Semantic Dementia Versus Nonfluent Progressive Aphasia: Neuropsychological Characterization and Differentiation

Differential linguistic features of verbal fluency in behavioral variant frontotemporal dementia and primary progressive aphasia

Frontotemporal dementia (FTD) is an early-onset neurodegenerative disorder with a heterogeneous clinical presentation. Verbal fluency is regularly used as a sensitive measure of language ability, semantic memory, and executive functioning, but qualitative changes in verbal fluency in FTD are currently overlooked. This retrospective study examined qualitative, linguistic features of verbal fluency in 137 patients with behavioral variant (bv)FTD (n = 50), or primary progressive aphasia (PPA) [25 non-fluent variant (nfvPPA), 27 semantic variant (svPPA), and 34 logopenic variant (lvPPA)] and 25 control participants. Between-group differences in clustering, switching, lexical frequency (LF), age of acquisition (AoA), neighborhood density (ND), and word length (WL) were examined in the category and letter fluency with analysis of variance adjusted for age, sex, and the total number of words. Associations with other cognitive functions were explored with linear regression analysis. The results showed that the verbal fluency performance of patients with svPPA could be distinguished from controls and other patient groups by fewer and smaller clusters, more switches, higher LF, and lower AoA (all p < 0.05). Patients with lvPPA specifically produced words with higher ND than the other patient groups (p < 0.05). Patients with bvFTD produced longer words than the PPA groups (p < 0.05). Clustering, switching, LF, AoA, and ND-but not WL-were differentially predicted by measures of language, memory, and executive functioning (range standardized regression coefficient 0.25-0.41). In addition to the total number of words, qualitative linguistic features differ between subtypes of FTD. These features provide additional information on lexical processing and semantic memory that may aid the differential diagnosis of FTD.

Characterization of the logopenic variant of Primary Progressive Aphasia: A systematic review and meta-analysis

The linguistic and anatomical variability of the logopenic variant of Primary Progressive Aphasia (lv-PPA) as defined by current diagnostic criteria has been the topic of an intense debate. The present review and meta-analysis aims at characterizing the profile of lv-PPA, by a comprehensive analysis of the available literature on the neuropsychological, neuroimaging, electrophysiological, pathological, and genetic features of lv-PPA. We conducted a systematic bibliographic search, leading to the inclusion of 207 papers. Of them, 12 were used for the Anatomical Likelihood Estimation meta-analysis on grey matter revealed by magnetic resonance imaging data. The results suggest that the current guidelines outline a relatively consistent syndrome, characterized by a core set of linguistic and, to a lesser extent, non-linguistic deficits, mirroring the involvement of left temporal and parietal regions typically affected by Alzheimer Disease pathology. Variations of the lv-PPA profile are discussed in terms of heterogeneity of the neuropsychological instruments and the diagnostic criteria adopted.

Sentence Comprehension in Primary Progressive Aphasia: A Study of the Application of the Brazilian Version of the Test for the Reception of Grammar (TROG2-Br)

Sentence-comprehension deficits have been described in patients with primary progressive aphasia (PPA). However, most instruments to address this domain in more detail and in a clinical context have not been adapted and translated into several languages, posing limitations to clinical practice and cross-language research.

Objectives

The study aimed to (1) test the applicability of the Brazilian version of the Test for Reception of Grammar (TROG2-Br) to detect morphosyntactic deficits in patients with PPA; (2) investigate the association between performance in the test and sociodemographic and clinical variables (age, years of formal education, and disease duration); (3) characterize the performance of individuals presenting with the three more common variants of PPA (non-fluent, semantic, and logopenic) and mixed PPA (PPA-Mx) and analyze whether TROG-2 may assist in the distinction of these clinical profiles.

Methods

A total of 74 cognitively healthy participants and 34 individuals diagnosed with PPA were assessed with TROG2-Br. Overall scores (correct items, passed blocks), types, and categories of errors were analyzed.

Results

In controls, block scores were significantly correlated with years of formal education (Spearman's r = 0.33, p = 004) but not with age. In PPA, age, education, and disease duration were not significantly associated with performance in the test. Controls presented a significantly higher performance on TROG2-Br compared to PPA individuals and their errors pattern pointed to mild general cognitive processing difficulties (attention, working memory). PPA error types pointed to processing and morphosyntactic deficits in nonfluent or agrammatic PPA, (PPA-NF/A), logopenic PPA (PPA-L), and PPA-Mx. The semantic PPA (PPA-S) subgroup was qualitatively more similar to controls (processing difficulties and lower percentage of morphosyntactic errors). TROG2-Br presented good internal consistency and concurrent validity.

Discussion

Our results corroborate findings with TROG-2 in other populations. The performance of typical older adults with heterogeneous levels of education is discussed along with recommendations for clinical use of the test and future directions of research.

The semantic storage loss score: An Algorithm for measuring an individual's level of semantic storage loss due to temporal lobe damage in neurodegenerative disease

Anomia is common in Primary Progressive Aphasia (PPA), and there is considerable evidence that semantic problems (as opposed to impaired access to output word phonology) exist in many PPA individuals irrespective of their strict subtype, including a loss of representations from semantic memory, which is typical for people with the semantic variant of PPA. In this manuscript we present a straightforward novel clinical algorithm that quantifies this degree of semantic storage impairment. We sought to produce an algorithm by employing tasks that would measure key elements of semantic storage loss: a) whether an unrecalled name could be retrieved with cues; b) if performance for items was consistent across tasks; and c) the degree to which a participant’s performance was related to general severity of cognitive impairment rather than semantic loss. More specifically, these tasks were given to 28 individuals with PPA (12 participants had a clinical diagnosis of atypical Alzheimer’s Disease with the logopenic variant of PPA; the remaining 16 participants received a clinical diagnosis of Frontotemporal dementia (11 were classified as the non-fluent variant of PPA and five were the semantic variant of PPA). Scores from these tasks produced a single omnibus semantic memory storage loss score (SSL score) for each person that ranged from 0.0 to 1.0, with scores closer to 0 more indicative of semantic storage loss. Indeed, supporting the hypothesis that our scores measure the degree of semantic storage loss, we found participants with the semantic variant of PPA had the lowest scores, and SSL scores could predict the degree of hypometabolism in the anterior temporal lobe; even when only people with the logopenic variant of PPA were examined. Thus, these scores show promise quantitating the degree of a person’s semantic representation loss.

The Relationship between Behavioural Changes, Cognitive Symptoms, and Functional Disability in Primary Progressive Aphasia: A Longitudinal Study

BACKGROUND

The contribution of behavioural changes to functional decline is yet to be explored in primary progressive aphasia (PPA).

OBJECTIVES

(1) investigate functional changes in two PPA variants [semantic (svPPA) and non-fluent (nfvPPA)], at baseline and after 12 months; (2) investigate baseline differences in behavioural changes between groups, and (3) explore predictors of functional decline after a 12-month period.

METHODS

A longitudinal study involving 29 people with PPA (18 svPPA; 11 nfvPPA) seen annually in Sydney/Australia was conducted. A total of 114 functional and behavioural assessments were included for within-group (repeated-measures ANOVA; annual rate of change; multiple regression analyses) and between-group analyses (pairwise comparisons).

RESULTS

Functional profiles in svPPA and nfvPPA were similar in people with up to 5 years of disease duration. Behavioural changes were marked in svPPA patients (stereotypical behaviour and apathy) but did not predict annual rate of change of functional abilities; global cognitive scores at baseline did. Despite mild behavioural changes in nfvPPA (disinhibition, apathy), these were significant predictors of annual rate of functional change.

CONCLUSIONS

The presentation and interplay of behavioural changes and functional disability differ in svPPA and nfvPPA. These varying factors should be taken into account when considering prognosis, disease management, and selection of outcome measures for interventions.

Disorders of representation and control in semantic cognition: Effects of familiarity, typicality, and specificity

We present a case-series comparison of patients with cross-modal semantic impairments consequent on either (a) bilateral anterior temporal lobe atrophy in semantic dementia (SD) or (b) left-hemisphere fronto-parietal and/or posterior temporal stroke in semantic aphasia (SA). Both groups were assessed on a new test battery designed to measure how performance is influenced by concept familiarity, typicality and specificity. In line with previous findings, performance in SD was strongly modulated by all of these factors, with better performance for more familiar items (regardless of typicality), for more typical items (regardless of familiarity) and for tasks that did not require very specific classification, consistent with the gradual degradation of conceptual knowledge in SD. The SA group showed significant impairments on all tasks but their sensitivity to familiarity, typicality and specificity was more variable and governed by task-specific effects of these factors on controlled semantic processing. The results are discussed with reference to theories about the complementary roles of representation and manipulation of semantic knowledge.

Neuropsychological Profiles Differ among the Three Variants of Primary Progressive Aphasia

The objective of this study was to describe the neuropsychological profiles of the three variants of primary progressive aphasia (PPA). Based on a comprehensive speech and language evaluation, 91 subjects were classified as logopenic (lvPPA=51), semantic (svPPA=13), or agrammatic (agPPA=27). All subjects completed a separate neuropsychological evaluation assessing verbal and visual memory, processing speed, executive function, and visuospatial function. The groups did not differ on demographic variables or on measures of disease duration or aphasia severity. There were group differences on aspects of learning and memory, as well as aspects of executive and visuospatial functions, primarily with the lvPPA group performing lower than the agPPA and svPPA groups. The agPPA group showed subtle deficits consistent with frontal lobe impairment, whereas neurocognitive weaknesses in the svPPA group were restricted to temporal lobe functions. The pattern of neurocognitive dysfunction in lvPPA suggests disease involvement of frontal lobe functions in addition to temporoparietal functions. These neurocognitive findings emphasize the value of a comprehensive neuropsychological evaluation of individuals who present with primary language disturbance, given the pattern of cognitive deficits may provide additive information for differentiating these clinical syndromes.

Supporting communication for patients with neurodegenerative disease

BACKGROUND

Communication supports, referred to as augmentative and alternative communication (AAC), are an integral part of medical speech-language pathology practice, yet many providers remain unfamiliar with assessment and intervention principles. For patients with complex communication impairments secondary to neurodegenerative disease, AAC services differ depending on whether their condition primarily affects speech and motor skills (ALS), language (primary progressive aphasia) or cognition (Alzheimer's disease). This review discusses symptom management for these three conditions, identifying behavioral strategies, low- and high-tech solutions for implementation during the natural course of disease. These AAC principles apply to all neurodegenerative diseases in which common symptoms appear.

OBJECTIVES

To present AAC interventions for patients with neurodegenerative diseases affecting speech, motor, language and cognitive domains. Three themes emerge: (1) timing of intervention: early referral, regular re-evaluations and continual treatment are essential; (2) communication partners must be included from the onset to establish AAC acceptance and use; and (3) strategies will change over time and use multiple modalities to capitalize on patients' strengths.

CONCLUSIONS

AAC should be standard practice for adults with neurodegenerative disease. Patients can maintain effective, functional communication with AAC supports. Individualized communication systems can be implemented ensuring patients remain active participants in daily activities.

Semantic memory for actions as assessed by the Kissing and Dancing Test: Education and age effects in cognitively healthy individuals

Action semantics is a relevant part of cognitive-linguistic assessment and the "Kissing and Dancing Test" (KDT) has been used extensively for this purpose, evidencing clinical distinctions among brain-damaged patients. To enhance its use, reference values are necessary, especially for populations with heterogeneous educational levels and socioeconomic backgrounds.

Objective

To analyze the effects of schooling and age on the KDT in cognitively unimpaired individuals.

Methods

The KDT was applied to seventy-four healthy subjects. Sociodemographic factors were investigated through correlational and between-group analyses. Reference values according to age and schooling were provided.

Results

KDT performance correlated significantly with schooling (r=0.757, p<0.01), age (r=-0.496, p<0.01) and socioeconomic status (r=0.418 p<0.01) but these variables were intercorrelated. Correlation with schooling and age remained significant when controlling for age and socioeconomic status (r=0.530, p<0.01), and for schooling (-0.305,<0.01), respectively. When controlling for schooling, correlation between socioeconomic status and KDT was not significant (p=0.164). Between-group analyses revealed no age effects. Significant differences were found in performance according to educational level. Scores below 39/52 and below 47/52 (percentile 25) for individuals with 8 or less years of schooling and for individuals with 9 or more years of schooling, respectively, seem suggestive of an impairment in Action Semantics Processing and shall be further investigated.

Conclusion

KDT performance was influenced both by age and schooling, indicating the need to consider these demographic features as covariates when analyzing performance on the test and to adjust cut-off scores according to these demographic characteristics in clinical practice.

Clinical and Neuropsychological Characteristics of a Nationwide Hospital-Based Registry of Frontotemporal Dementia Patients in Korea: A CREDOS-FTD Study

BACKGROUND

We investigated the demographic, clinical, and neuropsychological characteristics of frontotemporal dementia (FTD) from the Clinical Research Center for Dementia of South Korea (CREDOS)-FTD registry.

METHODS

A total of 200 consecutive patients with FTD recruited from 16 neurological clinics in Korea were evaluated by cognitive and functional assessments, a screening test for aphasia, behavioral questionnaires, motor assessments, and brain MRI or PET.

RESULTS

In our registry, 78 patients were classified as having been diagnosed with behavioral-variant FTD (bvFTD), 70 with semantic dementia (SD), 33 with progressive nonfluent aphasia (PNFA), and 8 with motor neuron disease plus syndrome (MND-plus). The patients with language variants of dementia were older than those with bvFTD. There were no differences in sex ratio, duration of illness, or level of education among the four subgroups. Overall, the patients with bvFTD showed a significantly better performance in cognitive tests. A higher frequency of motor symptoms and a lower frequency of behavioral symptoms were found in PNFA than in bvFTD and SD. The Global Language Index was significantly lower in SD than in bvFTD and PNFA. The MND-plus group had a poorer performance than all the others in all cognitive domains.

CONCLUSION

The neuropsychological, behavioral, motor, and language characteristics of the four subtypes are comparable with those from other series. However, the proportion of SD (37.0%), which was similar to that of bvFTD (41.3%), was higher in our registry than in other series.

Evolution of language assessment in patients with acquired neurological disorders in Brazil

The objective of this paper was to describe the evolution of language assessments in patients with acquired neurological diseases over a period of around 45 years from 1970, when interdisciplinarity in Neuropsychology first began in Brazil, to the present day. The first twenty years of data was based on memories of Speech Pathology University Professors who were in charge of teaching aphasia. We then show the contributions of Linguistics, Cognitive Psychology, as well as Psycholinguistic and Psychometric criteria, to language evaluation. Finally, the current panorama of adaptations and creations of validated and standardized instruments is given, based on a search of the databases Pubmed, Scopus and Lilacs. Our closing remarks highlight the diversity in evaluation approaches and the recent tendency of language evaluations linked to new technologies such as brain imaging and computational analysis.

Translation, cross-cultural adaptation and applicability of the Brazilian version of the Frontotemporal Dementia Rating Scale (FTD-FRS)

BACKGROUND

Staging scales for dementia have been devised for grading Alzheimer's disease (AD) but do not include the specific symptoms of frontotemporal lobar degeneration (FTLD).

OBJECTIVE

To translate and adapt the Frontotemporal Dementia Rating Scale (FTD-FRS) to Brazilian Portuguese.

METHODS

The cross-cultural adaptation process consisted of the following steps: translation, back-translation (prepared by independent translators), discussion with specialists, and development of a final version after minor adjustments. A pilot application was carried out with 12 patients diagnosed with bvFTD and 11 with AD, matched for disease severity (CDR=1.0). The evaluation protocol included: Addenbrooke's Cognitive Examination-Revised (ACE-R), Mini-Mental State Examination (MMSE), Executive Interview (EXIT-25), Neuropsychiatric Inventory (NPI), Frontotemporal Dementia Rating Scale (FTD-FRS) and Clinical Dementia Rating scale (CDR).

RESULTS

The Brazilian version of the FTD-FRS seemed appropriate for use in this country. Preliminary results revealed greater levels of disability in bvFTD than in AD patients (bvFTD: 25% mild, 50% moderate and 25% severe; AD: 36.36% mild, 63.64% moderate). It appears that the CDR underrates disease severity in bvFTD since a relevant proportion of patients rated as having mild dementia (CDR=1.0) in fact had moderate or severe levels of disability according to the FTD-FRS.

CONCLUSION

The Brazilian version of the FTD-FRS seems suitable to aid staging and determining disease progression.

Nonpharmacological interventions for cognitive impairments following primary progressive aphasia: a systematic review of the literature

This study provided a systematic review on nonpharmacological interventions applied to patients diagnosed with Primary Progressive Aphasia (PPA) and its variants: Semantic (SPPA), Nonfluent (NFPPA) and Logopenic (LPPA) to establish evidence-based recommendations for the clinical practice of cognitive rehabilitation for these patients.

METHODS

A PubMed and LILACS literature search with no time restriction was conducted with the keywords PPA (and its variants) AND rehabilitation OR training OR intervention OR therapy OR treatment OR effectiveness. To develop its evidence-based recommendations, a research committee identified questions to be addressed and determined the level of evidence for each study according to published criteria (Cicerone et al., 2000). Overall evidence for treatments was summarized and recommendations were derived.

RESULTS

Our search retrieved articles published from 1995 to 2013: 21 for SPPA, 8 for NFPPA, 3 for LPPA and 8 for PPA with no specification. Thirty-five studies were rated as Class III, consisting of studies with results obtained from one or more single-cases and that used appropriate single-subject methods with adequate quantification and analysis of results. The level of evidence of three functional interventions could not be established. One study was rated as Class II and consisted of a nonrandomized case-control investigation.

CONCLUSION

Positive results were reported in all reviewed studies. However, in order to be recommended, some investigation regarding the intervention efficacy was required. Results of the present review allows for recommendation of some nonpharmacological interventions for cognitive deficits following PPA as Practice Options. Suggestions for further studies on PPA interventions and future research are discussed.

Frontotemporal lobar degeneration: epidemiology, pathology, diagnosis and management

Frontotemporal lobar degeneration (FTLD) describes a spectrum of clinically, pathologically and genetically heterogeneous neurodegenerative disorders of unknown aetiology. FTLD spectrum disorders collectively represent a leading cause of early-onset dementia, with most cases presenting between 45 and 64 years of age. FTLD is characterized by progressive changes in behaviour, executive dysfunction and/or language impairment and can be differentiated clinically into three frontotemporal dementia (FTD) syndromes as follows: (i) behavioural variant (bvFTD); (ii) semantic dementia (SD); and (iii) progressive nonfluent aphasia (PNFA). Additionally, there is a significant clinical, pathological and genetic overlap between FTD and motor neuron disease/amyotrophic lateral sclerosis (FTD-ALS) and the atypical parkinsonian syndromes, progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). bvFTD is characterized by progressive behavioural impairment and a decline in executive function with frontal lobe-predominant atrophy, SD by a loss of object knowledge with prominent anomia and asymmetrical atrophy of the anterior temporal lobes and PNFA by expressive or motor speech deficits with predominantly left peri-sylvian atrophy. Recent advances in molecular biology and immunohistochemical staining techniques have further classified the FTLD spectrum disorders based upon the predominant neuropathological protein into three main categories: (i) microtubule-associated protein tau (FTLD-TAU); (ii) TAR DNA-binding protein-43 (FTLD-TDP); and (iii) fused in sarcoma protein (FTLD-FUS). Up to 40% of FTD patients report a family history of neurodegenerative illness, and one-third to one-half of familial cases of FTD follow an autosomal dominant inheritance pattern. Mutations in MAPT, PGRN, TARDBP, VCP and CHMP2B have been described, along with a recently identified C9ORF72 hexanucleotide repeat expansion. To date, there are no US FDA-approved treatments or disease-modifying therapies for FTD. Pharmacological strategies have focused on neurotransmitter replacement and modulation for the treatment of behavioural, motor and cognitive symptoms of FTD, and include selective serotonin reuptake inhibitors (SSRIs), atypical antipsychotics, acetylcholinesterase inhibitors and glutamate NMDA receptor antagonists. At present, adequate management of FTD symptoms involves a combination of pharmacological therapy with behavioural, physical and environmental modification techniques.

The consequences of progressive phonological impairment for reading aloud

The 'primary systems' view of reading disorders proposes that there are no neural regions devoted exclusively to reading, and therefore that acquired dyslexias should reliably co-occur with deficits in more general underlying capacities. This perspective predicted that surface dyslexia, a selective deficit in reading aloud 'exception' words (those with atypical spelling-sound characteristics), should be a consistent feature of semantic dementia, a progressive disorder of conceptual knowledge, and just such a pattern has been observed in previous research. In a similar vein, one might expect the gradual deterioration of phonological processing seen in the nonfluent forms of progressive aphasia to be accompanied by phonological dyslexia, a selective deficit in reading of unfamiliar letter strings, i.e., nonwords. The present study, reporting a case-series consideration of reading-aloud data from 16 progressive nonfluent aphasic patients, revealed a pattern in which both low-frequency exception word and nonword reading were comparably compromised. The severity of the reading disorder was predicted by scores on the expressive language task of picture naming but not the receptive task of spoken word-to-picture matching. Our hypothesis that a phonological deficit underpins diminished performance for both naming and reading was supported by the finding that reading-aloud performance was predicted specifically by the rate of phonological errors in picture naming. Moreover, the strength of this relationship was similar for low-frequency exception words and nonwords, suggesting that reading deficits for these two types of items in this disorder shared a common cause: a progressive impairment of phonological processing.