Adaptación cultural y validación de la versión chilena del Cuestionario de Discapacidad Roland-Morris / Validation and cultural adaptation of the Chilean version of the Roland-Morris Disability Questionnaire

Background: The evaluation of disability is highly relevant for the study and clinical follow-up of pain. Reliable and culturally valid instruments are required for this purpose. Aim: To adapt and to validate the Roland-Morris Disability Questionnaire (RDQ) to measure disability in low back pain Chilean patients and to study the psychometric properties of an abbreviated six item version of this instrument. Material and Methods: The instrument’s original version was translated and back translated into Spanish, and specialists ensured the cultural validation to Chile. Disability mental health using the Goldberg General Health Questionnaire (GHQ-12) and pain using a visual analogue scale (VAS) were evaluated in 206 patients, during a medical appointment due to acute low back pain. Results: The Chilean version of the original 24-item RDQ and the new six item version showed adequate internal consistency. The short version also showed a good convergent validity. It had the same pattern of correlations with VAS and GHQ-12 scales, as the original 24 item scale. Greater disability was associated with higher pain intensity and poorer mental health. The construct validity analysis identified one factor, for both versions of the RDQ. Conclusions: The adapted Chilean version of the original RDQ is a reliable and valid questionnaire, as well as the new abbreviated six items version, which showed adequate psychometric properties.

Determinantes psicosociales de la intención de donación de órganos en una muestra chilena / Psychosocial determinants of organ donation among Chilean university students

Background: Organ donation (OD) is a complex process that among other factors, depends on the consent of the potential donor's family. Previous evidences have shown that the intention of a behavior predicts that behavior in the future. Aim: To study the effect of believes, worries, knowledge and attitudes on the intention of OD after own death as well as OD of a deceased relative. Material and Methods: A total of 3,297 Chilean university students responded to a survey about the intention to donate organs through a web link. We conducted a path analysis and a structural equation technique was used. The model explained more than 50% of the variance of the dependent variables. Results: The intention of respondents to donate their own organs or those of family members after death were predicted by attitude toward OD, social influences and family discussion. Attitude was the main predictor of the model, which is determined by the negative effect of bodily apprehensions and the positive effect of knowledge about brain death. Conclusions: Attitude, knowledge and concerns are the main determinants of donation intention. The results prove the validity of the Theory of Reasoned Action as a theoretical model to explain the intentions of OD.

Plasticity in primary somatosensory cortex resulting from environmentally enriched stimulation and sensory discrimination training

We studied primary-somatosensory cortical plasticity due to selective stimulation of the sensory periphery by two procedures of active exploration in adult rats. Subjects, left with only three adjacent whiskers, were trained in a roughness discrimination task or maintained in a tactile enriched environment. Either training or enrichment produced 3-fold increases in the barrel cortex areas of behaviorally-engaged whisker representations, in their zones of overlap. While the overall areas of representation expanded dramatically, the domains of exclusive principal whisker responses were virtually identical in enriched vs normal rats and were significantly smaller than either group in roughness discrimination-trained rats. When animals were trained or exposed to enriched environments with the three whiskers arrayed in an are or row, very equivalent overlaps in representations were recorded across their greatly-enlarged whisker representation zones. This equivalence in distortion in these behavioral preparations is in contradistinction to the normal rat, where overlap is strongly biased only along rows, probably reflecting the establishment of different relations with the neighboring cortical columns. Overall, plasticity phenomena are argued to be consistent with the predictions of competitive Hebbian network plasticity.

Non-homogeneous spatial configuration of vibrissae cortical representation in layer IV of the barrel somatosensory cortex

In the present experiments we studied exclusive and overlapping cortical representational areas of the vibrissae in layer IV cells, across the entire barrel subfield of the rat somatosensory cortex, looking for evidences that would challenge the present assumptions of homogeneity and symmetry among cortical columns in this sensorial system. Our main findings were that in layer IV of the rat barrel cortex: A) Size of vibrissae cortical representational areas (X=0.4174mm²; SD=0.025) was not homo geneous, vibrissae in dorsal rows (A-B) had significantly smaller areas than those in ventral rows (D-E), a pattern that repeated itself in arcs 1-4. B) This difference arises from vibrissal representational overlap, and not from variations in exclusive zones, which are surprisingly homogeneous in size across the barrel cortex (X=0.079mm²; SD=0.0075); C) The extent of overlapping cortical areas varied systematically, with intra-row overlapping areas having a predominant bias (71.4 percent of total overlapping) independent of area sizes. Accordingly, vibrissae shared receptive fields with an average of 1.15 vibrissae in the same row and 0.38 in the same are. Barrel cortex has been viewed operationally as a conglomerate of essentially homogenous cortical columns that interact equivalently in the are and row dimensions. Our simple but global cortical reconstructions show that this predominant view should be revised. We postulate that the vibrissae/barrels spatial disposition in rows and ares has a relevant functional meaning, related to different sensory capabilities.