Kaoruko Takahashi

Indications and Results of Gentamycin Injection into the Middle Ear of Patients with Meniere's Disease

Forty-six cases in whom endolymphatic drainage surgery was performed between 1986 and 1992 were followed up for more than 2 years. The results of numerical values (1985 AAOHNS) revealed complete control of definite spells in 26 cases; substantial control of definite spells in 18 cases; limited control of definite spells in 1 case; and insignificant control of definite spells in 1 case. Hence, endolymphatic drainage surgery for Meniéres disease was effective. There are, however, cases who cannot be operated on because of old age or underlying diseases. In these, we injected gentamycin sulfates mixed with prednisolone through a ventilated tube into the middle ear. The results for gentamycin injection based on numerical values showed complete control of definite spells in 12 cases; and substantial control of definite spells in 7 cases. Our treatment of choice for Meniéres disease is endolymphatic drainage surgery which resulted in 96% control of vertigo. In patients for whom operation has failed, in old patients and in those with hearing impairment more than 50 dB, gentamycin injection into the middle ear has proved to be an effective procedure to control vertigo attacks.

Aging effects upon smooth pursuit induced by step–ramp stimulation

OBJECTIVE in predictable target movements, pursuit gains are extremely close to 1.0. Under these conditions, aging effects upon pursuit have not been detected. Step-ramp stimuli produced by unpredictable combinations would be favorable procedures to assess the properties of smooth pursuit between young and aged people. METHODS the target was a 0.5 degrees red laser spot. Eye movements of 49 normal subjects (26 younger subjects less than 49 years old and 23 older subjects more than 50 years old) were recorded with infrared reflection oculography and sampled at 250 Hz. Step direction and distance (2, 4, 6, 8 degrees) followed by 10 degrees /s ramp speed movement in the same (onward stimulus) or opposite to the direction (backward stimulus) were programmed in an unpredictable way before each set of ten tests. Both onward and backward stimulation were randomly given for each subject. RESULTS in the onward study, there was a close correlation between retinal slip velocity (RSV) and eye acceleration (EA), which was expressed as a regression curve, being steeper in the younger group. This means that the younger subjects could produce faster velocity and greater acceleration than the aged group (P<0.05). CONCLUSION subtle reduction in visual acuity, visual fields and contrast sensitivity will be one of possible causes, and the degradation of cortical areas crucial for visual processing might be one of possible causes of slowing of pursuit EA.

Visually guided eye movements in patients with Wallenberg's syndrome.

To determine the lesions and the lateralization in patients with Wallenbergs syndrome, visually-guided eye movements were quantitatively analysed and these findings were compared with a lesioned site as revealed by magnetic resonance imaging (MRI). The 8 patients could be clearly classified into two subgroups based on the functional test of eye movements. In 4 patients, optokinetic nystagmus (OKN), pursuit eye movements and fixation-suppression of caloric nystagmus (FS), utilizing the slow phase velocity as a parameter, were impaired toward the lesioned side in the medulla. In the remaining 4 patients, OKN and pursuit eye movements were impaired toward the side contralateral to the lesion, whereas FS toward the lesioned side, indicating a lesion affecting not only the medulla but also the inferior peduncle and/or the cerebellum. Therefore, the functional visually-guided eye movements can provide a useful test battery with which to detect the lesion site in Wallenbergs syndrome.

Aging Effects upon Pursuit Eye Movements

Quantitative assessment of aging effects upon pursuit eye movements was done in step-ramp stimulus conditions using 32 normal individuals. Eye movements were recorded with infrared reflection oculography. The target was a spot of 0.5 degree red lazar light. The light spot was blanked for 5 ms while the mirror galvanometer moved to a new position. Eye and target position were sampled at 250 Hz and analysed by a personal computer. In onward stimulation in which 2 degrees, 4 degrees, 6 degrees and 8 degrees position steps were followed by fixed ramp speed (10 degrees/s), and also in backward stimulation in which 2 degrees, 4 degrees, 6 degrees step positions were followed by 9 degrees, 17 degrees and 27 degrees/s, eye acceleration increased depending upon increase of retinal slip velocity in the younger group below 49 years. Among the factors effecting aging effects, the cerebrum might be important because visual recognition and eye acceleration are performed in the parietal lobe.

Usefulness of ENG Recordings in Patients with Vertigo As a Screening Test Battery

When patients with vertigo are seen in the clinic, the presence or absence of spontaneous nystagmus is generally tested using Frenzels glasses, and when spontaneous nystagmus is not found, a head-shaking test (HST) is conducted to detect spontaneous nystagmus. We recorded the ENG of these patients with eyes open in total darkness who showed no spontaneous nystagmus under Frenzels glasses. In patients with no nystagmus under Frenzels glasses, clear nystagmus was recognized with a maximum slow-phase velocity of 7.8°/sec and a minimum slow-phase velocity of 3.9°/sec. Therefore, in cases with a maximum slow-phase velocity of less than 7.8°/sec, the possibility that nystagmus may not be recognized with Frenzels glass was indicated. Thus, ENG recording is useful and we use this as an index for treatment and follow-up studies.