Primary progressive aphasia

Primary progressive aphasia
Classification and external resources
OMIM 607485
MeSH D018888

Primary progressive aphasia (PPA) is a type of dementia characterized most prominently by an insidious and progressive disorder of language and speech abilities. It was first described as a distinct syndrome by Mesulam in 1982.[1]

Contents

Diagnosis Criteria

The following diagnosis criteria were defined by Mesulam [2]

Classification

There is considerable controversy over the nosology (classification) of this disorder. Clinical and pathological overlap have led it to being considered as part of the frontotemporal lobar degeneration (FTLD) spectrum of disorders, although Mesulam in his reviews has acknowledged that one third of the cases have an underlying Alzheimer pathology.[3] In the classical Mesulam criteria for PPA there are 2 variants: a non-fluent type (progressive non-fluent aphasia or PNFA) and a fluent aphasia. However, recent work has suggested that the underlying cognitive impairment in patients with progressive fluent aphasias is loss of semantic knowledge (semantic dementia or SD).[4] In the consensus criteria for FTLD described by Neary, et al. in 1989, PNFA and SD are the two classifications used.

The San Francisco group have recently suggested that there is a third variant of PPA (so-called logopaenic progressive aphasia[5]). However, there are limited descriptions of this disorder in the medical literature, and early reports suggest that it is an atypical form of Alzheimer's disease rather than a disease falling into the frontotemporal lobar degeneration spectrum.

Risk

There are no known environmental risk factors for the progressive aphasias. However, one observational study has recently suggested that vasectomy could be a risk factor for PPA in men[6]. These results have yet to be replicated elsewhere.

PPA is not considered a hereditary disease. However, relatives of a person with any form of frontotemporal lobar degeneration, including PPA, are at slightly greater risk of developing PPA or another form of the condition.[7]

Treatment

There is no approved treatment. Rapid and sustained improvement in speech and dementia in a patient with primary progressive aphasia utilizing perispinal etanercept off-label, an anti-TNF treatment strategy also used for Alzheimer's, was recently reported[8]. A video depicting the patient's improvement was published in conjunction with the print article. These findings have not been independently replicated, and remain controversial.

References

  1. ^ Mesulam M (1982). "Slowly progressive aphasia without generalized dementia". Ann Neurol. 11 (6): 592–8. doi:10.1002/ana.410110607. PMID 7114808. 
  2. ^ Mesulam MM: Primary progressive aphasia—a language-based dementia. N Engl J Med 2003, 349:1535–1542
  3. ^ Mesulam MM (Apr 2001). "Primary progressive aphasia". Ann Neurol. 49 (4): 425–32. doi:10.1002/ana.91. PMID 11310619. 
  4. ^ Adlam AL, Patterson K, Rogers TT, et al. (Nov 2006). "Semantic dementia and fluent primary progressive aphasia: two sides of the same coin?". Brain 129 (Pt 11): 3066–80. doi:10.1093/brain/awl285. PMID 17071925. http://brain.oxfordjournals.org/cgi/content/full/129/11/3066. 
  5. ^ Gorno-Tempini ML, Dronkers NF, Rankin KP, et al. (Mar 2004). "Cognition and anatomy in three variants of primary progressive aphasia". Ann Neurol. 55 (3): 335–46. doi:10.1002/ana.10825. PMC 2362399. PMID 14991811. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2362399. 
  6. ^ Weintraub S, Fahey C, Johnson N, et al. (December 2006). "Vasectomy in men with primary progressive aphasia". Cogn Behav Neurol 19 (4): 190–3. doi:10.1097/01.wnn.0000213923.48632.ab. PMID 17159614.
  7. ^ Goldman JS, Farmer JM, Wood EM, et al. (Dec 2005). "Comparison of family histories in FTLD subtypes and related tauopathies". Neurology 65 (11): 1817–9. doi:10.1212/01.wnl.0000187068.92184.63. PMID 16344531. 
  8. ^ Tobinick E (2008). "Perispinal etanercept produces rapid improvement in primary progressive aphasia: identification of a novel, rapidly reversible TNF-mediated pathophysiologic mechanism". Medscape Journal of Medicine 10 (6): 135. PMC 2491668. PMID 18679537. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2491668. 

External links