動画記録15秒テスト―頚髄症定量評価の試み

Fifteen-Second Test. : A Novel Method of Quantifying Finger Paralysis in Cervical Myelopathy

　最大努力での手指握り開きを15秒間動画記録することによって頚髄症に伴う手指麻痺を定量的に評価した．対象は圧迫性頚髄症患者30名と健常対照群42名である．動画ファイルを5秒ずつに分割して無作為化のうえ，脊椎外科を専門とする整形外科医3人が回数を評価した．級内相関係数は0.989で，評価者間信頼性は極めて高かった．握り開きの合計回数はJOAスコアと有意に相関していた．健常者では回数は5秒ごとに有意に低下していった（疲労現象）が，頚髄症術前では最初の5秒と次の5秒の回数に有意差はなく，運動初期のすくみ（freezing）を示しているものと思われた．

　In this study, we validated a method of quantifying motor paralysis of the fingers in cervical myelopathy. Thirty patients with myelopathy and 42 healthy controls were asked to make a first and release it (FR) as rapidly as possible for 15 seconds. Movies taken with a digital camera were divided into three 5-second animation files and they were then slowed to half speed, and the files were randomly numbered. Three orthopedists independently counted the number of FRs in each file in a blinded manner. The mean interobserver intraclass coefficient was 0.989, which indicated high reliability of the measurement. In the healthy controls, the number of FRs significantly decreased with each 5 second (i.e., fatigue phenomenon), whereas, in the myelopathy patients, there was no significant difference between the number of FRs during the first 5 seconds and the second 5 seconds (i.e., the freezing phenomenon was observed). Two weeks after decompression surgery, however, the fatigue phenomenon was observed in the myelopathy patients the same as in the healty controls.