Quantitative findings in damped pendular rotation test (DPRT)--characteristics of vestibulogram and compensation process in peripheral vestibular lesions (author's transl)

Abstract

The author has studied the characteristics of induced nystagmus in damped pendular rotation test (DPRT) in peripheral vestibular lesions. This test, applied in clinical use by Greiner and Conraux, has been used as one of the routine vestibular examinations in the department of oto-laryngology of Keio University School of Medicine since 1971. During the test procedure, the velocity and acceleration of the chair decrese gradually until the chair stops, eliciting nystagmus in either direction. The diagnostic significance of nystagmus rhythm in this test has been studied in the author's clinic and it has been proved that valuable information could be obtained from this test in the diagnosis of brainstem lesions (Kanzaki, Sakagami, Takahashi 1973) as Greiner had already suggested from their clinical experiences.In this report, the author studied the characteristics of nystagmus response in DPRT and the compensation processes in 102 peripheral vestibular lesion.The results were as follows:1) The number of nystagmus in DPRT was linearly related to the logarithm of the maximum accerelation of the chair. 2) This relationship was well demonstrated in the vestbhulogram, in which the threshold of the induced nystagmus and its deviation in threshold level were quantitatively tabulated. 3) In irreversible peripheral vestibular lesions, the difference in the number of nystagmus in each direction, that is, the slope of the vestibulogram, became smaller as the time elapsed (compensation). In reversible disorders, especially in some type of Meniere's disease and Lermoyez's syndrome, recruitmentlike finding were noted in which the differences in induced nytagmus in each direction were greater in weaker stimulations than in stronger stimulations.4) Common mechanism among nystagmus elicited by DPRT, the one elicited by caloric test, and spontaneous nystagmus in peripheral vestibular lesions was speculated from the relationship between frequency of nystagmus and maximum slow phase velocity.