Several methods have been described in the 20th century. Most of them are closely related to well known physio- or speech therapy methods, such as manual stimulation and methods of improving body posture. In Scandinavia, the use of the methods described by Dr Rodolfo Castillo Morales of Cordova, Argentina, and his colleagues in Germany, have increased strongly during the 1990-s. These methods involve the use of palatal plates as facilitating or enhancing agents. The plates should be regarded as complementary to the general therapy, not as a treatment on its own .
Palatal plates stimulate the nervous and muscular activities in the oral region.
Thus, each case should be thoroughly analysed by an expert in the field, often a speech therapist. If multiple effects are desired, use more than one plate in a planned programme during the treatment period. We call the stimuli either 'passive' or 'active'. The mere presence in the mouth of the 'passive' stimuli offers the stimulation required. This type of stimuli are used in e.g. hypotonic patients or patients with difficulties to pronounce single fonems.