Preserved brain functional plasticity after upper limb task-oriented rehabilitation in progressive multiple sclerosis.

BACKGROUND AND PURPOSE: Limited research has been dedicated to upper limb (UL) rehabilitation in progressive multiple sclerosis (PMS). The objective in this pilot study was to investigate the effect of task-oriented UL rehabilitation in PMS and to perform explorative analyses of the magnetic resonance imaging (MRI) correlates of changes in motor performance. METHODS: Twenty-six PMS patients with mild UL impairment were prospectively enrolled and randomized into two groups: an active treatment group (ATG, n = 13) and a passive treatment group (PTG, n = 13). At baseline and after training, patients underwent MRI scans with structural and functional imaging and were evaluated with the action research arm test, the nine-hole peg test, the ABILHAND scale and the modified fatigue impact scale (MFIS). Measures of motor finger performance were obtained by engineered glove measuring. RESULTS: After rehabilitation, the ATG improved in several finger motor tasks (0.001 ≤ P ≤ 0.03, 0.72 ≤ Cohen's d ≤ 1.22) and showed reduced MFIS scores compared with the PTG (P = 0.03). The ATG showed increased functional connectivity within the cerebellar and thalamic resting state networks compared with the PTG (P < 0.05). Correlations were found between several measures of motor improvement and thalamic and sensorimotor networks (0.87 ≤ r ≤ 0.93, 0.001 ≤ P ≤ 0.03). No changes in cerebral volumes and diffusion tensor imaging derived measures were detected. CONCLUSIONS: Progressive multiple sclerosis patients with mild UL dysfunction benefit from task-oriented UL rehabilitation, which seems to be more efficient than simple passive mobilization. Despite a high burden of disability and brain damage, functional adaptive capacities seem to be preserved, thus providing a rationale for the use of rehabilitative treatments in late PMS.

Neural correlates of ankle movements during different motor tasks: A feasibility study.

This ongoing study investigates the neural correlates of ankle dorsi-plantar flexion in active, passive, and proprioceptive tasks. Specifically, we investigated two proprioceptive matching tasks that required a simple combination of active and passive ankle movements: (1) a memory-based ipsilateral matching task and (2) a contralateral concurrent matching task. As expected, during the passive tasks, subjects recruited the same brain areas involved in the correspondent active movements (primary motor cortex (M1), premotor cortex (PM) supplementary motor cortex (SMA) and primary somatosensory cortex (S1)), but the activations were lower. Instead, in both the proprioceptive matching tasks, subjects recruited more motor and sensory-motor areas of the brain and the activations were greater.

The Study of Solid/Liquid Interfaces with X-ray Standing Waves.

The principles and applications of the x-ray standing wave technique are described. Emphasis is placed on its utility for the study of structure, composition, and distribution of interfacial species especially at solid/liquid interfaces.

Diffuse-double layer at a membrane-aqueous interface measured with x-ray standing waves.

The ion distribution in an electrolyte solution in contact with a charged polymerized phospholipid membrane was directly measured with long-period x-ray standing waves. The 27-angstrom-thick lipid monolayer was supported on a tungsten/silicon mirror. X-ray standing waves were generated above the mirror surface by total external reflection of a 9.8-kiloelectron volt x-ray beam from a synchrotron undulator. The membrane surface, which contained negatively charged phosphate headgroups, was bathed in a dilute ZnCl2 solution. The concentration of Zn2+ in the condensed layer at the membrane surface and the Zn2+ distribution in the diffuse layer were measured as a function of headgroup charge. The Debye length of the diffuse layer varied between 3 and 58 angstroms. The results qualitatively agree with the Gouy-Chapman-Stern model.

X-ray standing waves: a molecular yardstick for biological membranes.

Structural information on an atomic scale has been obtained for a Langmuir-Blodgett (LB) trilayer system by means of long-period x-ray standing waves. The LB trilayer of zinc and cadmium arachidate was deposited on a layered synthetic microstructure (LSM) consisting of 200 tungsten/silicon layer pairs with a 25 A period. A 30 A thermally induced inward collapse of the zinc atom layer that was initially located in the LB trilayer at 53 A above the LSM surface has been observed. The mean position and width of the zinc atom layer was determined with a precision of +/- 0.3 A.