Table 2 Summary of the Havemeyer endoscopic laryngeal grading system [10]

I

All arytenoid cartilage movements are synchronous and symmetrical. Full arytenoid cartilage abduction can be achieved and maintained.

II

Arytenoid cartilage movements are asynchronous and/or larynx is asymmetrical at times, but full arytenoid cartilage abduction can be achieved and maintained.

1: Transient asynchrony, flutter or delayed movements seen.

2: There is asymmetry of the rima glottidis much of the time due to reduced mobility of the affected arytenoid and vocal fold, but there are occasions, typically after swallowing or nasal occlusion, when full symmetrical abduction is achieved and maintained.

III

Arytenoid cartilage movements are asynchronous and/or asymmetric. Full arytenoid cartilage abduction cannot be achieved and maintained.

1: There is asymmetry of the rima glottidis much of the time due to reduced mobility of the arytenoid and vocal fold, but there are occasions, typically after swallowing or nasal occlusion, when full symmetrical abduction is achieved, but not maintained.

2: Obvious arytenoid abductor deficit and arytenoid asymmetry. Full abduction is never achieved.

3: Marked, but not total arytenoid abductor deficit and asymmetry with little arytenoid movement. Full abduction is never achieved.

IV

Complete immobility of the arytenoid cartilage and vocal fold.