Cortical and behavioral correlates of alexia in primary progressive aphasia and Alzheimer's disease.

The underlying causes of reading impairment in neurodegenerative disease are not well understood. The current study seeks to determine the causes of surface alexia and phonological alexia in primary progressive aphasia (PPA) and typical (amnestic) Alzheimer's disease (AD). Participants included 24 with the logopenic variant (lvPPA), 17 with the nonfluent/agrammatic variant (nfvPPA), 12 with the semantic variant (svPPA), 19 with unclassifiable PPA (uPPA), and 16 with AD.

Cerebellar tDCS Enhances Functional Communication Skills in Chronic Aphasia.

Background: Transcranial direct current stimulation (tDCS) has emerged as a possible neuromodulatory tool to augment language therapy in post-stroke aphasia. However, there is limited information on whether tDCS may help to improve everyday functional communication.

Aims: To investigate whether cerebellar tDCS combined with computerized aphasia treatment improves functional communication skills in individuals with chronic aphasia.

An international core outcome set for primary progressive aphasia (COS-PPA): Consensus-based recommendations for communication interventions across research and clinical settings.

Introduction: Interventions to treat speech-language difficulties in primary progressive aphasia (PPA) often use word accuracy as a highly comparable outcome. However, there are more constructs of importance to people with PPA that have received less attention.

Methods: Following Core Outcome Set Standards for Development Recommendations (COSSTAD), this study comprised: Stage 1 - systematic review to identify measures; Stage 2 - consensus groups to identify important outcome constructs for people with PPA (n = 82) and care partners (n = 91); Stage 3 - e-Delphi consensus with 57 researchers.

Stability of ECoG high gamma signals during speech and implications for a speech BCI system in an individual with ALS: a year-long longitudinal study.

Speech brain-computer interfaces (BCIs) have the potential to augment communication in individuals with impaired speech due to muscle weakness, for example in amyotrophic lateral sclerosis (ALS) and other neurological disorders. However, to achieve long-term, reliable use of a speech BCI, it is essential for speech-related neural signal changes to be stable over long periods of time. Here we study, for the first time, the stability of speech-related electrocorticographic (ECoG) signals recorded from a chronically implanted ECoG BCI over a 12 month period.

Long-term, home-based transcranial direct current stimulation coupled with computerized cognitive training in frontotemporal dementia: A case report.

We present the case of a 62-year-old woman with probable behavioral variant of frontotemporal dementia (bvFTD) with cognitive/language deficits who demonstrated improved performance on cognitive/language testing and in functional tasks following long-term, home-based transcranial direct current stimulation (tDCS) coupled with computerized cognitive training (CCT). The patient underwent home-based tDCS (anode on the left prefrontal cortex and cathode on the right homologue) for 46 sessions over 10 weeks along with CCT. On post-treatment testing, the patient improved by 3 points on the Mini-Mental State Exam (MMSE) (23 to 26).

Home-Based Transcranial Direct Current Stimulation in Primary Progressive Aphasia: A Pilot Study.

Background: This study aims to determine (a) if home-based anodal transcranial direct current stimulation (a-tDCS) delivered to the left supramarginal gyrus (SMG) coupled with verbal short-term memory/working memory (vSTM/WM) treatment ("RAM", short for "Repeat After Me") is more effective than sham-tDCS in improving vSTM/WM in patients with primary progressive aphasia (PPA), and (b) whether tDCS effects generalize to other language and cognitive abilities.

Methods: Seven PPA participants received home-based a-tDCS and sham-tDCS coupled with RAM treatment in separate conditions in a double-blind design. The treatment task required participants to repeat word spans comprising semantically and phonologically unrelated words in the same and reverse order.

Online speech synthesis using a chronically implanted brain-computer interface in an individual with ALS.

Brain-computer interfaces (BCIs) that reconstruct and synthesize speech using brain activity recorded with intracranial electrodes may pave the way toward novel communication interfaces for people who have lost their ability to speak, or who are at high risk of losing this ability, due to neurological disorders. Here, we report online synthesis of intelligible words using a chronically implanted brain-computer interface (BCI) in a man with impaired articulation due to ALS, participating in a clinical trial (ClinicalTrials.gov, NCT03567213) exploring different strategies for BCI communication.

Baseline Conceptual-Semantic Impairment Predicts Longitudinal Treatment Effects for Anomia in Primary Progressive Aphasia and Alzheimer's Disease.

Background: An individual's diagnostic subtype may fail to predict the efficacy of a given type of treatment for anomia. Classification by conceptual-semantic impairment may be more informative.

Aims: This study examined the effects of conceptual-semantic impairment and diagnostic subtype on anomia treatment effects in primary progressive aphasia (PPA) and Alzheimer's disease (AD).

Criteria and Indicators for Centers of Clinical Excellence in Stroke Recovery and Rehabilitation: A Global Consensus Facilitated by ISRRA.

Background: The aim of the International Stroke Recovery and Rehabilitation Alliance is to create a world where worldwide collaboration brings major breakthroughs for the millions of people living with stroke. A key pillar of this work is to define globally relevant criteria for centers that aspire to deliver excellent clinical rehabilitation and generate exceptional outcomes for patients.

Objectives: This paper presents consensus work conducted with an international group of expert stroke recovery and rehabilitation researchers, clinicians, and people living with stroke to identify and define criteria and measurable indicators for Centers of Clinical Excellence (CoCE) in stroke recovery and rehabilitation.

Verb Frequency and Density Drive Naming Performance in Primary Progressive Aphasia.

Background: Recent work has highlighted the utility of the Boston Naming Test and Hopkins Action Naming Assessment (HANA) for distinguishing between semantic (svPPA), logopenic (lvPPA) and non-fluent agrammatic (nfavPPA) variants of primary progressive aphasia (PPA).

Aims: To determine whether item level differences between variants on when naming verbs on the HANA were able to be accounted for using common variables of lexical interest: word frequency, semantic density, concreteness, or valency. We also examined three specific hypotheses: (1) svPPA and lvPPA may result in increased difficulty with decreased semantic density compared to nfavPPA; (2) svPPA may result in increased difficulty with decreased concreteness; and (3) nfavPPA may result in increased difficulty with high syntactic valency.

Stable Decoding from a Speech BCI Enables Control for an Individual with ALS without Recalibration for 3 Months.

Brain-computer interfaces (BCIs) can be used to control assistive devices by patients with neurological disorders like amyotrophic lateral sclerosis (ALS) that limit speech and movement. For assistive control, it is desirable for BCI systems to be accurate and reliable, preferably with minimal setup time. In this study, a participant with severe dysarthria due to ALS operates computer applications with six intuitive speech commands via a chronic electrocorticographic (ECoG) implant over the ventral sensorimotor cortex.

When words first fail: Predicting the emergence of primary progressive aphasia variants from unclassifiable anomic performance in early disease.

Background: The majority of patients with primary progressive aphasia (PPA) can be distinguished into one of three variants: semantic, non-fluent/agrammatic, or logopenic. However, many do not meet criteria for any one variant.

Aim: To identify aspects of cognitive-linguistic performance that yield an early unclassifiable PPA designation that predicted the later emergence of a given variant.

Transcranial Direct-Current Stimulation in Subacute Aphasia: A Randomized Controlled Trial.

Background: Transcranial direct-current stimulation (tDCS) is a promising adjunct to therapy for chronic aphasia.

Methods: This single-center, randomized, double-blind, sham-controlled efficacy trial tested the hypothesis that anodal tDCS augments language therapy in subacute aphasia. Secondarily, we compared the effect of tDCS on discourse measures and quality of life and compared the effects on naming to previous findings in chronic stroke.

Association of Regional Atrophy With Naming Decline in Primary Progressive Aphasia.

Background And Objectives: Primary progressive aphasia (PPA) is a neurodegenerative condition that predominantly impairs language. Most investigations of how focal atrophy affects language consider 1 time point compared with healthy controls. However, true atrophy quantification requires comparing individual brains over time.

Neural regions underlying object and action naming: Complementary evidence from acute stroke and primary progressive aphasia.

Background: Naming impairment is commonly noted in individuals with aphasia. However, object naming receives more attention than action naming. Furthermore, most studies include participants with aphasia due to only one aetiology, commonly stroke.

Application of the dual stream model to neurodegenerative disease: Evidence from a multivariate classification tool in primary progressive aphasia.

Background: A clinical diagnosis of primary progressive aphasia relies on behavioral characteristics and patterns of atrophy to determine a variant: logopenic; nonfluent/agrammatic; or semantic. The dual stream model (Hickok & Poeppel, 2000; 2004; 2007; 2015) is a contemporary paradigm that has been applied widely to understand brain-behavior relationships; however, applications to neurodegenerative diseases like primary progressive aphasia are limited.

Aims: The primary aim of this study is to determine if the dual stream model can be applied to a neurodegenerative disease, such as primary progressive aphasia, using both behavioral and neuroimaging data.

Clinical and neuroimaging characteristics of primary progressive aphasia.

The chapter covers the clinical syndrome of a primary progressive aphasia (PPA), the demographics of this rare neurodegenerative disease, defining clinical and neuroanatomic characteristics of each PPA variant, disease progression, and behavioral features. The chapter begins with a brief introduction that includes references to seminal papers that defined this clinical syndrome and its three variants. The classic PPA subtypes discussed in the chapter are semantic variant PPA (svPPA), nonfluent/agrammatic PPA (nfaPPA), and logopenic variant PPA (lvPPA).

Task performance to discriminate among variants of primary progressive aphasia.

Primary progressive aphasia can be distinguished into one of three variants: semantic, non-fluent/agrammatic, and logopenic. While a considerable body of work exists characterizing each variant, few prior studies have addressed the problem of optimizing behavioral assessment in a typical outpatient evaluation setting. Our aim is to examine the sensitivity and specificity of a battery of cognitive and linguistic assessments and determine optimal scores for distinguishing patients' subtype based on these instruments.

Longitudinal decline in spoken word recognition and object knowledge in primary progressive aphasia.

The premise of this study is that spoken word recognition and object knowledge are impaired in semantic variant primary progressive aphasia (PPA) (svPPA) and are spared in logopenic variant (lvPPA) and nonfluent agrammatic primary progressive aphasia (nfaPPA) at disease onset. Over time, however, there may be heterogeneity in these abilities in lvPPA and nfaPPA. We hypothesized that individuals with svPPA would demonstrate poorer performance on baseline spoken word recognition and object knowledge than those with lvPPA and nfaPPA) as documented in the literature, but that rates of decline over time on spoken word recognition and object knowledge would be similar in all 3 PPA variants because these become less distinguishable with disease progression.

Visuomotor Figure Construction and Visual Figure Delayed Recall and Recognition in Primary Progressive Aphasia.

Background: Individuals with primary progressive aphasia (PPA) develop visuospatial deficits over time, and those with logopenic variant (lvPPA) are at greatest risk of developing such deficits. However, not all previous studies of visuospatial deficits in PPA have ensured equivalent duration of disease across variants and few have measured deficits longitudinally.

Aims: The aims of our study were to: 1) investigate differences in baseline visuomotor figure construction, visual figure delayed recall, and figure recognition in PPA variants with similar symptom duration at baseline, and 2) explore patterns of decline in these areas.

Cerebellar neuromodulation improves naming in post-stroke aphasia.

Transcranial direct current stimulation has been shown to increase the efficiency of language therapy in chronic aphasia; however, to date, an optimal stimulation site has not been identified. We investigated whether neuromodulation of the right cerebellum can improve naming skills in chronic aphasia. Using a randomized, double-blind, sham-controlled, within-subject crossover study design, participants received anodal cerebellar stimulation ( = 12) or cathodal cerebellar stimulation ( = 12) + computerized aphasia therapy then sham + computerized aphasia therapy, or the opposite order.

An Efficient Bedside Measure Yields Prognostic Implications for Language Recovery in Acute Stroke Patients.

Background: It is estimated that ∼30% of stroke survivors have aphasia, a language disorder resulting from damage to left-hemisphere language networks. In acute care settings, efficient identification of aphasia is critical, but there is a paucity of efficient bedside assessments.

Objective: To determine whether objective measures on a picture description task administered within 48 hours post stroke (a) predict language recovery, (b) estimate left-hemisphere lesion volume and location, and (c) correlate with other bedside language assessments.

White Matter Hyperintensities Contribute to Language Deficits in Primary Progressive Aphasia.

Objective: To determine the contribution of white matter hyperintensities (WMH) to language deficits while accounting for cortical atrophy in individuals with primary progressive aphasia (PPA).

Method: Forty-three individuals with PPA completed neuropsychological assessments of nonverbal semantics, naming, and sentence repetition plus T2-weighted and fluid-attenuated inversion recovery scans. Using three visual scales, we rated WMH and cerebral ventricle size for both scan types.

Ethical and Practical Challenges of the Communication and Behavioral Manifestations of Primary Progressive Aphasia.

The communication and behavioral manifestations of primary progressive aphasia (PPA) present ethical and practical challenges for individuals with this clinical syndrome as well as for individuals who are involved closely in their care. In this article, cases representing all three PPA variants (logopenic variant, nonfluent agrammatic, semantic variant) are presented to illustrate commonly encountered situations in which self-determination is at risk in decisions about housing, driving, social interactions, finances, and treatment interventions. Potential approaches, including patient/family education, implementation of safeguards, redirection to meaningful activities, and protections against vulnerability in treatment decisions, are described to preserve autonomy in patients with this neurodegenerative clinical syndrome.

Leukoaraiosis Severity Predicts Rate of Decline in Primary Progressive Aphasia.

Background: The rate of decline in language in Primary Progressive Aphasia (PPA) is highly variable and difficult to predict at baseline. The severity of diffuse white matter disease (leukoaraiosis), a marker of overall brain health, may substantially influence the rate of decline.

Aims: To test the hypothesis that leukoaraiosis is associated with a steeper decline in naming in PPA.