Laryngeal stroboscopy—Normative values for amplitude, open quotient, asymmetry and phase difference in young adults

• Published in: Clinical otolaryngology Vol. 44; no. 2; pp. 158 - 165
• Main Authors: Sielska‐Badurek, Ewelina M., Jędra, Katarzyna, Sobol, Maria, Niemczyk, Kazimierz, Osuch‐Wójcikiewicz, Ewa
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.03.2019
• Subjects: Adult; Adults; Amplitudes; Asymmetry; Case-Control Studies; Female; Females; Glottis; Glottis - physiology; Humans; Image processing; laryngovideostroboscopy; Male; Men; normative data; objectivisation; Parameterization; parametrisation; Patients; Phase shift; Phonation - physiology; Prospective Studies; Quotients; Reference Values; Sex Factors; Stroboscopy; Vibration; Vocal Cords - physiology; vocal fold imaging; Young Adult; Young adults; objectivisation; vocal fold imaging; laryngovideostroboscopy; normative data; parametrisation
• ISSN: 1749-4478; 1749-4486; 1749-4486
• DOI: 10.1111/coa.13247

Objective To provide the normative values for laryngeal stroboscopy (LS) concerning amplitude, open quotient, asymmetry and phase difference in healthy, young subjects. Study design Prospective case‐control study. Setting Patients treated at a single institute. Methods A total of 68 healthy subjects were included in the study (35 women, 33 men), aged 18‐35 years. After obtaining LS recordings, image processing was performed to attain parameters of vocal fold vibration. Results In women, the location of the maximum vibration amplitude is approximately in the 1/3 posterior part of the glottis, while in men, the location is moved to the glottis centre. In males, the relative amplitude vibration of the vocal folds in the 1/3 anterior part of the glottis was significantly higher than in females (P = 0.029). Women showed significantly higher open quotients (OQ) at the posterior part of the glottis than the male subjects (P < 0.001) and men presented significantly higher OQ at the anterior part of the glottis than the females (P < 0.001). The average OQ values for both sexes were almost the same. Females showed significantly higher relative glottal gap area (P = 0.044). Women presented a significantly lower amplitude asymmetry than men (P = 0.002). The weighted absolute left‐right phase difference reached up to 24° and remained insignificantly higher in the men than the women (P = 0.142). Conclusions The study provides normative values for LS in young adults for the measurement of therapy outcomes in patients with voice disorders and realisation of evidence‐based medicine. The LS parametrisation is easy to perform in clinical practice.