筋疾患における呼吸機能スクリーニングとしての最大発声時間

Maximum Phonation Time as a Tool of Screening Respiratory Muscle Weakness in Myopathic Patients

　要旨　最大発声時間（MPT）と肺活量（VC）の関係を調べ，筋疾患における呼吸機能スクリーニングとしてのMPTの有用性を検討した。健康成人18名，筋疾患患者32名で，坐位でVCを測定し，最大吸気の後「アー」と声の続く限り発声させ，その持続時間を測定した。さらに，患者6名で舌咽頭呼吸の有無によるVCとMPTの変化を調べた。健康成人ではMPTとVCに有意な相関はなかったが，患者ではMPTとVCは有意に正相関し，MPTが15秒未満の患者のVCは1.5l以下だった。また舌咽頭呼吸でMPTは増加した。筋疾患患者では，MPTはVC低下のスクリーニングや舌咽頭呼吸の有用性の判定に有用である。

　We examined the relation of maximum phonation time（MPT） and vital capacity（VC） and reviewed the usefulness of MPT as a respiratory function screening.

　Subjects : 18 healthy adult subjects（8 men and 10 women）, and 32 myopathic patients（24 men and 8 women）.

　Methods : MPT and VC were measured in sitting position. Six patients were tested with and without air-stacking by glossopharyngeal respiration.

　Results : In healthy subjects, MPT was 29.9±11.8 seconds in men and 21.7±7.8 seconds in women. Second trials showed good reproducibility. The healthy group had no correlation between MPT and VC. The patient group showed a significant positive correlation between MPT and VC（r²＝0.25, p＝0.003）. All patients with MPT less than 15 seconds showed VC less than 1.5l and %VC less than 50%. Air-stacking by glossopharyngeal respiration significantly increased the MPT.

　Conclusions : MPT is a useful screening test for respiratory muscle weakness. The patients are easily aware of the effect of air-stacking by glossopharyngeal respiration.

（Received : July 16, 2004）