When a driver is stopped based on suspicion of driving while influenced by drugs or alcohol, the next step is most often the field sobriety test. This test typically consists of three parts and is designed to identify physical symptoms of alcohol impairment. However, this test at times produces false positives, especially in the presence of certain health conditions.
Horizontal gaze nystagmus
The first part of the test is called the horizontal gaze nystagmus. It tests the ability to track objects with the eye and checks for involuntary twitching responses that typically increase when alcohol was consumed. People who have problems with their vision can have limited ability to focus on moving objects. Difficulty sustaining visual focus can also be a result of conditions affecting the nervous system.
Physical coordination test
The second part of the field sobriety test is known as the walk and turn. The officer asks the driver to walk and then turn around when instructed. This tests physical coordination and the capacity to understand and follow instructions. Another test of physical coordination involves standing on one leg. These tests can be difficult to impossible to pass for anyone suffering from mobility or balance issues. Conditions may include vertigo, neurological problems, seizure disorders, back or leg injuries and impaired mobility. A person does not have to be completely immobilized to be unable to complete this test. Even a relatively minor impairment such as a weak joint or ligament pain can prevent someone from successfully balancing or walking.
Cognitive function test
Many officers administering a field sobriety test will also ask drivers to perform seemingly simple cognitive tasks that are supposed to check awareness. Typical tasks include reciting the alphabet backwards or solving simple arithmetic. While law enforcement assumes that these are things any reasonable adult can do, there are certain conditions that affect this area of performance as well. Memory and focus problems can arise as a result of conditions such as anxiety or ADHD. Other factors include sleep deprivation, stress and nervousness from being stopped by police. Some medications can also have side effects that affect memory.
Even if you have taken and failed a sobriety test, you are not necessarily doomed to a DUI conviction. Medical conditions can certainly affect your performance; for many people, their symptoms are aggravated by the situational stress of being stopped by law enforcement. If you have medical symptoms that could have affected your test, speak with an experienced local attorney to learn more about handling any DUI charges.