Shoichi Ishigaki

Mean power frequency during speech in myalgia patients.

The purpose of this study was to clarify a difference of mean power frequency (MPF) during speech between control and myalgia patients groups. The control group consisted of 20 asymptomatic volunteers and the myalgia patients group consisted of 19 patients. A bilateral electromyogram (EMG) of masseter muscles during speech movement was recorded using surface electrodes, and the EMG data were stored and analysed with a computer-based EMG analyzer. The MPF during the entire duration of EMG burst during speech was compared between the control and myalgia group. The average (SD) MPFs during speech in the myalgia and control groups were 214.06 (17.23) and 183.39 (22.35) Hz, respectively, significantly higher in the former (P < 0.001). In myalgia patients, firing rates or recruitment of motor units innervated by high threshold motoneurons might decrease and lead to a higher MPF. The result suggests the possibility that muscle pain, that is a subjective experience, could be evaluated by objective data that is calculated from electromyographic activities which is recorded during speech.

Vibration analysis of temporomandibular joints with internal derangements during maximal opening and closing movement

顎関節雑音は顎関節の内部状態の指標となり得るものとして様々な方面から検討されてきた.しかし, 臨床においてはclickingやcrepitationなどの主観的な表現方法が一般的であり, 客観的な評価方法が確立されるには至っていない.そこで顎関節造影あるいはMR画像診査により診断の確定した顎関節における顎関節雑音の記録および分析を行ない, 正常顎関節との比較を行った.対照群として顎関節撮像により正常と診断された83顎関節, 異常群として復位性関節円板転位, 非復位性関節円板転位, 関節円板穿孔, 骨の退行性病変, のうちのいずれか, あるいは複数の存在が確認された214顎関節を選択した.最大開閉口運動時の顎関節バイブレーションは両側顎関節相当部皮膚表面より一対のpiezoelectric transducerを用いて検出し, 高速フーリエ変換によりpower spectrum density functionを求めた.復位性関節円板転位症例では正常顎関節と比べ検討した周波数帯のほぼ全域で高い値を示した.関節円板の復位の時期による差はほとんど見られなかった.非復位性関節円板転位症例では正常顎関節と比べ150Hz以下の帯域でのみ高い値を示したが, 復位性関節円板転位症例と比べほぼ全域で低い値を示した.関節円板穿孔症例および退行性病変症例では正常顎関節と比べ検討した周波数帯のほぼ全域で高い値を示した.後者は前者に比べ400Hzないし450Hzより上の帯域で高い値を示した.