逆むきのあぶみ骨筋反射について

NEGATIVE DEFLECTIONS IN THE STAPEDIAL REFLEX RECORDING

　最近インピーダンスメトリーが日常の耳科臨床で一般化しつつある。この検査のなかで臨床上価値の高いものはtympanometryとあぶみ骨筋反射である^1）。

　ここでいうあぶみ骨筋反射とは音響性耳小骨筋反射であぶみ骨筋のみならず鼓膜張筋の関与もある。あぶみ骨筋反射を記録すると通常はコンプライアンスの減少がみられるが，時にその逆の現象が観察される。

　When the stapedial reflex is elicited by a contralateral sound stimulation, a wave form of impedance increase is usually obtained. A double negative deflection and a downward deflection are wave forms which indicate impedance decrease.

　The double negative deflection has been said to be observed only in patients with early otosclerosis. However, the present study revealed that it was seen in normal hearing persons and patients with ear diseases other than early otosclerosis. The downward deflection had some characteristics in wave forms. This was due to inward movement of the eardrum by the middle ear muscles.