More than a piece of cake:Noun classifier processing in primary progressive aphasia

INTRODUCTION: Clinical understanding of primary progressive aphasia (PPA) has been primarily derived from Indo-European languages. Generalizing certain linguistic findings across languages is unfitting due to contrasting linguistic structures. While PPA patients showed noun classes impairments, Chinese languages lack noun classes. Instead, Chinese languages are classifier language, and how PPA patients manipulate classifiers is unknown. METHODS: We included 74 native Chinese speakers (22 controls, 52 PPA). For classifier production task, participants were asked to produce the classifiers of high-frequency items. In a classifier recognition task, participants were asked to choose the correct classifier. RESULTS: Both semantic variant (sv) PPA and logopenic variant (lv) PPA scored significantly lower in classifier production task. In classifier recognition task, lvPPA patients outperformed svPPA patients. The classifier production scores were correlated to cortical volume over left temporal and visual association cortices. DISCUSSION: This study highlights noun classifiers as linguistic markers to discriminate PPA syndromes in Chinese speakers. Highlights: Noun classifier processing varies in the different primary progressive aphasia (PPA) variants. Specifically, semantic variant PPA (svPPA) and logopenic variant PPA (lvPPA) patients showed significantly lower ability in producing specific classifiers. Compared to lvPPA, svPPA patients were less able to choose the accurate classifiers when presented with choices. In svPPA, classifier production score was positively correlated with gray matter volume over bilateral temporal and left visual association cortices in svPPA. Conversely, classifier production performance was correlated with volumetric changes over left ventral temporal and bilateral frontal regions in lvPPA. Comparable performance of mass and count classifier were noted in Chinese PPA patients, suggesting a common cognitive process between mass and count classifiers in Chinese languages.</p

Primary progressive aphasia: a model for neurodegenerative disease.

Purpose of reviewKnowledge on primary progressive aphasia (PPA) has expanded rapidly in the past few decades. Clinical characteristics, neuroimaging correlates, and neuropathological features of PPA are better delineated. This facilitates scientific studies on the disease pathophysiology and allows speech and language therapy to be more precisely targeted. This review article begins with a summary of the current understanding of PPA and discusses how PPA can serve as a model to promote scientific discovery in neurodegenerative diseases.Recent findingsStudies on the different variants of PPA have demonstrated the high compatibility between clinical presentations and neuroimaging features, and in turn, enhances the understanding of speech and language neuroanatomy. In addition to the traditional approach of lesion-based or voxel-based mapping, scientists have also adopted functional connectivity and network topology approaches that permits a more multidimensional understanding of neuroanatomy. As a result, pharmacological and cognitive therapeutic strategies can now be better targeted towards specific pathological/molecular and cognitive subtypes.SummaryRecent scientific advancement in PPA potentiates it to be an optimal model for studying brain network vulnerability, neurodevelopment influences and the effects of nonpharmacological intervention in neurodegenerative diseases

Neurodegenerative disorders of language and speech: Non-language-dominant diseases

Speech and language networks span vast cortical and subcortical regions in the human brain, including putative perisylvian areas but extending well beyond them. Accordingly, relevant functions can be compromised by diverse neural disruptions even in non-language-dominant neurodegenerative diseases (nldNDs) i.e., conditions that are not primarily typified by speech or language dysfunction. The present chapter offers a systematic overview of this topic, focusing on the three most prevalent nldNDs (Alzheimers disease, Parkinsons disease, and behavioral variant frontotemporal dementia). In each case, we offer detailed descriptions of spared and impaired skills across speech/language levels (phonetics, phonology, lexicosemantics, morphosyntax, discourse-level processing) and multidimensional accounts of their core neural signatures (including patterns of brain atrophy and tractographic abnormalities as well as alterations in regional activation, functional connectivity, event-related potentials, and oscillatory modulations). Next, we offer a brief contrastive summary of the core patterns in each disease. Finally, we address the main implications of the evidence and the prime challenges facing the field in the immediate future. Briefly, this chapter provides a fine-grained, multimodal, transnosological view of speech and language disruptions beyond the diseases typically associated with them.Fil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina. Universidad de San Andrés; Argentina. University of California; Estados UnidosFil: DeLeon, Jessica. University of California; Estados UnidosFil: Tee, Boon Lead. University of California; Estados Unido

Tonal and orthographic analysis in a Cantonese-speaking individual with nonfluent/agrammatic variant primary progressive aphasia

Clinical understanding of primary progressive aphasia (PPA) has been established based on English-speaking population. The lack of linguistic diversity in research hinders the diagnosis of PPA in non-English speaking patients. This case report describes the tonal and orthographic deficits of a multilingual native Cantonese-speaking woman with nonfluent/agrammatic variant PPA (nfvPPA) and progressive supranuclear palsy. Our findings suggest that Cantonese-speaking nfvPPA patients exhibit tone production impairments, tone perception deficits at the lexical selection processing, and linguistic dysgraphia errors unique to logographic script writer. These findings suggest that linguistic tailored approaches offer novel and effective tools in identifying non-English speaking PPA individuals

Correlation of Clinical and Imaging Findings in Early-Onset Alzheimer's Patients with Distinct Initial Symptoms

Background:&nbsp;Early-onset Alzheimer’s disease (EOAD), distinct from late-onset cases, tends to present with atypical cognitive decline, such as, progressive aphasia, apraxia, visuospatial and comportmental impairments,. This study aims to investigate correlations between clinical presentation and PET imaging findings in EOAD patients.&nbsp;Method:&nbsp;A retrospective analysis was conducted on CSF confirmed EOAD patients. Clinical assessments incorporated ACE-R cognitive tests, MRI and FDG-18 PET CT. MRIs were rated by an experienced neurologist using the Visual Atrophy Scale (VAS). Patients were stratified based on clinical presentation, and correlations between ACE-R domains and PET indices were examined. FDG-18 PET index was calculated as the count number (CN) of the same regions evaluated in VAS divided by CN of their cerebellum.&nbsp;Result:&nbsp;Nineteen patients (57.9% women) with a mean age at disease onset 55.7 (±6.57 StD) years participated. The mean disease duration was 5.1 (±3.14 StD) years. In the typical amnestic group (n=8); ACE-R total scores (52.63±15.3 StD) exhibited correlations with left parietal (r: 0.775, p: 0.025) and left occipital PET indices (r: 0.825, p: 0.012). Moreover, total memory scores (9.13±7.4 StD) correlated with left anterior temporal (r: 0.848, p: 0.008), and repetition scores correlated with left parietal PET indices (r: 0.907, p: 0.005). In the amnestic subgroup (n=5), a notable correlation was found between retrograde memory scores and left anterior temporal PET index (r: 0.905, p: 0.035). In the visuospatial group (n=8) orientation scores with left anterior temporal (r: 0.092, p: 0.02), and writing scores with right occipital (r: 0.968, p: 0.07) and left parietal (r: 0.941, p: 0.017) was found correlated. The behavioral variant group (n=3) showed a correlation with right orbitofrontal PET activity (r: 0.99, p: 0.02). A significant difference in attention scores was noted between aphasia and amnestic groups (p = 0.032), with the amnestic group scoring higher (6.20 (4.50-10.50); 16.44 (11.50-17.75)).&nbsp;Conclusion:&nbsp;Distinct correlations emerged between cognitive domains and PET activity based on early symptoms in EOAD patients, emphasizing the intricate heterogeneity within EOAD. The findings offer valuable insights for personalized interventions and advance our understanding of the multifaceted manifestations in the EOAD spectrum.</p

Neuroanatomical correlations of visuospatial processing in primary progressive aphasia.

Clinical phenotyping of primary progressive aphasia has largely focused on speech and language presentations, leaving other cognitive domains under-examined. This study investigated the diagnostic utility of visuospatial profiles and examined their neural basis among the three main primary progressive aphasia variants. We studied the neuropsychological performances of 118 primary progressive aphasia participants and 30 cognitively normal controls, across 11 measures of visuospatial cognition, and investigated their neural correlates via voxel-based morphometry analysis using visuospatial composite scores derived from principal component analysis. The principal component analysis identified three main factors: visuospatial-executive, visuospatial-memory and visuomotor components. Logopenic variant primary progressive aphasia performed significantly worst across all components; nonfluent/agrammatic variant primary progressive aphasia showed deficits in the visuospatial-executive and visuomotor components compared with controls; and the semantic variant primary progressive aphasia scored significantly lower than nonfluent/agrammatic variant primary progressive aphasia and control in the visuospatial-memory component. Grey matter volumes over the right parieto-occipital cortices correlated with visuospatial-executive performance; volumetric changes in the right anterior parahippocampal gyrus and amygdala were associated with visuospatial-memory function, and visuomotor composite scores correlated significantly with the grey matter volume at the right precentral gyrus. Discriminant function analysis identified three visuospatial measures: Visual Object and Space Perception and Benson figure copy and recall test, which classified 79.7% (94/118) of primary progressive aphasia into their specific variant. This study shows that each primary progressive aphasia variant also carries a distinctive visuospatial cognitive profile that corresponds with grey matter volumetric changes and in turn can be largely represented by their performance on the visuomotor, visuospatial-memory and executive functions