![]() However, the processing of non-verbal sounds has not been assessed systematically in PNFA or semantic dementia. These disorders might represent more general derangements of cortical signal processing and in particular, generic disorders of complex sound processing arising from more fundamental pathophysiological mechanisms in different PPA subtypes. An important issue concerns the true language specificity of disorders in the PPA spectrum. An accumulating body of convergent evidence suggests that disorders in the PPA spectrum are clinically, neuroanatomically and pathologically distinct, and further, that PNFA and semantic dementia are likely to have fundamentally different pathophysiological mechanisms (Nestor et al., 2003 Gorno-Tempini et al., 2004 Hodges and Patterson, 2007 Rohrer et al., 2008 a). The study of these disorders has focused on language deficits however, spoken language (speech) is a highly specialized signal in acoustic, cognitive and evolutionary terms, representing a particularly significant species of complex sound (Griffiths et al., 1999). Within the frontotemporal lobar degeneration spectrum, two canonical PPA syndromes are recognized: progressive non-fluent aphasia (PNFA), associated with speech production breakdown and agrammatism, and atrophy predominantly affecting left inferior frontal and peri-Sylvian cortex (Mesulam, 1982 Nestor et al., 2003 Rohrer et al., 2008 a, 2009) and semantic dementia, associated with impaired single word comprehension and additional non-verbal semantic deficits, and atrophy predominantly affecting the anterior temporal lobes with a left-sided emphasis (Warrington, 1975 Lambon Ralph et al., 2001 Hodges and Patterson, 2007 Rohrer et al., 2008 a, b, 2009). These disorders together constitute a paradigm for understanding the neurodegenerative pathologies that produce discrete neuropsychological syndromes associated with focal cortical atrophy. Since the key descriptions of Mesulam ( 1982) and Warrington ( 1975) the primary progressive aphasias (PPA) have attracted substantial clinical and neurobiological interest. These findings argue for the existence of core disorders of complex non-verbal sound perception and recognition in primary progressive aphasia and specific disorders at perceptual and semantic levels of cortical auditory processing in progressive non-fluent aphasia and semantic dementia, respectively. ![]() Patients with progressive non-fluent aphasia were more likely to show severe auditory than visual deficits as compared to patients with semantic dementia. Deficits of auditory early perceptual analysis were more common in progressive non-fluent aphasia, deficits of apperceptive processing occurred in both progressive non-fluent aphasia and semantic dementia, and deficits of semantic processing also occurred in both syndromes, but were relatively modality specific in progressive non-fluent aphasia and part of a more severe generic semantic deficit in semantic dementia. Patients with primary progressive aphasia had deficits of non-verbal sound analysis compared with healthy age-matched individuals. ![]() We designed a novel experimental neuropsychological battery to probe complex sound processing at early perceptual, apperceptive and semantic levels, using within-modality response procedures that minimized other cognitive demands and matching tests in the visual modality. Here, we investigated the processing of complex non-verbal sounds in detail, in a consecutive series of 20 patients with primary progressive aphasia. Little is known about the processing of non-verbal sounds in the primary progressive aphasias. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |