Hyperkinetic movements are unwanted or excess movements that are frequently seen in children with neurologic disorders. They are an important clinical finding with significant implications for diagnosis and treatment. However, the lack of agreement on standard terminology and definitions interferes with clinical treatment and research. We describe definitions of dystonia, chorea, athetosis, myoclonus, tremor, tics, and stereotypies that arose from a consensus meeting in June 2008 of specialists from different clinical and basic science fields. Dystonia is a movement disorder in which involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures, or both. Chorea is an ongoing random-appearing sequence of one or more discrete involuntary movements or movement fragments. Athetosis is a slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Myoclonus is a sequence of repeated, often non-rhythmic, brief shock-like jerks due to sudden involuntary contraction or relaxation of one or more muscles. Tremor is a rhythmic back-and-forth or oscillating involuntary movement about a joint axis. Tics are repeated, individually recognizable, intermittent movements or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. Stereotypies are repetitive, simple movements that can be voluntarily suppressed. We provide recommended techniques for clinical examination and suggestions for differentiating between the different types of hyperkinetic movements, noting that there may be overlap between conditions. These definitions and the diagnostic recommendations are intended to be reliable and useful for clinical practice, communication between clinicians and researchers, and for the design of quantitative tests that will guide and assess the outcome of future clinical trials.

Clumsiness has been proposed as a diagnostic feature of Asperger syndrome (AS), a type of pervasive developmental disorder recently introduced in the ICD-10 and DSM-IV. However, the extent to which this symptom is specific to AS is not clear. To investigate this issue, we compared a sample of AS children with age- and sex-matched groups of children with autistic disorder and pervasive developmental disorder not otherwise specified (PDDNOS). Twelve subjects with AS (ICD-10/DSM-IV; 11 males; average age 11.4 years; mean full-scale IQ 104.9) were compared with 12 subjects with autistic disorder (DSM-III-R; II males; average age 10.3 years; mean full-scale IQ 78.4) and 12 subjects with PDDNOS (DSM-III-R; 10 males; average age 10.1 years; mean full-scale IQ 78.2). The BruininksOseretsky test, a standardized test of motor coordination, was administered blind by the same investigator to all the three groups. While coordination deficits were found in all three groups, children with AS were found to be less impaired than those with autistic disorder and PDDNOS. However, no significant relationship was found between coordination scores and diagnosis after adjusting for the level of intelligence. These findings suggest that some patients with AS may be less clumsy than those with autistic disorder and that this difference may be the result of their higher level of intelligence. Studies based on larger samples using multiple measures of coordination are needed to further clarify the role of clumsiness in the classification of pervasive developmental disorders.

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The neurological basis of an increased incidence of cerebral palsy (CP) in preterm males is unknown. This study examined neonatal brain structure on magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) at term‐equivalent age, sex, and neurodevelopment at 1 year 6 months on the basis of the Amiel−Tison neurological examination, Gross Motor Function Classification System, and Bayley Scales of Infant Development in 78 very‐low‐birthweight preterm children (41 males, 37 females; mean gestational age 27.6wks, SD 2.5; mean birthweight 1021g, SD 339). Brain abnormalities on MRI and DTI were not different between males and females except in the splenium of the corpus callosum, where males had lower DTI fractional anisotropy (p=0.025) and a higher apparent diffusion coefficient (p=0.013), indicating delayed splenium development. In the 26 infants who were at higher risk on the basis of DTI, males had more abnormalities on MRI (p=0.034) and had lower fractional anisotropy and a higher apparent diffusion coefficient in the splenium (p=0.049; p=0.025) and right posterior limb of the internal capsule (PLIC; p=0.003; p=0.033). Abnormal neurodevelopment was more common in males (n=9) than in females (n=2; p=0.036). Children with abnormal neurodevelopment had more abnormalities on MRI (p=0.014) and reduced splenium and right PLIC fractional anisotropy (p=0.001; p=0.035). In children with abnormal neurodevelopment, right PLIC fractional anisotropy was lower than left (p=0.035), whereas in those with normal neurodevelopment right PLIC fractional anisotropy was higher than left (p=0.001). Right PLIC fractional anisotropy correlated to neurodevelopment (rho=0.371, p=0.002). Logistic regression predicted neurodevelopment with 94% accuracy; only right PLIC fractional anisotropy was a significant logistic coefficient. Results indicate that the higher incidence of abnormal neurodevelopment in preterm males relates to greater incidence and severity of brain abnormalities, including reduced PLIC and splenium development.

Neonatal microstructural development in the posterior limbs of the internal capsule (PLIC) was assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA) in 24 verylow-birthweight preterm infants at 37 weeks' gestational age and compared with the children's gait and motor deficits at 4 years of age. There were 14 participants with normal neonatal FA values (seven females, seven males; born at 27.6 weeks [SD 2.3] gestational age; birthweight 1027g [SD 229]) and 10 participants with low FA values in the PLIC (four females, six males; born at 28.4 weeks [SD 2.0] gestational age; birthweight 1041g [SD 322]). Seven of the 10 children with low FA and none of the children with normal FA had been diagnosed with CP by the time of gait testing. Among children with low neonatal FA, there was a strong negative correlation between FA of the combined left and right side PLIC and log NI (r=-0.89, p=0.001) and between FA and GMFCS (r=-0.65, p=0.04) at 4 years of age. There was no correlation between FA and gait NI or GMFCS at 4 years of age among children with normal neonatal FA. This preliminary study suggests neonatal DTI may be an important predictor of the severity of future gait and motor deficits.Cerebral palsy (CP) is the most common motor disorder in children born preterm, affecting over 15% of very-low-birthweight (VLBW) preterm infants (less than 1500g, less than 32wks gestation). Currently, most children with CP do not receive a specific prognosis or treatment plan until they present with gait deficits. Treatment depends on the severity of gait deficits, which range from toe walking in the mildly impaired, to a crouched, rotated gait in the more severely impaired. 4 Among children with CP who are not walking by age 2 years, only 10% walk independently by age 7 years. 25 This indicates a need for early and accurate prognosis, at an age when there is optimal neuronal plasticity and treatment may improve motor control, prevent growth related deformities, and reduce the need for orthopaedic surgery.The brain structure-function relations that influence motor control development in preterm children are not well understood. Previous studies have reported a global association between damage to neonatal white matter (WM), such as periventricular leukomalacia (PVL), in the region of the posterior limbs of the internal capsule (PLIC) on MRI and the risk of developing CP. 5,6 Selective vulnerability of the internal capsule (IC) to hypoxia-ischemia is thought to result from insufficient vascularization of the developing blood supply in the periventricular region in preterm infants. 5 Damage to WM, including PVL, is thought to be the major cause of motor dysfunction in preterm children with spastic CP. 3,6,7,8,17 A recent study of brain MRI in adolescents with CP found that motor dysfunction was more strongly correlated with the severity of damage in the IC and precentral gyrus than with the total WM volume loss. 22 These findings are consistent with the neuroanatomy. The descending motor axons of the corticospinal t...