Romberg testing is an important component of the neurological examination which assesses proprioception (i.e. sense of joint position/balance) which is a function of the dorsal columns of the spinal cord.
A Romberg test is performed by asking the patient to stand erect with their feet together and arms/hands at their side. You first ask the patient to stand this way with their eyes open for 1 minute and then with their eyes closed for 1 minute.
A positive Romberg test results if the patient exhibits clear swaying or even falling ONLY when their eyes are closed. This suggests that the patient's ataxia is sensory in nature (i.e. dorsal columns), rather than cerebellar.
Patients with cerebellar ataxia will typically loose their balance and sway even with their eyes open.
Classic neurological abnormalities associated with a positive Romberg test include tabes dorsalis (neurosyphilis) and sensory peripheral neurpathy, among others.
Be sure to cautiously standby while performing this test in order to protect the pateint should they fall.