I don't know what the PDMS is but DS scored in the 65th percentile on the Beery VMI a couple years ago and he just did it again, but only the motor coordination section, and was at .02 percentile. He also did the BOT and had subtest scores ranging from around the 5th percentile to 30th or 40th percentile (the motor coordination section of the Beery should have been very similar to one of the subtests of the BOT, and there is a big difference between .02 percentile and 5th percentile!).
My dyspraxic ds had both the Beery VMI and BOT when he was first diagnosed... I'm not so sure that the difference between the .02 percentile on the Beery and 5th percentile on BOT is significantly different... first, they are both very low scores (please know I'm not stating that to be negative, just descriptive!). Second, the Beery is designed to test the integration of visual/motor skills, and to tease out (via the two separate subtests) where a challenge is rooted - visual or fine motor. The BOT is a measure of gross and fine motor skills. My ds, for example, had the Beery first during a neurospych eval, then a few months later and the BOT through an OT. Based on the neuropsych's findings, I'd expected the OT testing to come up with similar scores, but instead his BOT scores were much higher than his Beery VMI (motor). The explanation from his OT was that this didn't negate the Beery, but meant that his fine motor ability (without the visual motor integration included) was high enough to indicate he was a candidate for successful handwriting and fine motor OT. Handwriting OT did help him - a lot, but it didn't "cure" his dyspraxia or dysgraphia.
Best wishes,
polarbear
ps - this is getting a bit off-track, but fwiw for bluemagic, I think the reason OT helped ds is that it was a very targeted form of what ds needs re learning motor skills due to dyspraxia - lots and lots and lots of repetition.
