Semantic dementia: Brazilian study of nineteen cases

Abstract The term semantic dementia was devised by Snowden et al. in 1989 and nowadays, the semantic dementia syndrome is recognized as one of the clinical forms of frontotemporal lobar degeneration (FTLD) and is characterized by a language semantic disturbance associated to non-verbal semantic memory impairment. Objectives: The aim of this study was to describe a Brazilian sample of 19 semantic dementia cases, emphasizing the clinical characteristics important for differential diagnosis of this syndrome. Methods: Nineteen cases with semantic dementia were evaluated between 1999 and 2007. All patients were submitted to neurological evaluation, neuroimaging exams and cognitive, language and semantic memory evaluation. Results: All patients presented fluent spontaneous speech, preservation of syntactic and phonological aspects of the language, word-finding difficulty, semantic paraphasias, word comprehension impairment, low performance in visual confrontation naming tasks, impairment on tests of non-verbal semantic memory and preservation of autobiographical memory and visuospatial skills. Regarding radiological investigations, temporal lobe atrophy and/or hypoperfusion were found in all patients. Conclusions: The cognitive, linguistic and of neuroimaging data in our case series corroborate other studies showing that semantic dementia constitutes a syndrome with well defined clinical characteristics associated to temporal lobe atrophy.

Download Full-text

A voxel-based morphometry study of semantic dementia: Relationship between temporal lobe atrophy and semantic memory

Annals of Neurology ◽

10.1002/1531-8249(200001)47:1<36::aid-ana8>3.0.co;2-l ◽

2000 ◽

Vol 47 (1) ◽

pp. 36-45 ◽

Cited By ~ 571

Author(s):

C. J. Mummery ◽

K. Patterson ◽

C. J. Price ◽

J. Ashburner ◽

R. S. J. Frackowiak ◽

...

Keyword(s):

Semantic Memory ◽

Temporal Lobe ◽

Semantic Dementia ◽

Voxel Based Morphometry ◽

Lobe Atrophy

Download Full-text

Defective production and recognition of actions in Pick's disease with temporal lobe atrophy (semantic dementia)

Higher Brain Function Research ◽

10.2496/hbfr.29.268 ◽

2009 ◽

Vol 29 (2) ◽

pp. 268-276 ◽

Cited By ~ 1

Author(s):

Masaki Kondo ◽

Satoshi Mochizuki ◽

Mutsutaka Kobayakawa ◽

Natsuko Tsuruya ◽

Mitsuru Kawamura

Keyword(s):

Temporal Lobe ◽

Semantic Dementia ◽

Pick's Disease ◽

Pick’S Disease ◽

Lobe Atrophy

Download Full-text

Anhedonia in Semantic Dementia—Exploring Right Hemispheric Contributions to the Loss of Pleasure

Brain Sciences ◽

10.3390/brainsci11080998 ◽

2021 ◽

Vol 11 (8) ◽

pp. 998

Author(s):

Siobhán R. Shaw ◽

Hashim El-Omar ◽

Siddharth Ramanan ◽

Olivier Piguet ◽

Rebekah M. Ahmed ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Temporal Lobe ◽

Rating Scale ◽

Right Hemisphere ◽

Semantic Knowledge ◽

Semantic Dementia ◽

Anterior Cingulate ◽

Functional Impairments ◽

Lobe Atrophy

Semantic dementia (SD) is a younger-onset neurodegenerative disease characterised by progressive deterioration of the semantic knowledge base in the context of predominantly left-lateralised anterior temporal lobe (ATL) atrophy. Mounting evidence indicates the emergence of florid socioemotional changes in SD as atrophy encroaches into right temporal regions. How lateralisation of temporal lobe pathology impacts the hedonic experience in SD remains largely unknown yet has important implications for understanding socioemotional and functional impairments in this syndrome. Here, we explored how lateralisation of temporal lobe atrophy impacts anhedonia severity on the Snaith–Hamilton Pleasure Scale in 28 SD patients presenting with variable right- (SD-R) and left-predominant (SD-L) profiles of temporal lobe atrophy compared to that of 30 participants with Alzheimer’s disease and 30 healthy older Control participants. Relative to Controls, SD-R but not SD-L or Alzheimer’s patients showed clinically significant anhedonia, representing a clear departure from premorbid levels. Overall, anhedonia was more strongly associated with functional impairment on the Frontotemporal Dementia Functional Rating Scale and motivational changes on the Cambridge Behavioural Inventory in SD than in Alzheimer’s disease patients. Voxel-based morphometry analyses revealed that anhedonia severity correlated with reduced grey matter intensity in a restricted set of regions centred on right orbitofrontal and temporopolar cortices, bilateral posterior temporal cortices, as well as the anterior cingulate gyrus and parahippocampal gyrus, bilaterally. Finally, regression and mediation analysis indicated a unique role for right temporal lobe structures in modulating anhedonia in SD. Our findings suggest that degeneration of predominantly right-hemisphere structures deleteriously impacts the capacity to experience pleasure in SD. These findings offer important insights into hemispheric lateralisation of motivational disturbances in dementia and suggest that anhedonia may emerge at different timescales in the SD disease trajectory depending on the integrity of the right hemisphere.

Download Full-text