RESUMEN
PURPOSE: The influential relationship between executive functioning and aphasia rehabilitation outcomes has been addressed in a number of studies, but few have studied the effect of adding executive function training to linguistic therapies. The present study aimed to measure the effects of combining, within therapy sessions, executive function training and anomia therapy on naming and discourse abilities in people with chronic aphasia. METHOD: A single-case experimental design with multiple baselines across participants was used. Four persons with chronic post-stroke aphasia received 12 sessions of a tailored treatment combining executive function training and semantic feature analysis (SFA) therapy. Naming accuracy of treated items was examined over the course of the treatment while control naming scores of untreated items and discourse measures were collected pre-treatment, immediately post-treatment, and 4 weeks post-treatment, in order to investigate the multidimensional effects of the treatment and their maintenance. RESULT: Naming skills improved in all participants for treated and untreated items, were maintained over time, and were accompanied by improved discourse abilities. Visual and statistical analyses showed a significant treatment effect for naming skills in three out of the four participants. CONCLUSION: A combination of executive function training and SFA treatment in people with chronic aphasia may improve both naming skills and discourse efficiency. Further studies are needed to substantiate these promising preliminary results.
RESUMEN
Self-assembled enzyme aggregates, prepared from magnetic iron oxide nanoparticles, avidin, and a biotinylated redox enzyme, were shown particularly useful for the simple, fast, and efficient construction of highly enzyme-loaded electrodes with the help of a magnet. The approach was illustrated in the case of the bioelectrocatalytic oxidation of NADH by a diaphorase oxidoreductase in the presence of a ferrocene mediator. Two different self-assembling procedures were tested, taking advantage of the spontaneous aggregation of the nanoparticles in the presence of avidin and also of the multivalency binding of biotinylated diaphorase toward avidin. Activities of the bound and unbound diaphorase were systematically controlled allowing determination of the number of active biotinylated diaphorase per nanoparticle incorporated within each magnetic enzyme aggregate. An active enzyme loading capacity of up to 2.35 nmol mg-1 was found for the best nanostructured enzyme assembly, which is 200 times better than for commercialized magnetic micrometer-sized beads coated with streptavidin and saturated with diaphorase. With the help of a permanent magnet, the magnetic enzyme aggregates were finally magnetically collected as a film on the surface of a small screen-printed carbon electrode and the catalytic currents recorded by cyclic voltammetry. From the analysis of the steady-state catalytic current responses and the kinetic rate constants of biotinylated diaphorase, it was possible to determine the enzyme concentration within the magnetic films. Owing to the high enzyme loading in the aggregates of nanoparticles (i.e., 130 microM), the catalytic current responses were definitely higher than the ones measured at an electrode coated with a closed-packed monolayer of diaphorase or at an electrode covered with a film of magnetic micrometer-sized streptavidin beads saturated with diaphorase.
