In this report we describe the outcome of a consensus meeting that occurred at the National Institutes of Health in Bethesda, Maryland, March 12 through 14, 2005. The meeting brought together 39 specialists from multiple clinical and research disciplines including developmental pediatrics, neurology, neurosurgery, orthopedic surgery, physical therapy, occupational therapy, physical medicine and rehabilitation, neurophysiology, muscle physiology, motor control, and biomechanics. The purpose of the meeting was to establish terminology and definitions for 4 aspects of motor disorders that occur in children: weakness, reduced selective motor control, ataxia, and deficits of praxis. The purpose of the definitions is to assist communication between clinicians, select homogeneous groups of children for clinical research trials, facilitate the development of rating scales to assess improvement or deterioration with time, and eventually to better match individual children with specific therapies. "Weakness" is defined as the inability to generate normal voluntary force in a muscle or normal voluntary torque about a joint. "Reduced selective motor control" is defined as the impaired ability to isolate the activation of muscles in a selected pattern in response to demands of a voluntary posture or movement. "Ataxia" is defined as an inability to generate a normal or expected voluntary movement trajectory that cannot be attributed to weakness or involuntary muscle activity about the affected joints. "Apraxia" is defined as an impairment in the ability to accomplish previously learned and performed complex motor actions that is not explained by ataxia, reduced selective motor control, weakness, or involuntary motor activity. "Developmental dyspraxia" is defined as a failure to have ever acquired the ability to perform age-appropriate complex motor actions that is not explained by the presence of inadequate demonstration or practice, ataxia, reduced selective motor control, weakness, or involuntary motor activity.

Purpose The purpose of this study is to develop a method to reliably characterize multiple features of the corticospinal system in a more efficient manner than typically done in transcranial magnetic stimulation (TMS) studies. Methods Forty TMS pulses of varying intensity were given over the first dorsal interosseous motor hot spot in 10 healthy adults. The FDI motor evoked potential (MEP) size was recorded during rest and activation to create recruitment curves. The Boltzmann sigmoidal function was fit to the data, and parameters relating to maximal MEP size, curve slope, and stimulus intensity leading to half-maximal MEP size were computed from the curve fit. Results Good to excellent test-retest reliability was found for all corticospinal parameters at rest and during activation with 40 TMS pulses. Conclusions Through the use of curve fitting, important features of the corticospinal system can be determined with fewer stimuli than typically used for the same information. Determining the recruitment curve provides a basis to understand the state of the corticospinal system and select subject-specific parameters for TMS testing quickly and without unnecessary exposure to magnetic stimulation. This method can be useful in individuals who have difficulty maintaining stillness, including children and patients with motor disorders.

This study explores the effects of functional electrical stimulation (FES) of the lumbar trunk extensors on the seated posture and bimanual workspace of subjects with spinal cord injury (SCI). Four subjects with motor complete SCI with implanted intramuscular stimulating electrodes to activate the lumbar erector spinae were studied. The positions of markers on the pelvis, trunk, and hands were monitored by a motion capture system during bimanual reaching maneuvers. To define three-dimensional functional workspace boundaries, subjects swept their hands through the extremes of their range of motion without losing balance while sitting. To characterize forward reach, subjects reached to targets in the sagittal plane while carrying various masses with and without FES. Reaching trials were rated on the seven-point usability rating scale to determine effort and subject preference and change in pelvic angle with stimulation was monitored. There was a consistent change in the seated posture with FES in all subjects that resulted in significant forward or upward (6.85 cm +/- 2.15 cm) shifts in the workspace. Workspace volumes increased for two of the four subjects tested. FES caused significant anterior rotation of the pelvis to restore a more natural lumbar curve without a backrest (19.81 degrees +/- 8.75 degrees). With a backrest, the change in posture with FES allowed individuals with SCI to reach further in the sagittal plane and carry heavier masses by shifting the trunk, allowing increased elbow extension, or a combination of the two mechanisms. Reaching with FES was consistently preferred over reaching without FES. This preliminary study is encouraging for future research on trunk stability and reaching ability with FES.