Posterior cortical atrophy

There is general agreement that perisylvian language cortex plays a major role in lexical and semantic processing; but the contribution of additional, more widespread, brain areas in the processing of different semantic word categories remains controversial. We investigated word processing in two groups of patients whose neurodegenerative diseases preferentially affect specific parts of the brain, to determine whether their performance would vary as a function of semantic categories proposed to recruit those brain regions...

OBJECTIVE: Patients with Lewy body disease develop a variety of psychotic and misperception symptoms, including visual hallucinations and delusions, as well as 'minor hallucinations', that is, a sense of presence, passage hallucinations and visual illusions. Although these symptoms have been suggested to have common underlying mechanisms, the commonalities and differences among them have not been systematically investigated at the neural level. METHODS: Sixty-seven patients with Parkinson's disease underwent neuropsychological and behavioural assessments, volumetric MRI and 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)...

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BACKGROUND: Nowadays, there are many techniques to compensate bone atrophies of the posterior maxilla in order to obtain an implant-supported rehabilitation. OBJECTIVE: This case series describes the Ebanist technique: a sinus lift procedure to be used in case of extremely resorbed bone crests (≤3 mm) allowing simultaneous implant placement. METHODS: With a dedicated cylindrical trephine bur, it is possible to harvest a cylinder of bone from a fresh mineralized frozen homologous bone block graft and to simultaneously create a trapdoor on the recipient site...

BACKGROUND/AIMS: Alzheimer's disease (AD) shows a characteristic pattern of brain atrophy, with predominant involvement of posterior limbic structures, and relative preservation of rostral limbic and primary cortical regions. We aimed to investigate the diagnostic utility of two gray matter volume ratios based on this pattern, and to develop a fully automated method to calculate them from unprocessed MRI files. PATIENTS AND METHODS: Cross-sectional study of 118 subjects from the ADNI database, including normal controls and patients with mild cognitive impairment (MCI) and AD...

Higher body mass index (BMI) at midlife is associated with greater decreases in cognitive function at older age as well as increased Alzheimer's disease (AD) risk, compared to those with normal BMI. Here, we tested whether BMI at midlife was associated with cortical thinning in brain regions known to be affected in early AD. We examined a large sample (n = 404) of midlife individuals (44-49 years) from the PATH population-based study. Individuals were scanned with magnetic resonance imaging (1.5T) on up to three occasions over eight years...

The purpose of this investigation is to evaluate 2 different methods for reducing cortical wall thickness in sinus floor augmentation surgery. A manual bone scraper was compared in terms of efficacy, speed, and safety to an ultrasonic insert for osteoplasty, in a randomized controlled clinical trial with a split-mouth design. Twenty-five patients with severe posterior maxillary atrophy were treated with bilateral sinus floor elevation with lateral approach. Antrostomies were randomly performed by eroding the cortical wall with a manual bone scraper (test site) or with an ultrasonic insert (control site) until the membrane was visible under a thin layer of bone, before outlining the window with a piezoelectric device...

A 63-year-old woman presented to her ophthalmologist complaining of reading difficulties for two years. Ophthalmological examination revealed a homonymous hemianopsia. Brain magnetic resonance imaging (MRI) scan was interpreted as normal, but positron emission tomography (PET) showed areas of posterior brain hypometabolism. This case highlights the high diagnostic suspicion that ophthalmologists should have regarding posterior cortical atrophy (including the visual variant of Alzheimer disease) in patients complaining of reading difficulties in the setting of a normal ophthalmic examination...

Alien hand syndrome (AHS) is a neurological illness characterized by limb movements which are carried out without being aware of it. Many patients describe these movements as aggressive and some perceive a strong feeling of estrangement and go so far as to deny ownership. The sense of body ownership is the perception that parts of one's body pertain to oneself, despite it is moving or not and if movement is intentional or unintentional. These anomalous self-experiences may arise in patients with focal brain lesions and provide unique opportunities to disclose the neural components underlying self-body perception...

BACKGROUND: A three-dimensionally favourable mandibular bone crest is desirable to be able to successfully implant placement to meet the aesthetic and functional criteria in the implant-prosthetic rehabilitation. Several surgical procedures have been advocated for bone augmentation of the atrophic mandible, and the sandwich osteotomy is one of these techniques. The aim of the present case report was to assess the suitability of segmental mandibular sandwich osteotomy combined with a tunnel technique of soft tissue...

Our brains represent spatial information in egocentric (self-based) or allocentric (landmark-based) coordinates. Rodent studies have demonstrated a critical role for the caudate in egocentric navigation and the hippocampus in allocentric navigation. We administered tests of egocentric and allocentric working memory to individuals with premotor Huntington's disease (pmHD), which is associated with early caudate nucleus atrophy, and controls. Each test had 80 trials during which subjects were asked to remember 2 locations over 1-sec delays...

Atrophy patterns on MRI can reliably predict three neuropathological subtypes of Alzheimer's disease (AD): typical, limbic-predominant, or hippocampal-sparing. A method to enable their investigation in the clinical routine is still lacking. We aimed to (1) validate the combined use of visual rating scales for identification of AD subtypes; (2) characterise these subtypes at baseline and over two years; and (3) investigate how atrophy patterns and non-memory cognitive domains contribute to memory impairment...

Age-related brain atrophy is a common finding, but neurodegenerative diseases such as Alzheimer's disease are associated with accelerated atrophy of the medial temporal lobe. In current practice for brain atrophy evaluation, several rating scales are being used such as the medial temporal atrophy (MTA), global cortical atrophy-frontal subscale (GCA-F) and posterior atrophy (PA) scales. Practical cut-offs to differentiate between normal and advanced brain atrophy are needed, because of their possible usefulness as a biomarker...

BACKGROUND: Flortaucipir (tau) positron emission tomography (PET) binding distinguishes individuals with clinically well-established posterior cortical atrophy (PCA) due to Alzheimer disease (AD) from cognitively normal (CN) controls. However, it is not known whether tau-PET binding patterns differentiate individuals with PCA from those with amnestic AD, particularly early in the symptomatic stages of disease. METHODS: Flortaucipir and florbetapir (β-amyloid) PET imaging were performed in individuals with early-stage PCA (N=5), amnestic AD dementia (N=22), and CN controls (N=47)...

PURPOSE: Treatment of severe bone atrophy of the posterior mandible requires an advanced surgical bone augmentation technique. This report describes a minimally invasive approach for a residual alveolar height less than 5 mm. MATERIAL AND METHODS: A retrospective case series was conducted in a single private dental clinic. Outcome variables were dental implant survival rate, intraoperative complications, occurrence of neurosensory disturbances, and marginal bone loss...

Posterior cortical atrophy (PCA) is a syndrome caused by a neurodegenerative disease that often presents with visuospatial deficits, and can be debilitating. PCA is often characterized by elements of Balint's syndrome and dyslexia. The most common underlying pathology has been found to be Alzheimer's disease. Signs of horizontal neglect are frequently associated with PCA, but the presence of vertical (or altitudinal) neglect has not yet been reported in a patient with PCA or other forms of neurodegenerative dementia...

Compromised autobiographical memory (ABM) retrieval is well established in dementia, attributable to degeneration of a core memory brain network. It remains unclear, however, how the progressive spread of atrophy with advancing disease severity impacts ABM retrieval across life epochs. To this end, we conducted a longitudinal study of recent and remote ABM in Alzheimer's disease (AD, n =11), and a frontotemporal lobar degeneration group (FTD, n =13) comprising 7 behavioral variant FTD and 6 semantic dementia patients, in comparison with 23 healthy older Controls...

Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, with peripheral vision. Thus, agnosic vision is like peripheral vision. We obtained 14 visual-object-recognition tests that are commonly used for diagnosis of visual agnosia...

BACKGROUND: Patients with multiple sclerosis (MS) frequently reveal social behavior disturbance. Nevertheless, little is known regarding the impact of MS on social cognition, particularly theory of mind (ToM), and its neural basis. OBJECTIVES: To explore how ToM is affected in MS and its neural correlates. METHODS: Enrolled 60 consecutive MS patients and 60 healthy controls (HC) matched on age, sex, and education. Participants underwent ToM testing (Eyes Test, Videos Test) and 3 T brain magnetic resonance imaging (MRI)...

OBJECTIVES: We hypothesize that the combined use of MRI cortical thickness measurement and subcortical gray matter volumetry could provide an early and accurate in vivo assessment of the structural impact of cardiac arrest and therefore could be used for long-term neuroprognostication in this setting. DESIGN: Prospective cohort study. SETTING: Five Intensive Critical Care Units affiliated to the University in Toulouse (France), Paris (France), Clermont-Ferrand (France), Liège (Belgium), and Monza (Italy)...