小脳障害例の迷路性眼運動系の動特性

抄録

In order to explain the role of the cerebellum in the vestibulo-ocular reflex, the transfer function (TF) of the oculomotor system was studied in 13 healthy male subjects and 17 patients with cerebellar disease.
For this purpose, the following three tests were performed, that is, the eye tracking test (ETT) and the head oscillation tests in the dark and light in order to examine the opto-oculomotor, vestibulocer-vico-oculomotor and optovestibulocervico-oculomotor systems.
The results obtained were as follows.
A. Normal subjects.
1) As to the Bode plots of the TF of the opto-oculomotor system, the gain and phase were flat from 0.4 to 0.9 Hz.
2) As to the Bode plots of the TF of the vestibulocervico-oculomotor system, the gain lineary in-creased at a rate of 5db per decade in the frequency range from 0.2 to 4 Hz.
3) As to the Bode plots of the TF of the optovestibulocervico-oculomotor system, the gain and phase were flat from 0.3 to 4 Hz.
B. Patients with cerebellar disease.
1) As to the Bode plots of the TF of the optooculomotor system, fourteen of the 17 patients showed normal patterns, two showed decrease in gain and one showed a shift of the break frequency toward low-frequency side.
2) As to the Bode plots of the TF of the vestibulocervico-oculomotor system, seven of the 17 patients showed normal patterns, two showed increase in gain and eight showed flatness in gain curve.,
3) As to the Bode plots of the TF of the optovestibulocervico-oculomotor system, four of the 17 patients showed normal patterns, ten showed a shift of the break frequency toward low-frequency side and three showed decrease in gain.
These results lead to the following conclusion.
On the observation of the dynamic characteristics of the vestibulo-ocular system, the increase of the gain in wide frequency range was uncommon in patients with cerebellar disease.