Which of the following is NOT a common cause of dizziness?

Tachycardia is not typically recognized as a common cause of dizziness. While it can lead to symptoms such as palpitations or a sensation of lightheadedness, especially if it results in reduced blood flow to the brain, it is not as directly associated with dizziness compared to the other options. Instead, anxiety, dehydration, and migraines are frequently cited causes of dizziness in clinical contexts.

Anxiety can lead to a range of physical symptoms, including dizziness due to hyperventilation or increased muscle tension. Dehydration affects the body's electrolyte balance and blood volume, leading to reduced cerebral perfusion and resulting in feelings of dizziness. Migraines are well-known for causing various neurological symptoms, including dizziness, as they can disrupt normal brain function.

Therefore, in the context of common causes of dizziness, tachycardia is less commonly associated than the other three options.