Widespread white matter and conduction defects in PSEN1-related spastic paraparesis

The mechanisms underlying PSEN1 mutation-associated spastic paraparesis (SP) are not clear. We compared diffusion and volumetric magnetic resonance measures between 3 persons with SP associated with the A431E mutation and 7 symptomatic persons with PSEN1 mutations without SP matched for symptom duration. We performed amyloid imaging and central motor and somatosensory conduction studies in one subject with SP. We found decreases in fractional anisotropy and increases in mean diffusivity in widespread white matter areas including the corpus callosum, occipital, parietal, and frontal lobes in PSEN1 mutation carriers with SP. Volumetric measures were not different and amyloid imaging showed low signal in sensorimotor cortex and other areas in a single subject with SP. Electrophysiological studies demonstrated both slowed motor and sensory conduction in the lower extremities in this same subject. Our results suggest that SP in carriers of the A431E PSEN1 mutation is a manifestation of widespread white matter abnormalities not confined to the corticospinal tract that is at most indirectly related to the mutation’s effect on APP processing and amyloid deposition

Información Investigador: Coutin Churchman, Pedro Eduardo

Resumen Curricular Doctor en Medicina, Universidad de La Habana, Cuba. Especialista de Primer Grado en Fisiología Normal y Patológica, Universidad de La Habana, Cuba. Especialista de Segundo Grado en Fisiología Normal y Patológica, Universidad de La Habana, Cuba.Doctorado33 - 2005; 28 - 2001Mayo de 2007Doctor en Medicina+58 274 2401471Facultad de [email protected] anterior # 8222569

Evoked potential correlates of right hemisfere involvement in the processing of a second language

The probe evoked potential paradigm was used to assess the relative engagement of both cerebral hemispheres in 10 Spanish-speaking subjects and in 12 subjects for whom Spanish was a second language, during the processing of verbal material presented in Spanish while listening to an irrelevant distractor (music), both presented acoustically through the same channel. Although the distractor condition produced attenuation of the probe EP, it was symmetrical in both groups. In agreement with previous findings, the probe EP showed task-specific activation in the left hemisphere during the activity of listening to the verbal material in the Spanish-speaking subjects, for whom the material was in their native language. However, the opposite effect, i.e. right hemisphere activation, was observed in the non-native group, suggesting an increased participation of the right hemisphere in the processing of foreign language [email protected]@gmail.co