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Influence of stimulant medication and response speed on lateralization of movement-related potentials in attention-deficit/hyperactivity disorder.

Bender S, Resch F, Klein C, Renner T, Fallgatter AJ, Weisbrod M, Romanos M - PLoS ONE (2012)

Bottom Line: However, it remains unclear in which way the motor system itself and its development are affected by the disorder.Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes.A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD.

View Article: PubMed Central - PubMed

Affiliation: Section for Clinical Neurophysiology and Multimodal NeuroImaging, Child and Adolscent Psychiatric Hospital of the University of Technology, Dresden, Germany. Stephan.Bender@uniklinikum-dresden.de

ABSTRACT

Background: Hyperactivity is one of the core symptoms in attention deficit hyperactivity disorder (ADHD). However, it remains unclear in which way the motor system itself and its development are affected by the disorder. Movement-related potentials (MRP) can separate different stages of movement execution, from the programming of a movement to motor post-processing and memory traces. Pre-movement MRP are absent or positive during early childhood and display a developmental increase of negativity.

Methods: We examined the influences of response-speed, an indicator of the level of attention, and stimulant medication on lateralized MRP in 16 children with combined type ADHD compared to 20 matched healthy controls.

Results: We detected a significantly diminished lateralisation of MRP over the pre-motor and primary motor cortex during movement execution (initial motor potential peak, iMP) in patients with ADHD. Fast reactions (indicating increased visuo-motor attention) led to increased lateralized negativity during movement execution only in healthy controls, while in children with ADHD faster reaction times were associated with more positive amplitudes. Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes.

Conclusions: A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD. A delayed maturation of the neuronal circuitry, which involves primary motor cortex, may contribute to ADHD pathophysiology.

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Related in: MedlinePlus

Scatterplot showing the correlation between response speed and lateralized initial motor potential peak amplitude (iMP’) for children with ADHD and healthy control children ([C3−C4]/2).
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pone-0039012-g005: Scatterplot showing the correlation between response speed and lateralized initial motor potential peak amplitude (iMP’) for children with ADHD and healthy control children ([C3−C4]/2).

Mentions: There was a trend towards a positive correlation between median reaction times and iMP’ amplitude in healthy controls (r = 0.43; t = 2.0; p = 0.06) but a negative correlation in the ADHD group (r = −0.50; t = 2.2; p = 0.048; Figure 5). The two correlations differed significantly (F(1;32) = 8.2; p = 0.007). Though there was one subject with a high reaction time median in the ADHD group, the results of the median split analysis given above supported the interpretation that the regression differences were not artificially caused by this outlier.


Influence of stimulant medication and response speed on lateralization of movement-related potentials in attention-deficit/hyperactivity disorder.

Bender S, Resch F, Klein C, Renner T, Fallgatter AJ, Weisbrod M, Romanos M - PLoS ONE (2012)

Scatterplot showing the correlation between response speed and lateralized initial motor potential peak amplitude (iMP’) for children with ADHD and healthy control children ([C3−C4]/2).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375242&req=5

pone-0039012-g005: Scatterplot showing the correlation between response speed and lateralized initial motor potential peak amplitude (iMP’) for children with ADHD and healthy control children ([C3−C4]/2).
Mentions: There was a trend towards a positive correlation between median reaction times and iMP’ amplitude in healthy controls (r = 0.43; t = 2.0; p = 0.06) but a negative correlation in the ADHD group (r = −0.50; t = 2.2; p = 0.048; Figure 5). The two correlations differed significantly (F(1;32) = 8.2; p = 0.007). Though there was one subject with a high reaction time median in the ADHD group, the results of the median split analysis given above supported the interpretation that the regression differences were not artificially caused by this outlier.

Bottom Line: However, it remains unclear in which way the motor system itself and its development are affected by the disorder.Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes.A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD.

View Article: PubMed Central - PubMed

Affiliation: Section for Clinical Neurophysiology and Multimodal NeuroImaging, Child and Adolscent Psychiatric Hospital of the University of Technology, Dresden, Germany. Stephan.Bender@uniklinikum-dresden.de

ABSTRACT

Background: Hyperactivity is one of the core symptoms in attention deficit hyperactivity disorder (ADHD). However, it remains unclear in which way the motor system itself and its development are affected by the disorder. Movement-related potentials (MRP) can separate different stages of movement execution, from the programming of a movement to motor post-processing and memory traces. Pre-movement MRP are absent or positive during early childhood and display a developmental increase of negativity.

Methods: We examined the influences of response-speed, an indicator of the level of attention, and stimulant medication on lateralized MRP in 16 children with combined type ADHD compared to 20 matched healthy controls.

Results: We detected a significantly diminished lateralisation of MRP over the pre-motor and primary motor cortex during movement execution (initial motor potential peak, iMP) in patients with ADHD. Fast reactions (indicating increased visuo-motor attention) led to increased lateralized negativity during movement execution only in healthy controls, while in children with ADHD faster reaction times were associated with more positive amplitudes. Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes.

Conclusions: A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD. A delayed maturation of the neuronal circuitry, which involves primary motor cortex, may contribute to ADHD pathophysiology.

Show MeSH
Related in: MedlinePlus