Police officers often use a walk and turn test to determine if a driver was operating a vehicle while under the influence. A person who has ingested too much alcohol will likely fail to keep balance while trying to walk and turn. However, drivers can still fail a walk and turn test for reasons that have nothing to do with how much alcohol they have in their bodies.
Health problems can make it hard to maintain balance or to walk straight. For example, people with diabetes may move in a jerky or unsteady fashion. Similarly, individuals with inner ear problems or other health disorders may experience problems with their balance.
Inner ear disorders
According to the Mayo Clinic, inner ear problems can be a direct cause of why people might experience balance issues. The vestibular system contained in the inner ear maintains balance. However, if the small crystals within the vestibular system do not work right, it can result in health issues that create a sensation of dizziness, like vertigo.
Headaches, particularly migraines, are a problem for some people. A driver who experiences a recent migraine may suffer from dizziness or sensitivity to motion, a condition also known as a vestibular migraine. In fact, many people who feel dizzy do so because they had recently experienced a migraine.
Some drivers have been in auto accidents where they had sustained a head injury. Even if a doctor gives clearance to resume driving, effects from the accident may still linger. Some head injury victims, for example, suffer occasional vertigo. This condition or other aftereffects from a head injury could manifest while trying to perform a walk and turn test.
Some people feel queasy after riding in a moving vehicle like a boat, an airplane, or an amusement park ride. Motion sickness affects a lot of people, and some who suffer from it still feel a little dizzy even after coming to a stop after a drive. Such dizziness may make it hard to walk straight and make turns.