The Effect of Dual Task on Attentional Performance in Children With ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder without validated objective markers. Oculomotor behavior and executive motor control could potentially be used to investigate attention disorders. The aim of this study was to explore an oculomotor and postural dual task in children with ADHD. Forty-two children were included in the study, gathering children with ADHD (n = 21) (mean 8.15 age ± years 0.36) and sex-, age-, and IQ-matched typically developing children (TD). Children performed two distinct fixation tasks in three different postural conditions. Eye movements and postural body sway were recorded simultaneously, using an eye tracker and a force platform. Results showed that children with ADHD had poor fixation capability and poor postural stability when compared to TD children. Both groups showed less postural control on the unstable platform and displayed more saccades during the fixation task. Surprisingly, in the dual unstable platform/fixation with distractor task, the instability of children with ADHD was similar to that observed in TD children. “Top-down” dys-regulation mediated by frontal-striatal dysfunction could be at the origin of both poor inhibitory oculomotor deficits and impaired body stability reported in children with ADHD. Finally, we could assume that the fact both groups of children focused their attention on a secondary task led to poor postural control. In the future it could be interesting to explore further this issue by developing new dual tasks in a more ecological situation in order to gain more insight on attentional processes in children with ADHD.HIGHLIGHTS– Children with ADHD showed poor fixation capability when compared to TD children.– “Top-down” dys-regulation mediated by frontal-striatal dysfunction could be at the origin of both poor inhibitory oculomotor deficits and impaired body stability reported in children with ADHD.– Both groups of children focused their attention on the visual fixation task leading to poor postural control.– In the future it could be interesting to develop new dual tasks in an ecological situation in order to gain more insight on attentional processes in children with ADHD

Controle postural e informação sensorial em idosos diabéticos praticantes e não praticantes de atividade física

O objetivo deste estudo foi avaliar o desempenho dos sistemas sensoriais e do controle postural de idosos diabéticos e investigar a relação entre as alterações destes sistemas e do controle postural desta população. Participaram deste estudo dez idosos diabéticos ativos (62±4,4 anos) (GDA), 10 diabéticos sedentários (65,5±7,4 anos) (GDS) e 10 idosos saudáveis ativos (63,2±4.5anos) (GCA) foram submetidos a avaliações sensoriais e de controle postural. As avaliações sensoriais foram compostas por avaliação somatossensorial (sensibilidade cutânea e sensibilidade ao movimento passivo). Para avaliar o controle postural foram analisadas medidas de oscilação corporal durante manutenção da postura ereta (em tandem stance e bipodal). Os resultados indicaram pior desempenho do GDS na avaliação do movimento passivo e de controle postural. Nas avaliações de controle postural, o GDS apresentou uma maior amplitude média de oscilação (AMO) (cm) nas condições de manutenção da postura ereta na posição tandem stance na direção médio-lateral. No teste de sensibilidade ao movimento passivo, o GDS precisou, em média, de um maior deslocamento angular para perceber o movimento das articulações do joelho e tornozelo. Estes resultados indicam, portanto, que as alterações estruturais e fisiológicas decorrentes do diabetes, resultam em piora do desempenho dos sistemas sensoriais e de controle postural. Além disso, a maior deterioração do sistema proprioceptivo em idosos diabéticos pode interferir negativamente no desempenho de controle postural dos mesmos. Desta forma, a atividade física minimiza a perda sensorial e ainda ajuda no controle postural dos diabéticos

Efeitos da manipulação do estímulo visual e da intenção na oscilação postural de idosas

Este estudo investigou a influência de características do estímulo visual e o efeito da intenção nas respostas do controle postural frente à manipulação visual de adultas idosas. As 20 participantes permaneceram em pé em uma sala móvel durante sete tentativas com duração de 1 minuto cada, olhando para um alvo fixo, medindo-se sua oscilação corporal. Na primeira tentativa não houve qualquer movimento da sala, porém a partir da segunda a sala foi movimentada no sentido ântero-posterior. Para dez participantes, a velocidade de pico da movimentação foi de 0,6 cm/s e, para as demais, de 1,0 cm/s. A partir da quinta tentativa, as participantes foram informadas do movimento da sala e orientadas a resistir à movimentação. Os resultados indicam que a oscilação corporal das idosas é induzida pelo movimento da sala móvel. Intenção e alteração da característica do estímulo visual reduzem a influência da informação visual na oscilação corporal, mas a manipulação de propriedade do estímulo (neste caso, velocidade), é menos efetiva que a intenção. Essa maior dependência da intenção para alterar a influência de um estímulo sensorial no controle postural indica que o funcionamento do sistema de controle postural em idosos não possibilita ajustes automáticos de respostas posturais frente a pequenas variações das condições ambientais. Iinformações sobre tais variações podem ser direcionadas de forma a compensar essa diferença.This study examined the influence of both visual stimulus features and intention on postural control responses due to visual manipulation of elderly women. Twenty participants stood upright inside a moving room, for seven trials for 1 min apiece, staring at a fixed target, their body sway being measured. The room was not moved during the first trial, but from the second trial on, it was continuously oscillated back and forward. For ten participants, the moving room oscillated with peak velocity of 0.6 cm/s and for the others, with peak velocity of 1.0 cm/s. From the fifth trial on, participants were informed about the movement of the room and instructed to resist to its influence. Results show that body sway is induced by visual manipulation in elderly adults. Intention and change in visual stimulus lead to less influence of the visual information on body sway, but changes in the stimulus properties (velocity, for that matter), is less effective than intention. This higher dependency on intention for changing sensory influence on postural control suggests that postural control in elderly adults does not benefit from automatic postural responses due to small environmental changes. Tips and information about such kind of environmental changes should be used in order to make up for such difference in automatic adjustments observed in the elderly

Analysis of postural control and muscle function performance of older adults participating in a multicomponent exercise program in primary health care

OBJECTIVES: This cross-sectional study aimed to investigate (1) postural control performance in different postural tasks and (2) muscle strength and power of the hip, knee, and ankle of active vs inactive older adults. METHODS: The sample consisted of 61 healthy community-dwelling older adults, classified into 2 groups: active, consisting of participants of a multicomponent exercise program offered through the Exercise Orientation Service; and inactive. Participants were considered physically active/inactive in the past 3 months. Postural control was assessed using a force plate in 8 postural tasks. Muscle function was evaluated using an isokinetic dynamometer. T-tests were used to compare clinical characteristics between the groups. ANCOVA and MANCOVA were used to compare differences in variables of postural control and muscle function. RESULTS: Active participants had higher levels of physical activity, clinical balance, and quality of life than inactive participants. The active group had lower values for area (center of pressure) than the inactive group under the following conditions: bipedal stance on an unstable surface with eyes open and with eyes closed, and semi-tandem stance on an unstable surface with eyes open. The active group showed greater muscle power, with higher mean power values for hip abduction and adduction, knee extension, and knee flexion and shorter time to peak torque for hip adduction and ankle dorsiflexion than the inactive group. CONCLUSIONS: Multicomponent exercise programs delivered in primary health care settings contributed to improving postural control and muscle power in this sample of older adults, which can potentially help prevent falls and improve quality of life.</p

Eye movements and postural control in dyslexic children performing different visual tasks.

The aim of this study was to examine eye movements and postural control performance among dyslexic children while reading a text and performing the Landolt reading task. Fifteen dyslexic and 15 non-dyslexic children were asked to stand upright while performing two experimental visual tasks: text reading and Landolt reading. In the text reading task, children were asked to silently read a text displayed on a monitor, while in the Landolt reading task, the letters in the text were replaced by closed circles and Landolt rings, and children were asked to scan each circle/ring in a reading-like fashion, from left to right, and to count the number of Landolt rings. Eye movements (Mobile T2®, SuriCog) and center of pressure excursions (Framiral®, Grasse, France) were recorded. Visual performance variables were total reading time, mean duration of fixation, number of pro- and retro-saccades, and amplitude of pro-saccades. Postural performance variable was the center of pressure area. The results showed that dyslexic children spent more time reading the text and had a longer duration of fixation than non-dyslexic children. However, no difference was observed between dyslexic and non-dyslexic children in the Landolt reading task. Dyslexic children performed a higher number of pro- and retro-saccades than non-dyslexic children in both text reading and Landolt reading tasks. Dyslexic children had smaller pro-saccade amplitude than non-dyslexic children in the text reading task. Finally, postural performance was poorer in dyslexic children than in non-dyslexic children. Reading difficulties in dyslexic children are related to eye movement strategies required to scan and obtain lexical and semantic meaning. However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements and might not also be related to different eye movement behavior

Sensorimotor Integration in Dyslexic Children under Different Sensory Stimulations

Dyslexic children, besides difficulties in mastering literacy, also show poor postural control that might be related to how sensory cues coming from different sensory channels are integrated into proper motor activity. Therefore, the aim of this study was to examine the relationship between sensory information and body sway, with visual and somatosensory information manipulated independent and concurrently, in dyslexic children. Thirty dyslexic and 30 non-dyslexic children were asked to stand as still as possible inside of a moving room either with eyes closed or open and either lightly touching a moveable surface or not for 60 seconds under five experimental conditions: (1) no vision and no touch; (2) moving room; (3) moving bar; (4) moving room and stationary touch; and (5) stationary room and moving bar. Body sway magnitude and the relationship between room/bar movement and body sway were examined. Results showed that dyslexic children swayed more than non-dyslexic children in all sensory condition. Moreover, in those trials with conflicting vision and touch manipulation, dyslexic children swayed less coherent with the stimulus manipulation compared to non-dyslexic children. Finally, dyslexic children showed higher body sway variability and applied higher force while touching the bar compared to non-dyslexic children. Based upon these results, we can suggest that dyslexic children are able to use visual and somatosensory information to control their posture and use the same underlying neural control processes as non-dyslexic children. However, dyslexic children show poorer performance and more variability while relating visual and somatosensory information and motor action even during a task that does not require an active cognitive and motor involvement. Further, in sensory conflict conditions, dyslexic children showed less coherent and more variable body sway. These results suggest that dyslexic children have difficulties in multisensory integration because they may suffer from integrating sensory cues coming from multiple sources. © 2013 Viana et al

Eye movement and postural sway in dyslexic children during sitting and standing

International audienceIn this study, we investigated the eye movement and postural control performance in dyslexic children while reading text and performing Landolt reading when sitting and standing. Fifteen dyslexic and 15 non-dyslexic children were asked to sit in a chair while the eye movements were recorded, and were then asked to stand on an unstable platform while eye movements and postural sway were recorded simultaneously at the time of Landolt reading and text reading. Eye movements were recorded binocularly by Mobile EyeBrain Tracker (MobileT2 ® , SuriCog) and center of pressure excursions were recorded by Multitest Equilibre (by Framiral ®). The dependent variables for visual performance in the reading tasks were: total reading time, mean duration of fixation, number of pro-and retro-saccades, and amplitude of pro-saccades. The dependent variable for postural performance was the center of pressure area. The results showed that dyslexic children spent more time reading the text compared to non-dyslexic children (p 0.05). Dyslexic children performed longer fixations in the sitting condition as compared to the standing (p 0.05). Finally, postural performance was poorer in dyslexic children than in non-dyslexic children in both the reading tasks (p < 0.02). However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements

Coherence.

<p>Mean coherence between the driving signal and trunks sway for both groups in the trials in which room or bar was moved (a) and in the trials with conflicting sensory information (b). Error bars represent standard error.</p

Use of monocular and binocular visual cues for postural control in children

The purpose of the present study was to examine how children's postural control is affected by different visual cues. Sixteen children, ages 8 and 12 years, and eight adults participated in the study. Each was asked to stand upright inside a moving room, which oscillated at 0.2 Hz, while facing the frontal wall at two distances: 75 and 150 cm, under monocular and binocular vision conditions. Vision manipulation induced corresponding body sway in all participants, but vision effect was the smallest in the monocular vision condition, at the greater distance ( 150 cm) from the front wall. More importantly, however, the influence of visual manipulation on body sway was age-dependent, with the younger children showing less visually induced body sway than the older children and adults. This aging effect was more dramatic in the monocular vision condition. These results suggest that development of the visual system is not fully completed until the age of 12 years and that eye movement and binocular vision might play an important role in how visual cues are coupled to body sway.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq