Fernanda Tebexreni Orsati

Transcranial direct current stimulation of the prefrontal cortex modulates the desire for specific foods.

We aimed to assess whether modulation of the dorsolateral prefrontal cortex (DLFPC) with noninvasive brain stimulation, namely transcranial direct current stimulation (tDCS), modifies food craving in healthy subjects. We performed a randomized sham-controlled cross-over study in which 23 subjects received sham and active tDCS (anode left/cathode right and anode right/cathode left) of the DLPFC. Subjects were exposed to food and also watched a movie of food associated with strong craving. Desire for food consumption was evaluated by visual analogue scales (VAS) and food consumption before and after treatment. In addition we measured visual attention to food using an eye tracking system. Craving for viewed foods as indexed by VAS was reduced by anode right/cathode left tDCS. After sham stimulation, exposure to real food or food-related movie increased craving; whereas after anode left/cathode right tDCS, the food-related stimuli did not increase craving levels, as revealed by the VAS scale. Moreover, compared with sham stimulation, subjects fixated food-related pictures less frequently after anode right/cathode left tDCS and consumed less food after both active stimulation conditions. These changes were not related to mood changes after any type of tDCS treatment. The effects of tDCS on food craving might be related to a modulation of neural circuits associated with reward and decision-making.

Low and high frequency repetitive transcranial magnetic stimulation for the treatment of spasticity

The development of non‐invasive techniques of cortical stimulation, such as transcranial magnetic stimulation (TMS), has opened new potential avenues for the treatment of neuropsychiatric diseases. We hypothesized that an increase in the activity in the motor cortex by cortical stimulation would increase its inhibitory influence on spinal excitability through the corticospinal tract and, thus, reduce the hyperactivity of the gamma and alpha neurons, improving spasticity. Seventeen participants (eight males, nine females; mean age 9y 1mo [SD 3y 2mo]) with cerebral palsy and spastic quadriplegia were randomized to receive sham, active 1Hz, or active 5Hz repetitive TMS of the primary motor cortex. Stimulation was applied for 5 consecutive days (90% of motor threshold). The results showed that there was a significant reduction of spasticity after 5Hz, but not sham or 1Hz, stimulation as indexed by the degree of passive movement; however this was not evident when using the Ashworth scale, although a trend for improvement was seen for elbow movement. The safety evaluation showed that stimulation with either 1Hz or 5Hz did not result in any adverse events as compared with sham stimulation. Results of this trial provide initial evidence to support further trials exploring the use of cortical stimulation in the treatment of spasticity.

Teleavaliação da habilidade de leitura no ensino infantil fundamental

Technological advances have permitted devising new Internet-mediated psychological assessment tools for the school context. It is necessary to evaluate the efficacy of such instruments. This study analyses the validity of The Silence Reading Skills Test-On-line for assessing lexical decision skills. The study involved 451 children with mean age of 8,24 (SD=1,23) from pre-school and primary school. The test was administered through Internet with automatic result recording. Results showed that scores increased significantly over successive school levels (except from 3rd to 4th grade). Error analysis revealed that pre-school children have difficulty with orthographic lexicon. The Web-based application produced response patterns equivalent to those obtained in the typical paper and pencil application. Results corroborated the feasibility of using the Internet for collecting data of tests based on theoretical constructs.

Development of a test battery to assess deaf language skills via WWW

A test battery (BALS Online) was created to assess the development of language skills in Portuguese and Libras (Brazilian Sign Language) by deaf students via WWW. The battery consists of six tests, namely: picture naming by matching written words (PNM Online), picture naming by spelling (PNS Online), sign naming by matching written words (SNM Online), sign naming by spelling (SNS Online), word reading competence (WRC Online), receptive sign vocabulary (RSV Online). The traditional paper-and-pencil versions have been standardized with a sample of 1158 deaf students. This study provides preliminary validation of three out of the six computerized battery tests with hearing children. By comparing data obtained with the computerized tests to data obtained with the paper-and-pencil tests, the study found out that they are compatible.

Análise dos padrões dos movimentos oculares em tarefas de busca visual: efeito da familiaridade e das características físicas do estímulo

PURPOSE To analyze eye movements in asymmetric visual search using the task of normal and mirrored position letters. To evaluate the effect of familiarity and stimulus features. METHODS Eighty-three university students with normal or corrected-to-normal vision were asked to search for a letter in inverted position to the letters in a group of either normal or mirrored letters. Four types of letters were used (Z, N, E and G) and the eye movements were tracked by a specialized computer-based system (eyetracking). The analyzed measurements were: reaction time, fixation number and duration, saccade distance and duration. RESULTS All measures varied with the type of letter. Reaction time, fixation number, and saccade distance were higher when the task was to find the normal letter in a group of mirrored letters. In this condition, fixation duration was smaller. Interaction was found between familiarity and the type of letter for the reaction time, fixation number and duration. The reaction time and fixation number increased together with the stimulus complexity, with a greater increase for the normal letter target. Fixation duration, however, decreased with the complexity of the stimuli and the search condition. CONCLUSIONS Finding a mirrored letter among normal letters proved to be easier than the contrary. The letter type also affected the performance. When the context is formed of unfamiliar complex stimuli, the fixation duration is shorter, indicating a narrower span for visual processing. Therefore, a greater number of fixations with shorter duration are needed for the unfamiliar context while less fixations with greater duration are needed for the familiar context.