In our earlier study we conducted a randomized, placebo-controlled, triple blind trial, and showed that pyridoxine treatment of pervasive developmental disorders with expressive verbal disorders and hypersensitivity to sound as significantly effective in improving VIQ scores. This study analyzed the long-term changes of the subjects. We confirmed that their VIQ scores improved over time. An analysis of the reports of their daily life provided by their parents and teachers showed that the children's hypersensitivity to sound was also improved. They became able to adjust to their daily life at home and school without any panic. Our results indicate there are PDD subgroups whose expressive language capabilities and hypersensitivity to sound can be improved by pyridoxine treatment.