Rehabilitación cognitiva en daño cerebral adquirido: variables que median en la respuesta al tratamiento / Cognitive rehabilitation in acquired brain injury: variables mediating treatment response

Objetivo. Identificar qué variables se relacionaban con la respuesta a un programa de rehabilitación cognitiva en una población de pacientes con daño cerebral adquirido. Material y métodos. En este estudio retrospectivo participaron 528 pacientes con daño cerebral adquirido que recibieron rehabilitación cognitiva en nuestro centro entre febrero de 2008 y enero de 2013. Mediante análisis de regresión logística se analizó la respuesta al tratamiento (variable dependiente). La respuesta al tratamiento se calculó a partir de las diferencias entre las exploraciones neuropsicológicas pre- y post-tratamiento para las variables atención, memoria y funciones ejecutivas. Resultados. La edad en el momento de la lesión (OR = 0,97; 95% CI: 0,96-0,98) y el lugar donde se realizó el tratamiento (OR = 0,45; 95% CI: 0,27-0,73) se asociaron positivamente con una mejor respuesta al tratamiento para el índice atencional. En el caso del índice mnésico fueron la edad (OR = 0,98; 95% CI: 0,96-0,99), etiología (OR = 0,63; 95% CI: 0,39-1) y lugar de realización del tratamiento (OR = 0,48; 95% CI: 0,29-0,79); tales variables también resultaron significativas para el índice ejecutivo. Conclusiones. Los resultados sugieren que parte de las diferencias interindividuales observadas en la respuesta al tratamiento cognitivo en pacientes con daño cerebral adquirido podrían ser explicadas por las variables edad, etiología y lugar de realización del tratamiento (AU)

Objective. To identify the variables related to response to a cognitive rehabilitation program in a population of patients with acquired brain injury. Material and methods. This retrospective study included 528 patients with acquired brain injury who received cognitive rehabilitation at our center between February 2008 and January 2013. We used logistic regression analysis to examine the impact of predictive variables on treatment response (dependent variable). Differences between pre- and post-treatment neuropsychological assessment were used to calculate treatment response in the domains of attention, memory, and executive function. Results. For the attention index, the variables positively associated with better treatment response were age at the time of injury (OR = 0.97, 95% CI: 0.96-0.98) and place of treatment (OR = 0.45, 95% CI: 0.27-0.73). For the memory index, the variables positively associated with better treatment response were age (OR = 0.98, 95% CI: 0.96 to 0.99), etiology (OR = 0.63, 95% CI: 0.39 to 1) and place of treatment (OR = 0.48, 95% CI: 0.29 to 0.79); these variables were also significant for the executive index. Conclusions. These findings suggest that part of the inter-individual differences in response to cognitive rehabilitation in patients with acquired brain injury could be explained by age, etiology and place of treatment (AU)

Inelastic scattering of low-energy electrons in liquid water computed from optical-data models of the Bethe surface.

PURPOSE: We provide a short overview of optical-data models for the description of inelastic scattering of low-energy electrons (10-10,000 eV) in liquid water. The effect on the inelastic scattering cross section due to different optical data and extension algorithms is examined with emphasis on some recent developments. MATERIALS AND METHODS: The optical-data method whereby experimental optical data and theoretical extension algorithms are used to describe the dependence of the dielectric response function on energy- and momentum-transfer and obtain the Bethe surface of the material, currently represents the most used method for computing the inelastic scattering of low-energy electrons in condensed media. Two sets of experimental optical data for liquid water obtained from reflectance and inelastic X-ray scattering spectroscopy, respectively, and the extension algorithms of Ritchie, Penn, and Ashley are examined. Recent developments are discussed along with the role of corrections to the random phase approximation (RPA) of electron gas theory. RESULTS: The inelastic scattering cross section in the energy range 200-10,000 eV was found to be rather insensitive (to within 10%) to the choice of optical data or the extension algorithm. In contrast, differences between model calculations increase rapidly below 200 eV with the influence of the extension algorithm being dominant. CONCLUSION: The choice of the extension algorithm used to extrapolate optical data to finite momentum transfer and obtain the Bethe surface is crucial in modelling the inelastic scattering of electrons with energies below 200 eV. A new set of measurements on the dielectric response function of liquid water beyond the optical limit and the development of extension algorithms that will go beyond RPA by considering the effect of (short-range) electron exchange and correlation should be of some priority.

A dielectric response study of the electronic stopping power of liquid water for energetic protons and a new I-value for water.

The electronic stopping power of liquid water for protons over the 50 keV to 10 MeV energy range is studied using an improved dielectric response model which is in good agreement with the best available experimental data. The mean excitation energy (I) of stopping power theory is calculated to be 77.8 eV. Shell corrections are accounted for in a self-consistent manner through analytic dispersion relations for the momentum dependence of the dielectric function. It is shown that widely used dispersion schemes based on the random-phase approximation (RPA) can result in sizeable errors due to the neglect of damping and local field effects that lead to a momentum broadening and shifting of the energy-loss function. Low-energy Born corrections for the Barkas, Bloch and charge-state effects practically cancel out down to 100 keV proton energies. Differences with ICRU Report 49 stopping power values and earlier calculations are found to be at the approximately 20% level in the region of the stopping maximum. The present work overcomes the limitations of the Bethe formula below 1 MeV and improves the accuracy of previous calculations through a more consistent account of the dielectric response properties of liquid water.

Hamaker Constants of Systems Involving Water Obtained from a Dielectric Function That Fulfills the f Sum Rule.

Hamaker constants of systems involving liquid water are evaluated, within the full Lifshitz theory, by means of a recently proposed model of the dielectric function of this substance [Dingfelder et al., Radiat. Phys. Chem. 53, 1 (1998)], which has been extended in the present work by including terms corresponding to infrared excitations and microwave relaxation. An important feature of the complete model is that, besides a good fit to experimental data, it satisfies the physical constraint provided by the f sum rule. For symmetrical systems interacting across water, calculated Hamaker constants are generally in good agreement with results obtained using the Ninham-Parsegian representation with the Roth and Lenhoff parameters for water. Copyright 2000 Academic Press.