Central Conduction Time of Magnetic Brain Stimulation in Attention-Deficit Hyperactivity Disorder

Abstract

Twenty-seven children and adolescents aged 4 to 18 years, fulfilling the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for attention-deficit hyperactivity disorder, were included in this study. The diagnosis was determined by a pediatric neurologist and a psychologist examined all 27 subjects with tests that included the Wechsler Intelligence Scale for Children-Revised (WISC-R) and reading, writing, handedness, personality, and anxiety scores. Subjects with histories of epilepsy, head injury, drug abuse, or psychotic disorders were excluded. Culturally based causes or emotional disorders were also excluded. Transcranial magnetic stimulation was performed on all subjects, with recording of the motor evoked potential at the biceps brachii. Central motor conduction time was calculated by cervical root stimulation. Due to shape variability, the amplitude of the motor responses was not measured in the study. The mean value of central conduction time in the subjects was very significantly increased (P < .001) compared to that in a group of normal controls, case-matched for IQ, age, and sex. A central motor conduction time greater than 12 ms indicates abnormality. A second finding in the subjects was the significant difference of central conduction time on the side-to-side stimulation (P = .03). These findings are correlated with delay in the maturation of the corticomotoneuronal system and might provide neurophysiologic data for diagnosis.

The Effects of Methylphenidate on Transcranial Magnetic Stimulation Parameters in Children with Attention Deficit Hyperactivity Disorder

“…The estimate is made by subtracting the spinal motor neuron to muscle latency from the cortex to muscle latency (12). The CMCT in ADHD subjects was found to be increased in previous studies (20,21). However, other studies did not find differences in the CMCT between healthy children and children with ADHD (16,17,19).…”

“…TMS procedure was well tolerated by all 24 children. Earlier studies have shown that ADHD subjects have longer CMCT than healthy children (20,21). Uclés et al suggested that increased CMCT in ADHD could be related to delay in the maturation of cortico-motoneuronal system (21).…”

Motor Skills in Children with ADHD: Comparative Study from the Farmacological Treatment

“…This includes repetitive movements (Carte y Hinshaw, 1996;Denckla y Rudel, 1978), difficulties in fine motor skills associated with hyperactiveimpulsive or disantención symtomps (Pitcher et al, 2003); coordination failures (Jucaite et al, 2003), problems in controlling the movements and especially when there is no visual feedback (Eliasson et al, 2004); balance deficiencies (Raberger y Wimmer, 2003); maladjustment in rhythmic beating sequential tasks (Lemura et al, 2000); excessive unnecessary movement (Mostofsky et al, 2003); difficulty with motor skills Acquisitions (Karatekin et al, 2003); and slow central motor skill processing (Ucles et al, 2000); lower motor skills and intervals and number of errors increase (Tantillo et al, 2002).…”

Transcranial magnetic stimulation: studying motor neurophysiology of psychiatric disorders

“…Another psychiatric disorder that was recently studied using TMS and motor neurophysiology is ADHD (Ucles et al 2000). Ucles et al (2000) studied 27 children and adolescents aged 4-18 years with ADHD.…”