The Hyperventilation test is commonly used in the vestibular bedside examination. It can identify latent vestibular asymmetry that causes nystagmus, which may occur either towards the healthy side (paretic nystagmus) or towards the affected side (irritative nystagmus). During the early stage of acute unilateral vestibulopathy, Hyperventilation-Induced Nystagmus is observed in many cases, manifesting as either paretic (which reinforces spontaneous nystagmus) or irritative (which inhibits or reverses spontaneous nystagmus). The differences between the paretic and irritative patterns can help differentiate between whether the acute damage has a neuritic or vascular origin.