Working with Voice Disorders

Theory and Practice

Stephanie Martin

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351371551
• Edition: 2
• Topic: Education
• Subtopic: Education General

An essential resource for clinicians of varying levels of experience from student to very specializer, "Working with Voice Disorders" provides practical insight and direction into all aspects of voice disorders from assessment and diagnosis to intervention and case management. This second edition retains the successful format of mixing theory and practice, a melding of scientific knowledge with clinical art, which was such a feature of the first edition. In recognition of changes in practice and theory over the past decade, it contains a wealth of new, up-to-date, evidence based material. This blends with a practical approach to clinical efficiencies and management of the voice service. The second edition of "Working with Voice Disorders" provides a sound theoretical framework to this specialism and also offers a rich variety of tried and tested, practical and photocopiable resource material, which is the result of the authors' wide experience, accumulated over several decades in the field of voice therapy. The multi-dimensional structure of the manual allows the clinician to look, not only at specific aspects of patient management, but also at aspects such as clinical effectiveness, clinical efficiencies and service management. The authors' aim is that this resource should provide clinicians with a pragmatic, patient-centred, easy to use and accessible resource, facilitating and informing decision-making along the clinical journey from referral to discharge. The contents of this title include: Anatomy overview; The Spectrum of Voice Disorders; The Case History; Assessment; Treatment Strategies; Management Strategies; Service Provision; Over 50 pages of practical, photocopiable exercises. Photocopiable Appendices: Voice Care Advice; Voice Disorders Summary Chart; Voice Assessment Sheet; Voice Record Sheet; and, Voice Diary.

Chapter 1:
Anatomy Overview

◆ INTRODUCTION

◆ THE RESPIRATORY SYSTEM

Principal Muscles of Inspiration

Accessory Muscles of Inspiration

Muscles of Expiration

Muscles that Aid Active Expiration

Innervation of the Respiratory System

Role of Respiration

Lung Volumes

Lung Capacities

◆ THE PHONATORY SYSTEM

Structure of the Larynx

◆ THE RESONATORY SYSTEM

Innervation of the Resonatory System

◆ THE AGEING PROCESS

Introduction

This chapter is intended principally as a brief overview of the anatomy, physiology and neuroanatomy of ‘voice production’. It does not attempt to supplant more detailed resources which are widely available both as texts and online. Its purpose is to offer an easily accessible review for readers outlining the structures and functions central to the production of voice and noting how they change over time.

Voice production is dependent on three different, but interrelated, systems:

• the respiratory system – responsible for the manner and pattern of breathing
• the phonatory system – responsible for how sound is produced at the level of the larynx
• the resonatory system – responsible for the modification of the sound.

These separate systems have been adapted to work together in the process of voice production, although their primary biological purpose is, of course, to assist in life support.

While recognising the interdependence of the three systems, for the purpose of this chapter it is probably clearer to differentiate each one from the others. It is, however, very important to remember that vocal quality changes are part of a composite and nuanced picture. Vocal quality changes that are recognised as disordered or different are often the result of cumulative changes within each system. Each system has its own individual and separate identity, but a change in one system may precipitate change in another, so a principal ‘cause’ of the disorder may be difficult to establish. Mathieson (2001) suggests that when a physiological change occurs in the larynx, a pathological change may well have been the precipitating feature or indeed pathological change may be the result of physiological change.

The Respiratory System

The main purpose of the respiratory system is to maintain life by carrying air into the lungs where the exchange of gases, oxygen and carbon dioxide takes place.

Oxygen enters the bloodstream and excess carbon dioxide moves out through the capillaries surrounding the alveoli within the lungs. The respiratory system can be said to begin at the nose and the mouth, and end with the alveoli in the lungs. Within this system two distinctive respiratory tracts are identified, the upper respiratory tract composed of the nasal and oral cavities, the pharynx and the larynx. The lower respiratory tract refers to the trachea, the bronchi and lungs, which are housed within the bony thoracic skeleton or ribcage. The upper and lower respiratory tracts comprise the vocal tract and, as may be surmised by their close alignment, are functionally interdependent so that modifications to one will affect the function of the other.

In addition to its role in respiration, the upper respiratory tract has multiple functions, such as the processes of chewing, swallowing, articulation, resonance and phonation. The lower respiratory tract, however, functions exclusively for the process of breathing for life and for phonation.

Air enters the respiratory tract through two parallel entrances, the nose and the mouth. These entrances merge into a common tract, known as the pharynx. The pharynx is a cone-shaped tube approximately 13 to 14cm long, composed of muscular and membranous layers, wider at the top where it is continuous with the nasal cavity and opening laterally into the mouth. At its lower and narrower end it leads into the laryngeal inlet anteriorly and the oesophagus posteriorly. The area behind the nose (the nasopharynx) and the area behind the mouth (the oropharynx) are separated by a muscular valve, the soft palate, which, when raised, closes off one section from the other, thus effectively preventing food or liquid escaping from the nose when swallowing. Along with the most inferior part of the pharynx, which contracts at rest and prevents any reflux of the stomach contents into the pharynx or air entering the oesophagus, the soft palate forms part of the involuntary protective mechanism in the respiratory tract. By far the most vigorous protective mechanisms, which are involuntary and reflexive, exist within the larynx. Some mechanisms attempt to ‘repel’ by closing off the airway and some attempt to ‘expel’ by forcing substances out of the respiratory tract.

The respiratory tract, passing through the laryngeal inlet, continues into the trachea, which divides into two branches, and subsequently into the smaller bronchi that enter the lungs, and ultimately into the alveoli. Protective mechanisms exist along the respiratory tract to prevent inadvertent damage, for example the lungs are encased by the bony thoracic skeleton, or ribcage, consisting of 12 pairs of ribs. The first pair is the shortest (the paired ribs increase in length up to rib 7 and then decrease in length up to rib 12) and immobile as they are fused to the breastbone or sternum at the front and at the back to the spinal vertebrae. Pairs two to seven are similarly attached, but by synovial joints which allow a degree of rotation, while pairs eight to ten are attached to each other at the front by flexible cartilage. Pairs 11 and 12, the so-called ‘floating ribs’, are fixed at the back to the spinal vertebrae but have no fixed attachment to the sternum. The somewhat idiosyncratic arrangement of the ribs is important, in that the pleural or membranous connection between the lungs and thoracic cavity allows expansion and contraction of this area as a single unit and along three planes for inspiration and expiration. During inspiration the vertical dimension is increased by contraction of the diaphragm, the upward movement of the ribs increases the transverse diameter while a simultaneous forward and upward movement of the sternum increases the antereo-posterior diameter. The orientation of the ribs controls their mobility (Bunch Dayme, 1995) and this flexible cavity, which also contains major organs such as the heart, the aorta and vena cava, the trachea and oesophagus, can then accommodate changes in the size of the pear-shaped lungs, which expand to contain the greater amounts of air needed to support speech or song. Indeed, the modification of the respiratory cycle to quick intake and slow release of air, which is essential for this process, may be contrasted with the equal phases of inspiration and expiration common to quiet, at rest, breathing for life, which is predominately under medullary control and heavily influenced by the level of carbon dioxide present in a particular environment.

The muscles of respiration have clearly defined roles and most are concerned either with inspiration or expiration but some, like the latissimus dorsi, have a more overarching function within respiration and are concerned with both inspiration and expiration.

In resting respiration, air is inspired at approximately a dozen times per minute, but this muscular activity goes largely unnoticed despite the fact that there is active muscular contraction to enlarge the thorax. The diaphragm and the external intercostals are most responsible for this activity. For the purposes of speech and song, inspiration needs to be more vigorous and, to this end, accessory muscles are recruited to help the diaphragm and external intercostals increase thoracic volume. The volume of air inspired and the effort exerted will, of course, vary depending on the demands made.

For the purposes of this review the following provides an at-a-glance guide to the muscles involved in inspiration and expiration.

Principal Muscles of Inspiration

The diaphragm – this large dome-shaped involuntary muscle is of great importance in respiration. During sleep and unconsciousness it maintains respiration under involuntary control.

The external intercostal muscles – these act to control the amount of space between the ribs and aid air intake.

Accessory Muscles of Inspiration

The sternocleidomastoid and scalene muscle group – these are accessory neck muscles which help to elevate the first and second ribs during inspiration.

The serratus posterior superior, latissimus dorsi and levatores costarum – these are accessory back muscles which contribute to rib movement during inspiration.

The pectoralis major and minor, the serratus anterior and the subclavious muscles – these are accessory pectoral muscles which contribute to the expansion of the upper ribcage.

The accessory muscles of inspiration are not usually recruited during normal respiration but may be accessed during prolonged exercise or in individuals with, for example, chronic obstructive airway disease (COAD) or severe asthma.

Muscles of Expiration

As with inspiration there are two types of expiration – passive and active. With passive expiration, expiration above the resting expiratory level usually is accomplished not by muscular effort but by non-muscular forces that may be said to be the result of the elastic recoil of the lungs. For controlled active expiration, in particular for increasing intensity or duration of sound, muscular activity is necessary over and above elastic recoil to reduce the volumes of the lungs and thorax. Two different muscle processes are involved to support active expiration: muscle...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• List of Tables
• List of Exercises
• Acknowledgements
• Introduction
• Chapter 1: Anatomy Overview
• Chapter 2: The Spectrum of Voice Disorders – Classification
• Chapter 3: The Spectrum of Voice Disorders – Presentation
• Chapter 4: Building the Patient Profile
• Chapter 5: Assessment
• Chapter 6: Treatment and Management Strategies
• Chapter 7: Therapeutic Intervention
• Chapter 8: Shaping the Future
• Appendix I: Voice Care Advice
• Appendix II: Case History Proforma
• Appendix III: Voice Assessment Sheet
• Appendix IV: Voice Record Sheet
• Appendix V: Voice Diary
• Appendix VI: Prognostic Indicator Check List
• Appendix VII: Vocal Tract Discomfort Scale (VTD)
• Bibliography