Yasutaka Aihara

Influence of vibration to the neck, trunk and lower extremity muscles on equilibrium in normal subjects and patients with unilateral labyrinthine dysfunction.

To investigate the role of proprioceptors of different skeletal muscles in postural control, in normal subjects and patients with unilateral labyrinthine dysfunction (ULD), the effect of vibration on these muscles was studied by postulography. The subjects comprised 59 normal subjects and 12 patients with ULD due to resection of acoustic tumours. Sagittal body sway was observed during vibration to the triceps surae, tibialis anterior and upper dorsal neck muscles. No significant change in sway was observed in the frontal plane in normal subjects. Significant differences between normal subjects and patients were found on stimulation of the muscle groups of triceps surae and biceps femoris during vibration. In patients with ULD, vibration to the dorsal neck muscles caused a deviation towards the diseased side. It can be speculated that the upper dorsal neck muscle plays an important role in maintaining the body balance in the frontal plane in patients with ULD. On the other hand, the lower extremity muscles, especially the muscles on the dorsal side of the body, play a significant role in adjusting the standing posture in the sagittal plane.To investigate the role of proprioceptors of different skeletal muscles in postural control, in normal subjects and patients with unilateral labyrinthine dysfunction (ULD), the effect of vibration on these muscles was studied by postulography. The subjects comprised 59 normal subjects and 12 patients with ULD due to resection of acoustic tumours. Sagittal body sway was observed during vibration to the triceps surae, tibialis anterior and upper dorsal neck muscles. No significant change in sway was observed in the frontal plane in normal subjects. Significant differences between normal subjects and patients were found on stimulation of the muscle groups of triceps surae and biceps femoris during vibration. In patients with ULD, vibration to the dorsal neck muscles caused a deviation towards the diseased side. It can be speculated that the upper dorsal neck muscle plays an important role in maintaining the body balance in the frontal plane in patients with ULD. On the other hand, the lower extremity muscles, especially the muscles on the dorsal side of the body, play a significant role in adjusting the standing posture in the sagittal plane.

Speech Audiometry One Year after Tympanoplasty.

Speech reception thresholds were analyzed in 71 patients with chronic otitis media one month before and after and one year after typmpanoplasty. Bone conduction thresholds of all the subjects were within the normal range.In 19% of the subjects improvement in the reception threshold was observed one month and one year after the operation. The air conduction threshold was also markedly improved after both one month and one year.In 12% of the subjects the speech reception threshold improved after on month, but one year later the threshold had reverted to the pre-operation level. The air conduction threshold was improved after one month, but after one year it was in the low frequency zone.In 17% of the subjects the speech reception threshold remained the same after one month but had improved by one year after surgery. The air conduction threshold also showed no significant change after one month but was improved after one year.In 33% of the subjects no significant change was noted in the speech reception threshold either one month or one year after the operation. The air conduction threshold the same.The results suggest that it is too early to judge the improvement of the speech reception threshold one month after tympanoplasty. Therefore, speech audiometry should be carried out one year after tympanoplasty.In several cases the changes in the air conduction threshold and those in the speech reception threshold were different. Accordingly, pure tone audiometry and speech audiometry are considered necessary to evaluate hearing after tympanoplasty.