semantic aphasia

*** TO DO *** Revise definition. Confirm that this is a disease and not just a syndrome. aphasia characterized by the loss of recognition of the meaning of words and phrases. Semantic dementia (SD) is a progressive neurodegenerative disorder characterized by loss of semantic memory in both the verbal and non-verbal domains. The most common presenting symptoms are in the verbal domain however (with loss of word meaning) and it is therefore often characterized (incorrectly) as a primary language disorder (a so-called progressive fluent aphasia). SD patients sometimes show symptoms of surface dyslexia, a relatively selective impairment in reading low-frequency words with exceptional or atypical spelling-to-sound correspondences. SD is one of the three canonical clinical syndromes associated with frontotemporal lobar degeneration. SD is a clinically-defined syndrome, but is associated with predominantly temporal lobe atrophy (left greater than right) and hence is sometimes called temporal variant FTLD (tvFTLD). The majority of patients with SD will have ubiquitin-positive, TDP-43 positive, tau-negative inclusions, although other pathologies have been described more infrequently, namely tau-positive Pick's disease and Alzheimer's pathology.

http://purl.obolibrary.org/obo/ND_0000153

*** TO DO *** Revise definition. Confirm that this is a disease and not just a syndrome.

SD

Alexander P. Cox

http://www.merriam-webster.com/medical/semantic%20aphasia

http://en.wikipedia.org/wiki/Semantic_dementia

semantic aphasia

ND:0000153

semantic aphasia

aphasia characterized by the loss of recognition of the meaning of words and phrases.

Semantic dementia (SD) is a progressive neurodegenerative disorder characterized by loss of semantic memory in both the verbal and non-verbal domains. The most common presenting symptoms are in the verbal domain however (with loss of word meaning) and it is therefore often characterized (incorrectly) as a primary language disorder (a so-called progressive fluent aphasia). SD patients sometimes show symptoms of surface dyslexia, a relatively selective impairment in reading low-frequency words with exceptional or atypical spelling-to-sound correspondences. SD is one of the three canonical clinical syndromes associated with frontotemporal lobar degeneration. SD is a clinically-defined syndrome, but is associated with predominantly temporal lobe atrophy (left greater than right) and hence is sometimes called temporal variant FTLD (tvFTLD). The majority of patients with SD will have ubiquitin-positive, TDP-43 positive, tau-negative inclusions, although other pathologies have been described more infrequently, namely tau-positive Pick's disease and Alzheimer's pathology.

http://purl.obolibrary.org/obo/ND_0000167