A Rios

Brigham and Women's Hospital , Boston, MA, United States

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Publications (4)12.7 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: To investigate the influence of the presenilin-1 gene (PS-1) mutation on regional cerebral perfusion, SPECT was evaluated in 57 individuals. The subjects were members of a large pedigree from Colombia, South America, many of whom carry a PS-1 mutation for early-onset AD. Members of this large kindred who were cognitively normal and did not carry the PS-1 mutation (n = 23) were compared with subjects who were carriers of the mutation but were asymptomatic (n = 18) and with individuals with the mutation and a clinical diagnosis of AD (n = 16). Cerebral perfusion was measured in each subject using hexamethylpropyleneamine oxime SPECT. The data were analyzed in two ways: 1) Mean cerebral perfusion in each of 4320 voxels in the brain was compared among the groups using t-tests (t-maps); and 2) each individual received a weighted score on 20 vectors (factors), based on a large normative sample (n = 200), using a method known as singular value decomposition (SVD). Based on t-maps, subjects with the PS-1 mutation who were asymptomatic demonstrated reduced perfusion in comparison with the normal control subjects in the hippocampal complex, anterior and posterior cingulate, posterior parietal lobe, and anterior frontal lobe. The AD patients demonstrated decreased perfusion in the posterior parietal and superior frontal cortex in comparison with the normal control subjects. Discriminant function analysis of the vector scores derived from SVD (adjusted for age and gender) accurately discriminated 86% of the subjects in the three groups (p < 0.0005). Regional cerebral perfusion abnormalities based on SPECT are detectable before development of the clinical symptoms of AD in carriers of the PS-1 mutation.
    Neurology 06/2001; 56(11):1545-51. · 8.25 Impact Factor
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    ABSTRACT: To determine changes in clinical manifestations and cerebral blood flow (CBF) before and after administration of ECT to patients with catatonia due to schizophrenia or mood disorders. A sample of nine patients who met DSM-IV criteria for catatonia was studied. Patients received between 5 and 15 sessions (thrice per week) of ECT. Severity of catatonia was measured with the Modified Rogers Scale (MRS). Changes in CBF were measured with a brain single positron emission computer tomography (SPECT) that was performed 1 week before the first ECT and 1 week after the last ECT. Catatonia was due to schizophrenia in five patients and mood disorders in four patients. There were no significant clinical and brain SPECT differences between these two groups before treatment. Pre- vs. post-ECT comparisons showed significant reduction of catatonic symptoms in both groups. However, patients with mood disorders needed less ECT sessions and showed greater clinical improvement. Brain SPECT showed significant increase in CBF in parietal, temporal, and occipital regions in patients with mood disorder and no significant changes in patients with schizophrenia. These results support the efficacy of ECT for treatment of catatonic patients, especially secondary to mood disorders, which seem to be correlated with improvements in CBF.
    Journal of Psychosomatic Research 01/2001; 49(6):423-9. · 3.27 Impact Factor
  • Revista de neurologia 40(4):253-4. · 1.18 Impact Factor
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