Yes, if you understand what you’re doing when you enter a legal contract. Having an impairment will only affect your legal capacity to enter into legal contracts if you don’t understand what you’re doing. The more complicated the contract and the more money involved, the greater the level of understanding you’ll need to have.
But if you’ve already appointed someone to make decisions for you about your money and property under an enduring power of attorney, or if the Family Court has appointed a property manager for you, then that other person will be able to make decisions for you about legal contracts.