Other effects can include gradual loss of finger extension, leading to a clawlike appearance. Cold & hot temperatures exacerbate MMN symptoms to such an extent, unlike other neuropathies, that this temperature response is being investigated as a diagnostic tool. Cause
MMN is thought to be caused by alterations in the immune system, such that certain proteins (antibodies) that would normally protect one from viruses and bacteria begin to attack constituents of peripheral nerves. Antibodies may be directed against "GM-1", a ganglioside found at the Nodes of Ranvier. These antibodies have been detected in at least one-third of MMN patients. More recent studies also suggest that newer tests for antibodies directed against GM-1, as well as a number of related gangliosides, are positive in over 80% of MMN patients. There are increasing reasons to believe these antibodies are the cause of MMN. Diagnosis
The diagnosis of MMN depends on demonstrating that a patient has a purely motor disorder affecting individual nerves, that there are no upper motor neuron (UMN) signs, that there are no sensory deficits, and that there is evidence of conduction block.
Velopharyngeal incompetency occurs when the soft palate and the lateral/posterior pharyngeal walls fail to separate the oral cavity from the nasal cavity during speech. Although the definitions are similar, the etiologies correlated with each term differ slightly. However, in the field of medical professionals these terms are typically used interchangeably. References
Conley SF, Gosain AK, Marks SM, Larson DL (1997). "Identification and assessment of velopharyngeal inadequacy". Am J Otolaryngol. 18 (1): 38–46. doi:10.1016/S0196-0709(97)90047-8. PMID 9006676. Johns DF, Rohrich RJ, Awada M (2003). "Velopharyngeal incompetence: a guide for clinical evaluation". Plast. Reconstr. Surg. 112 (7): 1890–7, quiz 1898, 1982. doi:10.1097/01.PRS.0000091245.32905.D5. PMID 14663236. McWilliams, Betty Jane; Peterson-Falzone, Sally J.; Hardin-Jones, Mary A.; Karnell, Michael P. (2001). Cleft palate speech. St. Louis: Mosby. ISBN 0-8151-3153-4. Hardin-Jones, Mary A.; Peterson-Falzone, Sally J.; Judith Trost-Cardamone; Karnell, Michael P. (2005). The Clinicians Guide to Treating Cleft Palate Speech. St. Louis: Mosby-Year Book. ISBN 0-323-02526-9. Willging JP (1999). "Velopharyngeal insufficiency". Int. J. Pediatr. Otorhinolaryngol. 49 Suppl 1: S307–9. doi:10.1016/S0165-5876(99)00182-2. PMID 10577827. == External links ==