Habituation to Repeated Rotatory Stimuli (Cupulo-Metry) and the Effect of Antinausea Drugs and Alcohol on the Results

Abstract

Repeated rotatory tests performed as cupulometry every second day five times resulted in a response decline which was significant only for the sensation cupulogram. This response decline was more pronounced the stronger the rotatory stimuli used. In a second series the cupulogram before and two hours after the intake of four different antinauseadrugs were compared. A fifth test was performed with a placebo tablet. The twenty subjects tested all five possibilities. The statistical analyses showed that in the sensation cupulograms the placebo test had such an “effect” that every conclusion regarding therapeutical effects on post-rotatory sensation was valueless. Regarding the nystagmus cupulograms the results were somewhat better, but the placebo test showed that the more frequent rotatory stimuli involved in the second series resulted in a slight response decline. Only one drug consisting of methylscopolamini nitras 0.5 mg and pentymalum 50 mg (Veryl^©, Pharmacia) reduced the post-rotatory nystagmic response significantly. In fighter pilots with a marked response decline to rotatory stimuli, attributed to their occupational training, alcohol intoxication made the response decline disappear during moderate intoxications of up to 1.0 per mille maximal blood alcohol concentration. From experimental data and the results of this investigation it seeins rcasonable to assume that alcohol acts as a slight anaesthetic eliminating the response decline, which it thus seems justified to call habituation. It must be of central origin and probably is the result of an alcohol depressor effect above the brain stem and cerebellar level.