RESUMO
BACKGROUND: Episodic memory impairment may occur in progressive supranuclear palsy (PSP). However, it remains uncertain whether this is due to executive dysfunction or to the involvement of brain areas responsible for memory. OBJECTIVES: To investigate the specific brain regions underlying episodic memory impairment in PSP. METHODS: Twenty-one patients with PSP and 20 healthy controls underwent the Figure Memory Test (FMT) from the Brief Cognitive Screening Battery and brain MRI. We explored correlations between gray matter volumes and memory scores in PSP patients, adjusting for age and performance on the Frontal Assessment Battery. RESULTS: PSP patients performed worse than controls (p < 0.001) on delayed recall in the FMT. Delayed recall scores correlated to bilateral hippocampal and parahippocampal volumes in PSP patients. CONCLUSIONS: Medial temporal structures may play a role in episodic memory impairment in PSP, suggesting that amnesia in PSP is not solely due to executive dysfunction.
Assuntos
Memória Episódica , Paralisia Supranuclear Progressiva , Encéfalo/diagnóstico por imagem , Humanos , Transtornos da Memória/diagnóstico por imagem , Transtornos da Memória/etiologia , Neuroimagem , Testes Neuropsicológicos , Paralisia Supranuclear Progressiva/complicações , Paralisia Supranuclear Progressiva/diagnóstico por imagemRESUMO
Working Memory (WM) impairment is the most common cognitive deficit of patients with Multiple Sclerosis (MS). However, evidence of its neurobiological mechanisms is scarce. Here we recorded electroencephalographic activity of twenty patients with relapsing-remitting MS and minimal cognitive deficit, and 20 healthy control (HC) subjects while they solved a WM task. In spite of similar performance, the HC group demonstrated both a correlation between temporoparietal theta activity and memory load, and a correlation between medial frontal theta activity and successful memory performances. MS patients did not show theses correlations leading significant differences between groups. Moreover, cortical connectivity analyses using granger causality and phase-amplitude coupling between theta and gamma revealed that HC group, but not MS group, presented a load-modulated progression of the frontal-to-parietal connectivity. This connectivity correlated with working memory capacity in MS groups. This early alterations in the oscillatory dynamics underlaying working memory could be useful for plan therapeutic interventions.
Assuntos
Lobo Frontal/fisiopatologia , Transtornos da Memória/fisiopatologia , Memória de Curto Prazo/fisiologia , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/psicologia , Lobo Parietal/fisiopatologia , Adulto , Estudos de Casos e Controles , Eletroencefalografia , Feminino , Lobo Frontal/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Transtornos da Memória/diagnóstico por imagem , Transtornos da Memória/etiologia , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/etiologia , Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Lobo Parietal/diagnóstico por imagem , Tempo de Reação , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiopatologiaRESUMO
BACKGROUND AND PURPOSE: Hypoxia and cerebral ischemia (HI) events are capable of triggering important changes in brain metabolism, including glucose metabolism abnormalities, which may be related to the severity of the insult. Using positron emission microtomography (microPET) with [18F]fluorodeoxyglucose (18F-FDG), this study proposes to assess abnormalities of brain glucose metabolism in adult rats previously submitted to the neonatal HI model. We hypothesize that cerebral metabolic outcomes will be associated with cognitive deficits and magnitude of brain injury. METHODS: Seven-day-old rats were subjected to an HI model, induced by permanent occlusion of the right common carotid artery and systemic hypoxia. 18F-FDG-microPET was used to assess regional and whole brain glucose metabolism in rats at 60 postnatal days (PND 60). An interregional cross-correlation matrix was utilized to construct metabolic brain networks (MBN). Rats were also subjected to the Morris Water Maze (MWM) to evaluate spatial memory and their brains were processed for volumetric evaluation. RESULTS: Brain glucose metabolism changes were observed in adult rats after neonatal HI insult, limited to the right brain hemisphere. However, not all HI animals exhibited significant cerebral hypometabolism. Hippocampal glucose metabolism was used to stratify HI animals into HI hypometabolic (HI-h) and HI non-hypometabolic (HI non-h) groups. The HI-h group had drastic MBN disturbance, cognitive deficit, and brain tissue loss, concomitantly. Conversely, HI non-h rats had normal brain glucose metabolism and brain tissue preserved, but also presented MBN changes and spatial memory impairment. Furthermore, data showed that brain glucose metabolism correlated with cognitive deficits and brain volume outcomes. CONCLUSIONS: Our findings demonstrated that long-term changes in MBN drive memory impairments in adult rats subjected to neonatal hypoxic ischemia, using in vivo imaging microPET-FDG. The MBN analyses identified glucose metabolism abnormalities in HI non-h animals, which were not detected by conventional 18F-FDG standardized uptake value (SUVr) measurements. These animals exhibited a metabolic brain signature that may explain the cognitive deficit even with no identifiable brain damage.
Assuntos
Encéfalo/metabolismo , Hipóxia-Isquemia Encefálica/metabolismo , Transtornos da Memória/metabolismo , Rede Nervosa/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Modelos Animais de Doenças , Glucose/metabolismo , Hipóxia-Isquemia Encefálica/complicações , Hipóxia-Isquemia Encefálica/diagnóstico por imagem , Masculino , Transtornos da Memória/diagnóstico por imagem , Transtornos da Memória/etiologia , Rede Nervosa/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Ratos , Ratos WistarRESUMO
PURPOSE: Cognitive dysfunction is common in neuropsychiatric systemic lupus erythematosus (SLE). Memory is a commonly affected cognitive domain. Clinically, however, it is difficult to detect memory deficits. The objective of this study is to evaluate whether normal controls and SLE patients with and without memory deficit differ in terms of white-matter integrity. METHODS: Twenty SLE patients with memory deficit were compared to 47 SLE patients without memory deficit and 22 sex-, age-, and education-matched control individuals. Diffusion tensor imaging (DTI) was performed in a 1.5-Tesla scanner. For tract-based spatial statistics analysis, a white-matter skeleton was created. A permutation-based inference with 5000 permutations with a threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were also projected onto the mean FA skeleton. RESULTS: Compared to controls, SLE patients with and without memory deficit had decreased FA in: bilateral anterior thalamic radiation, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus, corticospinal tract, genu, and body of the corpus callosum. SLE patients with and without memory deficit also presented increased MD and RD values compared to controls in these areas. Comparison between SLE patients with and without memory deficit did not present significant differences in DTI parameters. CONCLUSION: DTI can detect extensive abnormalities in the normal-appearing white matter of SLE patients with and without memory deficit, compared to controls. However, there was no difference, in terms of white-matter integrity, between the groups of SLE patients.
Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Lúpus Eritematoso Sistêmico/patologia , Transtornos da Memória/patologia , Substância Branca/diagnóstico por imagem , Adulto , Anisotropia , Mapeamento Encefálico , Estudos de Casos e Controles , Transtornos Cognitivos/diagnóstico por imagem , Transtornos Cognitivos/etiologia , Corpo Caloso/diagnóstico por imagem , Feminino , Humanos , Lúpus Eritematoso Sistêmico/diagnóstico por imagem , Masculino , Transtornos da Memória/diagnóstico por imagem , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Testes Neuropsicológicos , Estudos RetrospectivosRESUMO
The relation between hypertension and cognitive impairment is an undisputable fact. The aims of this study were to determine the prevalence of cognitive impairment in hypertensive patients, to identify the most affected cognitive domain, and to observe the association with different parameters of hypertension and other vascular risk factors. A multicentre study was carried out, and 1281 hypertensive patients of both genders and ≥21 years of age were included. Data on the following parameters were obtained: cognitive status (Minimal Cognitive Examination), behavioural status (Hospital Anxiety and Depression Scale), blood pressure, anthropometry, and biochemical profile. The average age was 60.2±13.5 years (71% female), and the educational level was 9.9±5.1 years. Global cognitive impairment was seen in 22.1%, executive dysfunction in 36.2%, and semantic memory impairment in 48.9%. Cognitive impairment was higher in males (36.8% vs. 30.06%) within both the 70-79-year-old and the ≥80-year-old (50% vs. 40%) age groups. Abnormal Clock Drawing Test results were related to high pulse pressure (p<0.0036), and abnormal Mini-Boston Naming Test results to both high systolic blood pressure (p<0.052) and pulse pressure (p<0.001). The treated/uncontrolled hypertensive group showed abnormal results both in the Mini Mental State Examination (OR, 0.73; p=0.036) and the Mini-Boston Naming Test (OR, 1.36; p=0.021). Among patients without cognitive impairment (MMSE >24), 29.4% presented executive dysfunction, and 41.5% semantic memory impairment. Cognitive impairment was higher in hypertensive patients than in the general population. Executive functions and semantic memory were the most affected cognitive domains. High systolic blood pressure and pulse pressure were associated with abnormal results in cognitive tests.
Assuntos
Disfunção Cognitiva/etiologia , Hipertensão/complicações , Fatores Etários , Idoso , Antropometria , Argentina/epidemiologia , Pressão Sanguínea , Disfunção Cognitiva/diagnóstico por imagem , Estudos Transversais , Função Executiva , Feminino , Humanos , Hipertensão/psicologia , Masculino , Transtornos da Memória/diagnóstico por imagem , Transtornos da Memória/etiologia , Testes de Estado Mental e Demência , Pessoa de Meia-Idade , Fatores de Risco , Fatores Sexuais , População UrbanaRESUMO
The low-educated elderly are a vulnerable population in whom studying the role of white matter integrity on memory may provide insights for understanding how memory declines with aging and disease. METHODS: Thirty-one participants (22 women), 23 cognitively healthy and eight with cognitive impairment-no dementia, aged 80.4 ± 3.8 years, with 2.2 ± 1.9 years of education, underwent an MRI scan with diffusion tensor imaging (DTI) acquisition. We verified if there were correlations between the performance on the Brief Cognitive Screening Battery (BCSB) and the Rey Auditory Verbal Learning Test (RAVLT) with DTI parameters. RESULTS: The BCSB delayed recall task correlated with frontotemporoparietal connection bundles, with the hippocampal part of the cingulum bilaterally and with the right superior longitudinal fasciculus. The RAVLT learning and delayed recall scores also correlated with the hippocampal part of the cingulum bilaterally. CONCLUSIONS: Although preliminary, our study suggests that the integrity of white matter frontotemporoparietal fasciculi seems to play a role in episodic memory performance in the low-educated elderly. This finding opens opportunities to study potential targets for memory decline prevention in vulnerable populations.
Assuntos
Transtornos da Memória/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Imagem de Tensor de Difusão , Escolaridade , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Transtornos da Memória/etiologia , Transtornos da Memória/patologia , Testes Neuropsicológicos , Substância Branca/patologiaRESUMO
ABSTRACT The low-educated elderly are a vulnerable population in whom studying the role of white matter integrity on memory may provide insights for understanding how memory declines with aging and disease. Methods: Thirty-one participants (22 women), 23 cognitively healthy and eight with cognitive impairment-no dementia, aged 80.4 ± 3.8 years, with 2.2 ± 1.9 years of education, underwent an MRI scan with diffusion tensor imaging (DTI) acquisition. We verified if there were correlations between the performance on the Brief Cognitive Screening Battery (BCSB) and the Rey Auditory Verbal Learning Test (RAVLT) with DTI parameters. Results: The BCSB delayed recall task correlated with frontotemporoparietal connection bundles, with the hippocampal part of the cingulum bilaterally and with the right superior longitudinal fasciculus. The RAVLT learning and delayed recall scores also correlated with the hippocampal part of the cingulum bilaterally. Conclusions: Although preliminary, our study suggests that the integrity of white matter frontotemporoparietal fasciculi seems to play a role in episodic memory performance in the low-educated elderly. This finding opens opportunities to study potential targets for memory decline prevention in vulnerable populations.
RESUMO Idosos de baixo nível educacional representam uma população vulnerável em que o estudo do papel da integridade da substância branca na memória pode revelar como essa declina no envelhecimento. Métodos: Trinta e um indivíduos (22 mulheres), sendo 23 cognitivamente saudáveis, oito com comprometimento cognitivo não demência, 80,4 ± 3,8 anos de idade e 2,2 ± 1,9 anos de escolaridade, foram submetidos à RM com imagem de tensor de difusão, cujos parâmetros foram correlacionados com a Bateria Cognitiva Breve (BCSB) e o Teste Auditivo Verbal de Rey (RAVLT). Resultados: A evocação tardia da BCSB correlacionou-se com fascículos de conexão frontotemporoparietal, fascículo longitudinal superior direito e cíngulo parte hipocampal bilateral, sendo que esse último também correlacionou com o RAVLT (aprendizado e evocação tardia). Conclusão: Apesar de preliminar, nosso estudo sugere que a integridade da substância branca parece ser importante para a memória em idosos de baixa escolaridade, achado que revela alvo potencial na prevenção do seu declínio em populações vulneráveis.
Assuntos
Humanos , Masculino , Feminino , Idoso , Idoso de 80 Anos ou mais , Substância Branca/diagnóstico por imagem , Transtornos da Memória/diagnóstico por imagem , Imageamento por Ressonância Magnética , Escolaridade , Imagem de Tensor de Difusão , Substância Branca/patologia , Transtornos da Memória/etiologia , Transtornos da Memória/patologia , Testes NeuropsicológicosRESUMO
Interictal hypometabolism is commonly measured by 18-fluoro-deoxyglucose Positron Emission Tomography (FDG-PET) in the temporal lobe of patients with mesial temporal lobe epilepsy (MTLE-HS). Left temporal lobe interictal FDG-PET hypometabolism has been associated with verbal memory impairment, while right temporal lobe FDG-PET hypometabolism is associated with nonverbal memory impairment. The biochemical mechanisms involved in these findings remain unknown. In comparison to healthy controls (n=21), surgically treated patients with MTLE-HS (n=32, left side=17) had significant lower scores in the Rey Auditory Verbal Learning Test (RAVLT retention and delayed), Logical Memory II (LMII), Boston Naming test (BNT), Letter Fluency and Category Fluency. We investigated whether enzymatic activities of the mitochondrial enzymes Complex I (C I), Complex II (C II), Complex IV (C IV) and Succinate Dehydrogenase (SDH) from the resected samples of the middle temporal neocortex (mTCx), amygdala (AMY) and hippocampus (HIP) were associated with performance in the RAVLT, LMII, BNT and fluency tests of our patients. After controlling for the side of hippocampus sclerosis, years of education, disease duration, antiepileptic treatment and seizure outcome after surgery, no independent associations were observed between the cognitive test scores and the analyzed mitochondrial enzymatic activities (p>0.37). Results indicate that memory and language impairment observed in MTLE-HS patients are not strongly associated with the levels of mitochondrial CI, CII, SDH and C IV enzymatic activities in the temporal lobe structures ipsilateral to the HS lesion.