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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

Motor PINV topography for healthy control children.(top; from left to right: all responses, fast responses below median reaction time, slow responses above median reaction time) and children with ADHD (bottom; from left to right: responses off and on methylphenidate) for the motor PINV time interval (500–800 ms after the response trigger, motor post-processing).
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pone-0039012-g002: Motor PINV topography for healthy control children.(top; from left to right: all responses, fast responses below median reaction time, slow responses above median reaction time) and children with ADHD (bottom; from left to right: responses off and on methylphenidate) for the motor PINV time interval (500–800 ms after the response trigger, motor post-processing).

Mentions: For control children, averages of all responses are illustrated together with a separate presentation of averages of fast (below median reaction time) and slow responses (above median reaction time). For children with ADHD, responses on and off methylphenidate are presented. For effects of response speed in ADHD see Figure 4. Note how the rather symmetrically distributed stimulus-related P300 shadowed MRP in the topography before the subtraction of symmetrically distributed potential components by the calculation of lateralization. iMP time-course (thick black arrows) and lateralized topography around C3 (grey arrows) are in good agreement with previous literature. mPINV (lateralized negativity at C3 in the time interval 500–800 ms) was not shadowed by P300 any more. Its topography is presented in Figure 2.


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)

Motor PINV topography for healthy control children.(top; from left to right: all responses, fast responses below median reaction time, slow responses above median reaction time) and children with ADHD (bottom; from left to right: responses off and on methylphenidate) for the motor PINV time interval (500–800 ms after the response trigger, motor post-processing).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0039012-g002: Motor PINV topography for healthy control children.(top; from left to right: all responses, fast responses below median reaction time, slow responses above median reaction time) and children with ADHD (bottom; from left to right: responses off and on methylphenidate) for the motor PINV time interval (500–800 ms after the response trigger, motor post-processing).
Mentions: For control children, averages of all responses are illustrated together with a separate presentation of averages of fast (below median reaction time) and slow responses (above median reaction time). For children with ADHD, responses on and off methylphenidate are presented. For effects of response speed in ADHD see Figure 4. Note how the rather symmetrically distributed stimulus-related P300 shadowed MRP in the topography before the subtraction of symmetrically distributed potential components by the calculation of lateralization. iMP time-course (thick black arrows) and lateralized topography around C3 (grey arrows) are in good agreement with previous literature. mPINV (lateralized negativity at C3 in the time interval 500–800 ms) was not shadowed by P300 any more. Its topography is presented in Figure 2.

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