Field sobriety tests are designed to measure balance, coordination, and focus. Officers use them to decide if someone might be under the influence. But these tests are not perfect. Medical conditions can sometimes cause results that look like impairment, even when no alcohol or drugs are involved. Understanding how health issues play a role can show why results may not be accurate.
How balance disorders affect test results
Conditions such as inner ear problems, vertigo, or neurological issues can make standing still or walking in a straight line very difficult. When someone struggles with balance, the “walk-and-turn” or “one-leg stand” may appear failed, even if alcohol played no part. These conditions often worsen when stress or fatigue is present, making the tests even less reliable.
Physical limitations and injuries
Old injuries, joint pain, or arthritis can interfere with mobility. A person with limited flexibility or chronic pain may sway, stumble, or show signs of imbalance during field tests. These challenges have nothing to do with intoxication but can still be misread as signs of alcohol use.
Medical conditions that mimic intoxication
Certain health problems can create symptoms similar to alcohol impairment. Diabetes, for example, may cause dizziness, confusion, or slurred speech during low or high blood sugar episodes. Gastrointestinal disorders like acid reflux or rare conditions such as auto-brewery syndrome can even affect breath tests by altering alcohol readings inside the body. When this happens, the test results can paint an inaccurate picture of what is actually going on.
Medications and side effects
Prescription medications often list drowsiness, blurred vision, or poor coordination as possible side effects. Someone taking these medications as directed may have difficulty completing tasks that demand quick reflexes or steady movement. Over-the-counter remedies can sometimes create similar problems, further complicating the results of field sobriety tests.
Field sobriety tests are not reliable indicators of alcohol use in every case. When medical conditions or medications interfere, results can be misleading. Recognizing these possibilities strengthens a DUI defense by showing how medical conditions may explain test performance without proving actual impairment.