Comparison of Vibratory Patterns of Clinically Diagnosed Vocal Fold Paresis and Paralysis Using High-Speed...

High-speed video laryngoscopy (HSV) captures asynchronous vibrations in paralysis and paresis that are difficult to resolve with stroboscopy. This study characterizes vibratory patterns of patients with a clinical diagnosis of paralysis and paresis using HSV and digital kymography (DKG) and compares them with stroboscopy.

Two laryngologists rated HSV and stroboscopy findings in patients with a clinical diagnosis of paralysis and paresis. A standard set of ratings was used for each examination, including periodicity, amplitude, phase shift, multiple frequency vocal fold oscillators, and vibratory pattern at onset and offset. The HSV was analyzed using multi-slice DKG software.

Twenty-one patients with paralysis (N = 10) and paresis (N = 11) were recorded. Periodicity, phase shifts, and increased amplitude on the affected side were more commonly observed in paresis patients. Multiple frequency vocal fold oscillators and greater amplitude of the affected side were seen frequently in paralysis. The combination of HSV and vibrogram analysis demonstrated differences in vibratory pattern at onset and offset; in paresis, the affected side stopped vibrating first, while in paralysis, the affected side started vibrating first. Subharmonics to the fundamental frequency and chaotic and asymmetric vibration during voice onset and offset could only be visualized by HSV.

HSV recording and analysis provide additional information about vibratory abnormalities in paralysis and paresis. Chaotic vibration can only be resolved with HSV. HSV adds additional imaging characteristics to solidify endoscopic diagnosis of paresis and paralysis.