Per the IRS, "For purposes of this section, an individual shall be considered to be disabled
if he is unable to engage in any substantial gainful activity by reason
of any medically determinable physical or mental impairment which can
be expected to result in death or to be of long-continued and indefinite
duration. An individual shall not be considered to be disabled unless he furnishes proof of the existence thereof in such form and manner as the Secretary may require"
As long as you meet the disability definition above and have proof, such as a doctor's letter or statement, therefore the distribution amount would not incur the 10% early withdrawal penalty, however still liable for the regular tax.
