The attorneys also don't believe Spears, 26, is capable of giving a deposition or signed declaration, Flanagan said.
Earlier this month, a judge placed Spears under the conservatorship of her father and an attorney after more than a year of increasingly bizarre behavior by the singer.
Spears hit a parked car on Aug. 6, 2007, and left without notifying the owner. She was originally cited for hit and run and driving without a license, but the hit-and-run charge was dropped.