Tandem gait is a gait

Gait

Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...

 (method of walking or running) where the toes of the back foot touch the heel of the front foot at each step. Neurologist

Neurologist

A neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...

s sometimes ask patients to walk in a straight line using tandem gait as a test to help diagnose ataxia

Ataxia

Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...

, especially truncal ataxia, because sufferers of these disorders will have an unsteady gait. However, the results are not definitive, because many disorders or problems can cause unsteady gait (such as vision difficulties and problems with the motor neurons or associative cortex). Therefore, inability to walk correctly in tandem gait does not prove the presence of ataxia.

Profoundly affected tandem gait with no other perceptible deficits is a defining feature of posterior vermal split syndrome.

Suspects may also be asked to perform a tandem gait walk during the "walk and turn" part of a field sobriety test.