Abnormal Vocal Sounds (Resonance)
Patient is asked to speak a word, usually ’99’ to produce resonance.
NORMAL: As a vocal sound is transmitted from the larynx down through the trachea, the bronchi, the alveoli and then to the chest wall, the sound becomes less distinct and much softer than when heard directly.
ABNORMAL: If bronchophony is present, the sound remains very clear and very loud. Bronchophony occurs over areas of the lung in which the alveoli are filled with fluid or replaced by solid tissue. It can be heard in consolidation due to pneumonia, collapse, or tumours.
Listen to the audio of bronchophony: Patient is telling ‘ninety nine’
Egophony (also aegophony) is an increased resonance of voice sounds heard when auscultating the lungs, often caused by compressed lung tissue due to pleural effusion, or consolidation due to infection (pneumonia) or tumor.
While listening on the chest with a stethoscope, the patient is asked to say ‘e’. If we hear it like the sound of ‘a’ then the patient has egophony.
The sound here assumes a ‘nasal quality’. To demonstrate this, just try closing your nose with your fingers and then say ‘e’. You will hear ‘a’, which is how it will be heard in a patient with egophony. It is due to better transmission of high-frequency sounds across the abnormal tissues mentioned above, with lower frequencies being filtered out. It results in a high-pitched nasal or bleating quality in the affected person’s voice, when auscultated over the affected area.
Listen to the audio of egophony: Patient is telling ‘eee’