The speed of adaptation is dependent on the load type during target reaching by intact human subjects

A pilot study: effect of somatosensory loss on motor corrections in response to unknown loads in a reaching task by chronic stroke survivors

Despite recent studies indicating a significant correlation between somatosensory deficits and rehabilitation outcomes, how prevailing somatosensory deficits affect stroke survivors' ability to correct their movements and recover overall remains unclear. To explore how major deficits in somatosensory systems impede stroke survivors' motor correction to various external loads, we conducted a study with 13 chronic stroke survivors who had hemiparesis. An inertial, elastic, or viscous load, which was designed to impose perturbing forces with various force profiles, was introduced unexpectedly during the reaching task using a programmable haptic robot. Participants' proprioception and cutaneous sensation were also assessed using passive movement detection, finger-to-nose, mirror, repositioning, and Weinstein pressure tests. These measures were then analyzed to determine whether the somatosensory measures significantly correlated with the estimated reaching performance parameters, such as initial directional error, positional deviation, velocity deviations, and speed of motor correction were measured. Of 13 participants, 5 had impaired proprioception, as they could not recognize the passive movement of their elbow joint, and they kept showing larger initial directional errors even after the familiarization block. Such continuously found inaccurate initial movement direction might be correlated with the inability to develop the spatial body map especially for calculating the initial joint torques when starting the reaching movement. Regardless of whether proprioception was impaired or not, all participants could show the stabilized, constant reaching movement trajectories. This highlights the role of proprioception especially in the execution of a planned movement at the early stage of reaching movement.

Evaluation of Ayres Sensory Integration® Intervention on Sensory Processing and Motor Function in a Child with Rubinstein-Taybi Syndrome: A Case Report

The Rubinstein-Taybi Syndrome (RSTS) literature is limited about sensory integration, which is a foundational neurological function of the central nervous system that may affect the development of cognitive, social, and motor skills. The aim of this case report was to investigate the effects of Ayres Sensory Integration® (ASI) intervention on processing and integrating sensations, motor functions and parental goals of 3-year-old child with RSTS. Analysis of assessment data reviewed before and after treatment. Assessment collected by interview, Sensory Profile (SP), Sensory Processing Measure-Preschool (SPM-P) Home, Peabody Developmental Motor Scales-2 (PDMS-2), Gross Motor Function Measurement-88 (GMFM-88), and Gross Motor Function Classification System (GMFCS). Progress toward goals and objectives was measured with Goal Attainment Scale (GAS). ASI intervention was implemented 3 times per week for 8 weeks. At pre-intervention, SP and SPM-P Home revealed prominent sensory processing and integration difficulties in this case. PDMS-2 scores indicated the child was far behind his peers in fine and gross motor areas. In addition, systematic observations determined that the child's GMFCS level was III. After 8 weeks of ASI intervention significant improvements were found in parent reports of sensory processing in the areas of vestibular, tactile, and oral functioning on the Sensory Profile. Gains in functional motor skills were found on the GMFM-88 and the GMFCS. Consistent with these results, significant gains at or above expected levels of performance were found on GAS goals which reflected the family's main concerns for social participation, feeding, play, and movement. There are limited studies on sensory processing and integration in children with RSTS. This case report identified sensory processing and integration difficulties for the first time in a child with RSTS. Results also provide preliminary support for the positive effects of ASI intervention on sensory processing, functional motor skills, and parental goals of a child with RSTS.

Neural Control of Stopping and Stabilizing the Arm

Stopping is a crucial yet under-studied action for planning and producing meaningful and efficient movements. In this review, we discuss classical human psychophysics studies as well as those using engineered systems that aim to develop models of motor control of the upper limb. We present evidence for a hybrid model of motor control, which has an evolutionary advantage due to division of labor between cerebral hemispheres. Stopping is a fundamental aspect of movement that deserves more attention in research than it currently receives. Such research may provide a basis for understanding arm stabilization deficits that can occur following central nervous system (CNS) damage.