The effect of gravity of positional alcohol nystagmus phase II in man

On request from the Swedish state authorities for health and civil air transport (Socialstyrelsen and Luftfartsstyrelsen) experiments were performed in order to establish the duration of the vestibular disturbances after alcohol intake related to rules for aviation safety. It is known that the threshold for provocation of positional alcohol nystagmus (PAN) is lowered under the influence of gavity forces above normal. It has been suggested that PAN II could be provoked by g-loads as late as 48 hours after a small alcohol intake. Our experiments were performed in a human centrifuge with g-values 2 and 3. Whisky (43 vol%, 2.5 cc/kg b.w.) was given in a single dose and blood alcohol analyses were frequently taken. The results show that vestibular disturbances appearing as g-provoked PAN II do not persist for any considerable time. Consequently the present limit of 24 hours' sobriety before flight seems sufficient. Positional nystagmus provoked by g-load even without alcohol intake in the test persons is a new observation.