Functional imaging of working memory in Parkinson's disease: compensations and deficits.

Background And Purpose: Over and above typical motor alterations, executive and working memory (WM) impairment can also occur in early idiopathic Parkinson's disease (PD). We aimed to investigate the compensatory neural processes involved in WM performance, as well as the networks involved in the long-term memory transfer from short-term stores in PD.

Methods: Relative cerebral blood flow (rCBF) was mapped with H2O(15)-PET in eight treated nondemented PD patients while performing a WM verbal double-task (Brown-Peterson paradigm) using both short (6-second) and long (18-second) delays.

Neuropsychological and 18FDG-PET studies in a family with idiopathic basal ganglia calcifications.

Idiopathic basal ganglia calcification (FIBGC) is a rare autosomal dominant neurodegenerative disease, the main clinical signs of which are parkinsonism, cognitive deterioration and/or psychiatric troubles. Familial forms are rare. The underlying basis is not known.

Utility of the Mattis dementia rating scale to assess the efficacy of rivastigmine in dementia associated with Parkinson's disease.

Introduction: The severe, cortical, cholinergic depletion accompanying Parkinson's disease (PD) is considered as a highly probable correlate of cognitive and behavioural dysfunction. Recent studies have demonstrated that cholinesterase inhibitors (notably rivastigmine) are beneficial in patients suffering from dementia associated with PD (PDD). However, the primary efficacy variables used in such work came from scales designed for Alzheimer's disease (AD), even though the cognitive symptoms in PD and AD dementia do not overlap completely.

Virtual action planning in Parkinson's disease: a control study.

Cognitive planning deficits affect patients with Parkinson's disease (PD) and traditional psychometric tests meet difficulties to evaluate their impact on daily life activities. Virtual reality (VR) may provide a new means of assessment. The objective of this study was firstly to develop a virtual environment (VE) useful to explore planning and secondly to examine the effectiveness of using VR in the assessment of cognitive planning for patients with PD.

Reduced thalamic and cerebellar rest metabolism in relapsing-remitting multiple sclerosis, a positron emission tomography study: correlations to lesion load.

Magnetic resonance imaging (MRI) is the main tool for detecting central nervous system lesions in MS. However, classical anatomical MRI is unable to assess exactly disease related injury in normal-appearing brain tissue and to give information about the functional consequences of the disease, explaining weak correlation frequently observed between lesion load and clinical data. Recently, functional brain imaging techniques have provided new insights concerning pathophysiological processes of the disease.

Impairments of executive/attentional functions in schizophrenia with primary and secondary negative symptoms.

Frontal cognitive inabilities have been amply described in schizophrenic patients with negative symptoms, but findings are controversial. These discrepancies could be due to the fact that negative symptoms are heterogeneous, composed of primary and secondary negative symptoms. The hypothesis tested was that executive/attentional dysfunctions would be significantly more impaired in patients with primary than in patients with secondary negative symptoms independently of IQ, the severity of negative or positive symptoms, treatments and side effects.

[Frontal dysexecutive syndromes].

Investigation of executive functions is an approach which began with the early description of behavioral disorders induced by frontal damage. The development of neuropsychology has led to the description of a large variety of cognitive disorders. This type of approach has generated a large number of tests which are still used in clinical practice.

Executive processes in Parkinson's disease: FDG-PET and network analysis.

It is assumed widely that the clinical expression of Parkinson's Disease (PD), both motor and cognitive, is subtended by topographically distributed brain networks. However, little is known about the functional neuroanatomy of executive dysfunction in PD. Our objective was to validate further in a PD group the use of network analysis to assess the relationship between executive processes and pathological disorganization of frontostriatal networks.

Working memory and dopamine: clinical and experimental clues.

Working memory has been successively considered as a mnesic or executive process. The cognitive processes involved in working memory and the executive functions are closely linked. Most authors currently agree that executive functions include planning, attentional maintenance, mental flexibility and attentional inhibition.

Behavioral and neurofunctional changes over time in healthy and aphasic subjects: a PET Language Activation Study.

Background And Purpose: Follow-up neuroimaging studies of aphasia never addressed a comparison between aphasic and healthy subjects. Investigation of changes over time in healthy subjects during language tasks seems a prerequisite before interpretation of longitudinal changes in aphasic patients.

Methods: Six healthy subjects and 8 aphasic patients were PET scanned twice (PET1 and PET2) at a 1-year interval during a word generation task.

Functional imaging of cognition in Parkinson's disease.

Purpose Of Review: Cognitive deficits that occur even early in the course of Parkinson's disease have received increasing attention in current imaging research. The exact physio-pathological processes mediating the deficits and the complex relationship of cognitive signs and antiparkinsonian treatment are not well understood. A clearer understanding of these mechanisms could potentially influence treatment choices, drug development and, ultimately, patient care.

Verbal learning and memory in schizophrenic and Parkinson's disease patients.

The purpose of this study was to investigate the neurofunctional substrate of verbal learning and memory impairments in schizophrenic patients. In this pilot study, our aim was to compare the memory disturbance of schizophrenic patients to the subcortico-frontal memory profile of Parkinson's disease (PD) patients. The California Verbal Learning Test, a verbal episodic memory test, was administered to 60 subjects, 20 patients with schizophrenia, 20 patients with PD and 20 healthy control subjects.

Executive/attentional cognitive functions in schizophrenic patients and their parents: a preliminary study.

The aim of this study was to determine whether executive/attentional cognitive performances could be considered as markers of vulnerability to schizophrenia. The Stroop Color Word and fluency tests were significantly impaired in schizophrenic patients and their parents compared to controls matched on age and sex while performances on Nelson's Modified Card Sorting Test and the Trail Making Test did not differ. The impairments on the Stroop and fluency could be considered as endophenotypic markers of schizophrenia.