takei Scientific Co., Ltd., Niigata, Japan). Participants were asked to pronounce a monosyllable as quickly as possible for 5 s. The device recorded the number of repetitions for each syllable and calculated the number of syllables produced per second. The monosyllables ‘‘pa,’’ ‘‘ta,’’ and ‘‘ka’’ were used to evaluate the ability of the lips, the tip of the tongue, and the posterior region of the tongue, respectively