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Resumen Introduccion La diabetes mellitus tipo 2 (DMT2) es una enfermedad cronica que continua produciendo complicaciones neurologicas a pesar de las mejorias en las estrategias terapeuticas. Ademas de la clasica neuropatia diabetica periferica (NDP), el deterioro cognitivo (DC), podria considerarse una mas de estas complicaciones. Objetivo Analisis del Alzheimer disease assessment scale–cognitive (ADAS-COG), en una poblacion de sujetos con DMT2 y determinar su posible asociacion con la presencia de NDP. Materiales y metodos Se estudiaron 54 pacientes con DMT2, media de edad: 71,1 ± 5,6; varones: 22, mujeres: 32. Grupo control: n = 32, media de edad: 70,5 ± 7,2, varones 15, mujeres 17. El grupo con DMT2, se dividio en dos subgrupos: uno con NDP (n = 37) y otro sin NDP (n = 17). El test de Wilcoxon, para muestras apareadas, se empleo para la comparacion de los puntajes del ADAS-COG entre los diferentes subgrupos. Resultados La comparacion de los puntajes del ADAS-COG entre los diferentes grupos mostraron: a) diferencias significativas (p Conclusiones Nuestros resultados proveen evidencia de la existencia de un DC en algunos pacientes con DMt2. Este deterioro se hallaria asociado a la presencia de NDP. Estas observaciones permitirian plantear la presencia de un DC asociado a la DMt2 y considerar al mismo como una complicacion tardia mas de la enfermedad.

A wide range of studies have found late positive ERP components in response to anomalies during processing of structured sequences. In language studies, this component is named Syntactic Positive Shift (SPS) or P600. It is characterized by an increase in potential peaking around 600 ms after the appearance of the syntactic anomaly and has a centroparietal topography. Similar late positive components were found more recently in non-linguistic contexts. These results have led to the hypothesis that these components index the detection of anomalies in rule-governed sequences, or the access to abstract rule representations, regardless of the nature of the stimuli. Additionally, there is evidence showing that the SPS/P600 is sensitive to probability manipulations, which affect the subjects’ expectancy of the stimuli. Our aim in the present work was to address the hypothesis that the late positive component is modulated by the subject's expectancy of the stimuli. To do so, we employed an artificial grammar learning task, and controlled the frequency of presentation to different kind of sequences during training. Results showed that certain sequence types elicited a late positive component which was modulated by different factors in two distinct time windows. In an earlier window, the component was higher for sequences which had a low or null probability of occurrence during training, while in a later window, the component was higher for incorrect than correct sequences. Furthermore, this late window effect was absent in those subjects whose performance was not significantly above chance. Two possible explanations for this effect are suggested.

• Brain-stem auditory evoked potentials were recorded in 35 human immunodeficiency virus (HIV)—seropositive subjects from the Centers for Disease Control groups III and IV, 24 HIV-negative drug abusers, and 62 normal healthy controls. None of the patients had evidence of neurological complications. History of alcohol consumption was an exclusion criterion. The values of central conduction times I-V and III-V showed significant differences between the HIV-seropositive subjects and normal healthy controls, as well as between the HIV-seropositive subjects and HIV-negative drug abusers. Central conduction times I-III showed no differences between groups, except in the left ear of Centers for Disease Control group IV compared with controls. No statistical differences were found in the central conduction times between HIV-negative drug abusers and normal healthy controls. The results suggest a subclinical involvement of the upper brain stem in HIV infection. It could be produced by direct action of the virus on central nervous system structures.