Influence of Stimulant Medication and Response Speed on Lateralization of Movement-Related Potentials in Attention-Deficit/Hyperactivity Disorder

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. 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. 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.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

Dissertatio Inauguralis Continens Expositionem L. IV. C. Fin. Reg. Et Positiones Ex J. Can. De Procurationibus

Straßburg, Univ., Jur. Diss., 1717Quam ... Solenniori eruditorum disquisitioni sistet Ad Diem 20. Septbemb. Anno M. DCC XVII. Franciscus Henricus Resh Türckhemio-AlsatusAutopsie nach Ex. der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Argentorati Literis Johannis Welperi

Similarities in trabecular hypertrophy with site-specific differences in cortical morphology between men and women with type 2 diabetes mellitus.

The goal of our study was to investigate interactions between sex and type 2 diabetes mellitus (T2DM) with regard to morphology of the peripheral skeleton. We recruited 85 subjects (mean age, 57±11.4 years): women with and without T2DM (n = 17; n = 16); and men with and without T2DM (n = 26; n = 26). All patients underwent high-resolution, peripheral, quantitative, computed tomography (HR-pQCT) imaging of the ultradistal radius (UR) and tibia (UT). Local bone geometry, bone mineral density (BMD), and bone microarchitecture were obtained by quantitative analysis of HR-pQCT images. To reduce the amount of data and avoid multi-collinearity, we performed a factor-analysis of HR-pQCT parameters. Based on factor weight, trabecular BMD, trabecular number, cortical thickness, cortical BMD, and total area were chosen for post-hoc analyses. At the radius and tibia, diabetic men and women exhibited trabecular hypertrophy, with a significant positive main effect of T2DM on trabecular number. At the radius, cortical thickness was higher in diabetic subjects (+20.1%, p = 0.003). Interestingly, there was a statistical trend that suggested attenuation of tibial cortical hypertrophy in diabetic men (cortical thickness, pinteraction = 0.052). Moreover, we found an expected sexual dichotomy, with higher trabecular BMD, Tb.N, cortical BMD, Ct.Th, and total area in men than in women (p≤ 0.003) at both measurement sites. Our results suggest that skeletal hypertrophy associated with T2DM is present in men and women, but appears attenuated at the tibial cortex in men

HR-pQCT parameters of the ultradistal radius and the ultradistal tibia in men and women with and without type 2 diabetes mellitus.

<p>HR-pQCT parameters of the ultradistal radius and the ultradistal tibia in men and women with and without type 2 diabetes mellitus.</p

Demographics and clinical characteristics.

<p>Demographics and clinical characteristics.</p

HR-pQCT of the ultradistal radius: Representative images.

<p>A) Woman with T2DM. B) Woman without T2DM. C) Man with T2DM. D) Man without T2DM.</p

Factor-analysis of HR-pQCT parameters of the ultradistal radius and the ultradistal tibia.

<p>Numbers in columns are factor loadings per parameter (in rows).</p

HR-pQCT of the ultradistal tibia: Representative images.

<p>A) Woman with T2DM. B) Woman without T2DM. C) Man with T2DM. D) Man without T2DM.</p