Yes. Even though you are required to start drawing down the account, you can continue to add to it through deductible contributions as long as you have net earnings from self-employment. However, you can no longer contribute to a traditional IRA if you had otherwise been able to do so; no contribution is allowed for the year in which you turn age 70-1/2 or any later year. There is no age limit for making Roth IRA contributions as long as you continue to have earned income.
Test for determining deductibility of IRA deductions. Active participants in employer retirement plans are subject to IRA deduction phase-out rules if adjusted gross income exceeds certain threshold.