
Braingamer |

Looking under the 'Creating a Broken Soul' heading, we find this ability:
Torturous Touch (Su): A broken soul can make a touch attack to cause hideous, painful wounds to rip open in the target’s body. This touch deals 2d6 points of slashing damage and 1d6 points of Dexterity damage, and causes the touched creature to fall prone in a fit of convulsions and be dazed for 1d4 rounds. A successful Fortitude save negates the Dexterity damage and the convulsive fit.
Looking at the attack on the Broken Soul Lillend itself, we've got
torturous touch +11 touch (2d6 plus 1d6 Dex damage and convulsions)
2d6 slashing, 1d6 Dex damage, and prone and 1d4 rounds of daze is in the ability description. It looks like the convulsions is prone and 1d4 rounds of Daze.

mplindustries |

The text I see on the srd is:
"A broken soul can make a touch attack to cause hideous, painful wounds to rip open in the target's body. This touch deals 2d6 points of slashing damage and 1d6 points of Dexterity damage, and causes the touched creature to fall prone in a fit of convulsions and be dazed for 1d4 rounds. A successful Fortitude save negates the Dexterity damage and the convulsive fit."
So, convulsions are just a flavorful descriptor for being prone and dazed.