ORS 316.771: Proof of status for exemption credit.

Each person qualifying for the additional personal exemption credit allowed in ORS 316.758 and 316.765 may claim the credit on the personal income tax return. However, the claim shall be substantiated by a letter from a licensed physician describing the nature and extent of the physical disability. The requirement for substantiation may be waived partially, conditionally or absolutely, as provided under ORS 315.063.