Cortical and subcortical aphasias compared

Abstract

Controversy surrounds differences between cortical and subcortical aphasias and their underlying pathophysiological mechanisms, but the necessary direct comparisons between clinical characteristics of patients with the two lesion types are lacking. We compared 36 stroke patients with subcortical lesions to 42 with cortical lesions of similar volume to determine the frequency, severity, and types of aphasia found in each group, and to examine subcortical clinicoanatomical correlations. Tested on the Western Aphasia Battery (WAB), the two groups did not significantly differ either in overall aphasia severity or on any WAB subtest scores. Although some individuals had relative preservation of repetition, we did not confirm an overall difference between patients with cortical and subcortical lesions in their ability to repeat. All subcortical patients were classifiable using the WAB and a broad spectrum of aphasia types was seen. Lesion volume did not significantly correlate with aphasia severity but anatomical features of subcortical lesions on computerized tomography (CT) could be related in many instances to the type of aphasia seen. However, variability in the deficits of patients with similar subcortical lesions still precludes the establishment of firm clinicoanatomical correlations or a unifying theory of subcortical involvement in language based on these data.     

Neuropeptide Y Attenuates Stress‐Induced Bone Loss Through Suppression of Noradrenaline Circuits

Chronic stress and depression have adverse consequences on many organ systems, including the skeleton, but the mechanisms underlying stress‐induced bone loss remain unclear. Here we demonstrate that neuropeptide Y (NPY), centrally and peripherally, plays a critical role in protecting against stress‐induced bone loss. Mice lacking the anxiolytic factor NPY exhibit more anxious behavior and elevated corticosterone levels. Additionally, following a 6‐week restraint, or cold‐stress protocol, Npy‐null mice exhibit three‐fold greater bone loss compared to wild‐type mice, owing to suppression of osteoblast activity. This stress‐protective NPY pathway acts specifically through Y2 receptors. Centrally, Y2 receptors suppress corticotropin‐releasing factor expression and inhibit activation of noradrenergic neurons in the paraventricular nucleus. In the periphery, they act to control noradrenaline release from sympathetic neurons. Specific deletion of arcuate Y2 receptors recapitulates the Npy‐null stress response, coincident with elevated serum noradrenaline. Importantly, specific reintroduction of NPY solely in noradrenergic neurons of otherwise Npy‐null mice blocks the increase in circulating noradrenaline and the stress‐induced bone loss. Thus, NPY protects against excessive stress‐induced bone loss, through Y2 receptor‐mediated modulation of central and peripheral noradrenergic neurons. © 2014 American Society for Bone and Mineral Research.     

The patterns of progression in primary progressive aphasia—Implications for assessment and management

Background: Primary progressive aphasia (PPA) is a progressive language disorder with preserved cognitive function for at least 2 years from onset. The main variants currently distinguished are: non-fluent/agrammatic (nfvPPA), semantic (svPPA), and logopenic (lvPPA). Patients with initial language presentation may subsequently develop other symptoms, such as behavioural dysfunction or apraxia. The clinical pattern of PPA depends on the location of atrophy, the underlying pathology, and the stage of the disease.

Aims: This review aims at characterising longitudinal changes in clinical presentations of different PPA variants and at presenting implications of these changes for the assessment, diagnosis, and management.

Main contribution: The three PPA variants differ not only in terms of language impairment, but also with regard to cognitive and behavioural profile. Apraxia and rigidity frequently occur in the course of nfvPPA. Patients with lvPPA seem to follow the pattern of aphasic Alzheimer’s disease, where language impairment is accompanied by episodic memory deficit. Individuals diagnosed with svPPA often develop behavioural dysfunction similar to that observed in behavioural variant of frontotemporal dementia.

Conclusions: Implications for patient care are dependent on PPA variant and on the stage of the disease. In svPPA, emphasis should be on the management of semantic and behavioural problems in daily life. Caregivers of nfvPPA patients should be informed about the possible emergence of apraxia and other movement disorders. In contrast, families of individuals with lvPPA should be made aware of and trained to cope with an episodic memory decline and possible progression to other varieties of PPA.     

The use of 7-amino actinomycin D in identifying apoptosis: simplicity of use and broad spectrum of application compared with other techniques

The detection and quantitation of apoptotic cells is becoming increasingly important in the investigation of the role of apoptosis in cellular proliferation and differentiation. The pathogenesis of hematologic disorders such as aplastic anemia and the development of neoplasia are believed to involve dysregulation of apoptosis. To quantitate accurately the proportion of apoptosis cells within different cell types of a heterogeneous cell population such as blood or bone marrow, a method is required that combines the analysis of large numbers of cells with concurrent immunophenotyping of cell surface antigens. In this study, we have evaluated such a method using the fluorescent DNA binding agent, 7-amino actinomycin D (7AAD), to stain three diverse human cell lines, induced to undergo apoptosis by three different stimuli. Flow cytometric analysis defines three populations on the basis of 7AAD fluorescence and forward light scatter. We have shown by cell sorting and subsequent morphological assessment and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling that the populations defined by 7AAD represent live, apoptotic, and late-apoptotic/dead cells. This method is quick, simple, reproducible, and cheap and will be a valuable tool in the investigation of the role of apoptosis in normal physiology and in disease states.     

Primary progressive aphasia: a review of the neurobiology of a common presentation of Pick complex

Primary progressive aphasia (PPA) is an identifiable and distinct form of clinical presentation of focal degenerative disease. The underlying pathology is often considered heterogeneous, but we propose that, in fact, this syndrome has a characteristic underlying neurobiology related to Pick's disease and frontotemporal dementia. The authors reviewed the literature of PPA andfound 58 cases with autopsy. The majority of the cases had related underlying pathology, termed "Pick complex," a form of non-Alzheimer's dementia. This includes Pick's disease, corticobasal degeneration, dementia lacking distinctive histology, and motor neuron disease inclusions. Several of the cases described with focal Alzheimer's pathology do not fulfill the criteria of PPA, but have Alzheimer's disease with a major aphasic component.     

The corticobasal degeneration syndrome overlaps progressive aphasia and frontotemporal dementia

OBJECTIVE: To provide evidence for the hypothesis that the corticobasal degeneration syndrome (CBDs) overlaps significantly with primary progressive aphasia and frontotemporal dementia, and that CBDs is part of the Pick complex. BACKGROUND: Corticobasal degeneration has been mainly described as a movement disorder, but cognitive impairment is also increasingly noted. METHODS: Thirty-five cases of clinically diagnosed CBDs were followed-up with clinical, neuropsychological, and neuroimaging investigations. Twenty-nine patients were seen prospectively in movement disorder and cognitive neurology clinics; five of these came to autopsy. Six other autopsied cases that fulfilled the clinical criteria of CBDs were added with retrospective review of records. RESULTS: All 15 patients presenting with movement disorders developed behavioral, cognitive, or language deficits shortly after onset or after several years. Patients presenting with cognitive problems (n = 20), progressive aphasia (n = 13), or frontotemporal dementia (n = 7) developed the movement disorder subsequently. Eleven cases with autopsy had CBD or other forms of the Pick complex. CONCLUSIONS: There is a clinical overlap between CBD, frontotemporal dementia, and primary progressive aphasia. There is also a pathologic overlap between these clinical syndromes. The recognition of this overlap will facilitate the diagnosis and avoid consideration of CBD as "heterogenous."     

Volumetric study of lobar atrophy in Pick complex and Alzheimer's disease

BACKGROUND: Lobar atrophy is an important neuroimaging feature of Pick complex (PiC). However, differences in patterns of focal brain atrophy between PiC and Alzheimer's disease (AD), and among PiC subgroups, have not been studied quantitatively. OBJECTIVE: To compare volumetric measures among primary progressive aphasia (PPA), frontotemporal dementia (FTD) and AD; to assess association between brain atrophy and cognition. PATIENTS: Seventeen patients with PPA, 11 with FTD and 24 with probable AD were studied. METHODS: We measured total and regional volume quantitatively using MRI and computerized volumetry. Contributing factors were controlled statistically or by adopting brain volume ratios. We investigated the classifying power of volumetry and correlated regional brain volume with cognitive and language test scores. RESULTS: The ratio for fronto-temporo-central region was smaller on the left in PPA and on the right in FTD. AD and some PPA patients had smaller parietal lobes. The frontal ratios correctly classified 93% of PPA and FTD patients, but only 50% of the entire PiC and AD patients. Language-dependent examinations correlated with the left fronto-temporal volume. CONCLUSIONS: Brain atrophy differs in PPA, FTD and AD, but there is some morphological overlap between PiC and AD in parietal volumes. Focal brain atrophy is most consistently associated with language impairments.