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.

Inadequate physical fitness is a major problem affecting the function and health of children with cerebral palsy (CP). Lack of optimal physical activity may contribute to the development of secondary conditions associated with CP such as chronic pain, fatigue, and osteoporosis. The purpose of this article is to highlight the content and recommendations of a Pediatrics Research Summit developed to foster collaborative research in this area. Two components of physical fitness-muscle strength and cardiorespiratory fitness-were emphasized. Although there is evidence to support the use of physical fitness interventions, there are many gaps in our current knowledge. Additional research of higher quality and rigor is needed in order to make definitive recommendations regarding the mode, intensity, frequency, and duration of exercise. Outcome measurements have focused on the body functions and structures level of the International Classification of Functioning, Disability and Health (ICF), and much less is known about effects at the activities and participation levels. Additionally, the influence of nutritional and growth factors on physical fitness has not been studied in this population, in which poor growth and skeletal fragility have been identified as serious health issues. Current intervention protocols and outcome measurements were critically evaluated, and recommendations were made for future research.

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Muscle strength, neuromuscular activation, and motor-unit firing characteristics (firing rate, recruitment, and short-term synchronization) were assessed during voluntary contractions of the medial gastrocnemius (GAS) and tibialis anterior (TA) muscles of 10 participants with spastic diplegic or hemiplegic cerebral palsy (CP). The participants (six females, four males; age range 6 to 37y) walked with equinus gait at Gross Motor Function Classification System levels II to III. These were compared with 10 age-matched controls (five females; age range 7 to 35y). Neuromuscular activation was estimated by the ratio of surface electromyogram amplitude to M-wave amplitude elicited by supramaximal electrical nerve stimulation. Participants with CP produced significantly less torque (normalized by leg length) compared with controls (TA: mean 2.3, SD 1.6 vs mean 8.9, SD 3.4Nm/m; GAS mean 13.7, SD 7.1 vs mean 28.6, SD 5.1Nm/m, p < 0.001). Neuromuscular activation during maximum voluntary contraction was significantly reduced in the participants with CP compared with controls (mean 2.4, SD 1.5 vs mean 9.7, SD 2.7Nm/m for TA; mean 1.04, SD 0.41 vs mean 3.1, SD 1.2Nm/m for GAS, p < 0.001). When compared at the same submaximal level of neuromuscular activation, motor-unit recruitment and firing rates were not different between the groups, although short-term synchronization in TA was reduced in the participants with CP. These data indicate that weakness, known to be an important component of the motor deficit in CP, has a strong central component. Although the relation between recruitment and firing rate remained substantially intact at the low and moderate force contractions tested, results suggest that the participants with CP were unable to recruit higher threshold motor units or to drive lower threshold motor units to higher firing rates.

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.