Attorney John Galligan said Hasan told him that he has no feeling in his legs and that it may be permanent, The Mirror reports.
Hasan also complained of severe hand pain, he added.
The 39-year-old psychiatrist was shot four times by police officers as he ran amok during last week's shootings at America's largest military base, Fort Hood Hasan, who remains hospitalized, has been charged with 13 counts of premeditated murder in the attack.
He has emerged from a coma and has invoked his right to a lawyer, but he could face the death penalty if convicted.
Investigators are still waiting to interview him.
Meanwhile, US President Barack Obama has ordered a review to determine if warning signs were mishandled by intelligence agencies.