Voice pathology in the United Kingdom

Each year over 50 000 patients with dysphonia (“voice problems”) are referred by their general practitioners to otolaryngology or voice clinics in the United Kingdom.¹ The cause of dysphonia is often multifactorial and extends far beyond the identification of disease.² Differential diagnosis requires a laryngology or special voice pathology team, which includes speech therapists who specialise in voice disorders. Complex problems may require involving other specialties such as neurology, gastroenterology, psychology, psychiatry, and respiratory medicine.² Voice clinic services continue to develop, following a variety of designs in order to meet clinical need. Acknowledgement of the need for high quality voice pathology services in the United Kingdom is increasing.³

Most voice pathology is the result of aberrant vocal use.¹,⁴ Poor vocal technique, vocal hygiene (due to smoking, dehydration, and abusive behaviour), and repeated laryngeal infection may result in deteriorating quality of the voice, vocal fatigue, and vocal strain.⁴ Patients with chronic problems develop symptoms such as “globus hystericus” (a feeling of a lump in the throat), dysphonia due to laryngeal muscle tension, and even benign lesions on the vibrating surface of the vocal folds.² Not surprisingly dysphonia is particularly prevalent in people using their voice professionally (for example, teachers, lawyers, salespeople) and in performers (for example, actors and singers).²,⁴ The financial and psychosocial consequences of dysphonia for these professional groups are clear.⁴ The numbers of people affected are likely to increase as the modern world places increasing demands on the human voice via mobile telephones, voice recognition software, and interpersonal verbal communications. In advanced societies, the voice is essential for approximately one third of the labour force.⁵

However, change in the quality of the voice may also be the first sign of a wide variety of systemic, neurological, and structural disorders.²,⁶ Early and subtle laryngeal manifestations may be the result of a variety of systemic illnesses including bacterial, viral, and fungal infection, rheumatoid arthritis, hypothyroidism, gastrooesophageal reflux, and vascular and cardiac disease.²,⁶ Isolated change in the voice may also indicate early lower motor neurone disease (for example, Parkinson's disease, myasthenia gravis, or benign hereditary “essential” tremor) or focal upper motor neurone lesions.²,⁶ Structural lesions on the vibrating edge of the vocal folds affect their mass, regularity of vibration, and adduction. These structural changes can be the result of many factors including voice abuse (vocal nodules, vocal fold haemorrhage), viruses (laryngeal papillomatosis), inflammatory irritants (Reinke's oedema, contact granulomas), congenital malformation (laryngeal web, laryngomalacia), and malignancy.²,⁶,⁷

The science of diagnostic laryngeal or voice pathology has been revolutionised in the past 20 years.²,⁷,⁸ Technological advances in laryngeal examination and vocal function have led to a more precise understanding of the function and dysfunction of the vocal tract.⁷,⁸ Fibreoptic endoscopy enables extensive examination of the laryngeal structures during all types of vocal activity (for example, speaking, singing, and shouting). Applying the principles of stroboscopy (a means of “sampling” images to create the visual illusion of “slowing down” the movement) to the endoscopic examination allows detailed observation of the membranous layer of the vocal folds during phonation.²,⁷ Voice pathologists use other instrumental and perceptual techniques to measure a wide range of aspects of voice production including vocal frequency, amplitude, stability, range, regularity, and aerodynamic efficiency.⁸

These advances in voice clinics and voice laboratories have resulted in greater accuracy of diagnosis and better selection of treatment.²,⁷,⁸ Appreciation of the subtle vibratory (mucosal waveform) characteristics of the vocal folds has dramatically changed the principles of surgical intervention for pathological laryngeal disorders.²,⁷ Microlaryngeal surgery now extends beyond the primary aim of establishing a histological diagnosis and incorporates a wide variety of techniques to restore or improve the disordered voice.²,⁷ Voice therapy remains the treatment of choice for most non-organic and some organic voice pathology.⁸,⁹ One achievement of recent research in voice pathology has been the establishment of level II evidence to support the efficacy of voice therapy for the most common disorders.¹,⁹

Despite all of these advances, clinical research in voice pathology still remains in its infancy. The tools of diagnosis and functional measurement are now ready for rigorous application to the clinical field.⁸ For example, the impact of gastro-oesophageal reflux disease, inhalatory steroids, and mental illness on voice disorders are largely unknown.²,⁶ Equally, the techniques of differential diagnosis for less common disorders such as laryngeal dystonia, superior laryngeal nerve paralysis, and organic tremor remain controversial.²,⁶ Furthermore, the pathophysiology of laryngeal disorders such as papillomatosis, polypoidal degeneration, and paradoxical vocal fold movement are poorly understood.²,⁶ The efficacy of surgical techniques to improve voice quality (phonosurgery) remains largely unevaluated.⁸ Clinical research needs to complement the growth in clinical services. Several postgraduate specialist research degrees now exist, and some doctoral students with a clinical background are being attracted into the field. Hopefully with an appropriate academic infrastructure in place these issues in research in voice pathology will begin to be addressed.