Permanent and total disability defined
3 rules
An individual is permanently and totally 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 which has lasted or can be expected to last for a continuous period of not less than 12 months. An individual shall not be considered to be permanently and totally disabled unless he furnishes proof of the existence thereof in such form and manner, and at such times, as the Secretary may require.