Zastosowanie laryngografii w ocenie zaburzeń ruchowych krtani

Do oceny funkcji fonacyjnej krtani stosuje się urządzenie zwane laryngografem. Znajduje ono zastosowanie w badaniu stopnia upośledzenia czynności głośni w przypadkach porażeń fałdów głosowych. Omówiono zasady działania laryngografu oraz sposób wykonania badania i interpretacji jego wyników. Przedstawiono przypadek chorego leczonego laryngologicznie z powodu porażenia lewego fałdu głosowego, powstałego w wyniku infekcji grypowej.

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Laryngograph Processor PCLX can be used to assess phonatory function of the larynx and the degree of impairment of the glottis closure in case of vocal fold palsy. The laryngograph measures electric impedance between two electrodes located on both sides of the neck at the level of thyroid cartilage of the larynx. The impedance is lowest when vocal folds are in median position and the glottis is closed. The device can eliminate the influence of other impedances within the neck on electroglottographic (EGG) tracings thanks to conducting rings surrounding the electrodes. EGG wave can be divided into three phases. The rapid increase of impedance at the beginning of the glottal cycle is caused by closing of the glottis and is called closing phase. It is followed by opening phase being result of separation of the vocal folds and opening of the glottis. Next phase is called open phase. This part of the wave corresponds to the time when glottis is open. The laryngograph is supplied with electrodes and a microphone. The EGG tracings can be acquired and analyzed in PCwave and PCpitch views. SpeechStudio 1.04 software, operating in Microsoft Windows environment, can also measure irregularity of the frequency of the glottal cycles. The irregularity is expressed in percent. A patient must repeat the test list a few times. The list is composed of single utterances of vowels, single words and phrases. A case of patient with left vocal fold palsy after viral infection of the upper respiratory airways is presented. The EGG wave at first measurement shows slightly prolonged closing phase and irregularity of 38%. After three months of treatment and follow-up the shape of the wave was closer to normal with irregularity of 14%. The patient’s voice was clinically normal. The aryngograph is useful tool for predicting clinical outcome in patients with vocal fold paresis.