Can there be a different inference in vocal resonance and fremitus (vibrations felt on the chest during speech)?

From the Guidelines

Yes, there can be a different inference in vocal resonance and fremitus, as these two clinical signs can be affected differently by various pathological conditions, including those that cause dysphonia, such as head and neck cancer, neurologic disorders, and pulmonary diseases. When evaluating patients with dysphonia, it is essential to consider the potential underlying causes, as highlighted in the clinical practice guideline on hoarseness (dysphonia) update 1. The difference in findings between vocal resonance and fremitus can be attributed to the distinct ways sound is transmitted through the lung tissue and the chest wall. Some conditions, such as pleural effusion or pneumonia, can alter the density and air content of the lung tissue, resulting in variations in sound transmission and, consequently, differences in vocal resonance and fremitus. For instance, in pleural effusion, the fluid in the pleural space can dampen the vibrations felt on the chest wall, leading to decreased tactile fremitus, while the vocal resonance may remain unaffected or even increased in certain areas. In contrast, pneumonia with patent airways can cause increased tactile fremitus due to the consolidation of lung tissue, but the vocal resonance may vary depending on the extent and location of the consolidation. These differences underscore the importance of carefully assessing both vocal resonance and fremitus during physical examinations to gather complementary diagnostic information. The clinical practice guideline on hoarseness (dysphonia) update 1 emphasizes the need to evaluate the larynx in patients with dysphonia, as failure to do so can delay cancer diagnosis and result in higher staging, more aggressive treatment, and reduced survival rates. By considering the potential underlying causes of dysphonia and carefully evaluating vocal resonance and fremitus, healthcare providers can make more accurate diagnoses and develop effective treatment plans. Key points to consider when evaluating vocal resonance and fremitus include:

• The underlying causes of dysphonia, such as head and neck cancer, neurologic disorders, and pulmonary diseases
• The potential for differences in sound transmission through lung tissue and the chest wall
• The importance of carefully assessing both vocal resonance and fremitus during physical examinations
• The need to evaluate the larynx in patients with dysphonia to avoid delayed cancer diagnosis and poor outcomes, as emphasized in the clinical practice guideline on hoarseness (dysphonia) update 1.

From the Research

Vocal Resonance and Fremitus

• Vocal resonance and fremitus are part of the routine clinical examination of the respiratory system by physicians, which helps in the diagnosis of consolidation of the lung 2.
• Assessment of vocal fremitus (VF) and vocal resonance (VR) is an established art of physical examination of the respiratory system 3.
• There are different types of voice-generated sounds, including bronchophony, whispering pectoriloquy, and egophony, which can provide important diagnostic clues 4.

Differences in Vocal Resonance

• Morphologic differences in the vocal tract resonance cavities among voice professionals have been observed using MRI, with differences in the volumes measured during the production of some vowels 5.
• The oral cavity volume increases in singing voices, resulting in an increase in the overall volumes measured, while in acting voices, both the resonance cavities of the vocal tract contribute to the differences measured 5.

Clinical Usefulness

• The clinical usefulness of vocal fremitus and vocal resonance is recognized by physicians, with GP perceptions and practice indicating their importance in physical examination 3.
• However, the quality of clinical examination skills is declining, and physicians often rely more on technology, considering clinical examinations less relevant 4.

Diagnostic Accuracy

• The accuracy of vocal resonance in diagnosing lung consolidation has been studied, with certain frequency regions in the power spectral density proved to be significant indicators of lung consolidation using t-tests 2.
• The diagnostic testing for vocal fold paralysis is not well supported by evidence-based medicine, with current practice not well founded for serum testing and only by retrospective case series with regard to imaging 6.