Year-end Sale % OFF 
Abstract
Recognition of nonverbal sounds in semantic dementia and other syndromes of anterior temporal lobe degeneration may determine clinical symptoms and help to define phenotypic profiles. However, nonverbal auditory semantic function has not been widely studied in these syndromes. Here we investigated semantic processing in two key nonverbal auditory domains – environmental sounds and melodies – in patients with semantic dementia (SD group; n=9) and in patients with anterior temporal lobe atrophy presenting with behavioural decline (TL group; n=7, including four cases with MAPT mutations) in relation to healthy older controls (n=20). We assessed auditory semantic performance in each domain using novel, uniform within-modality neuropsychological procedures that determined sound identification based on semantic classification of sound pairs. Both the SD and TL groups showed comparable overall impairments of environmental sound and melody identification; individual patients generally showed superior identification of environmental sounds than melodies, however relative sparing of melody over environmental sound identification also occurred in both groups. Our findings suggest that nonverbal auditory semantic impairment is a common feature of neurodegenerative syndromes with anterior temporal lobe atrophy. However, the profile of auditory domain involvement varies substantially between individuals.
Highlights
Semantic dementia (SD) is a focal neurodegenerative syndrome characterised by insidiously progressive impairment of semantic memory due to selective, asymmetric antero-medial temporal lobe atrophy [1]
We have demonstrated that patients with clinically significant anterior temporal lobe atrophy have deficits of semantic processing in two key nonverbal auditory domains, identification of environmental sounds and melodies
Whereas the SD group here showed more severe impairment of verbal semantic function than the TL group, nonverbal auditory semantic impairment was comparable in patients with anterior temporal lobe degeneration irrespective of whether they present with typical SD or with behavioural decline underpinned by an alternative pathogenic process
Summary
Semantic dementia (SD) is a focal neurodegenerative syndrome characterised by insidiously progressive impairment of semantic memory due to selective, asymmetric antero-medial temporal lobe atrophy [1]. Research consensus diagnostic criteria have been developed for stratifying the major syndromes of FTLD [10,11], in practice the SD syndrome often shows substantial overlap clinically and anatomically with other syndromes of FTLD, in particular behavioural variant frontotemporal dementia (bvFTD) [12,13]. Not the presenting feature, semantic deficits are often prominent in such cases; this spectrum includes cases with selective ( nondominant) temporal lobe atrophy [12,13,14,15] and the important subgroup represented by MAPT mutations, characteristically accompanied by focal bilateral anterior temporal lobe atrophy [12,16, 17]. SD is commonly associated with early and prominent behavioural abnormalities that overlap closely with bvFTD [18]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
