Estimulação cerebral não invasiva excitatória sobre a atenção de adultos com sintomas do transtorno de déficit de atenção e hiperatividade / Excitatory non-invasive brain stimulation over attention of adults with symptoms of Attention-deficit hyperactivity disorder

Objetivos: avaliar a atenção de adultos com sintomas de transtorno de déficit de atenção e hiperatividade (TDAH), quando submetidos a técnicas de estimulação cerebral não invasiva (ECNI) excitatória. Métodos: nesse estudo crossover 20 voluntários foram submetidos a uma sessão real e uma sham de Estimulação Magnética Transcraniana Repetitiva (EMTr) ou Estimulação Transcraniana por Corrente Contínua (ETCC). A EMTr (10Hz) foi aplicada no córtex dorsolateral esquerdo. A ETCC foi aplicada colocando-se o ânodo no mesmo local e cátodo na região supraorbital contralateral (1mA e 20 minutos). A avaliação foi realizada através de testes neuropsicológicos, considerando os desfechos: atenção focada e sustentada; amplitude atencional, manipulação mental e resistência à interferência. Resultados: observou-se que a ECNI excitatória exerceu efeito distinto entre os grupos, prejudicando o desempenho atencional dos adultos saudáveis e beneficiando os pacientes com TDAH. Destaca-se que em relação à estimulação sham o grupo controle aumentou o desempenho atencional de forma significativa, possivelmente decorrente do efeito de aprendizagem, enquanto o grupo com TDAH só obteve aumento no desempenho após a aplicação da estimulação real. Conclusão: os achados ratificam a compreensão que a ECNI excitatória pode contribuir para melhora cognitiva em adultos com TDAH e sugerem que processo inverso pode acontecer em relação aos saudáveis.

Purpose: evaluate the attentional performance of adults with symptoms of Attention-deficit hyperactivity disorder (ADHD) when submitted to excitatory non-invasive brain stimulation (NIBS). Methods: a crossover design were performed with 20 volunteers underwent to a real session and sham session using repetitive Transcranial magnetic stimulation (rTMS) or Transcranial direct current stimulation (tDCS). The rTMS (10Hz) was applied over left dorsolateral cortex. The tDCS was applied in the same place and the cathode over the contralateral orbital region (1mA and 20 minutes). The evaluation was done trought the neuropsycologhical tests regarding the following outcomes: focused and sustained attention; Attentional amplitude, mental manipulation (and resistance to interference. Results: it was observed that excitatory stimulation induces a distinct effect between groups, harming the atentional performance of health adults and improving the performance of the subjects with Attention-deficit hyperactivity disorder. It is important to highlight that the sham stimulation in control group increase the attentional performance, possible due the learning effect. In the other hand, the group with Attention-deficit hyperactivity disorder symptoms only has an increase in performance after the real stimulation. Conclusion: this findings help in urderstading of excitatory NIBS could contribute to improve the cognitive performance in adults with ADHD and the opposite can happen with healthy subjects.

Intensity-dependent effects of cycling exercise on corticospinal excitability in healthy humans: a pilot study

Abstract Aims the aim of this study was to verify the effects of different intensities of locomotor exercise on corticospinal excitability. Methods 18 healthy subjects (27.6 ± 6.5 years,) participated in a design study of three different exercise protocols on a cycle ergometer: (i) 10 min at 75% Wmax (high intensity); (ii) 15min at 60% Wmax (moderate intensity) or (iii) 30 min at 45% Wmax (low intensity). The protocols of lower body cycling were assigned in random order in separate sessions. A control session was done with subjects at rest. Corticospinal excitability was assessed before (baseline) and every 5 min for 15min after the end of exercise/rest (time: 0, 5, 10 and 15) by measurement of the motor evoked potential (MEP) elicited by transcranial magnetic stimulation in the relaxed first-dorsal interosseus muscle. Results Compared to the resting session, a significant decrease (64%) in the motor evoked potential amplitudes was found only in the session of exercise of high intensity. This result seems depend on the level of physical activity of subject. No change was found after rest, low and moderate exercises. Conclusions These findings suggest that changes in the corticospinal excitability depend on exercise intensity and level of physical activity of subjects.(AU)