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P Nestor

Publications and source records attributed to P Nestor.

9 recordsLinked to original sources
PubMed2001

A quantitative MR measure of the fornix in schizophrenia.

Some cognitive disturbances accompanying schizophrenia may be due to abnormalities in the thalamus and components of the limbic system. The fornix is an important white-matter relay pathway connecting these structures and is likely to be affected in schizophrenia as well.Magnetic resonance images of the fornix were analyzed in 15 schizophrenic patients and 15 matched comparison group subjects. Fornix volume was compared between the two groups and was also correlated with the volumes of other neuroanatomical structures, as well as with illness presentation, clinical status, and cognitive/psychological measures. There was no significant difference in fornix volume between the two groups. Of note, fornix volume correlated significantly with the volumes of the hippocampus, parahippocampus, and the superior temporal gyrus in the schizophrenic subjects, but not in the controls. Moreover, the correlation between fornix and parahippocampal gyrus volumes differed significantly between the two groups. No association was found between fornix volume and illness presentation or between fornix and cognitive/clinical measures.Results suggest that there are no marked changes in fornix volume in schizophrenia by MRI. The fornix, however, may be part of a network of structures affected in schizophrenia, as indicated by correlated volumetric changes.

Adult↗
PubMed2000

The effect of family status and schizotypy on electrophysiologic measures of attention and semantic processing.

BACKGROUND: Disturbances in both attention and language are central to the phenomenology of the schizophrenia spectrum disorders. The purpose of this study was to investigate the relative contributions of two factors, family status and schizotypy, on electrophysiologic measures of attention and semantic processing in family members of individuals with schizophrenia. METHODS: Fifteen first-degree relatives of individuals with schizophrenia and 15 comparison subject controls participated in diagnostic evaluations, an assessment of schizotypy, and two event-related potential (ERP) paradigms. The first paradigm was an auditory P300 "oddball" task designed to assess attentional functioning. The second was an N400 sentence paradigm particularly sensitive to language processing. RESULTS: Both relatives and individuals higher in schizotypy, but not their respective comparison groups, showed reductions in P300 amplitude. In the N400 paradigm, individuals higher in schizotypy, but not relatives, showed a reduced N400 effect. There were no differences in latency for either group on either component. CONCLUSIONS: The results suggest that both family status and schizotypal presentation independently contribute to disturbances in electrophysiologic measures sensitive to attention and language. Whereas higher levels of schizotypy appear to be associated with disturbances in both attention and language processing, family membership appears to place individuals at risk for attentional deficits alone.

Adult↗
PubMed2000

Non-Alzheimer dementias.

The past decade has seen a considerable resurgence of interest in non-Alzheimer forms of neurodegenerative dementia. Advances in our understanding and classification of these conditions have taken place over a diverse range of disciplines: from genetics and immunohistochemistry to neuropsychology and psychiatry. The aim of this article is to review, from a clinician's perspective, our current understanding of the major degenerative dementias that fall into the differential diagnosis of Alzheimer's disease. The clinical variants of frontotemporal dementia (semantic dementia, progressive nonfluent aphasia, and dementia of a frontal type), amyotrophic lateral sclerosis associated dementia, corticobasal degeneration, and dementia with Lewy bodies are considered.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Dementia handbook

Explore the source record for details and available documents.

Journal Article↗
PubMed1998

Identification of novel chicken estrogen receptor-alpha messenger ribonucleic acid isoforms generated by alternative splicing and promoter usage.

Using the rapid amplification of complementary DNA ends (RACE) methodology we have identified three new chicken estrogen receptor-alpha (cER alpha) messenger RNA (mRNA) variants in addition to the previously described form (isoform A). Whereas one of the new variants (isoform B) presents a 5'-extremity contiguous to the 5'-end of isoform A, the two other forms (isoforms C and D) are generated by alternative splicing of upstream exons (C and D) to a common site situated 70 nucleotides upstream of the translation start site in the previously assigned exon 1 (A). The 3'-end of exon 1C has been located at position -1334 upstream of the transcription start site of the A isoform (+1). Whereas the genomic location of exon 1D is unknown, 700 bp 5' to this exon were isolated by genomic walking, and their sequence was determined. The transcription start sites of the cER alpha mRNA isoforms were defined. In transfection experiments, the regions immediately upstream of the A-D cER alpha mRNA isoforms were shown to possess cell-specific promoter activities. Three of these promoters were down-regulated in the presence of estradiol and ER alpha protein. It is concluded, therefore, that the expression of the four different cER alpha mRNA isoforms is under the control of four different promoters. Finally, RT-PCR, S1 nuclease mapping, and primer extension analysis of these different cER alpha mRNA isoforms revealed a differential pattern of expression of the cER alpha gene in chicken tissues. Together, the results suggest that alternative 5'-splicing and promoter usage may be mechanisms used to modulate the levels of expression of the chicken ER alpha gene in a tissue-specific and/or developmental stage-specific manner.

Alternative Splicing↗
PubMed1993

Attention and driving. Assessment in elderly individuals with dementia.

Older drivers with dementia are involved in more crashes than healthy older drivers. Some investigators, therefore, have proposed that a diagnosis of dementia (DAT or other type) should lead to the automatic revocation of a driver's license. In the authors' view, however, renewal of license should be based on criteria related to driving competence rather than solely on chronologic age or a medical diagnosis. Unfortunately, current competency testing procedures do not assess the attentional factors discussed herewith that have been found to be important for safe driving. As the studies reviewed in this article reveal, there is good evidence that a skill test that predicts crash involvement in older drivers should incorporate attentional measures, in particular tests of attentional shifting based on dichotic listening and related tests. There is also evidence that attention-shifting measures are diagnostic of attention impairment in the early stages of Alzheimer-type dementia. Further research is needed to determine whether other attentional skills, such as sustained and divided attention, also need to be assessed. Additional work also is needed to refine attention tests for ease of use in the clinical setting. Lastly, although these attention measures account for only some of the variance contributing to crash involvement, they may allow for better predictive capability when combined with measures of other skills involved in driving. Driver training programs can complement driver testing procedures in serving the dual requirement for reducing crash risk among drivers with dementia while continuing to be responsive to their mobility needs. Information on the role of attention and other cognitive skills in safe driving should be made available, so that drivers (or their family members) who think they may have declining skills can seek further evaluation. Organizations such as automobile associations and retired persons groups can provide self-assessment inventories for completion by older drivers or referral for medical and neuropsychological evaluation. Finally, training techniques for improving attentional skills in drivers with DAT need to be developed and tested.

Adult↗
PubMed1989

Sustained-attention capacity in young and older adults.

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.

Adult↗