Positional Alcohol Nystagmus (PAN)

Positional alcohol nystagmus (PAN) occurs because alcohol creates an imbalance in the blood and the ear canals (the vestibular canals). As you know if you have ever experienced an ear infection, the ear canals help us control our balance and coordination. The eyes are affected by the condition of the vestibular canals. Therefore, under the influence of alcohol, a person’s sense of balance and their eyes cannot work in tandem.

Those who get intoxicated may know this feeling as spinning or dizziness and it often causes nausea. It is created when the semicircular canals are affected by alcohol.

PAN I occurs during intake of alcohol when the alcohol in the person’s bloodstream is increasing. PAN II occurs during the ‘morning after’ stage – or hangover – as the BAC is decreasing as alcohol is being eliminated from the bloodstream. The vestibular canals are beginning to regain balance. Positional alcohol nystagmus occurs most clearly when a person is lying down, eyes closed, and head turned to either side.

These effects have been measured up to 40 hours after alcohol ingestion, making it unwise to operate any machinery or a vehicle for some time after heavy drinking.