嚥下音・呼気音を利用した嚥下障害の客観的評価  [in Japanese] Diagnosing of Dysphagia Using Acoustic Characteristics of Swallowing and Expiratory Sounds  [in Japanese]

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Author(s)

    • 高田 嘉尚 TAKADA Yoshinao
    • 昭和大学歯学部顎口腔疾患制御外科学教室 Department of Oral and Maxillofacial Surgery, Showa University School of Dentistry
    • 高橋 浩二 TAKAHASHI Koji
    • 昭和大学歯学部口腔リハビリテーション教室 Department of Oral Rehabilitation, Showa University School of Dentistry
    • 中山 裕司 NAKAYAMA Hiroshi
    • 昭和大学歯学部顎口腔疾患制御外科学教室 Department of Oral and Maxillofacial Surgery, Showa University School of Dentistry
    • 宇山 理紗 UYAMA Risa
    • 昭和大学歯学部口腔リハビリテーション教室 Department of Oral Rehabilitation, Showa University School of Dentistry
    • 平野 薫 HIRANO Kaoru
    • 昭和大学歯学部口腔リハビリテーション教室 Department of Oral Rehabilitation, Showa University School of Dentistry
    • 深澤 美樹 FUKASAWA Miki
    • 昭和大学歯学部顎口腔疾患制御外科学教室 Department of Oral and Maxillofacial Surgery, Showa University School of Dentistry
    • 南雲 正男 NAGUMO Masao
    • 昭和大学歯学部顎口腔疾患制御外科学教室 Department of Oral and Maxillofacial Surgery, Showa University School of Dentistry

Abstract

本研究は嚥下音と呼気音の音響特性を利用して嚥下障害を客観的に鑑別することを目的として企画されたものである.対象は嚥下障害を有する頭頚部腫瘍患者26名である.VF検査中嚥下音ならびに嚥下直後に意識的に産生した呼気音をわれわれの方法によって採取し, 嚥下と呼気産生時の動態のVF画像とともにデジタルビデオレコーダーに記録した.嚥下音と呼気音の音響信号はわれわれの音響解析コンピュータシステムによって分析を行い, 嚥下音については持続時間を計測し, 呼気音については1/3オクターブバンド分析により, 中心周波数63Hzから200Hzまでの6帯域の平均補正音圧レベルを求めた.嚥下音と嚥下後に意識的に産生した呼気音92サンプルずつについて, これらの分析が行われ, VF所見との比較が行われた.その結果, 嚥下音の持続時間では, Abnorma1群 (誤嚥あるいは喉頭侵入のVF所見を示した群) はSafety群 (前記のVF所見のない群) に比べ, 持続時間が延長する傾向がみられ, 呼気音の補正音圧レベルでは, Abnorma1群はSafety群に比べ, 音圧レベルが大きい傾向を示した.次に嚥下障害を鑑別するために嚥下音の音響信号の持続時間の臨界値として0.88秒を設定し, 同様に呼気音の音響信号の補正音圧レベルの臨界値として17.2dBを設定した.嚥下音と呼気音の分析値の両者がともにこれらの臨界値を超えた場合, そのときの嚥下は障害があると評価した.これらの評価とVF所見との判定一致率は感度82.6% (38/46), 特異度100% (46/46), 陽性反応的中度100% (38/38), 陰性反応的中度85.2% (46/54), 判定-致率91.3% (84/92) となった.以上の結果より嚥下音の持続時間と呼気音の補正音圧レベルは嚥下障害を検出するために利用できることが示唆された.

This study was designed to objectively differentiate dysphagic swallow from safe swallow using acoustic characteristics of swallowing and expiratory sounds. Twenty-six postsurgical head and neck cancer patients with swallowing disorder were served as subjects. During VF examination, swallowing sounds and voluntary expiratory sounds after the swallows were detected using our method and fed to a digital video recorder with VF images of these swallows and expiratory events. Acoustic signals of swallowing and expiratory sounds were analyzed by our computed acoustic analyzing system to obtain the duration of swallowing sounds and the averaged revised levels of the six target bands from 63 Hz to 200 Hz of expiratory sounds using the 1/3 octave band analyses. Both 92 swallowing sounds and 46 voluntary expiratory sounds after the swallows were analyzed and compared with the VF findings. Compared with the abnormal group (aspiration or penetration was found on VF image), the safety group without these findings was longer in duration of swallowing sound signals and greater in revised levels of the expiratory sound signals. Zero point eightyeight seconds was set as the critical duration of swallowing sound signals in order to differentiate dysphagic swallows from safe swallows. Seventeen point two dB was also set as the critical revised levels of the expiratory sound signals for differentiating dysphagic from safe swallows. If the both analyzed data of swallowing and expiratory sound signals were over these critical values, the swallows were assessed to be dysphagic. Comparison of these assessments with the differentiations from the VF findings showed significant agreement. Sensitivity was 82.6% (38/46), specificity was 100% (46/46), positive predictive value was 100% (38/38), negative predictive value was 85.2% (46/54) and percent agreement was 91.3% (84/92). These results suggest that duration of the swallowing sounds and revised levels of the expiratory sounds can be used for detecting dysphagic swallow.

Journal

  • The Journal of Showa University Dental Society

    The Journal of Showa University Dental Society 26(1), 68-74, 2006-03-31

    Showa University Dental Society

References:  11

Cited by:  1

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