Which of the following typically increases with normal aging?

The correct response indicates that reaction time typically increases with normal aging. As individuals age, physiological changes occur throughout the nervous system, which can lead to longer times needed for responses to stimuli. This increase in reaction time may be attributed to factors such as slowed neural processing speeds and changes in muscle response capabilities.

As people age, the efficiency of motor neuron conduction can decline, thereby affecting their ability to react quickly to various stimuli. This phenomenon is often observed in older adults during activities that require quick responses, such as sports or even daily tasks that involve physical coordination.

The other options involve aspects that generally do not increase with age. For instance, the speed of impulse transmission typically decreases due to age-related changes in nerve fiber integrity. Cognitive processing speed is also generally found to decline with age due to factors such as decreased neuroplasticity and slower neural transmission. Additionally, the number of nerve cells in the brain tends to decrease with aging, resulting in cognitive changes rather than an increase. Understanding these dynamics is crucial in geriatric physical therapy, where practitioners must accommodate age-related changes in their intervention strategies.