Sayyiduna Abd al-Rahman bin Abi Bakr (may Allah be pleased with them both) said: Al-Hakam bin Abi al-As used to sit with the Prophet (peace and blessings be upon him). Whenever the Prophet (peace and blessings be upon him) spoke, he would first twitch (his face, mockingly). the Prophet (peace and blessings be upon him) noticed him and said: "Be like that." So he remained afflicted with that twitching (of the face) until he died.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3154