RESUMO
Several studies have reported that transcranial direct current stimulation (tDCS), a non-invasive method of neuromodulation, enhances some aspects of working memory in healthy and Parkinson disease subjects. The aim of this study was to investigate the impact of anodal tDCS on recognition memory, working memory and selective attention in Alzheimer disease (AD). Ten patients with diagnosis of AD received three sessions of anodal tDCS (left dorsolateral prefrontal cortex, left temporal cortex and sham stimulation) with an intensity of 2 mA for 30 min. Sessions were performed in different days in a randomised order. The following tests were assessed during stimulation: Stroop, Digit Span and a Visual Recognition Memory task (VRM). The results showed a significant effect of stimulation condition on VRM (p = 0.0085), and post hoc analysis showed an improvement after temporal (p = 0.01) and prefrontal (p = 0.01) tDCS as compared with sham stimulation. There were no significant changes in attention as indexed by Stroop task performance. As far as is known, this is the first trial showing that tDCS can enhance a component of recognition memory. The potential mechanisms of action and the implications of these results are discussed.
Assuntos
Doença de Alzheimer/psicologia , Doença de Alzheimer/terapia , Terapia por Estimulação Elétrica , Memória/fisiologia , Reconhecimento Psicológico/fisiologia , Lobo Temporal/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Atenção/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Testes Neuropsicológicos , Desempenho Psicomotor/fisiologia , Lobo Temporal/patologiaRESUMO
BACKGROUND: Rett syndrome (RS) is a pervasive developmental disorder with cognitive and neuromotor impairments (including loss of handiness and loss of communicative skills). OBJECTIVE: To verify whether girls with RS use their gaze intentionally, by observing their performance in three cognitive tasks: (1) verbal instruction condition (look at picture X), (2) recognition and matching of pictures (look at the one that is the same), and (3) categorization of pictures (look at the one that is similar). METHOD: Seven girls diagnosed with RS according to DSM-IV criteria were studied. Eyegaze technology was used to record the girls' eye movements' responses to visual stimulation. RESULTS: The comparison of fixation time on the alternatives revealed a higher percentage (62.4%) of correct alternatives (chi(2) = 76.31; P = 0.000). Of the seven children assessed, only one did not present predominance of fixations on the correct alternatives in any one of the tasks. One did well in all tasks. Six responded correctly to all verbal instructions. CONCLUSION: The rate of correct answers suggests that there is measurable and intentional gaze in RS girls and it can be used as a path to explore their cognitive performance.