Bruxism bruxism), but also possibly grinding, and is often associated with other semivoluntary oral habits such as cheek biting, nail biting, chewing on a pen or pencil absent mindedly, or tongue thrusting (where the tongue is pushed against the front teeth forcefully). There is evidence that sleep bruxism is caused by mechanisms related to the central nervous system, involving sleep arousal and neurotransmitter abnormalities. Underlying these factors may be psychosocial factors including daytime stress which is disrupting peaceful sleep. Sleep bruxism is mainly characterized by "rhythmic masticatory muscle activity" (RMMA) at a frequency of about once per second, and also with
Habitual be the introduction, and subsequent loss of habitual "do (be)" in America, which was also the problem with the first expansion of the diffusion hypothesis. Another hypothesis for the origins of habitual "be" in NWBE and afterwards into AAE is the most logical and the strongest of the lot. The decreolization theory for the emergence of habitual "be" in AAE is the most likely and most supported of the theories of its origin. It involves the decreolization process of Caribbean English creole, with the loss of "does (be)", which itself is a decreolization of a previous creole habitual marker and its