Browsing by Author "Santiago, B"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- Apolipoprotein E epsilon4 allele is a risk factor for Alzheimer's disease: the central region of portugal (Coimbra) as a case studyPublication . Fernandes, MA; Oliveira, CR; Oliveira, LM; Nogueira, AJ; Santiago, B; Santana, I
- Discriminative capacity and construct validity of the Clock Drawing Test in Mild Cognitive Impairment and Alzheimer's diseasePublication . Duro, D; Freitas, S; Tábuas-Pereira, M; Santiago, B; Botelho, MA; Santana, IOBJECTIVES: The aim of this study was to analyze the psychometric and diagnostic properties of the Clock Drawing Test (CDT), scored according to the Babins, Rouleau, and Cahn scoring systems, for Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) screening, and develop corresponding cutoff scores. Additionally, we assessed the construct validity of the CDT through exploratory and confirmatory factor analysis. METHODS: We developed a cross-sectional study of ambulatory MCI and AD patients, divided in two clinical groups (450 MCI and 250 mild AD patients) and a normal control group (N = 400). All participants were assessed with the CDT, Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) for convergent validity. RESULTS: The selected scoring systems presented adequate validity and reliability values. The proposed cutoff scores showed 60 to 65% sensitivity and 58 to 62% specificity to identify MCI patients. The corresponding values for AD were 84 to 90% sensitivity and 76 to 78% specificity. Exploratory and confirmatory factor analysis revealed that the Babins scoring system had good construct validity and allowed us to propose a three-factor model for this system. CONCLUSIONS: Our results confirmed the complexity of the CDT and support it as a cognitive screening instrument particularly sensitive to AD. The use of the CDT with MCI patients should be interpreted with more caution due to the lower sensitivity and specificity for milder forms of cognitive impairment.
- Downbeat nystagmus elicited by eyelid closurePublication . Lemos, J; Pereira, D; Amorim, M; Santiago, B; Paiva, A; Cunha, LWe describe a patient with downbeat nystagmus (DBN) evoked only by eye closure. Brain and spinal cord magnetic resonance imaging revealed a T2 paramedian lesion in the left lower basis pontis and other white matter lesions consistent with multiple sclerosis. One potential mechanism for DBN in this case involves transverse ephaptic spread of excitation from areas that subserve coordinated lid closure to the decussating ventral tegmental tract.
- Epidermal nevus syndrome: an unusual cerebellar involvementPublication . Pereira, S; Serra, D; Melo Freitas, P; Santiago, B; Brito, OThe epidermal nevus syndrome is characterized by several developmental anomalies associated with an epidermal nevus. In addition to the skin, other organs commonly affected include the brain, eyes and musculoskeletal system. We report here on a 24-year-old woman with this syndrome who presented with hemifacial hypertrophy, hearing abnormalities, arrhythmia and an unusual infratentorial brain involvement.
- Frontotemporal dementia and mitochondrial DNA transitionsPublication . Grazina, M; Silva, F; Santana, I; Santiago, B; Mendes, C; Simões, M; Oliveira, M; Cunha, L; Oliveira, CRFrontotemporal dementia (FTD) is the second most common type of primary degenerative dementia. Some patients present an overlap between Alzheimer's disease (AD) and FTD both in neuropathological and clinical aspects. This may suggest a similar overlap in physiopathology, namely an involvement of mitochondrial DNA (mtDNA) in FTD, as it has been associated to AD. To determine if mtDNA is involved in FTD, we performed a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis, specific to mtDNA NADH Dehydrogenase subunit 1 (ND1) nucleotides 3337-3340, searching for mutations previously described in Parkinson's and AD patients. We could identify one FTD patient with two mtDNA transitions: one already known (3316 G-to-A) and another unreported (3337 G-to-A). Additionally, mitochondrial respiratory chain complex I activity was reduced in leukocytes of this patient (36% of the control mean activity). To our knowledge, this is the first report of mtDNA variants in FTD patients.
- Mitochondrial DNA Variants in a Portuguese Population of Patients with Alzheimer’s DiseasePublication . Grazina, M; Silva, F; Santana, I; Pratas, J; Santiago, B; Oliveira, M; Carreira, I; Cunha, L; Oliveira, CRAlzheimer's disease (AD) is the most common neurodegenerative disorder associated with dementia in late adulthood. Mitochondrial respiratory chain impairment has been detected in the brain, muscle, fibroblasts and platelets of AD patients, indicating a possible involvement of mitochondrial DNA (mtDNA) in the etiology of the disease. Several reports have identified mtDNA mutations in AD patients, but there is no consensual opinion regarding the cause of the impairment. We have studied mtDNA NADH dehydrogenase subunit 1 nucleotides 3337-3340, searching for mutations. Our study group included 129 AD patients and 125 healthy age-matched controls. We have found alterations in two AD patients: one had two already known mtDNA modifications (3197 T-C and 3338 T-C) and the other a novel transition (3199 T-C) which, to our knowledge, has not been described before.