My father had a total hip replacement about six months ago. I notice since the operation, he can’t walk and talk at the same time. Why is that?

You are observing the lack of a skill called automaticity. This is the ability to do two things at once. In this case, your father can’t combine a motor task (walking) with a cognitive task (talking).

Experts refer to the interruption of one task while doing another as dual-task interference. Attention-demanding activities such as talking can interfere with tasks that are usually automatic. Decline in these skills can affect activities of daily living. You’ve already noticed this with your father.

Some older adults may be able to talk while walking but when they do so, the speed of their gait slows down quite a bit. Automaticity is influenced by how complex or demanding the tasks are. Sometimes a hearing loss affects automaticity.

Reduced or absent automaticity is a risk factor for falls among older adults. You may want to think about having your father tested for hearing loss. A cognitive assessment might be a good idea, too. Early identification and treatment can prevent many other problems from occurring.