Voice disorders can be caused by a number of issues and anomalies. This can range from serious conditions, such as Head and Neck cancer, to maladaptive speaking tendencies, such as poor posture that causes excess tension in the vocal muscles. Causes of voice disorders are typically divided into organic (structural or neurologic), functional, and psychogenic classifications. Some voice disorders may be diagnosed exclusively by a speech-language pathologist, while others require medical examination by an Ear Nose and Throat Specialist (ENT) or other professional. Speech-language pathologists work with related professionals to provide assessment and treatment.