中枢障害例における減衰振子様回転検査所見

抄録

Damping pendular rotation test (PRT) was performed in fifty-five central lesions, in which the diagnosis was confirmed surgically or by neurological examinations, and the results of PRT were compared with those of optokinetic pattern test (OKP-test) and eye tracking test (ETT).
Postoperatively patients with acoustic neuromas, which were mostly operated through suboccipital approach or by combined method (both translabyrinthine and suboccipital method), showed dysrhythmia, narrow writing (petite ecriture), and/or pathological habituation or markedly reduced responses. These findings could be regarded as central in origin, because they were found after the surgical procedures in cerebellopontine angle space. (Fig. 1)
Dysrhythmia was also found after injection of diphenidol, which is reported to inhibit neuronal activity in vestibular nucleus. (Fig. 4)
Dysrhythmia, which is thought to be a manifestation of the disturbance of the rhythm of the quick phase of nystagmus, was mostly seen in brainstem lesions (Fig. 5, 8), but not in cerebral and cerebellar lesions. (Fig. 7, 9) On the other hand, reduced response, ipsilateral or bilateral, was seen in cerebellar and brainstem lesions in which either contralateral or both labyrinth were normal. (Fig. 9)
The possibility of correct diagnosis in central lesions was suggested with PRT in combination with OKN or OKP-test and ETT, though the final diagnosis should be made with a battery of audiological and vestibular tests including neurological and neurosurgical examinations. (Table 1)
Dysrythmia or narrow writing could be seen in normal persons over 50 years old, in which these findings might probably be due to vascular changes in the brain with aging, and in younger persons under 10 years old in which nystagmus rhythm seems to be still immature, and also in some with Meniere's disease, but rarely in vestibular neuronitis.