Електроглотография като приложим инструмент за диагностика на спазмодична дисфония
Electroglottography as an applicable instrument in spasmodic dysphonia assessment

Summary/Abstract: PHYLOSOPHY OF MEDICINE / The electroglottography (EGG) is an invasive instrument for routine voice assessment and visual feedback in treatment process. Nowadays, EGG is an useful tool to supplement the evaluation and treatment of vocal pathology. The EGG could be used to demonstrate hard/soft glottal attack. The EGG signal is unaffected by other activity such as vocal resonance or environmental noise. The present article treats the problem of EGG application regarding to the spasmodic dysphonia. The theoretical presentation shows typical EGGs in a normal voice phonation (pulse register, modal register, falsetto register), and also represent different abnormal modes of vocal fold vibration (“pressed” phonation, “breathy” phonation, diplophonic phonation etc.). KayPentax model of EGG is an easily transportable electroglottograph that can interface with Computerized Speech Lab to offer a number of voice analysis options. The EGG waveform displays variable resistance and serves as an analogue of vocal fold opening and closing gestures during vibration, with peaks and troughs representing maximum points of abduction and adduction. EGG has an ability to demonstrate contact change in both the horizontal and vertical planes and could quite effectively document the normal (see figure 2 and 3) and pathologic voice registers, as well as abnormal and unstable modes of vibration (see figure 5, 6, 7, 8). The article describes what is a contact quotient – it is used to compare the duration of the contact phase to the period of the vibratory cycle. It would be describe to have access toa single parameter that could be computed from the electroglottographic signal, and which would reflect the movement and status of the vocal folds during phonation. Such a parameter might be derived from the duration of the vocal fold contact during each single vibratory cycle. As a measure of the “relative vocal fold abduction” we used the term “contact quotient”. Under typical vocal circumstances, the contact quotient is within the range of 40-60%, and despite the tendency for a posterior glottal chink in women, there does not seem to be a significant sex effect. Second part of the article describes the concept of spasmodic (spastic) dysphonia. The term spasmodic dysphonia is more descriptive and used more frequently by clinicians to better differentiate two spastic forms of this dysphonia from the dysphonia associated with spastic dysarthria. Spasmodic dysphonia is described as adductor, abductor, and mixed forms. In the present article we pay attention to the adductor spasmodic dysphonia (ASD) - a term used to describe a type of voice disorder in which the vocal folds are approximated so tightly that is impossible to produce sustained vocal fold vibration. The essential symptoms of ASD are vocal and unvocal. The vocal symptoms are: nonspecific hoarseness with associated pitch and phonation breaks; strained, squeezed voice, staccato phonation; ...

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