Why does alcohol make walking unsteady and speech slurred? · Grey Matter

The cerebellum is especially sensitive to alcohol, which disturbs the signalling of its Purkinje cells and the circuits feeding them.

Why does alcohol make walking unsteady and speech slurred?

The cerebellum is especially sensitive to alcohol, which disturbs the signalling of its Purkinje cells and the circuits feeding them. With the predictive correction impaired, gait widens and sways, movements overshoot and speech loses its timing, the same signs a neurologist looks for in cerebellar disease (which is why the roadside test asks for walking heel to toe and touching the nose). Years of heavy drinking can make the change permanent by degenerating the front of the vermis, which leaves a broad, unsteady gait.