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Atrophy – flexible scope best for visualization:

–Atrophy is one of the main factors accounting for diplophonia because vocal cords with different mass tend to vibrate at different frequencies

–Often requires topical anesthesia to view vocal cord thickness or mass

–Sniffing stretches the vocal cords and augments more subtle atrophy

Slow motion helpful for viewing thinning secondary to sniffing

Phonation first followed by sniffing also augments thinness

–Can infer atrophy from enlarged ventricle

–Inspiratory Bernoulli effect if atrophic and if near opposite vocal cord

–Fasciculations (visible on superior vocal cord surface as well as in subglottis)

–Lack of tension

In paralysis (complete paresis), atrophy is often severe and evident, even from above as bowing

–Bowing is augmented visually at lower pitch

Must remove cricothyroid compensation in partial paresis – so lower pitch during exam

If supraglottic squeeze is predominant – implies glottic incompetence more often than intentional hyperfunction

Topical anesthesia allows passage of endoscope between false cords for a view of cords during phonation

–Augment abnormal vibrations by increasing subglottic pressure; visualized as

Flutter – random oscillation, or

Biphasic – one central node of oscillation with two segments

–Oscillation

Lateral to axis (Excursion amplified by low pitch)

Normal cord oscillates nearly symmetrically around central axis

Normal compensation by cricothyroid muscle leads to obligate falsetto – high comfortable speaking pitch

Keeps cords near each other

Keeps cords in phase or almost in phase (patients tend to avoid diplophonia – especially during an exam)

–Stability

Increased subglottic pressure blows weak vocal process laterally