Right hemispheric activation on chronognosia: a preliminary study by rheoencephalography.

Using an impedance plethysmography technique, we measured the regional cerebral blood flow variation at rest and during time period estimation in 21 normal volunteers. A significant increase was observed in the right hemisphere. The overestimators without internal counting show a significant increase in the right frontal region. The underestimators without internal counting display no right frontal modification but their right temporo-occipital regions show a significant increase.