Assessment of Correlation between Maximum Phonatory Duration and Lung Vital Capacity in Voice Change Patients: A Prospective Comparison Study

managing dysphonia effectively, and preventative strategies are essential for maintaining vocal health.Maximum phonation duration (MPD) is a common assessment procedure done in patients with voice disorders.Here, the evaluator measures the time (in seconds) for which the patient can prolong a vowel sound during a single expiration, after first taking a full breath (maximal inhalation).MPD IntroductIonVoice and speech are essential in everyday life.They enable us to express our thoughts, convey emotions, and showcase our unique identities and personalities.For many professionals, their voice is also a key source of income.Thus, voice and speech are critical functions, and any disruption can severely impact one's psychological health and lifestyle.The production of the human voice involves a complex coordination between the respiratory system, larynx, and articulatory structures.The lungs provide the necessary airflow, the vocal cords within the larynx generate sound through vibration, and the articulators shape this sound into intelligible speech.By understanding these mechanisms, we gain insight into the intricate processes that enable us to communicate effectively through speech. 1,2Voice and speech dysfunction encompasses a range of symptoms and diagnoses, with hoarseness being among the most prevalent symptoms.Hoarseness is characterized by a rough, harsh, or breathy quality to the voice and can be noticed by the individual or others during communication.This condition can arise from various causes, such as mass lesions, trauma, or infections of the larynx. 3Dysphonia describes a range of voice disorders characterized by impaired vocal quality, ranging from mild hoarseness to complete voice loss.It is not a disease in itself but a symptom indicative of various underlying conditions.Dysphonia can be classified based on its origins into functional, organic, or neurological categories.Accurate diagnosis and personalized treatment are crucial for 1,