The participants included female patients with thyroid gland disorders, such as hypothyroidism and hyperthyroidism, who were treated at the clinic center. The aim of this study was to determine the acoustic and perceptual characteristics of the voice of patients with thyroid gland disorders, such as hypothyroidism and hyperthyroidism, immediately after the diagnosis was made and 6 months after drug therapy. Currently, few studies are available regarding the impact of thyroid diseases on voice production, and thyroid gland dysfunction is mainly reported after surgery with regard to the paralysis of the recurrent laryngeal nerve or the superior laryngeal nerve and its impact on patientsвЂ™ voice. Patients with untreated thyroid gland diseases experience a wide range of symptoms that have a very high impact on the quality of life. Follow-up studies have shown that voice changes are present in 27% of patients with hyperthyroidism and in 2%вЂ“98% of patients with hypothyroidism. Other changes may not only include hoarseness, roughness, and loss of voice but also trembling voice, reduced intensity of voice, and audible breathing. The most commonly occurring change is the reduction of the fundamental frequency (F0) of the voice. Дysphonia can be caused by excessive thyroid hormone production or hyperthyroidism. Hypothyroidism can cause notable voice changes, such as low voice, roughness, reduced range, and vocal fatigue.

Voice changes may occur even in the cases of mild thyroid failure since thyroid hormone receptors have been found in the larynx, which proves that the thyroid hormone acts on the laryngeal tissue. The symptoms of hypothyroidism are even more subtle than those of hyperthyroidism, and changes in the voice are one of the well-known symptoms of hypothyroidism. Endocrine imbalances, such as hypothyroidism, are one of the common causes of tissue irritation. Hypothyroidism is the most common thyroid gland disorder caused by an underactive thyroid not producing sufficient hormones. Thyroid gland diseases and disruptions in the function of parathyroid glands are the most common endocrine disorders that can cause phonation disturbances. Although several hormones are produced in the body, evidence has shown that the sex hormones and thyroid hormones directly affect particularly the voice. Hormones are known to have a major impact on the voice quality.

Deeper voice in the morning