The neural correlates of cognitive impairment in schizophrenia / Els correlats neurals del dèficit cognitiu en l’esquizofrènia
Background: In recent years it has become recognized that schizophrenia is associated with cognitive impairment, which affects particularly executive function and memory. Although cognitive impairment implies brain damage or dysfunction, little is known about the relationship of cognitive impairment...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2012 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/91283 |
| Acceso en línea: | http://hdl.handle.net/10803/91283 |
| Access Level: | acceso abierto |
| Palabra clave: | Esquizofrènia Esquizofrenia Schizophrenia Déficits cognitivos Dèficits cognitius Cognitive impairments Neuropsicologia Neuropsicología Neuropsychology Ressonància magnètica Resonancia magnética Magnetic resonance Ciències de la Salut 616.89 |
| Sumario: | Background: In recent years it has become recognized that schizophrenia is associated with cognitive impairment, which affects particularly executive function and memory. Although cognitive impairment implies brain damage or dysfunction, little is known about the relationship of cognitive impairment in schizophrenia to the structural and functional brain abnormalities that characterize the disorder. Aims and hypothesis: This study aimed to identify structural and/or functional brain abnormalities associated with cognitive impairment in schizophrenia. According to the literature reviewed, the general hypothesis is that the cognitive deficits of schizophrenic patients are reflected in both structural and functional brain changes. Accordingly, we expect that patients with cognitive impairment will have more GM reductions and more dysfunctional patterns of brain activity than patents without such deficits. Method. structural MRI and voxel-based morphometry was carried out in 26 cognitively impaired and 23 cognitively preserved schizophrenia patients, plus 39 matched controls. Nineteen cognitively impaired patients, 18 cognitively preserved patients and 34 controls also underwent fMRI during performance of a working memory task. Some subjects, partly corresponding to the ones participating in the neuroimaging study, were also administered a battery of tests of different cognitive functions. Altogether, 25 participants with schizophrenia and relatively preserved cognitive function, 29 with impaired functions and 22 healthy participants were included in this part of the study. Results: The participants with cognitive impairment in executive functioning and memory also perform worse on visuospatial and language tasks when compared to other patients intact in memory and executive function and controls. These differences are independent of estimated premorbid IQ. No differences were found between the cognitively intact and cognitively impaired groups in lateral ventricular volume or whole brain volume. Voxel-based morphometry also failed to reveal clusters of significant difference in either GM or WM volume between the two patient groups. However, during performance of the n-back task, the cases with schizophrenia and impaired cognitition showed hypoactivation compared to the cognitively intact patients in DLPFC among other brain regions. Conclusions: This study provides evidence that structural brain abnormality in schizophrenia is a function of having the disorder, not the cognitive impairment that accompanies it. In contrast, a substantial part of the task-related functional imaging abnormality appears to reflect cognitive impairment. |
|---|