RESUMEN
OBJECTIVE: This study aims to record the overall perception of healthcare professionals on child abuse and identify potential affecting factors in a nationwide scale in Greece as well as to provide information that might be useful for future educational actions. MATERIALS AND METHODS: A total of 1,185 healthcare professionals in 60 hospitals with pediatric departments across Greece participated in this cross-sectional study. Participants included pediatricians, pediatric surgeons, residents, nurses, psychiatrists, psychologists, and social workers. Sections under investigation involved experience and training in child abuse, knowledge of formal and judicial issues, clinical knowledge, and self-assessment. RESULTS: Although more than half of the participants had confronted child abuse (n=712, 60.08%), only 273 (38.34% of them) submitted reports. One third of participants reported that they had received some training (n=440, 37.13%), mainly of postgraduate nature and based on personal initiative. Of those who reported child abuse, 175 (64.10%) had been trained. Each professional category was aware of topics regarding its own interest, without adequate knowledge of other disciplines. One third of psychiatrists, psychologists, and social workers felt confident in discussing with children and parents. Relevant scores were lower in the other categories. The lower scores were recorded among nurses and residents. The training deficit and reluctance to engage with judicial issues were the main causes of avoidance to deal with child abuse. CONCLUSIONS: Focused and organized training in child abuse is crucial to create reliable professionals in the field. The internet is a considerably helpful tool. Professionalism must characterize knowledge and practice in child abuse at the same level as in other medical topics. Motivation to engage should be early inspired and developed during the graduate years.
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Maltrato a los Niños , Niño , Humanos , Grecia , Estudios Transversales , Hospitales , Atención a la SaludRESUMEN
Shame is a crucial issue for Roma. The purpose of the present study was to evaluate the severity of shame and anxiety feelings in a Roma population living in Greece and assess the differentiation of these feelings between Roma men and women. A quota sample of 194 Roma adult men and women living in Southern Greece was retrieved. The Experiences of Shame Scale (ESS), the Other As Shamer Scale (OAS) and the Spielberg's State/Trait Anxiety Inventory (STAI) questionnaires were used. Women scored statistically significantly higher than men on ESS, whereas men scored higher on OAS scale (52.27 ± 16.91 vs 45.42 ± 9.98 and 35.93 ± 16.94 vs 30.87 ± 13.72 respectively). Women scored higher than men in both STAI subscales, however significant differences were observed only in State Anxiety scale (48.83 ± 9.26 vs 43.20 ± 9.81). OAS total score was inversely related to state anxiety, whereas ESS total score was positive related to trait anxiety, all correlations being significant at p < 0.05 level. Roma men and women exhibit high levels of shame and anxiety. Cultural, social and minority issues contribute to feelings of inferiority and anxiety experience.
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Ansiedad/etnología , Grupos Minoritarios/psicología , Romaní/psicología , Vergüenza , Adulto , Ansiedad/psicología , Emociones , Femenino , Grecia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Inventario de Personalidad , Romaní/etnología , Factores Sexuales , Factores Socioeconómicos , Adulto JovenRESUMEN
BACKGROUND: Although the pathophysiology remains unknown, most nondemented patients with PD have difficulty with frontal tasks, including trial-and-error sequence learning. If given time, they can perform cognitive tasks of moderate difficulty as well as controls. However, it is not known how brain function is altered during this time period to preserve higher cortical function in the face of PD pathology. METHOD: To evaluate this phenomenon, the authors matched sequence learning between PD and control subjects for the last 30 seconds of a PET scan. Learning during the initial 50 seconds of PET was unconstrained. RESULTS: Learning indices were equivalent between groups during the last 30 seconds of the scan, whereas rates of acquisition, correct movements, and forgetting differed in the first 30 seconds. In normal controls sequence learning was associated with activations in the right prefrontal, premotor, parietal, rostral supplementary motor area, and precuneus regions. To achieve equal performance, the PD group activated greater volume within these same regions, and also their left sided cortical homologs and the lateral cerebellum bilaterally. CONCLUSIONS: Mildly affected patients with PD demonstrated only modest impairment of learning during the first 30 seconds of the task and performed equivalently with controls thereafter. However, the mechanism by which they achieved equiperformance involved considerable changes in brain function. The PD group had to activate four times as much neural tissue as the controls, including recruiting brain from homologous cortical regions and bilateral lateral cerebellum.
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Encéfalo/fisiopatología , Enfermedad de Parkinson/fisiopatología , Aprendizaje Seriado , Anciano , Encéfalo/diagnóstico por imagen , Trastornos del Conocimiento/complicaciones , Trastornos del Conocimiento/diagnóstico por imagen , Trastornos del Conocimiento/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Actividad Motora , Pruebas Neuropsicológicas , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/diagnóstico por imagen , Valores de Referencia , Factores de Tiempo , Tomografía Computarizada de EmisiónRESUMEN
BACKGROUND: Clinical improvement with levodopa therapy for PD is associated with specific regional changes in cerebral glucose metabolism. However, it is unknown how these effects of treatment in the resting state relate to alterations in brain function that occur during movement. In this study, the authors used PET to assess the effects of levodopa on motor activation responses and determined how these changes related to on-line recordings of movement speed and accuracy. METHODS: Seven right-handed PD patients were scanned with H(2)15O/PET while performing a predictable paced sequence of reaching movements and while observing the same screen displays and tones. PET studies were performed during "on" and "off" states with an individually titrated constant rate levodopa infusion; movements were kinematically controlled across treatment conditions. RESULTS: Levodopa improved "off" state UPDRS motor ratings (34%; p < 0.006) and movement time (18%; p = 0.001). Spatial errors worsened during levodopa infusion (24%; p = 0.02). Concurrent regional cerebral blood flow (rCBF) recordings revealed significant enhancement of motor activation responses in the posterior putamen bilaterally (p < 0.001), left ventral thalamus (p < 0.002), and pons (p < 0.005). Movement time improvement with treatment correlated with rCBF increases in the left globus pallidus and left ventral thalamus (p < 0.01). By contrast, the increase in spatial errors correlated with rCBF increases in the cerebellar vermis (p < 0.01). CONCLUSION: These results suggest that levodopa infusion may improve aspects of motor performance while worsening others. Different components of the motor cortico-striato-pallido-thalamo-cortical loop and related pathways may underlie motor improvement and adverse motoric effects of levodopa therapy for PD.
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Antiparkinsonianos/farmacología , Circulación Cerebrovascular/efectos de los fármacos , Dopaminérgicos/farmacología , Levodopa/farmacología , Enfermedad de Parkinson/tratamiento farmacológico , Enfermedad de Parkinson/fisiopatología , Desempeño Psicomotor/efectos de los fármacos , Anciano , Antiparkinsonianos/administración & dosificación , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Dopaminérgicos/administración & dosificación , Femenino , Humanos , Infusiones Intravenosas , Levodopa/administración & dosificación , Masculino , Persona de Mediana Edad , Radioisótopos de Oxígeno , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/metabolismo , Radiofármacos , Tomografía Computarizada de Emisión/métodosRESUMEN
We have shown that fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane ([(18)F]FPCIT) and PET offer a valuable means of quantifying regional abnormality in dopamine transporter (DAT) imaging associated with Parkinson's disease (PD). The objective of this study was to delineate the topographic distribution of DAT binding in early stage idiopathic PD using statistical parametric analysis of [(18)F]FPCIT PET data. We performed dynamic PET studies in 15 hemi-parkinsonian (Hoehn & Yahr I) patients and 10 age-matched normal volunteers over 100 min and calculated images of [(18)F]FPCIT binding ratios on a pixel-by-pixel basis. Statistical parametric mapping (SPM) was then used to localize binding reductions in PD and to compute the absolute change relative to normal. [(18)F]FPCIT binding decreased significantly in the contralateral posterior putamen of the PD group (P < 0.001, corrected). A significant reduction was also seen in the ipsilateral putamen, which was smaller in extent but localized more posteriorly. A quantitative comparison of DAT binding in the two clusters showed that the onset of motor symptoms in PD was associated with an approximate 70% loss relative to the normal mean in the contralateral posterior putamen. These results suggest that SPM analysis of [(18)F]FPCIT PET data can be used to quantify and map abnormalities in DAT activity within the human striatum. This method provides a useful tool to track the onset and progression of PD at its earliest stages.
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Cuerpo Estriado/metabolismo , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana/metabolismo , Proteínas del Tejido Nervioso , Enfermedad de Parkinson/metabolismo , Tomografía Computarizada de Emisión , Tropanos , Anciano , Mapeo Encefálico , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nortropanos/metabolismo , Enfermedad de Parkinson/diagnóstico por imagen , Radiofármacos/metabolismo , Tomografía Computarizada de Emisión/métodosRESUMEN
OBJECTIVE: To assess the effects of levodopa on resting-state brain metabolism in PD. BACKGROUND: In previous studies the authors used [18F] fluorodeoxyglucose (FDG) and PET to quantify regional metabolic abnormalities in PD. They found that this disease is characterized reproducibly by a specific abnormal PD-related pattern (PDRP). In this study the authors used IV levodopa infusion to quantify the effects of dopamine replacement on regional metabolism and PDRP network activity. They tested the hypothesis that clinical response to dopaminergic therapy correlates with these metabolic changes. METHODS: The authors used FDG/PET to measure resting-state regional brain metabolism in seven patients with PD (age, 59.4 +/- 4.2 years; Hoehn and Yahr stage, 1.9 +/- 0.7, mean +/- SD); subjects were scanned both off levodopa and during an individually titrated constant-rate IV levodopa infusion. The authors used statistical parametric mapping to identify significant changes in regional brain metabolism that occurred with this intervention. They also quantified levodopa-induced changes in PDRP expression. Metabolic changes with levodopa correlated with clinical improvement as measured by changes in Unified PD Rating Scale (UPDRS) motor scores. RESULTS: Levodopa infusion improved UPDRS motor ratings (30.6% +/- 12.0%, p < 0.002) and significantly decreased regional glucose metabolism in the left putamen, right thalamus, bilateral cerebellum, and left primary motor cortex (p < 0.001). Changes in pallidal metabolism correlated significantly with clinical improvement in UPDRS motor ratings (p < 0.01). Levodopa infusion also resulted in a significant (p = 0.01) decline in PDRP expression. The changes in PDRP activity mediated by levodopa correlated significantly with clinical improvement in UPDRS motor ratings (r = -0.78, p < 0.04). CONCLUSION: Levodopa reduces brain metabolism in the putamen, thalamus, and cerebellum in patients with PD. Additionally, levodopa reduces PD-related pattern activity, and the degree of network suppression correlates with clinical improvement. The response to dopaminergic therapy in Patients with PD may be determined by the modulation of cortico-striato-pallido-thalamocortical pathways.
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Metabolismo Energético/efectos de los fármacos , Levodopa/uso terapéutico , Enfermedad de Parkinson/tratamiento farmacológico , Tomografía Computarizada de Emisión , Anciano , Glucemia/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/efectos de los fármacos , Mapeo Encefálico , Femenino , Fluorodesoxiglucosa F18 , Humanos , Levodopa/efectos adversos , Masculino , Persona de Mediana Edad , Examen Neurológico/efectos de los fármacos , Enfermedad de Parkinson/diagnóstico por imagen , Valores de ReferenciaRESUMEN
We studied 6 advanced-stage Parkinson's disease patients with [18F] fluorodeoxyglucose/positron emission tomography before and 3 months after unilateral ablation of the subthalamic nucleus performed with microelectrode mapping. Operative changes in glucose metabolism were assessed by comparing baseline and postoperative scans. We also quantified operative changes in the activity of an abnormal Parkinson's disease-related metabolic network that we had identified in previous [18F] fluorodeoxyglucose/positron emission tomography studies. Following unilateral subthalamic nucleus ablation, a highly significant reduction in glucose utilization was present in the midbrain ipsilateral to the lesion site, most pronounced in the vicinity of the substantia nigra pars reticularis. Significant metabolic reductions were also present in the ipsilateral internal globus pallidus, ventral thalamus, and pons. Operative changes in Parkinson's disease network activity differed significantly for the lesioned and unlesioned hemispheres. In the lesioned hemisphere, network activity declined significantly following surgery, but was unaltered in the contralateral, unlesioned hemisphere. These results suggest that subthalamotomy reduces basal ganglia output through internal globus pallidus/substantia nigra pars reticularis and also influences downstream neural activity in the pons and ventral thalamus. This procedure also reduces the activity of abnormal Parkinson's disease-related metabolic brain networks, suggesting a widespread modulation of motor circuitry.
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Glucosa/metabolismo , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/cirugía , Núcleo Subtalámico/cirugía , Adulto , Núcleos Cerebelosos/metabolismo , Femenino , Fluorodesoxiglucosa F18 , Globo Pálido/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/diagnóstico por imagen , Puente/metabolismo , Radiofármacos , Tálamo/metabolismo , Tomografía Computarizada de Emisión , Resultado del TratamientoRESUMEN
Little is known about acetylcholine (ACh) modulation of central visual processing in humans. Receptor densities in visual brain regions are differentially distributed suggesting that receptor subtypes have different functions. Using PET, we have previously described the brain regions activated by a simple pattern-flash stimulus in healthy elderly subjects. To evaluate muscarinic and nicotinic contributions to ACh modulation of visual processing, we scanned elderly subjects watching the pattern-flash stimulus during no drug, during physostigmine augmentation, and during scopolamine antagonism of physostigmine's action. These manipulations of ACh significantly altered regional cerebral blood flow (rCBF) in brain regions activated by the task. The pattern of rCBF values across drug conditions suggested that muscarinic and nicotinic effects were dissociated. Muscarinic action predominated in striate cortex (Brodmann Area, BA 17) and lateral visual association areas (BA 18, 19), while nicotinic action predominated in the thalamus and inferior parietal regions (BA 39/40). Both muscarinic and nicotinic actions increased rCBF in some regions while decreasing it in others. A parsimonious reconciliation of these results with functional anatomy suggests that muscarinic action modulates visual attribute processing, while nicotinic action modulates arousal and selective attention to the visual task.
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Atención/efectos de los fármacos , Receptores Muscarínicos/efectos de los fármacos , Receptores Nicotínicos/efectos de los fármacos , Percepción Visual/efectos de los fármacos , Anciano , Química Encefálica/efectos de los fármacos , Circulación Cerebrovascular/efectos de los fármacos , Inhibidores de la Colinesterasa/farmacología , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Antagonistas Muscarínicos/farmacología , Pruebas Neuropsicológicas , Estimulación Luminosa , Fisostigmina/efectos adversos , Fisostigmina/farmacología , Escopolamina/efectos adversos , Escopolamina/farmacología , Tomografía Computarizada de EmisiónRESUMEN
Employing [(18)F]fluorodeoxyglucose (FDG) and PET, we have found previously that stereotaxic ablation of the internal globus pallidus (GPi) for Parkinson's disease causes resting metabolic changes in brain regions remote from the lesion site. In this study we determined whether similar metabolic changes occur in Parkinson's disease patients treated with deep brain stimulation (DBS) of the GPi. We studied seven Parkinson's disease patients with FDG-PET to measure resting regional cerebral glucose utilization on and off GPi stimulation. We used statistical parametric mapping to identify significant changes in regional brain metabolism that occurred with this intervention. We also quantified stimulation-related changes in the expression of a specific abnormal Parkinson's disease-related pattern of metabolic covariation (PDRP) that had been identified in earlier FDG-PET studies. Metabolic changes with DBS were correlated with clinical improvement as measured by changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor ratings off medication. GPi DBS improved UPDRS motor ratings (36%, P < 0.001) and significantly increased regional glucose metabolism in the premotor cortex ipsilateral to stimulation and in the cerebellum bilaterally. GPi DBS also resulted in a significant (P < 0.01) decline in PDRP activity ipsilateral to stimulation, which correlated significantly with clinical improvement in UPDRS motor ratings (P < 0.03). Clinical improvement with GPi DBS is associated with reduced expression of an abnormal Parkinson's disease-related metabolic network involving elements of the cortico-striato-pallido-thalamocortical and the cerebello-cortical motor loops.
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Globo Pálido/fisiología , Glucosa/metabolismo , Red Nerviosa/fisiología , Enfermedad de Parkinson/fisiopatología , Adulto , Estimulación Eléctrica , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Radiofármacos , Tomografía Computarizada de EmisiónRESUMEN
We examined the neural circuitry underlying the explicit learning of motor sequences in normal subjects and patients with early stage Parkinson's disease (PD) using 15O-water (H2 15O) positron emission tomography (PET) and network analysis. All subjects were scanned while learning motor sequences in a task emphasizing explicit learning, and during a kinematically controlled motor execution reference task. Because different brain networks are thought to subserve target acquisition and retrieval during motor sequence learning, we used separate behavioral indices to quantify these aspects of learning during the PET experiments. In the normal cohort, network analysis of the PET data revealed a significant covariance pattern associated with acquisition performance. This topography was characterized by activations in the left dorsolateral prefrontal cortex (PFdl), rostral supplementary motor area (preSMA), anterior cingulate cortex, and in the left caudate/putamen. A second independent covariance pattern was associated with retrieval performance. This topography was characterized by bilateral activations in the premotor cortex (PMC), and in the right precuneus and posterior parietal cortex. The normal learning-related topographies failed to predict acquisition performance in PD patients and predicted retrieval performance less accurately in the controls. A separate network analysis was performed to identify discrete learning-related topographies in the PD cohort. In PD patients, acquisition performance was associated with a covariance pattern characterized by activations in the left PFdl, ventral prefrontal, and rostral premotor regions, but not in the striatum. Retrieval performance in PD patients was associated with a covariance pattern characterized by activations in the right PFdl, and bilaterally in the PMC, posterior parietal cortex, and precuneus. These results suggest that in early stage PD sequence learning networks are associated with additional cortical activation compensating for abnormalities in basal ganglia function.
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Mapeo Encefálico , Corteza Motora/fisiopatología , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/fisiopatología , Tomografía Computarizada de Emisión , Adulto , Anciano , Estudios de Cohortes , Femenino , Humanos , Aprendizaje/fisiología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Actividad Motora/fisiología , Desempeño Psicomotor/fisiología , PsicofísicaRESUMEN
We measured regional cerebral blood flow with H2 15O and positron emission tomography (PET) scanning at rest and during a motor task to study the mechanism of motor improvement induced by deep brain stimulation of the internal globus pallidus in Parkinson's disease. Six right-handed patients with Parkinson's disease were scanned while performing a predictable paced sequence of reaching movements and while observing the same screen displays and tones. PET studies were performed ON and OFF stimulation in a medication-free state. Internal globus pallidus deep brain stimulation improved off-state United Parkinson's Disease Rating Scale motor ratings (37%, p < 0.002) and reduced timing errors (movement onset time, 55%, p < 0.01) as well as spatial errors (10%, p < 0.02). Concurrent regional cerebral blood flow recordings revealed a significant enhancement of motor activation responses in the left sensorimotor cortex (Brodmann area [BA] 4), bilaterally in the supplementary motor area (BA 6), and in the right anterior cingulate cortex (BA 24/32). Significant correlations were evident between the improvement in motor performance and the regional cerebral blood flow changes mediated by stimulation. With internal globus pallidus deep brain stimulation, improved movement initiation correlated with regional cerebral blood flow increases in the left sensorimotor cortex and ventrolateral thalamus and in the contralateral cerebellum. By contrast, improved spatial accuracy correlated with regional cerebral blood flow increases in both cerebellar hemispheres and in the left sensorimotor cortex. These results suggest that internal globus pallidus deep brain stimulation may selectively improve different aspects of motor performance. Multiple, overlapping neural pathways may be modulated by this intervention.
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Terapia por Estimulación Eléctrica , Globo Pálido/fisiopatología , Enfermedad de Parkinson/terapia , Adulto , Femenino , Globo Pálido/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/fisiopatología , Tomografía Computarizada de EmisiónRESUMEN
In imaging studies of brain functions using pharmacological probes, identification of the time point at which central effects of intravenously infused drugs become stable is crucial to separate the effects of experimental variables from the concomitant changes in drug effects over time. We evaluated the time courses of the pharmacokinetics and pharmacodynamics, including butyrylcholinesterase inhibition and central neural responses, of physostigmine in healthy young subjects. Ten positron emission tomography (PET) scans that alternated between a rest condition (eyes open, ears unplugged) and a working memory for faces (WM) task were acquired in healthy subjects. Subjects in the drug group received a saline infusion for the first two scans, providing a baseline measure, then received an infusion of physostigmine for all subsequent scans. Subjects in the control group received a placebo infusion of saline for all scans. Physostigmine plasma levels and percent butyrylcholinesterase inhibition increased over time (p < 0. 0001), and both became stable by 40 min. Physostigmine decreased reaction time (RT) (p = 0.0005), and this effect was detected after 20 min of infusion and stable thereafter. Physostigmine also decreased regional cerebral blood flow (rCBF) in right prefrontal cortex during task (p = 0.0002), and this effect was detected after 40 min of infusion and stable thereafter. No change in RT or rCBF was observed in the control group. These results indicate that a 40-min infusion of physostigmine was necessary to obtain stable central effects. More generally, we have demonstrated that experimental effects can vary with time, especially during the initial phases of a drug infusion, indicating that it is critical that these changes are controlled.
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Encéfalo/metabolismo , Fisostigmina/farmacocinética , Adulto , Análisis de Varianza , Encéfalo/diagnóstico por imagen , Encéfalo/efectos de los fármacos , Inhibidores de la Colinesterasa/farmacocinética , Inhibidores de la Colinesterasa/farmacología , Cognición/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fisostigmina/farmacología , Desempeño Psicomotor/efectos de los fármacos , Factores de Tiempo , Tomografía Computarizada de EmisiónRESUMEN
To examine the variations in regional cerebral blood flow during execution and learning of reaching movements, we employed a family of kinematically and dynamically controlled motor tasks in which cognitive, mnemonic and executive features of performance were differentiated and characterized quantitatively. During 15O-labeled water positron emission tomography (PET) scans, twelve right-handed subjects moved their dominant hand on a digitizing tablet from a central location to equidistant targets displayed with a cursor on a computer screen in synchrony with a tone. In the preceding week, all subjects practiced three motor tasks: 1) movements to a predictable sequence of targets; 2) learning of new visuomotor transformations in which screen cursor motion was rotated by 30 degrees -60 degrees; 3) learning new target sequences by trial and error, by using previously acquired routines in a task placing heavy load on spatial working memory. The control condition was observing screen and audio displays. Subtraction images were analyzed with Statistical Parametric Mapping to identify significant brain activation foci. Execution of predictable sequences was characterized by a modest decrease in movement time and spatial error. The underlying pattern of activation involved primary motor and sensory areas, cerebellum, basal ganglia. Adaptation to a rotated reference frame, a form of procedural learning, was associated with decrease in the imposed directional bias. This task was associated with activation in the right posterior parietal cortex. New sequences were learned explicitly. Significant activation was found in dorsolateral prefrontal and anterior cingulate cortices. In this study, we have introduced a series of flexible motor tasks with similar kinematic characteristics and different spatial attributes. These tasks can be used to assess specific aspects of motor learning with imaging in health and disease.
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Mapeo Encefálico/métodos , Encéfalo/fisiología , Circulación Cerebrovascular , Actividad Motora/fisiología , Desempeño Psicomotor/fisiología , Adulto , Encéfalo/irrigación sanguínea , Encéfalo/diagnóstico por imagen , Cognición , Femenino , Lateralidad Funcional , Humanos , Aprendizaje , Masculino , Persona de Mediana Edad , Especificidad de Órganos , Radioisótopos de Oxígeno , Tomografía Computarizada de EmisiónRESUMEN
UNLABELLED: Alzheimer's disease is associated with reductions in resting-state brain metabolism, as measured by PET, progressing with dementia severity. The purpose of this study was to see to what extent brain regions with reduced resting-state metabolic rates in Alzheimer patients could be activated by a passive audiovisual stimulation test and to compare the result with activation in age-matched healthy volunteers. The extent of activation in Alzheimer's disease is considered to reflect the integrity of synaptic function, or inherent viability, and the potential responsiveness of the Alzheimer brain to drug therapy. METHODS: Regional cerebral metabolic rates for glucose (rCMRglc, in mg/ 100 g tissue/min) were measured in the resting state (eyes and ears covered) and during passive audiovisual stimulation (watching a movie) in 15 otherwise healthy Alzheimer patients of differing dementia severity (Mattis Dementia Rating Scale score, 23-128) and in 14 age-matched healthy volunteers (score, 141 +/- 3) using PET with 2 sequential injections of FDG. RESULTS: In the volunteers, audiovisual stimulation caused significant rCMRglc increases in visual and auditory cortical areas but significant decreases in frontal areas. In the mildly demented patients, rCMRglc responses were within 2 SDs of the mean in volunteers. However, the magnitude of the rCMRglc responses during stimulation declined significantly with dementia severity in the right occipitotemporal, right and left occipital association, and left calcarine cortical regions. CONCLUSION: Functional brain responsiveness, evaluated by a passive audiovisual stimulation paradigm with PET, is within normal limits in mildly demented Alzheimer patients but fails with worsening dementia severity. Declining responsiveness may account for the limited success of neurotransmitter replacement therapy in Alzheimer patients with moderate-to-severe dementia.
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Enfermedad de Alzheimer/diagnóstico por imagen , Encéfalo/metabolismo , Tomografía Computarizada de Emisión , Estimulación Acústica , Anciano , Enfermedad de Alzheimer/fisiopatología , Encéfalo/diagnóstico por imagen , Estudios de Casos y Controles , Femenino , Radioisótopos de Flúor , Fluorodesoxiglucosa F18 , Glucosa/metabolismo , Humanos , Masculino , Estimulación Luminosa , RadiofármacosRESUMEN
OBJECTIVE: It was thought that premutation carriers of fragile X syndrome (FraX) have no neurobiological abnormalities, but there have been no quantitative studies of brain morphometry and metabolism. Thus the authors investigated brain structure and metabolism in premutation carriers of FraX. METHOD: Eight normal IQ, healthy female permutation FraX carriers aged 39 +/- 9 years (mean +/- SD) and 32 age-sex-handedness-matched controls (39 +/- 10 years) were studied; in vivo brain morphometry was measured using volumetric magnetic resonances imaging, and regional cerebral metabolic rates for glucose were measured using positron emission tomography and (18F)-2-fluoro-2-deoxy-D-glucose. RESULTS: Compared with controls, FraX premutation carriers had a significant (1) decrease in volume of whole brain, and caudate and thalamic nuclei bilaterally; (2) increase in volume of hippocampus and peripheral CSF bilaterally, and third ventricle; (3) relative hypometabolism of right parietal, temporal, and occipital association areas; (4) bilateral relative hypermetabolism of hippocampus; (5) relative hypermetabolism of left cerebellum; and (6) difference in right-left asymmetry of the Wernicke and Broca language areas. CONCLUSIONS: Premutation carriers of FraX, as defined by analysis of peripheral lymphocytes, have abnormalities in brain anatomy and metabolism. The biological basis for this is unknown, but most likely it includes tissue heterogeneity for mutation status. The findings may be of relevance to people counseling families with FraX and to understanding other neuropsychiatric disorders which are associated with expansion of triplet repeats and genetic anticipation.
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Encéfalo/anomalías , Encéfalo/metabolismo , Síndrome del Cromosoma X Frágil/genética , Heterocigoto , Trastornos Mentales/genética , Mutación , Adulto , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Estudios de Casos y Controles , Factores de Confusión Epidemiológicos , Femenino , Fluorodesoxiglucosa F18 , Humanos , Imagen por Resonancia Magnética , Radiofármacos , Tomografía Computarizada de EmisiónRESUMEN
We sought to investigate how individual differences in the regional patterns of cerebral blood flow (rCBF) relate to task performance during the perceptual matching of faces. We analyzed rCBF data obtained by PET and H2150 from nine young healthy, right-handed, adult males (mean age 29i3 years) using a statistical model of regional covariance, the Scaled Subprofile Model (SSM). SSM analysis performed on a voxel-basis for scan subtractions comparing face-matching and control tasks extracted two patterns whose subject expression in a multiple regression analysis was highly predictive of task accuracy (R2 = 0.87, p < 0.002). The pattern reflecting this linear combination was principally characterized by higher rCBF in regions of bilateral occipital and occipitotemporal cortex, right orbitofrontal cortex, left thalamus, basal ganglia, midbrain, and cerebellum with relatively lower rCBF in anterior cingulate, regions in bilateral prefrontal and temporal cortex, right thalamus, and right inferior parietal cortex. The results indicate that individual subject differences in face matching performance are specifically associated with the functional interaction of cortical and subcortical brain regions previously implicated in aspects of object perception and visual attentional processing.
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Atención/fisiología , Cara , Percepción de Forma/fisiología , Tomografía Computarizada de Emisión , Adulto , Circulación Cerebrovascular , Cognición/fisiología , Humanos , Masculino , Estimulación Luminosa , Valor Predictivo de las Pruebas , Análisis de Regresión , Lóbulo Temporal/irrigación sanguínea , Lóbulo Temporal/fisiología , Corteza Visual/irrigación sanguínea , Corteza Visual/fisiologíaRESUMEN
UNLABELLED: In a previous [18F]fluorodeoxyglucose (FDG) PET study we analyzed regional metabolic data from a combined group of Parkinson's disease (PD) patients and healthy volunteers (N), using network analysis. By this method, we identified a unique pattern of regional metabolic covariation with an expression which accurately discriminated patients from healthy volunteers. To assess the reproducibility of this pattern as a potential marker for PD, we compared the pattern's topography with that of the disease-related covariance patterns identified in three other independent populations of patients with PD and healthy individuals studied in different PET laboratories. METHODS: The following patient populations were studied: group A (original cohort: 22 PD, 20 N; resolution: 7.5 mm full width at half maximum [FWHM]); group B (18 PD, 12 N; resolution: 4.2 mm FWHM); group C (25 PD, 15 N; resolution: 8.0 mm FWHM); and group D (14 PD, 10 N; resolution: 10 mm FWHM). Region weights for the PD-related covariance pattern (PDRP) identified in the group A analysis were correlated with those for the disease-related patterns identified in the analyses of groups B, C and D. In addition, subject scores for the group A PDRP were computed prospectively for every individual in each of the study populations. PDRP scores for PD and N within each cohort were compared. RESULTS: The PDRP topography identified in group A was highly correlated with each of the corresponding topographies identified in the other populations (r2 approximately 0.60, P < 0.0001). Prospectively computed subject scores for the group A PDRP significantly discriminated PD from N in each population (P < 0.004). CONCLUSION: The PDRP topography identified previously in Group A is highly reproducible across patient populations and tomographs. Prospectively computed PDRP scores can accurately discriminate patients from controls in multiple populations studied with different tomographs. Brain network imaging with FDG PET can provide robust metabolic markers for the diagnosis of PD.
Asunto(s)
Tomografía Computarizada de Emisión/normas , Encéfalo/diagnóstico por imagen , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Radiofármacos , Reproducibilidad de los ResultadosRESUMEN
OBJECTIVE: This study tested the hypothesis that regional cerebral glucose metabolism during neuronal activation is a more sensitive index of neuronal dysfunction and clinical severity in Alzheimer's disease than is glucose metabolism at rest. METHOD: The subjects were 15 Alzheimer's disease patients with a wide range of Mattis Dementia Rating Scale scores (23-128). By using positron emission tomography, absolute glucose metabolism was measured in the parietal, occipital (visual areas), and temporal (auditory areas) cortical regions during rest (eyes/ears covered) and audiovisual stimulation. RESULTS: In the parietal cortex, glucose metabolism correlated with dementia severity in both conditions. In contrast, in the relatively preserved visual and auditory cortical regions, glucose metabolism predicted dementia severity during stimulation but not at rest. CONCLUSIONS: These findings suggest that regional cerebral glucose metabolism during stimulation is a more sensitive index of the functional/metabolic failure of neuronal systems than is metabolism at rest.
Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Encéfalo/metabolismo , Glucosa/metabolismo , Tomografía Computarizada de Emisión/métodos , Estimulación Acústica , Anciano , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/fisiopatología , Corteza Auditiva/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Lóbulo Parietal/metabolismo , Estimulación Luminosa , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Índice de Severidad de la Enfermedad , Corteza Visual/metabolismoRESUMEN
To define brain regions involved in feature extraction or elementary form perception, regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET) in subjects viewing two classes of achromatic textures. Textures composed of local features (e.g. extended contours and rectangular blocks) produced activation or increased rCBF along the occipitotemporal pathway relative to textures with the same mean luminance, contrast, and spatial-frequency content but lacking organized form elements or local features. Significant activation was observed in striate, extrastriate, lingual, and fusiform cortices as well as the hippocampus and brain stem. On a scan-by-scan basis, increases in rCBF shifted from the occipitotemporal visual cortices to medial temporal (hippocampus) and frontal lobes with increased exposure to only those textures containing local features. These results suggest that local feature extraction occurs throughout the occipitotemporal (ventral) pathway during extended exposure to visually salient stimuli, and may indicate the presence of similar receptive-field mechanisms in both occipital and temporal visual areas of the human brain.
Asunto(s)
Percepción de Forma/fisiología , Lóbulo Occipital/fisiología , Lóbulo Temporal/fisiología , Tomografía Computarizada de Emisión , Vías Visuales/fisiología , Adulto , Velocidad del Flujo Sanguíneo , Encéfalo/irrigación sanguínea , Circulación Cerebrovascular , Femenino , Humanos , Masculino , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Temporal/diagnóstico por imagen , Vías Visuales/diagnóstico por imagenRESUMEN
A growing body of literature suggests that in utero cocaine exposure may place a child at risk for impaired language development. Because the field of gestational drug exposure and its effects on communicative development is young, the research is still limited and the data are contradictory, plagued by many methodological problems. The accumulating evidence, however, suggests that the development of specific aspects of language may be compromised in a percentage of children and that outcome is affected by a wide range of prenatal and postnatal biological and environmental factors. The data also suggest that deficits are best identified through the use of focused test batteries and may be evident only under stressful or difficult conditions. This article provides a critique and general overview of the literature on the early communicative and language development of prenatally cocaine-exposed children. Potential reasons for compromised language development and the clinical implications of these findings are discussed.