Dimethicone, which is a silicone oil, is often preferred due to the low risk of side effects. Pyrethroids such as permethrin have been commonly used; however, they have become less effective due to increasing pesticide resistance. There is little evidence for alternative medicines.Head-lice infestations are common, especially in children. In Europe, they infect between 1 and 20% of different groups of people. In the United States, between 6 and 12 million children are infected a year. They occur more often in girls than boys. It has been suggested that historically, head lice infection were beneficial, as they protected against the more dangerous body louse. Infestations may cause stigmatization of the infected individual. Epidemiology
Reliable data describing the usual incidence of infestation in the general public, in the average school community, or during specific times of the year are lacking. The number of cases of human louse infestations (or pediculosis) has increased worldwide since the mid-1960s, reaching hundreds of millions annually. It is estimated between 1 and 20% of specific groups in Europe are infected.Despite improvements in medical treatment and prevention of human diseases during the 20th century, head louse infestation remains stubbornly prevalent. In 1997, 80% of American elementary schools reported at least one outbreak of lice. Lice infestation during that same period was more prevalent than chickenpox.About 6–12 million children between the ages of 3 and 11 are treated annually for head lice in the United States alone.
History
M.-Marsel Mesulam coined the term primary progressive aphasia. See also
References
Further reading
Amici S, Ogar J, Brambati SM,  et al. (Dec 2007). "Performance in specific language tasks correlates with regional volume changes in progressive aphasia". Cognitive & Behavioral Neurology. 20 (4): 203–11. doi:10.1097/WNN.0b013e31815e6265. PMID 18091068. S2CID 18090918. Gliebus G (March 2010). "Primary progressive aphasia: clinical, imaging, and neuropathological findings". Am J Alzheimers Dis Other Demen. 25 (2): 125–7. doi:10.1177/1533317509356691. PMID 20124255. S2CID 29195502. Henry ML, Beeson PM, Alexander GE, Rapcsak SZ (February 2012). "Written language impairments in primary progressive aphasia: a reflection of damage to central semantic and phonological processes". J Cogn Neurosci. 24 (2): 261–75. doi:10.1162/jocn_a_00153. PMC 3307525. PMID 22004048. Henry ML, Gorno-Tempini ML (December 2010). "The logopenic variant of primary progressive aphasia". Current Opinion in Neurology. 23 (6): 633–7. doi:10.1097/WCO.0b013e32833fb93e. PMC 3201824. PMID 20852419. Reilly J, Rodriguez AD, Lamy M, Neils-Strunjas J (2010). "Cognition, language, and clinical pathological features of non-Alzheimers dementias: an overview". J Commun Disord. 43 (5): 438–52. doi:10.1016/j.jcomdis.2010.04.011. PMC 2922444. PMID 20493496. Rohrer JD, Knight WD, Warren JE, Fox NC, Rossor MN, Warren JD (January 2008). "Word-finding difficulty: a clinical analysis of the progressive aphasias". Brain. 131 (Pt 1): 8–38. doi:10.1093/brain/awm251. PMC 2373641. PMID 17947337. == External links ==